Mercedes-Benz Forum banner

21 - 38 of 38 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #21
(1) So it looks like pin 1 is connected to the ignition coil low voltage side from your picture. Perhaps it is providing a virtual ground (or battery voltage) when you take measurements. Maybe that's why it sort of works.

(2) Some meters will give you garbage if you reverse connect the leads. Mine does. Even though it is a very good meter. Though yours seem to work that way I would not trust it 100%, always go ground to signal and do the math. Safer that way.

I also have an '89 M103. I can take some measurements and collaborate your results and connections. Not for a few days though, it is raining heavily here, and will do so for a week or so.

Seems you need to hit the books anyway. Good luck with the finals.....

- Cheers!
So, it is very much of an intermittent sort of problem, sometime it is like this(on the video), sometimes it is alright, and what i have noticed yesterday, the light in the car(dashboard and the other bulbs flicker, and turning on or off the any electrical stuff in the car causes rpms go down significantly and than fluctuates. Also i noticed it drains the battery(battery is new, 8 months old), i'm still able to start the car in the morning, but i can feel that battery doesn't have much of juice, then i drive during the day, battery again is juicy for starting. During the holidays, i haven't started the car for 2 days, it drained the battery completely, had to jump start it. Also, i bought a new Voltage regulator(KAE) original, and on the third day after i installed it, i noticed that, when i turn off the engine and pull the key out, the check engine light stays on as if in the 1st key position and i can hear the idle control valve clicking and some other electronic works under the hood. I switched the voltage regulator back to old one and that problem was fixed, but i think, that there is some short or something, that killed it, I don't think it died itself in 3 days for no reason(both fuses were not burnt on regulator, what's weird).
2612721
 

Attachments

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,637 Posts
Well this changes things......
A picture (video) is certainly worth more than a 1000 words in this case.

You seem to have some electrical issues on top of a vacuum leak.

(1) Your Econ gauge needs to be pegged all the way to the left, particularly at 1000 rpm.
Mine is pegged even at 700 rpm. Leak could be benign at the vacuum actuators for HVAC so do not panic about that just yet. Are there any hissing sounds coming from the flaps/actuators under the dash? If there are leaks there it is just your meter that is wrong because the the loss would be between the intake and the meter. Not a big deal.

You also have some electrical problems, so your RPM stability should be the least of your worries at this point.

(2) I would recommend buying a $12 cigarette lighter USB charger online that has the voltmeter display built in it.
Stick it in the lighter and observe your system voltage for a while. I've been riding around with mine for 2 years now. It is pretty valuable to have with the M103 cars in my opinion.

Without bottoming out on items 1 and 2 above I would not start chasing your idle issues.

- Cheers!
 

·
Premium Member
'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
Joined
·
10,301 Posts
Run your car at idle....put all your accessories on including headlights. Read your battery voltage across its terminals....should be around 14.3 volts. This proves your alt is doing its job. These cars are wholly dependent on a well charged battery and voltages being at a minimum to spec. Consider you may have a bad chassis ground, bad ignition switch and/or a parasitic drain going on. To check for a voltage parasitic drain, there are a number of good YouTube vids. One of my favorites is from a guy called Eric the Car Guy. He goes straight to it without the usual YouTube craziness.

You definitively have a electric problem....I don't know the history of the car, but some PO might have inadvertently sabotaged your electric system....who knows. A vacuum leak is minor to your problems right now.

Kevin
 

·
Premium Member
1993 300CE Cabriolet (mine) ; 1994 E320 Wagon (wife's) ; 1990 Benz 300E 2.6 (son's)
Joined
·
7,038 Posts
with everything on at idle, I'd expect 13.8 V or better to be adequate voltage. if its much below 13.6, you definitely have a problem. 14.x V is 'absorption phase' which the regulators on the original w124's didn't do.
 

·
Registered
00' ML55 AMG, 95' S320
Joined
·
97 Posts
Where is the vehicle from originally? Any chance it's from California? Also if you haven't yet, replace the 4-pin Coolant Temp Sensor. You should also go through the FSM and do all the Ecu-to-sensor wiring tests. Another necessity is a parasitic draw test.

One other thing... KAE (Kaehler) brand is junk, garbage. I see those relays fail all the time. I would replace anything branded KAE with a genuine MB part. You won't regret it.
 

·
Premium Member
1993 300CE Cabriolet (mine) ; 1994 E320 Wagon (wife's) ; 1990 Benz 300E 2.6 (son's)
Joined
·
7,038 Posts
air leaks caused my 1990 300E 2.6 to stumble and stall occasionally comign off ldle. it was very erratic, it could drive great for a week, then you're hitting the gas when its your turn to go from a full stop, and it would just choke, stumble and stall.

after spending better than a year trying to determine the cause it turned out to be air leaks around the CIS injectors, the seals were not consistently keeping air out.

I'm not saying those seals are your problem, jsut that /any/ pinhole air leaks between the air flap and intake manifold will throw things off and cause it to starve for fuel at rpms.
 

