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Discussion Starter #42
Update - Finally received back Fuel Distributor and test results of my injectors. 6 of 8 injectors failed either leak down, trigger or spray. Old diaphragm also appeared to have a number of pin holes and was badly worn. Put FD back on, new injectors and rest of hoses etc back together last evening. Did not jump fuel pump due to being able to see pic of my FD tested on flow bench from rebuilder. Within three or 4 30 second cranks it fired up. Few minor adjustments with stubborn to connect hoses that I thought were connected and it was time for a test drive.


So far I've put about 8 or so miles on it, not quite ready to say it runs perfectly just yet however the difference in throttle response and overall power is remarkable. I intend to put some more miles on it as I suspect there may be some air in the line going to the cold start injector perhaps and/or maybe some other air bubbles in a line or two that need to be worked through. Overall it's a big improvement! Will update with a bit more time on motor.

Side note I was able to find the throttle was not opening up fully and with a quick adjustment to the 10m bolt on the throttle bracket coming out of the firewall it's amazing how much more top end there is as well as proper trans kickdown.
 

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Discussion Starter #43
Second update - can say now for certain after a few more miles I can say an adjustment is needed. Runs exceptionally well under throttle, but not the smoothest idle. I should have paid attention to.this, but it would appear as though the throttle mixture was adjusted previously correct?

Vehicle had rough idle when I bought it so wouldn't be surprised. Throttle plate does seem to have appropriate play before hitting plunger (not 100% certain)

Makes me wonder about EHA.
 

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... now for certain after a few more miles I can say an adjustment is needed. ...
I don‘t know, what “adjustment“ you have in mind, but before you touch adjustment screws I recommend to mind what I said in posts 19, 22, 26, 32 & 37:

... adjustments via adjustment tower should be done only in order to readjust a deviated EHA operating range according to EHA current / duty cycle … and only if all potential problems that cause the deviation have been checked and, if necessary, fixed or manufacturing tolerances of replacement parts require it ! ...
... old-fashioned as I am when it comes to troubleshooting and a number of other things :D ... I would do what I usually do before I touch any adjustment screws or replace any parts, namely test & diagnose ...
... CIS-E engine issues in general should be addressed by respective troubleshooting processes instead of by tampering with the Lambda adjustment screw, let alone the EHA adjustment screw. … Only if all respective potential fuel combustion affecting causes (which already a simple duty cycle check can point to) are checked and, if necessary, fixed, changing the setting of the Lambda adjustment screw (solely according to duty cycle or, better, EHA current !) is in order. ...
... the purpose of a duty cycle check is to get diagnostic information. Unprofessional tampering with the Lambda and/or EHA screw(s) distorts and ruins that information. … … Only if both of these screws have never been unprofessionally tampered with, the duty cycle provides reliable & valuable diagnostic information !
If you don‘t know whether one or both of these screws [Lambda adjustment screw & EHA adjustment screw] has/have been tampered with, a deviated duty cycle either points to specific fuel combustion affecting problems, or it shows that one or both of these screws has/have been tampered with. The problem is that you can not tell which of these two is the case … which takes you to that point in post 40 of https://www.benzworld.org/forums/w126-s-se-sec-sel-sd/2720049-ke-jetronic-lambda-control-duty-cycle.html, where I said:
“... without at least knowing exactly how far in which direction the adjustment screw has been turned, valuable diagnostic information is gone for good (!) and everything that has an effect on fuel combustion (see examples under “Please note“ in post #2) has to be checked first before further touching the adjustment screw, in order to reliably restore a proper condition of the system. ...“
... As explained in my Lambda control thread, with the Lambda adjustment screw … (I recommend to not even think of it as “mixture screw“, for reasons I explained in that thread) … turned according to anything other than EHA current (respectively duty cycle) without knowing what the EHA current (respectively the duty cycle) was before it was turned or how far exactly in what direction it has been turned, the duty cycle‘s diagnostic information is gone for good. ...
H.D.

P.S.: Without email notifications and the forum not functioning properly anymore (at least not on my smartphones) I may not notice new posts until I log in via PC, which I do only occasionally.
 

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From all I have read the lambda screw should not be turned with the engine running. adjust in 1/8th or 1/16th turns and then measure again.

Personally I would put the EHA back where your found it and then read and adjust your duty cycle until that is in spec.
 

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JR420: From what I see in the pic, the anti tamper portion was removed from the tower, so yes, appears at some point and adjustment was made via that adjustment allen head inside the tower.

HD is giving you the correct guidance. And rumb's guidance is good as well

I'd suggest not touching the EHA screw

I also suggest that IF you touch the towers allen, you do it with engine off and make a TINY change that you track. That way if the results arent positive, you can easily put it back to where it was before you touched it.
Also, after you make any change? I suggest driving it for a few miles, turn ac on, turn ac off, go on the highway, go in stop and go, etc. Let the system fully adapt to the tiny change you make. Then make your decision as to whether any improvement, was made.
 

