1990 420sel - PeachParts Mercedes-Benz Forum

just-n-time · #1 10-14-2006, 09:04 PM

just-n-time here, I got the chance to look into the car tonight,and found that I have great spark,at the distributor,coil lead.We can look to wards something else keeping it from firring. It just seems so strange that after changing the rpm sensor it ran with a little roughness but it ran,the only symptom that showed was an intermittent abs light and a slight serge at the time that the light would come on,then we got a flashing check Eng. light,it would soon smooth out and all the lights would go out and drove fine for a time and start up again,In my attempt to readjust the fuel did I mess up something? thanks for reading jnt.

jdc1244 · #2 10-15-2006, 12:22 AM

The slight surge with the ABS light sounds like engine management – might want to check the condition of the OVP relay as it provides power to the ECU.

just-n-time · #3 10-17-2006, 01:00 PM

Quote:

Originally Posted by jdc1244

The slight surge with the ABS light sounds like engine management – might want to check the condition of the OVP relay as it provides power to the ECU.

ovp is one of the first things replaced,update on testing,I went to the shop this morning and she fire up first time,let it run for five min.and it began that slight roll as if searching for a balance of air fuel ratio,I then unplugged the EHA and it smoothed out,I then plugged up the EHA and it stalled immediately,but fired up on demand[turn of the key]ran the same test again same result.just-n-time thanks for the look!

just-n-time · #4 10-17-2006, 07:31 PM

Quote:

Originally Posted by bribenz

did you try driving it with the eha wires unplugged ? when the throttle position sensor is faulty it can cause your symptoms [ surging ], and unpluging the eha will allow it to run better [ no surging ] ;; but it will change the idle speed and it will be slightly harder to start ;; this is just to eliminate the throttle position sensor as the problem not a cure ;; obviuosly

Will give it a try in a couple of days,my youngest son just informed me that I need to work on the work truck because of nose in the rear axel,don't you love being the owner,certainly not the boss,though I try.thaks for the reply just-n-time.

david s poole · #5 10-18-2006, 10:26 AM

have smoke test done on intake manifold to look for vac leaks[lots of little ones not one big one]with the age on these cars i'm finding that a complete o/haul of intake is almost mandatory.

just-n-time · #6 10-18-2006, 06:41 PM

Quote:

Originally Posted by david s poole

have smoke test done on intake manifold to look for vac leaks[lots of little ones not one big one]with the age on these cars i'm finding that a complete o/haul of intake is almost mandatory.

Hi Dave,I have thought as much my self,I have injector rubbers and a complete set of intake dough nuts and intake gaskets,I replaced part of the idle air lines,found a crack in one.
I have a bee keepers smoker think that will work? thanks j-n-t