·
Registered
00' ML55 AMG, 95' S320
Joined
·
97 Posts
air leaks caused my 1990 300E 2.6 to stumble and stall occasionally comign off ldle. it was very erratic, it could drive great for a week, then you're hitting the gas when its your turn to go from a full stop, and it would just choke, stumble and stall.

after spending better than a year trying to determine the cause it turned out to be air leaks around the CIS injectors, the seals were not consistently keeping air out.

I'm not saying those seals are your problem, jsut that /any/ pinhole air leaks between the air flap and intake manifold will throw things off and cause it to starve for fuel at rpms.

This is perfect advice for the M103 engine. The injectors and their seals are basically maintenance items. I don't see them last much beyond 60k miles. I think the original parts were of a better quality than the replacements you can get today. You also must replace the white nylon injector holders (and their o-rings), and make SURE you install the correct spark plugs as these engines are very sensitive to that. I have had nothing but success with Bosch H9DCO (non-resistor). FCP Euro sells them as "Genuine Mercedes" for a very reasonable price.
 

·
Premium Member
'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
Joined
·
10,301 Posts
Low vacuum is the least of his issues....flickering dash trouble lights, a draining battery and other electrical oddities are the immediate problem here. As I suggested, the parasitic draw test is an absolute necessity.....so is testing his ignition switch and checking charging voltage at his battery.

Kevin
 

·
Registered
00' ML55 AMG, 95' S320
Joined
·
97 Posts
Sure, but all points are certainly relevant here! I'll leave his order of operations to his discretion lol.
 

·
Premium Member
'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
Joined
·
10,301 Posts
Indeed, but let's get him through his electrical issues first. These are the issues that will leave him stranded somewhere. A rough or low idle you can live with until tomorrow....flickering trouble lights and a draining battery you cannot.

Kevin
 

·
Registered
Joined
·
11 Posts
Discussion Starter #31 (Edited)
Well this changes things......
A picture (video) is certainly worth more than a 1000 words in this case.

You seem to have some electrical issues on top of a vacuum leak.

(1) Your Econ gauge needs to be pegged all the way to the left, particularly at 1000 rpm.
Mine is pegged even at 700 rpm. Leak could be benign at the vacuum actuators for HVAC so do not panic about that just yet. Are there any hissing sounds coming from the flaps/actuators under the dash? If there are leaks there it is just your meter that is wrong because the the loss would be between the intake and the meter. Not a big deal.

You also have some electrical problems, so your RPM stability should be the least of your worries at this point.

(2) I would recommend buying a $12 cigarette lighter USB charger online that has the voltmeter display built in it.
Stick it in the lighter and observe your system voltage for a while. I've been riding around with mine for 2 years now. It is pretty valuable to have with the M103 cars in my opinion.

Without bottoming out on items 1 and 2 above I would not start chasing your idle issues.

- Cheers!
I've been busy for a while, but now came to visit my friend on holidays, and asked his multimeter to try it out, and it worked(pins 2 and 3), so my 2 meters are bad or faulty or just garbage idk. The only thing is when reading off the current from EHA, it seams to fluctuate around 0mA at around 60% duty, tried to play with the screw on EHA, anyway always fluctuates around around 0 mA at 60%duty, if the duty is around 50% the current on EHA is somewhere around -3.3mA. so for now i set it when at 2500rpm EHA fluctuates around 0mA and duty cycle around 60% and duty stays pretty much the same any rpms.
Regarding the vacuum, i changed all the hoses and the economy gauge went a little bit more to the left, but still far from being all the way pegged to the left, and tested all the hoses and the airflow meter for leaks and didn't find anything. I live at high altitude and my friend told me that could be the reason of low vacuum pressure.
2615039
2615036
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,637 Posts
I think we drifted with this posting a bit.

(1) For your vacuum pictures, always show the vacuum gauge and capture rpm's together. They are related. Your RPM's appear to be low.
(2) For your duty cycle, are you getting the same (well 100 minus) results with reversing the leads? Your picture shows black on #3 (reversed polarity)
(3) Trust your EHA current more than your duty cycle. The EHA current is the real deal, duty cycle is just your ECU converting your EHA current to an AC signal. Something could be going wrong there.

But more importantly:
(4) You were having electrical issues and idle fluctuations which was the primary complaint, what happened to those?

- Cheers!
 

·
Registered
Joined
·
11 Posts
Discussion Starter #33
I think we drifted with this posting a bit.

(1) For your vacuum pictures, always show the vacuum gauge and capture rpm's together. They are related. Your RPM's appear to be low.
(2) For your duty cycle, are you getting the same (well 100 minus) results with reversing the leads? Your picture shows black on #3 (reversed polarity)
(3) Trust your EHA current more than your duty cycle. The EHA current is the real deal, duty cycle is just your ECU converting your EHA current to an AC signal. Something could be going wrong there.

But more importantly:
(4) You were having electrical issues and idle fluctuations which was the primary complaint, what happened to those?