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Gentlemen, maybe you should really contemplate doing what I said in post 19:
... “adjustments via adjustment tower should be done only in order to readjust a deviated EHA operating range according to EHA current / duty cycle … and only if all potential problems that cause the deviation have been checked and, if necessary, fixed or manufacturing tolerances of replacement parts require it ! … Maybe it wouldn‘t be a bad idea to print that sentence on adhesive film and stick it somewhere clearly visible in CIS-E car‘s engine bays. …
… and really stick that sentence somewhere clearly visible in your engine bays. … :wink

You say that, from all you have read “the lambda screw should not be turned with the engine running“. That tells me that you've probably not read my Lambda control thread that I mentioned in posts 19, 22 & 32. … In that thread I explained under “Adjustment procedures“ in post 2, that the adjustment is always done while the engine is running at idle speed ! … :wink_2:

And again:
Before touching that adjustment screw, I warmly recommend to follow the above quote ! … But this is not my thread and what you (suggest to) do is up to you, of course. I‘ll not further interfere. … :)

H.D.
 

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My (personal) experience with adjusting the rather sensitive Allen in the tower, is that with a poorly tuned vibrating engine runs, the engine movement can make it a bit challenging to achieve minute adjustments while simultaneously knowing precisely how much you’ve adjusted that Allen.

Again, just my experience. Not a substitute for doing things the “right” way.
 

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Discussion Starter #49
Yes thanks HD, I should have paid more attention to the tower, but I did not know what tamper proof cover looked like until researching. It became clear that it was previously removed and already adjusted unfortunately for me.

I suspect this was done to pass am emission failure (recorded on carfax).

Now with renewed fuel system the previous owners adjustment to compensate for something or somethings that should have been addressed need to be reversed.

Thinking I might be better off going to an indy who can use an oscilloscope and exhaust analyzer to properly adjust?

Additional info - I have not adjusted EHA, but have no idea if previous owner did. I do know they messed with idle mixture screw though or a tamper proof cap would still be in place. I don't intend to touch EHA as it pulls strong, but idle is off. Seems to me as mentioned above that the exact science of it would use an exhaust gas analyzer/oscilloscope and then proper CO output could be achieved.

Neither tool do I own and good ones are costly thus my thinking is an indy that knows what there doing should be able to properly adjust in an hours time? Don't like the idea of engine running rich or lean.
 

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Discussion Starter #50
After reading additional info is it even possible to bring car back to original settings if EHA and tower adjustment screw was changed or do I need to replace EHA before shop does fine adjustments on tower adjustment screw?

Seems like if both have been adjusted (not certain again on EHS, but wouldn't be surprised) that it would be very difficult to attain with so many variables.
 

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... the previous owners adjustment to compensate for something or somethings that should have been addressed need to be reversed. ...
That is exactly the point where you (and lesguy) are now … which should incite you to follow the advice quoted in post 44 (!) … first starting with:
“... without at least knowing exactly how far in which direction the adjustment screw has been turned, valuable diagnostic information is gone for good (!) and everything that has an effect on fuel combustion (see examples under “Please note“ in post #2) has to be checked first before further touching the adjustment screw, in order to reliably restore a proper condition of the system. ...“

Without following that advice your issue(s) will not be properly taken care of, no matter how much subjectively perceived improvement tampering with the Lambda adjustment screw and/or the EHA adjustment screw brings.

And when that is done, proceed to the third quote in post 44, where I said:
“… Only if all respective potential fuel combustion affecting causes [for duty cycle deviation] (which already a simple duty cycle check can point to) are checked and, if necessary, fixed, changing the setting of the Lambda adjustment screw (solely according to duty cycle or, better, EHA current !) is in order. ...“


Which advice you follow is up to you, of course. :) … However, as an engineer who was involved in several MB CIS-E engines (before they went into mass production) I warmly recommend to generally be very careful about online CIS-E info & advice. Most of it reveals substantial lack of understanding this (least understood & most underestimated) injection system … which leads me to another warm recommendation :), namely to follow the advice in https://www.benzworld.org/forums/w126-s-se-sec-sel-sd/2720049-ke-jetronic-lambda-control-duty-cycle.html. … Those who love their CIS-E engines and do not know or understand what's posted there (like probably more than 95% of indy‘s) I recommend to stay away from the Lambda adjustment screw and/or the EHA adjustment screw and to let someone who understands these things assist you … again: no matter how much subjectively perceived improvement tampering with these screws brings !

BTW … contrary to common believe, these adjustment screws should not be turned based on what an exhaust gas analyzer reads and an oscilloscope is not necessary to do adjustments, both of which you will find out in detail by following the above link. … And if someone tells you that the purpose of the Lambda adjustment screw is to adjust the “mixture“ or exhaust gas emissions, I recommend to keep him away from your engine bay.

