All good info, and after I get it running, I will do a full tune-up. But it runs very well with gas dumped into the intake, or even just energizing the fuel pump and depressing the air valve for a few seconds---enough fuel get injected to run for a few seconds--but not enough for prolonged running. I am thinking that I will just spring for a set of injectors and pop them in. If it refuses to run even then--then it becomes the parts car. If it runs at all, then it will get that tune-up and all new injector seals and tubes and vacuum lines, and a new inlet air temp sensor.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

MS:

You have noted earlier that the engine would run for about 20 seconds, then shut off. That is about enough time for the (heated) O2 sensor to come up to operating temperature, and deliver a usable signal. It is also about the time programmed for post-start enrichment. After post-start, and with a good O2 signal, the ECU will drive the mixture in the lean direction. If the last, um, "mechanic" moved the main mixture adjustment in the lean direction, the observed symptoms are quite likely. If you have not already done so, give the mixture screw (in the tower between FD & air meter) a 1/8-1/4 turn CW (after pushing down to engage the screw underneath). That is enough to make a significant change. Keep track of the amount moved.

It sounds like a vacuum leak because if it's getting air from somewhere else then it's not going to pull the air flow meter enough.

the hoses going to idle air valve and air valve to intake manifold can be suspect, as can be the injector seals and other small stuff. 1990 and newer M103 have egr so make sure that the egr valve isn't stuck open or isn't starting to open when the car dies.

Smoke test works best for finding vacuum leaks but if you don't have it then a visual inspection will have to do.

Your car should run perfectly fine without the inlet air temp sensor so don't waste time/money on it.

Also check my post #11 because back when I had ignition issues car would start fine and then run like c**p


that adjustment screw is blocked off from the factory by a small steel ball and the adjustment tower is bolted on by 2 sheared-off safety bolts to prevent anyone from messing with it.

And if you find that it's still blocked then don't mess with it.

There's a simple on-the-car test for the fuel accumulator. Search for THREADS started by me. There may be two on this subject one on the FA test and the other reports the results with photos from my failure analysis.

Duke

I will check the hoses--the idle control works when energized by 12 volts

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

Well, it runs!!!!!.....sort of
I had it running for over 10 minutes today. I had to supply 12 v to the cold start injector. There is no signal coming from the harness, so I will need to check that out, but it did run. Tomorrow, I will let it get fully up to temperature and attempt to drive around the property.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

because there's not supposed to be any signal going to it usually. Cold start injector only gets power when you turn the starter. Enrichment when running cold is done by the black EHA valve on the distributor.


having 12v going to it constantly is like dumping fuel to compensate for a vacuum leak or a stuck/bad EHA valve.

Your fuel pressures looked good also make sure that the wires going to the EHA valve go in from the top not the bottom (possible to hook it up backwards)

OK--I checked voltage to the cold start injector.....I have battery voltage when cranking.

The EHA is not leaking. I pulled the connector to check current draw as er another "how to" .pdf, and there was no current draw. In fact, there is no voltage present at the EHA connector.
I also found 3 small vacuum leaks--one hose disconnected and 2 fitting with no hoses connected---
I also removed the idle control to check the large hoses connected to it--I cannot remove the hose from the intake manifold side, under the cold start injector, bit it seems to be whole and not cracked. The other hose that goes to the bottom of the Air Valve is also intact.
I also reset the mixture screw. According the .pdf I found, with the fuel pump bridged, I should see fuel just rising in the fittings on top of the FD where the injector lines connect. So, when I get back to the car, I will finish connecting the injector lines and give it another try.

Thank you for your help----Every time I "decide" to revert to the original plan and use it as parts for my 300SD, you give me just enough light and hope to try again. I have made that decision many times, and yet, here i am, trying to save it.
Here is a different question----Can I use the CV axles from the '91 on my '82 SD? Would I need to remove the differential cover and remove the clip from the end and use it like the earlier axle, or can they not be interchanged?

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

ECU should be working then

Ok here are a few things about the EHA:

The good thing about a mechanical fuel injection is that 10 - 15 seconds after cold start your car should idle smooth with EHA disconnected. Not only idle smooth but also drive smooth (mine does).

Doing this can help you narrow down a problem (you eliminate possible electronic glitches by disconnecting the EHA).

Current to EHA is usually very small (mA) and can go both ways (negative to limit/cut fuel positive to richen up) and during normal driving it tries to be as close to 0 as it can.

Testing for current is more difficult than testing voltage (meter has to be in line with the circuit fully connected)

What do you mean by reset?

I don't think there should be fuel coming out unless you depress the AFM.

For troubleshooting (not driving) you can plug all this stuff up. You need as much vacuum as possible.

also check the 2 small vacuum hoses coming out of the throttle body (facing the motor side. can be hard to get to).

I highly recommend you check that the large boot is tight around the throttle body. If somebody removed it it can be difficult to get it to seal against the TB. Usually when the ends of the clamp are touching it's a sign that the boot is not fully around the TB. That can cause a no start (happened to me).

You're welcome. What are your plans for the car when you get it running?

Flip or a keeper?

How many miles on it?

"Reset mixture"---set the mixture to a "basic starting point" According to the .pdf, this basic starting point is when the fuel is just shy of rising in the fuel injector ports... " If no fuel is rising...rotate the 3mm allen key clockwise until fuel just starts rising. When the fuel starts rising, back the allen key off...about 15 degrees. This should give a basic starting point..."

Yes, the 2 vacuum ports under the throttle body were 2 of the three I found and plugged.

Big rubber boot appears to be tight...I can't tighten the screw on the clamp any further and the ends are not touching.

Plan is to keep and drive.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags