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'89 300 SE
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Discussion Starter #101
These spark plugs are fairly new, I replaced them in August and have driven the car little since then. 500 miles or less would be my ballpark estimate.

Is there a particular brand of fuel additive you'd recommend? I've used SeaFoam in the past but it's been a while.

Between pins 1 & 2 the resistance is .2. The resistance goes to infinite just after the throttle linkage disengages from the wheel on the unit labeled s27/2 in the image attached to post 86. This corresponds to a slight depress of the gas pedal, maybe 1/8th of the full range of motion. s27/2 is the decel fuel shutoff switch or something like that, correct?
As for pins 3&2 I had infinite resistance regardless of throttle position. This proved true whether actuating the throttle with the gas pedal or manualing moving the linkage.

As for checking the camshaft, is there anything in particular I need to look for? Is removing the oil dripper absolutely necessary or just recomended? Where can I use that 27mm socket to turn the crankshaft and how would removing the sparkplugs make it easier? Is cleanliness a major concern? Most of the places I would be able to perform this are relatively dirty (farm garages or woodshops) and my engine has a lot of grease and grime on the exterior.
 

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... Is there a particular brand of fuel additive you'd recommend? I've used SeaFoam in the past but it's been a while. ...
I’m not familiar with injection system cleaning additives in the US market. It should be a petroleum-based product. I had good experience with “Injection Reiniger” from “Liqui Moly”.

... Between pins 1 & 2 the resistance is .2. The resistance goes to infinite just after the throttle linkage disengages from the wheel on the unit labeled s27/2 in the image attached to post 86. This corresponds to a slight depress of the gas pedal, maybe 1/8th of the full range of motion. s27/2 is the decel fuel shutoff switch or something like that, correct? ...
That’s how it should be. But you should see the same resistance between terminal 13 & 2 at the ECU connector ! … I suggest to check the resistance there again and if you still measure what you reported in post 98 (4.97 Ω with the pedal depressed), measure again with the TPS connector disconnected.
The micro switch S27/2 does several things, but ECU terminal 13 is the input terminal for the closed-signal of the TPS (Throttle Posisiton Switch). S27/2 is supposed to open before the TPS opens, as you observed.

... As for pins 3&2 I had infinite resistance regardless of throttle position. This proved true whether actuating the throttle with the gas pedal or manualing moving the linkage. ...
If you don’t see less than 1 Ω between pins 3 & 2 with the pedal completely depressed or with the throttle completely opened manually, there is a problem with the TPS’s WOT-signal, which is not relevant as for the symptoms you have reported so far and can be taken care of later.

... As for checking the camshaft, is there anything in particular I need to look for? Is removing the oil dripper absolutely necessary or just recomended? Where can I use that 27mm socket to turn the crankshaft and how would removing the sparkplugs make it easier? Is cleanliness a major concern? Most of the places I would be able to perform this are relatively dirty (farm garages or woodshops) and my engine has a lot of grease and grime on the exterior.
If you can see any camshaft lobe that resembles the first one in the attached image with the oil dripper installed, then you have seen enough and don’t need to remove it.

The 27 mm socket is used on the head of the bolt that sits in the front end of the crankshaft (behind the fan). With the spark plugs removed there’s no compression, which reduces the torque required to turn the crankshaft significantly.
If turning the crankshaft manually is too much trouble under the given circumstances, you can also use the starter via ignition key. However, you should deactivate the ignition system to prevent the engine from firing. You can do that by disconnecting the coaxial CPS plug from port 2 of the ignition control unit (see attached image). It’s located on the left fender well.

As for cleanness … if the valve cover is dirty, clean it a little, so that no dirt gets into the valve train area when you remove it and when you put it back. If not too much dust is flying around in these farm garages or woodshops, it’s okay … and if chicken are running around there, keep ’em out of the engine bay while the valve cover is off. … :wink_2:

H.D.
 

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89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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Looks like the cam I replaced 5 months ago. Happy to be rid of that one.
#1 intake (like shown in the photo is the first one to check.

Happy new Year!
 

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Discussion Starter #104
Tank 1 of fuel + additive is under way!