- Cheers!
1)The pic of the economy gauge is at the idle rpm(around 650 rpm i believe).
2)The leads are reversed on purpose, so i get 70% with key in on position, not 30%(because MB uses the reverse way duty). i get around 97 HZ on 2 and 3 with this meter, which i believe is ok. Reverse gives me 30% duty.
4)I didn't have time to mess with electrical stuff, got another brand new ovp once again, check engine doesn't come up with the key out, that one must have been faulty. also have the new power regulator for my alternator. Battery does not die after some time by itself, there is no parasitic drain now. the is slight change in rpms when turning on any electrical stuff, but not significant. Getting a new(used) ecu from ebay in couple days, will see what that changes, but don't hope for much.
Thanks for help.
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,637 Posts
Overall things seem to be in order then.

(1) Is your latest vacuum photo/video with AC on or off?
(2) Yes the altitude does make some difference. I remember when I used to go to tahoe at 6000 ft, the vacuum was not pegged. But that was a long time back, so my memory could be fading
(3) Maybe shoot a video of the latest state of affairs with the rpm's when you get a chance. Let's see if it is acceptable.

- Cheers!
 

·
Premium Member
'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
Joined
·
10,301 Posts
The FD and the EHA are a matched, calibrated set. Adjusting the EHA is usually specific to the fuel pressure readings on the FD; upper and lower. The purpose of testing the duty cycle is to bring your engine dwell to spec and to see that your O2 sensor is cycling in closed loop mode. I usually advise against fooling with the EHA unless your FD pressure tests are showing off. And then you have the issue of dealing with aging fuel pump(s) BEFORE you test pressure at the FD, upper & lower.

Of course if you or a PO fooled with the EHA, all bets are off. When adjusting the EHA you move that screw in VERY small increments and then let the car idle a few minutes, then retest. You can rent a metric FI gauge test kit from most box store now including NAPA.

If you read HD's testing procedures, you can bring your EHA back to spec with a good multimeter. But if you pump(s) can't deliver the specific volume and pressure....you are going around in circles.

Kevin
 

·
Registered
Joined
·
11 Posts
Discussion Starter #36
Overall things seem to be in order then.

(1) Is your latest vacuum photo/video with AC on or off?
(2) Yes the altitude does make some difference. I remember when I used to go to tahoe at 6000 ft, the vacuum was not pegged. But that was a long time back, so my memory could be fading
(3) Maybe shoot a video of the latest state of affairs with the rpm's when you get a chance. Let's see if it is acceptable.

- Cheers!
1) the ac was off.
how i adjusted the EHA without pressure gauge(might get one soon):
was running the engine at 2500 rpm, if current was going into negatives, adjusting counter-clockwise(1/8 of a turn at a time) or opposite way if current was going into positive at 2500 rpm.
also: if on cold the acceleration is sluggish(like 25 sec 0-60), it meant to me it needs some enrichment.
but I do understand that without gauges it is quite dumb to try to do that, so working on getting it and measure the pressure to 100% sure.
So by today I adjusted EHA by 1/8 clockwise because acceleration was extremely sluggish on cold, and adjusted duty after. What i found out today is that my car sees 60%(by 10% leaner) duty perfect, because 60% duty makes EHA current fluctuate around 0 mA at idle and at 2500rpm. The EHA adjustment is around 7.5 turns from being fully screwed in, that's i believe a little rich from what i could find on the internet. I fully unscrewed it because it started to leak a week ago, so i unscrewed it and filled with carb cleaner for a while and then put it back together having tiny hope that fixes it cause the part is very expensive, and it did stop leaking until today it was absolutely dry even after I drove 300 miles to my friend, but today it started to leak again.
What I still want to test:
Pressure on FD(lower and upper chambers).
How evenly the FD puts fuel into each cylinder (full load and at close to idle engine speeds).
Try out another ECU which is actually already delivered to my home address but I'm coming home only after new year, to see if it acts the same way regarding EHA current and duty.
I'll shoot the video as soon as i can, but as of right now now busy with the holiday stuff. Happy holidays to everyone here.
 

·
Premium Member
'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
Joined
·
10,301 Posts
If your EHA is leaking gas, there's no way to rehab it. One rare examples it's just the two O-rings; replace with the 'green' ones rated for the job.

Yeah, it's a stupidly expensive piece of kit. Many have gone the eBay used route and after an average of 3, they get one to work properly. I guess it depends on your patience level. But what I can tell you long-term is EHA's HATE ethanol gas.

Kevin
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,637 Posts
If your EHA is leaking gas, there's no way to rehab it. One rare examples it's just the two O-rings; replace with the 'green' ones rated for the job.

Yeah, it's a stupidly expensive piece of kit. Many have gone the eBay used route and after an average of 3, they get one to work properly. I guess it depends on your patience level. But what I can tell you long-term is EHA's HATE ethanol gas.

Kevin
Yeah, I think the times when the o rings leak are those rare occasions in which the owners have not changed the rings during a previous EHA replacement.
Seems the EHA life is 90K miles on the clock, give or take a few thou. Rings go a lot longer. Just have to bite the bullet and buy new, that way you know they are also adjusted right.

My suspicion here is that when EHA was adjusted it moved the normal operating range mechanically and that may have temporarily achieved better sealing, but it is worn so started leaking very shortly there after. Just a theory, no science behind this one.

- Cheers!
 
21 - 38 of 38 Posts
Top