:wink

H.D.
 

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Discussion Starter #52
Thanks HD, I have reviewed all of posts previously mentioned above and feel confident there are no other ignition or fuel related issues other than restoring lambda adjustment to original settings with the unknown being previous potential EHA adjustment.

Am I understanding correctly in that diagnostic will never be accurate issue if both have been tampered with meaning in order to correctly adjust I would need to start with a new EHA?
 

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A competent person can tune EHA to original settings by using a pressure gauge. That has been explained in MB manuals and also for example on this video:



Manuals can be found in the stickies of this forum section. If the car has no other problems causing misfires than KE -jetronic bad tuning and has no leaks on exhaust at front of O2 sensor then all that is needed for tuning it is pressure gauge and digital multimeter.
 

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Discussion Starter #54
Thanks and great video! Seems like best place to begin would be with EHA fuel pressure measurement then going about HD's recommended procedure.

Need to procure proper fuel pressure gauge fittings next.
 

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... Am I understanding correctly in that diagnostic will never be accurate issue if both have been tampered with ...
Yes … also if only one of them has been tampered with.

... meaning in order to correctly adjust I would need to start with a new EHA? ...
If the EHA has been tampered with and you really want to do it right … yes ... unless you know how to properly check the EHA‘s calibration (volume flow !) and, if necessary, how to readjust it to its original calibration.

That, BTW, is not explained in the video in post 53. … (See what I said about EHA adjustment in https://www.benzworld.org/forums/w126-s-se-sec-sel-sd/2948841-tune-your-eha-while-driving.html) … ;)

... feel confident there are no other ignition or fuel related issues ...
If you are sure that there are no more fuel combustion affecting issues, you should check and, if necessary (as very likely), readjust the duty cycle, respectively the EHA current.

Just don‘t overlook any issues, like fuel pressure problems or a leaky CSV, or vacuum leaks, or problems with the o2 sensor & other sensor input to the ECU, the ECU‘s Lambda control function, the EHA‘s electrical resistance, tiny dirt particles in the FD (which can easily get into it during reinstalation … you might be surprised about the effect a ≥ 0.3 mm particle can have), …
And let‘s hope that the FD was not only properly cleaned & refurbished, but also its calibration was correctly checked and, if necessary, readjusted after refurbishment. You might at least want to check for equal volume flow through each injector pipe port.

H.D.

P.S.: The man in the video in post 55 seems to have been taken in by one of the common misconceptions about the KE-Jetronic. He thinks that, with the difference between SP & LCP being above spec, his engine will run richer. That is not the case, at least not with the engine running at operating temperature, unless Lambda control is not working or the Lambda leaning limit is exceeded (duty cycle = 0%) … which, needless to say, should be prevented, of course. … ;)
 

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Discussion Starter #57
Thanks, I have looked for videos and also posts on adjusting duty cycle. I haven't found yet anything other then using a multi meter that measures duty cycle on the diagnostic ports. Could it be that easy?
 

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Wanted to update this thread with pics of my plugs condition after about 350 (300 highway) miles after install of rebuilt distributor, new Bosch injectors, and tinkering with the EHA adjustment and tower Allen screw. Also adjusted gap to .040 for each, as a test to see if larger gap smoothens idle a bit more. New Lemforder motor mounts go in on Monday evening if no rain
 

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@JR420 & lesguy:

As I said, without knowing if the Lambda adjustment screw and/or EHA adjustment screw have/has been unprofessionally tampered with before, everything that has an effect on fuel combustion has to be checked before further touching the adjustment screw in order to reliably restore a proper condition of the system.

That, of course, does not mean that you should otherwise not further touch the adjustment screw. On the contrary, now that both of you know for sure that the adjustment screw has been tampered with (you did it yourself), you should at least check and, if necessary, readjust the duty cycle via the Lambda adjustment screw in order to help Lambda control to do the best it can do under the given circumstances.
However, without first checking everything that has an effect on fuel combustion or at least being sure that there are no further fuel combustion affecting problems, you‘ll never really know whether the system is in proper condition or not, no matter how well it subjectively perceived works.

I do recommend both of you to do at least a proper fuel pressure test (SP & LCP) though before you readjust the duty cycle (!) … in order to get more insight into (not only) both of your EHA‘s. … ;)


... I have looked for videos and also posts on adjusting duty cycle. I haven't found yet anything other then using a multi meter that measures duty cycle on the diagnostic ports. Could it be that easy?
You‘ll find out (in detail) by reading post 2 of the Lambda control thread I‘ve mentioned several times in this thread. … :wink_2:

H.D.
 

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While she appears to be running very well now, H.D. I do plan to check my duty cycle and fuel pressures soon, as a starting point. I’m pretty positive there’s no chance I got lucky enough to nail the adjustments just by touch/feel using no gauges/no proper process/proper tools
 
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