Rechecked, and the value is 5.02 k ohm with the throttle depressed fully (or otherwise depressed.) If I take off the TPS the value is at 5.02k ohm regardless of throttle position. These test regarding throttle position have all been done with engine at or close to ambient temperature, which has been below 40 F.

Just to make sure I understand what I'm looking at.. the wear is the recessed surface on the cam correct? I've attached an image circling what I think we're talking about.

So now that I've had some time to drive the car after adjusting the duty cycle the main symptom I'm still having is a lack of power before the car heats up. The engine seems very bogged down, and if I fully depress the gas pedal this gets worse. Theres a sweet spot just slightly before max throttle. Some additional (most likely unrelated to this discussion) are the heat stops working about around 60-70 mph and no cruise control. The lack of cruise has been an issue for a while, but the heat is relatively new, but I haven't drove the car much in the winter so I could be wrong. Again I don't believe these are relevant to this discussion and I'm not necessarily asking for the solution, just thought I'd throw them out there in case they actually are relevant
 

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... Just to make sure I understand what I'm looking at.. the wear is the recessed surface on the cam correct? I've attached an image circling what I think we're talking about. ...
Correct.

Your resistance measurements match the cold engine‘s behavior you describe. … I‘ll come back to that and the other things tomorrow … it‘s already midnight here. :)

H.D.
 

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1989 300SE (Mitzi); 2003 CLK 430 cabrio (Clifford)
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If you can see any camshaft lobe that resembles the first one in the attached image with the oil dripper installed, then you have seen enough and don’t need to remove it.
So it seems like @codycool55 and I have M103s with potentially worn camshafts. That's a bummer, because I have no idea how to take one out of a junkyard engine even were I able to find one. If I have mine replaced, I'm going to have to put a big dent in my wallet because I'll get the valves and the valve stem seals done at the same time. Cha-ching. In the meantime, though, the camshaft pic from @H.D. left me wondering which of these cams is worn. So I attached a pic that asks that question. I also assume that the #1 cylinder's intake valve is the most susceptible—for reasons that have to do with the oil dripper?

When I cold start the engine and it occasionally taps very loudly until the oil is pumped up into the valve train—usually after sitting for days or weeks—what exactly am I hearing? It strikes me as much louder than a valve whacking its seat, so is it the lifter that's kind of whacking the cam lobe as it spins around? When I hear that sound it makes me sad, because—grab your Kleenex—I kind of anthropomorphize things like car engines, and I feel like it's wounded when it makes sounds like that. Makes me cringe. I know—you're probably gagging right about now. :grin
 

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Note: The picture shows the engine bay of my 300CE. Your engine bay looks a little different, but the regeneration valve should look the same.
All I can say here is wow. Wow. Wow. Wow. LOOK at that engine bay. @H.D., I have but one word: Respect! That car is immaculate. And here I thought I keep my cars spiffy. I can't hold a candle to this. Well done, sir!
 

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... Rechecked, and the value is 5.02 k ohm with the throttle depressed fully (or otherwise depressed.) If I take off the TPS the value is at 5.02k ohm regardless of throttle position. ...
According to the resistance between pins 1 & 2 of the TPS connector you reported in post 101 the TPS provides correct “throttle closed“ / “throttle opened“ signals.
But these 5 kΩ you measure between the CIS-ECU terminals 13 & 2 while the TPS is disconnected (or while the TPS is connected and the throttle opened) point to a connection between these two terminals that should not be there, and which prevents the ECU from correctly detecting the TPS‘s “throttle opened“ signal.

During the warm-up phase and depending on the load the engine requires “acceleration enrichments“ of the fuel/air mixture. … But without a proper “throttle opened“ signal getting to the ECU (represented by infinite resistance between 13 & 2) that function is deactivated … which leads to the symptoms you describe (“a lack of power before the car heats up. The engine seems very bogged down, and if I fully depress the gas pedal this gets worse.“).

It doesn‘t have to be a direct connection between the two wires of terminal 13 & 2. Since terminal 2 is connected to engine ground, the wire of terminal 13 might have a (5 kΩ) connection to engine ground via some other path. I suggest to start the search by checking the resistance between terminal 13 and all other terminals of the ECU connector, with the TPS connector disconnected !

... Some additional (most likely unrelated to this discussion) are the heat stops working about around 60-70 mph and no cruise control. ...
Regarding the not working heat … there might be a problem with the coolant circulating pump. Let‘s take care of the cruise control, and possibly other problems, later.

H.D.
 

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So it seems like @codycool55 and I have M103s with potentially worn camshafts. ...
That‘s the right expression … ‘potentially‘ worn camshaft and rocker arm(s). The part beside the camshaft is one of the rocker arms (not a lifter).
So, before you try to find suitable replacement parts at junkyards, I recommend both of you to first check the installed camshaft.

... If I have mine replaced, I'm going to have to put a big dent in my wallet because I'll get the valves and the valve stem seals done at the same time. ...
There may be no need to do the valves or the valve guides, even with 200,000 miles or more on the clock. What should be done though, especially if it has never been done before, is the valve stem seals. (See also what I said in post 100)

... In the meantime, though, the camshaft pic from @H.D. left me wondering which of these cams is worn. So I attached a pic that asks that question. I also assume that the #1 cylinder's intake valve is the most susceptible—for reasons that have to do with the oil dripper? ...
Yes, that‘s the worn spot on the camshaft lobe … in this case the lobe for the first intake valve, which is the most susceptible, which may also have to do with the oil dripper. But also other lobes can be involved.

The spot on the rocker arm you point to in the pic is a spot that has never touched the camshaft lobe. The recessed spot further to the right is the worn spot. That spot and the spot on the camshaft lobe have worn each other.

... When I cold start the engine and it occasionally taps very loudly until the oil is pumped up into the valve train—usually after sitting for days or weeks—what exactly am I hearing? ...
Might be failing lifters. In that case I suggest to replace them when you replace the valve stem seals. They‘re not very expensive either. If you don‘t buy them at the MB dealership, I recommend the ones made by “INA“.

... I kind of anthropomorphize things like car engines ...
You too? … :smile

Thanks for the compliment about my 300CE … my wife, who actually doesn’t care so much about cars, kept me from selling it about 10 years ago … she loves cruising around with it.

That picture of the engine bay, btw, also shows something that you usually don‘t see there (the grey plastic cap below the arrow. It‘s part of an on-board CIS-E test device … something those who plan to keep their CIS-E cars for the longer term might want to consider. This link leads to more details about it:
http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/2906786-board-ke-jetronic-test-device.html

H.D.
 

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So it seems like @codycool55 and I have M103s with potentially worn camshafts. That's a bummer, because I have no idea how to take one out of a junkyard engine even were I able to find one. If I have mine replaced, I'm going to have to put a big dent in my wallet because I'll get the valves and the valve stem seals done at the same time. Cha-ching. In the meantime, though, the camshaft pic from @H.D. left me wondering which of these cams is worn. So I attached a pic that asks that question. I also assume that the #1 cylinder's intake valve is the most susceptible—for reasons that have to do with the oil dripper?

When I cold start the engine and it occasionally taps very loudly until the oil is pumped up into the valve train—usually after sitting for days or weeks—what exactly am I hearing? It strikes me as much louder than a valve whacking its seat, so is it the lifter that's kind of whacking the cam lobe as it spins around? When I hear that sound it makes me sad, because—grab your Kleenex—I kind of anthropomorphize things like car engines, and I feel like it's wounded when it makes sounds like that. Makes me cringe. I know—you're probably gagging right about now. :grin
Yep, the lobe you point to is worn about 2mm or so and the matched rocker appears to be worn too. It should not have the dent on it. That combo probably shortchanges the valve opening more than 3 mm's. But all those lobes are starting to show some wear. A good cam does not have the "non-shiny" yellow edges. But of course the big problem is where the lobe has some serious metal missing.

Changing the cam and rockers is actually not that difficult (compared to pulling the head). What I did was to do it in steps. Find a donor car first, that is probably the most difficult part. With me, I was very fortune, my first visit to the JY and find the perfect donor. That was a year ago, I have not seen a car like that ever since after maybe a dozen trips to the JY for various small ticket items.

At the same time you need to take the v shaped washer that holds down the dripper at the point where the oil comes in from the head. I believe the problem is that there is some pressure loss at that joint because oil may seep out in certain conditons and there is not enough oil pressure to deliver a good flow at either ends of the pripper. Because the dripper oil inlet is off-set, number one cylinder is more vulnerable. At least this is what I'm told.

I do not believe doing the cam and guides together saves you that much money. Probably less than 2 hours of labor and if you replace the cams yourself that is free.

I was quoted $5K for the entire job. Pretty pricey.

Doing the cam yourself is less than $100 (An entire head with all the hardware is $69 at pick and pull)

Guide's will set you back $2000-$2500. Mostly labor
 

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@codycool55 and @Strassenkreuzer:

I suggest to first check the camshaft … before worrying about the details of changing it. There are quite a few more details worth considering than the ones mentioned in this thread so far.

And don‘t worry about the "“non-shiny" yellow edges“ mentioned in post 110 ! … They‘re very normal and there's nothing wrong with them. On the cams they are areas the rocker arms never had contact with, and on the journals they are areas the bearings never had contact with.

And again, don‘t rashly follow suggestions to change the valve guides ! … (see what I said about them in posts 75, 100 and 109)

H.D.
 

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1989 300SE (Mitzi); 2003 CLK 430 cabrio (Clifford)
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That‘s the right expression … ‘potentially‘ worn camshaft and rocker arm(s). The part beside the camshaft is one of the rocker arms (not a lifter).
So, before you try to find suitable replacement parts at junkyards, I recommend both of you to first check the installed camshaft.
Yes. When time permits, I'm going to remove the valve cover and see if I can get a good look at the camshaft—with emphasis on cylinder #1's lobes. Is there anything that can be done to make the oil dripper more effective? It's my understanding that this is the weakness that causes the premature wear on these lobes.


There may be no need to do the valves or the valve guides, even with 200,000 miles or more on the clock. What should be done though, especially if it has never been done before, is the valve stem seals. (See also what I said in post 100)
I hope you're right. My concern is that with burning a quart or so of oil every several hundred miles, the engine suffers carbon build up from burning tiny amounts of oil that have leaked through the stem seals. This is why I regularly add either of LiquidMoly or Seafoam or Lucas upper engine fuel treatment. I guess my question is: How do you determine that valves need replacement without dismantling the entire upper part of the engine? Seems a bit of a catch-22 in that if you're going to the trouble of replacing the camshaft and rocker arms, wouldn't you do a valve inspection then—instead of buttoning everything up to see if the replaced camshaft and rocker arms along with stem seals solves the problem?


Might be failing lifters. In that case I suggest to replace them when you replace the valve stem seals. They‘re not very expensive either. If you don‘t buy them at the MB dealership, I recommend the ones made by “INA“.
So just what is a "failing lifter"? If they're hydraulic, I can understand that perhaps the mechanism is worn and needs replacing because there are oil and springs involved. If they're not hydraulic, then how does a lifter wear out? And if one replaces one lifter, shouldn't I replace all twelve?


You too? … :smile

Thanks for the compliment about my 300CE … my wife, who actually doesn’t care so much about cars, kept me from selling it about 10 years ago … she loves cruising around with it.

That picture of the engine bay, btw, also shows something that you usually don‘t see there (the grey plastic cap below the arrow. It‘s part of an on-board CIS-E test device … something those who plan to keep their CIS-E cars for the longer term might want to consider. This link leads to more details about it:
http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/2906786-board-ke-jetronic-test-device.html
I'd love to own a fleet of 126s; I love these cars. Today a friend sent a pic of a 1991 420SEL for sale—with a mere 61,000 original miles on the clock, and I'd love to have it for the $14,500 they're asking. BUT...my 300 SE is more nostalgic, and I love the color. I budget permits, I'm going to have her painted this year. And the M103 is more economical than the 4.2L V-8 of that era. Essentially, the shorty 300SE is an easier 126 to maintain even if it lacks a few of the bells and whistles. And the '91 I found is black—which, while beautiful, is a bit too "limousine-esque" for me; I'd feel too self-conscious driving it. Nevertheless, one of these days I'll have my 300SE's valve cover repainted and get the entire engine bay properly cleaned and detailed.
 

