I'm a bit late to this party.

I assume this vehicle has been sitting for a while - as you mention "three year old gas"

Injectors are probably clogged and corroded. If you have a pop tester remove the injectors and see if they dribble / leak don't spray nicely. When working correctly these things stutter making a kind of a weird almost screeching noise. (Remember this is a CONTINUOUS injection system so they need to do this all the time)

The plunger for the fuel distributor also needs to be free and able to move nicely. The best way to check this is to remove it check visually for leaks and good motion. They can get a little sticky especially after sitting for a while.

The best thing you can do for the car is to chuck that old fuel - failing that use some sort of fuel stabiliser.

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As for messing about with the air flow potentiometer - well that might have been a bit of a mistake - they should read about 0.7 VDC between pins one and two at an idle of 800 rpm (ish). Problem is you need the good operating temperature - idle - and duty cycle for this to come good. So it can be a pain in the arse - very difficult to adjust this when you've got problems elsewhere on the engine.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Let me clarify. The parts I pulled are off of a car that sat for three years. My car hasn't, I have been driving it for nearly two years. I have had a few parts fail before that I have replaced concerning the fuel and ignition system. It has new plugs (denso non-resistor), wires (NGK, seem to be better quality than Bosch), a good used distributor and rotor (seriously looked mint, Bosch & Beru), new injectors with deals and orings (Bosch), good used EHA, good used speedometer sensor, new oxygen sensor (Bosch). I also recently changed the entire fuel distributor/air plates assembly over because my air flow potentiometer was bad and I didn't want to mess with taking a known good one off and then having to get it adjusted correctly. This one was still at the factory set position. It also had the air plate adjustment at the factory position because the ball was still in the tower. Once I installed that, the engine ran better than ever before it started having the current issues.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

Oh right - OK - a bit different than I thought.

(But) the new airflow plate assembly: Did you change the fuel distributor with it?

You see strange low idle speeds might be due to sticky fuel delivery components such as the plunger in the fuel distributor, the air flow plate and the EHA (in the wrong position)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

I switched over the fuel distributor itself and started it. It started poorly and bogged, while revving it seemed like it wasn't giving even fuel delivery. I don't know if that could be because of the system losing pressure or what, I didn't have enough fuel in the car to run it for long. I guess my next course of action will be to get more fuel, test it again, then if that didn't work I will pull the air flow plate assembly and spray it with carb cleaner to get any junk out that might be causing it to be sticky. I don't know if the EHA is adjusted properly, I currently have one from a 3 liter on it, which I assume is adjusted differently. I have a 2.6 one that was on the engine before but I switched it to see if maybe the EHA was bad but it didn't seem to be the case. I know there are ways to adjust it but I don't have any of the tools for that and unless I can rent them for cheap I would rather not mess with it. This car is eventually getting the 3 liter M103 I have sitting in my garage with electronic fuel injection (Megasquirt III) or a M104 3.2L that already has EFI

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

The EHA adjustment instructions on the internet seem to me to be of the "twist it a quarter turn it'll be amazing" advice that I personally avoid like the plague. Always best to measure what you are adjusting rather than using the force. If you don't have the fuel pressure kit with the 2 way switch forget it.

The first step I can recommend is to simply remove the fuel distributor from the top of the mixture device and check for a freely moving plunger.

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

When did you do the ignition system tune up?

__________________
Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2

I was about 10K miles ago. I am thinking I will remove the distributor cap and check for carbon buildup on it tomorrow.

__________________
Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

I wanted to follow up on this thread for anyone who may be reading this later as I find it annoying to read thread after thread about an issue and no answer as to what the fix was.

The fix was replacing the OVP. I had tried swapping between the one in my car and a spare but it didn't change a thing. I figured my OVP was fine since nothing changed between going between the original and the spare. I tracked down my starting issue to the cold start injector. It wasn't firing. I looked at the wiring diagram and there were 3 main items on the circuit that could make the injector not fire, the MAS relay (AC and fuel pump relay in one, check you fuel pump relay if you have na older car), the CIS temp sensor, and you guessed it, the OVP. Since I couldn't do anything about the sensor or MAS relay until I got new parts, I decided to take my spare OVP and resolder it. Plugged it in and that was that. Car starts and runs so much better now.

__________________
Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

a really interesting trail of experiments and tests..conjecture and assumption..You assumed the OVP relay was fine after changing it and having the same results, right? Lots to follow here..Just as I assumed my fuel pumps were okay becuaase just previously I disconnected one pump and suddenly the car ran fine on the other pump only..Then when it died I refused to test the pumps because having TWO fail immediately at the same time?? No way..but this is exactly what happened. I was tearing the car apart looking for failed wiring and pricing out ECU replacements when finally I checked the rear pumps and sure enough, dead dead..and same with the middle pump..Easy fix but went against my assumption of the odds. Someone who did not know the car's history would have been more open minded and fixed it in 15 minutes while I chased my foregone conclusions..Thanks for the details! All useful information..