Kokopelli

My nephew's car broke down in the rain about a month ago. We let it sit over night in a parking lot and then went back to get it the next day. It fired up on the first try and he was able to drive t back to my house. Later that day when he was trying to leave it would not start.

So far I have replaced the OVP but that made no difference. At least now he has an extra when it does eventually fail.

The fuel pumps come on and I get fuel to the fuel distributer but nothing makes it from there to the cylinders. Any ideas on what to check next?


thanks
Mike

jcjcrespo

I'm pretty sure you already know this, but that engine needs three things to start and run: air/fuel mixture, spark and compression.

Fuel is metered and delivered in direct relation to air intake volume, which is determined by airflow sensor plate position. In theory, pushing the plate down slightly while cranking the engine should result in fuel being delivered to the cylinders.

Spark is generated at the coil, which is controlled by the EZL based on signals it gets from the crankshaft position sensor.

Compression is achieved when pistons and valves work in a predetermined rhythm in a sealed environment.

Any one of these things could be the cause of the no start

Kokopelli

I thought I knew something about cars having built several 500whp subaru engines but I find this Mercedes to be a little humbling.

I am looking for reasons why fuel would make it to the distribution but not to the injector. I just tried what you said by pushing the plate down some but there is still no fuel making it to the injector. What other sensors control the fueling? Everything I read about the OVP and MAS indicate that they control the fuel pump which I have confirmed is working.

I have so many spare parts for a Subaru that I can just keep swapping things out until I find the bad part. Unfortunately I don't have the spare parts or the money to do that with this car.

jcjcrespo

Here is a great write-up on CIS:
http://arrc.ebsco*********/ebsco_stat...CTION_SYST.htm

tvasr1

On a recent road trip my 91 E 300 died a couple of times. It had all the symptoms of bad fuel pumps. Hauled it home and changed pumps. Still wouldn't run. Then I read the post here and checked the fire. Turned out the contact inside the cap was worn too short to make contact. New cap and rotor and the old gal runs great. Keep an open mind and double check the basics. Good luck , Taylor.

jcjcrespo

Thanks for the post, tvasr1.
I gotta tell ya, it's hard to understand for someone like Kokopelli and me, both money-challenged folk, why a person would replace something as expensive as fuel pumps based solely on 'symptoms' without first performing a thorough diagnosis...

tvasr1

What can I say? Bad advice and poor judgement!