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... with emphasis on cylinder #1's lobes. Is there anything that can be done to make the oil dripper more effective? It's my understanding that this is the weakness that causes the premature wear on these lobes. ...
There is something that can be done to keep it from becoming less effective … make sure that it doesn‘t get clogged by old dirty engine oil ! … :wink_2:

This is a perfect opportunity to caution against the seemingly logic idea of enlarging the oil dripper holes. That affects the oil pressure and can severely reduce the oil flow through the bearings (crankshaft, connecting rods, camshaft, rocker arms). … Baaaad idea !!

The main cause for the premature wear is actually a quality problem with the inductively hardened surface of the lobes … or more precisely, with the hardening process in the camshaft production line. With a little luck your camshaft is still okay, even with 200,000 miles or more on the clock … if you‘re less fortunate you have worn lobes (even with very frequent oil changes).

A quick answer to the question why the intake cam lobes are usually hit hardest is: they are hit harder … LOL … has to do with the camshaft‘s direction of rotation.

... How do you determine that valves need replacement without dismantling the entire upper part of the engine? ...
When I replace valve stem seals I grab the valve shaft with my fingers … with the piston of the respective cyclinder sitting high enough to prevent the valve from falling so deep that the valve stem completely disappears into the valve guide … and feel how it sits in the guide. And I visually check the part of the valve stem that moves in and out of the guide during operation. … Then I compare these impressions with the intended future of the engine/car. … If you have never done that, I suggest to have it done by an experienced and trustable mechanic.

... So just what is a "failing lifter"? If they're hydraulic, I can understand that perhaps the mechanism is worn and needs replacing because there are oil and springs involved. If they're not hydraulic, then how does a lifter wear out? And if one replaces one lifter, shouldn't I replace all twelve? ...
They work hydraulically and they fail hydraulically if their mechanism wears. If you hear a suspicious ticking sound coming from the valve train area (when the engine is cold) I suggest to replace all 12 lifters when you replace the valve stem seals.

H.D.
 

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I found problems on my m103 after removing the valve cover to replace the gasket seal . On removal I saw lots of old black paint that had come from in side the valve cover .This is the remainder of the spray paint from new .The spray job is done on a jig and if the spray gun is set to low you get lots of over spray get inside the valve cover . This over time will find its way down into the cam shaft and rockers immersed in the oil .So if your in the stage of replacing the valve cover gasket seal , do a good job removing the old paint bubbles inside the valve cover .Clean out both holes in the valve cover for the breathers ,these holes alone can if not kept open cause problems in the breathing system . Paint a thick oil on the inside of the valve cover .Replace the valve cover with a new gasket seal from mb without sealant bolts set to 10nm .Hope this helps .
 

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ADMINS, any way to get "MB Engine Forums"? Too much good info spread across at least two forums as it is.

H.D., As I have only been introduced to your posts today, and have only had the time to read a few, I wonder if you have spent much time on the bottom end. My M103 and the one I bought at the junkyard both had enough bottom end wear to cause my oil consumption, which can slowly foul the O2 sensor leading to problems x,y,z..... With your systematic approach, I wonder where you place the bottom end in your list of things to check.

All, H.D. mentions checking the play of the AFM in an earlier post. The focus seemed to go to adjusting the height of the plate and its exact position in the aluminum body, but I didn't see enough stress placed on making sure the plunger in the middle of the FD was NOT depressed while the motor idles. Here is what I posted to the peachparts forum back in 2011 as an update to the head and CIS-E rebuild:

"My rich idle was the result of the fuel distributor’s plunger extending too far down onto the roller on the flapper. Adjusting the position of the roller with the 3 mm CO screw did not work for me. I could get the idle mixture correct but then something else went wrong: bad throttle response, hard restarts, surging idle, high RPM idle, etc. The rich idle could have been the result of the flapper spring fatiguing over time as well. Who knows? Bottom line, adjusting the plunger (moving it up into the distributor) about half a turn allowed the other parts of the fuel system to work as designed."
 

