Not so fast!!-the car ran but then it wanted to stall. I got it home but it does not want to start again!! My pententiometer is most likely a dud as the motor surges and sticks at 2500 and sometimes fall back to 7-800 rpm. I did lean the fuel/mix adjuster-perhaps too much as the one of the spark plugs I pulled was bone dry!! I should add the car wanted to stall even before I adjusted the fuel air mix but at least i got it to run for a while. The car ran fantastically with the new coolant sensor just a desire to stall at low speed.

The plugs should be "bone dry".

Have you tested the throttle position sensor yet? It's far more likely to be a dud than the air flow sensor. Just hook up an ohmeter and slowly press down on the gas pedal (with the car off). The resistance should increase/decrease smoothly as you move the pedal. If the resistance drops out or increases suddenly, you've got a bad TPS.

What are you doing when you say the motor surges & sticks "at 2500 and sometimes fall back to 7-800 rpm"? Are you driving it? Are you idling?

Do you have an FSM?

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

the plugs were bone-dry after cranking the motor with no start several times-that does not seem right to me. I failed to specify.

DhJenkins-I believe you mean the pententiometer resistance test-think thats different from the TPS which is supposed to click when closed. I did that test and the numbers jumped-I have had a surging engine for some time but thats another matter I believe. I have a new pentetiometer ready to install. Thanks for your input.

reread and see you mean TPS as another test-sorry about that-would this cause a no start even with the EHA disconnected?

Yes, having dry plugs after several no-starts probably means no fuel; depends on the chamber design.

So you did a test which showed you had a bad part and you're not replacing that first?!

And it's POTentiometer.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

I hear you dh!! I have been paying on-line with a tech guy and he assures me that with the EHA disconnected that pentetniometer is out of the equation with regard to a no-start, the reason being that although the fuel is not being fine tuned by sensors, it still will be getting some fuel mimicing what I had with a bad OVP which did start with some difficulty.

I disconnected the fuel relay and spayed ether but the spark plugs are totally dry. It appears to be drawing in fuel and or ether and at other times not-I say that with a fair amount of confidence having had wet spark plugs at times and other times dry plugs after cranking. Thanks.

What I believe contradicts the tech guy on-line is that if i recall, I had a misbehaving idle even withthe EHA disconnected but i could be mistaken.

On your system, the EHA direcly controls the air/fuel mixture. Depending upon the shape of the vane inside the fuel distributor, disconnecting it may completely shut off fuel, even though it's designed to allow a very small amount of fuel to keep a *warm* engine running. This is the "limp home" mode.

The tech is right, sort of. The fuel mix cannot be fine-tuned because it is the EHA alone that does the fine-tuning; the computer will still be getting all of the other signals and will attempt to correct things via the cold-start valve, warm-up regulator, idle control valve, etc... during start-up, though.

Have you tested your fuel pressure regulator? Your's isn't integrated into the fuel distributor like older models, so if it is sticking or has a torn diaphram, it will not deliver the correct volume or pressure of fuel to the fuel distributor. You might also check your fuel return line at the engine compartment. You should be able to blow into it (or use an air tool with the pressure set at 20psi) and hear bubbles in the gas tank (remove the fuel cap first!). If there is any obstruction, then you've probably got a stuck fuel return check valve. If no fuel can go back into the tank, very little fuel can leave the tank.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Oh, and a guy in another thread had a very long no-start problem with his 190E. The problem ended up being too much fuel in his oil, which caused cylinder wash and super low compression - no start.

He changed the oil and it started right up. Something to think about. If you have a compression tester, see what you're getting.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.