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... H.D., ... I wonder if you have spent much time on the bottom end.
From ‘83 to ‘84 I spent 8 hours a day on almost nothing but the M103‘s bottom & top end … LOL

... My M103 and the one I bought at the junkyard both had enough bottom end wear to cause my oil consumption, which can slowly foul the O2 sensor leading to problems x,y,z..... With your systematic approach, I wonder where you place the bottom end in your list of things to check. ...
Oil consumption can, of course, foul the o2 sensor … (see what I said in post 30).
According to my experiences with the M103 (after it came off the production line :)) oil consumption is much more often caused by hardened valve stem seals than by bottom end wear. Since they can relatively easily be replaced (with the head installed) I suggest to replace the valve stem seals first … certainly if they have never been replaced.

As for oil loss, the M103 is equipped with something that here in Germany is often called “Sollsiffstelle“ (“predetermined drooling point“) … LOL … It‘s often wrongly diagnosed as “head gasket failure“, but it‘s only a failure of the much easier to fix upper front cover sealing.

... All, H.D. mentions checking the play of the AFM in an earlier post. The focus seemed to go to adjusting the height of the plate and its exact position in the aluminum body, but I didn't see enough stress placed on making sure the plunger in the middle of the FD was NOT depressed while the motor idles. ...
Did you read posts 39, 41, 45, 49, 52, 82, 84, 86 and 91 ?

... The rich idle could have been the result of the flapper spring fatiguing over time as well. ...
On the M103 the AFM does not have a flapper spring, it has a counterweight. … See what I said about the movability / resistance of the AFM up from post 39 !

In order to not confuse the OP, I think it‘s best to do one step at a time. A few problems on this car have been fixed during this thread. The remaining problem (at this point) is:

“a lack of power before the car heats up. The engine seems very bogged down, and if I fully depress the gas pedal this gets worse.“


It‘s evident (since post 108) that the CIS-ECU does not receive a proper signal that is necessary for acceleration enrichment. So, IMHO, that should definitely be taken care of first. … And if that does not completely fix this remaining problem, I haven‘t cancelled the EHA on my list of suspects yet. … :wink_2:

H.D.
 

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Cody, The following is to H.D. I am hoping that he can teach me something as well.

>>Did you read posts 39, 41, 45, 49, 52, 82, 84, 86 and 91 ?<<

Habe ich. Sogar ein paar Mal. ;)

>>Originally Posted by codycool55 Post 51
... Checking the zero position now I notice when I depress the meter slightly, (just before the resistance from the CP kicks in) the gap disappears, and both sides appear to sit within the "rim." ...
and H.D. replies in Post 52:
Sounds correct.<<


That Cody did not really understand this, you did have to ask several times, tells me that it could have been one of many items that was lost. You will note that I stated, "but I didn't see enough stress placed on making sure the plunger in the middle of the FD was NOT depressed while the motor idles."

As I did all of my tuning back in 2010 and 2011, I didn't remember it all that well. Once I reread my posts quite a bit came back, including the importance of the flapper not applying pressure to the plunger in the FD while the motor was at idle. It seemed to me that your tests with Cody were sometimes engine off and sometimes engine running. The AFM flapper tests seem like the former. Perhaps you could clarify?

As I recall there was a spring in there somewhere, perhaps in the FD above the plunger. Regardless, there was a reason for me to believe that nobody had ever been inside my AFM or FD or EHA (can't remember now what that was), and that lead me to believe that as these systems and parts age, they fall away from the original spec.

I love your approach, but I found that with my car, I needed to do it iteratively. I also decided to work from what I thought was the most important side, fuel delivery (the injectors) back. I pulled all of the injectors, checked their crack pressures, also found a bunch of hard seals needing love, and then checked the flow of all together. This is perhaps not a sight that would sit well with you, as the FD assembly was unbolted from the flapper assembly and the injectors and lines were up in the air with plastic bottles under all of the injectors. So, perhaps ugly, but very illustrative. Here is what I posted seven years ago.

To do this I pulled the fuel distributor (no wires connected) off the base (three Torx bolts-watch out for the o-ring around the plunger when you pull the distributor off the base) and put plastic water bottles over each injector. I weighed the bottles empty since I did not have seven (cold start injector-CSI) that matched and wrote the empty weights on the bottles. I then ran wires directly from a battery near the rear wheel to both pumps. I ran the pumps for about a minute as I pushed the plunger all the way up into the distributor (WOT). Wide Open Throttle

After removing the bottles and getting the fuel weights, the first run gave the following results.
60 – 65 – 68 – 62 – 64 – 72 with nothing from the CSI - 0

I then removed the cap screw on the bottom of the fuel distributor corresponding to injector 6 and turned the exposed set screw IN one turn and then recapped. Performing nearly the same flow test as above, but this time varying the amount that the plunger was pushed in (simulating varying throttle position), I got the following results.
70 – 75 – 79 – 72 – 73 – 66 (0 CSI) That told me that varied or fully depressed, the flows stayed about the same (relative).
Three runs later and a ¼ turn here and an 1/8 turn there (NEVER touching #4) I ended up with the following results after a longer run (plunger fully depressed since WOT was a bigger issue for me to match than idle).
123 – 122 – 123 – 121 – 123 – 121


Note the 20% difference between injectors 1 and 6 after the first test. Like Cody, I was chasing my tail for a while until I balanced the flow, then I was able to get meaningful results adjusting the EHA and the CO and the FD plunger.

Here was my follow up:

If I had to do it again on a running car I would:

-Make notes of fuel economy, idle mixture and fuel pressures at the top and bottom of the distributor (there are removable plugs on the top and bottom where you can attach your FP gauge) before I took anything apart. I would also remove the air filter and make a note of the position of the flapper when it just contacts the fuel distributor’s (FD's) plunger with the motor just turned off (residual fuel pressure in the distributor). This is a feel thing and a magnet helps to lift the flapper so you can let it drop just until you feel the point of greater resistance. Now mark that point on the aluminum housing around the flapper. Start the car and see if the flapper has moved down past the mark. If so, measure the drop. The ratio of flapper movement to plunger movement is 7 to 1. If I read the specs correctly, there should be from 0.1 to 2 mm of free play at the flapper at idle. That means 0.014 to 0.29 mm at the roller/plunger which you really can’t measure, but you can “feel”. Point is that the flapper should NOT push the roller into the plunger at idle. I do not know the thread pitch of the screw on the plunger but I assume it is a 1.0 mm pitch. If the flapper moves down 7 mm at idle from the resistance point you felt with the car off then you need to turn the plunger screw IN just over one turn. More likely you will need less. While you have it all taken apart, check the injectors for flow with plunger all the way out (idle) and all the way in and then adjust flow of up to five of the six injectors until all are matched. The min spec is 4-6 cc/min but suggested is 6.0 – 6.6 cc/min. A cc of water is a gram. Fuel is about 75% less massive, so 4.5 – 5 grams of fuel per minute is your target if you use a scale and plastic water bottles as I did. I flowed mine for three minutes at idle and was over the spec. Also check flow rates with the plunger pressed all the way in. There are two specs here: 100 – 109 cc/min (75 – 82 grams/min) and 140 cc/min. The 140 is a max. I just got the idle numbers in spec and then used the high flow to more precisely match the injectors. Since I removed the fuel distributor from the flapper assembly while flow matching I had no way to know how far the flapper was depressing the plunger so I could not check the “full” numbers. I saw mid 80 grams per minute with the plunger completely pressed into the distributor, so I concluded the fuel distributor was okay.

-Check the resistances of the air temp and water temp sensors at the computer’s connector. If out of spec (or more likely completely open or closed circuits), fix. Check the O2 sensor on the bench with a volt meter and torch.

-Put it all back together and go back to your notes. The differential pressure should be 3 – 4.5 Bar (difference between pressures at the top and bottom of the fuel distributor). If you are out of spec, remove the EHA and adjust the small Allen behind the cap screw. Be careful here. The lower pressure changes as the car warms up, so make notes of the ranges you see. If you can’t start the car after the EHA adjustment, you will need to adjust the idle/CO screw. If you turned the EHA CW a ¼ turn you will need to turn the idle/CO screw about ½ turn CCW, or the other way and twice as much (roughly). Careful again. If you had to go CCW on the EHA and CW on the idle/CO too much you will/might have allowed the flapper roller to contact the FD’s plunger at idle….meaning another adjustment to the plunger screw, sorry it all comes apart again.


So, anything in there that you might incorporate into your current approach to help people in the future?
 

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... So, anything in there that you might incorporate into your current approach to help people in the future?
On aging systems and also in case of FD refurbishment, the things you talk about in your post can, of course, be relevant. I've refurbished quite a few FD‘s over the years, never without checking their alibration afterwards. And in about half of these cases, I had to recalibrate them … and reused original EHA‘s often needed to be adjusted too.

For now I suggest to focus on the remaining problem of the OP‘s car … “lack of power before the car heats up“. And taking care of the matchingly missing, but necessary, proper signal to the CIS-ECU to activate acceleration enrichment (as confirmed in post 104) should be the next step, shouldn't it.

And, as I said, if that does not (completely) fix this remaining problem, I‘ll suggest specific EHA tests. And the results of these tests would determine the further approach … possibly including things you mentioned in your post.

H.D.
 

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>>“lack of power before the car heats up“. And taking care of the matchingly missing, but necessary, proper signal to the CIS-ECU to activate acceleration enrichment (as confirmed in post 104) should be the next step, shouldn't it.<<

I am not sure. 5k ohms seems like an odd amount. 5M ohms maybe, which for all intents and purposes is an open circuit. When I go back to the original post, I see other signs that the engine is getting too much fuel. Stepping on the gas to start the car opens the micro switch, which, I believe, takes the car out of its start programming, which in most cases has fuel enrichment built in. i.e. cracking the throttle during start up actually supplies less fuel, which may have been why he was able to start the car that way. Note that I had to do just that, in fact, I put a little piece of vacuum hose under the micro switch to keep it open until I figured out that my FD was delivering too much fuel at idle and made what became the problem solving adjustment. No more micro switch always open band aide required. :)
 

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… I am not sure. 5k ohms seems like an odd amount. 5M ohms maybe, which for all intents and purposes is an open circuit. ...
See what I said in post 108 about that 5 kΩ connection to engine ground … and note that I mentioned “some other path“ ! … :wink

… When I go back to the original post, I see other signs that the engine is getting too much fuel. …
The original post is almost 2 ½ years old … there‘s been some change since then.

… Stepping on the gas to start the car opens the micro switch, which, I believe, takes the car out of its start programming, which in most cases has fuel enrichment built in. i.e. cracking the throttle during start up actually supplies less fuel …
Please allow me to correct that. … The KE-Jetronic cold start program has fuel enrichment built in by default, not only in most cases. … And that is not switched off when the throttle, or the micro switch, is opened.

… Once I reread my posts quite a bit came back, including the importance of the flapper not applying pressure to the plunger in the FD while the motor was at idle. …
Please allow me to correct that too. … The AFM / FD unit is designed in such a way that the “flapper“ does apply pressure to the CP (Control Plunger) when the engine is running at idle speed … by which the CP is slightly pushed up, thus slightly opening the metering slits.

If, while the motor is running at idle speed, the CP is not slightly pushed up by the roller of the air sensor lever, then because of (at least one of) the following reasons:
- the CP can not descend all the way to the set screw (e.g. due to contamination)
- the CP set screw is screwed in too far
- the CP or/and CP guide is/are (significantly) worn
- the metering slit o-rings are worn


You said “I love your approach“. … Since I‘m a little short of time, this is currently the only thread I‘m active in, and I‘m trying to keep it systematic and to prevent confusion … and I really think that, not least in view of the hint I gave with the first sentence above, waiting for the results of the test I suggested in post 108 (possibly followed by further test steps) is in order. … :wink_2:

H.D.
 
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