Vehicle: 1990 Mercedes 300CE, Black/Black - H&R, Bilstein, etc.
Location: Los Angeles, CA
Posts: 78
High Idle and ABS light on--bad OVP?
Somy car is idling at about 1000-1200 RPM, and my ABS light is on... are these symptoms of a bad OVP? I've already checked the fuse and it looks good. Can I test the OVP itself with a multimeter? TIA!
same problem with my car.
Never really found solution
Cold startups are a nightmare. At stationary car idles between 800-900. Turn the AC and itu goes down to 650-700.
Sometimes ABS lights up, and most of the time it goes off after 2 or 3 seconds.
If after 2 or 3 second it doesn't go off, i do a restart and then the light goes off.
Somy car is idling at about 1000-1200 RPM, and my ABS light is on... are these symptoms of a bad OVP? I've already checked the fuse and it looks good. Can I test the OVP itself with a multimeter? TIA!
OVP would be my guess. Tap the OVP and see if anything changes when you do that.
I know the MAS Control unit also plays a role in cold starts. My cold starts are terrible. It takes 3 or 4 cranks and some revving to get it to fire. Once it does, it's pretty much fine. My ABS light turns on for probably 3-4 seconds when I start the car as well, but it always goes away.
Note that I replaced my OVP about a month ago and it made pretty much no difference.
EDIT: I have an MAS Control Unit on the way, btw. I will let you guys know if it fixes my problems! I also have a rough idle, and I'm hoping that the fuel pump relay housed in the MAS Control unit will also fix that problem.
Last edited by Bigpete123 : 12-04-2006 at 11:25 AM.
1.) I have swapped the OVP from a same car & still no change. So i didn't replace the OVP.
2.) I have swapped the KE-Jetronic control unit from same car & still no change.
Next for me :
1) i''m going to replcace my fuel pump & filter (it''s due anyway)
2) check the idle control unit
will post any updates
thx
Quote:
Originally Posted by Bigpete123
I know the MAS Control unit also plays a role in cold starts. My cold starts are terrible. It takes 3 or 4 cranks and some revving to get it to fire. Once it does, it's pretty much fine. My ABS light turns on for probably 3-4 seconds when I start the car as well, but it always goes away.
Note that I replaced my OVP about a month ago and it made pretty much no difference.
EDIT: I have an MAS Control Unit on the way, btw. I will let you guys know if it fixes my problems! I also have a rough idle, and I'm hoping that the fuel pump relay housed in the MAS Control unit will also fix that problem.
From my personal archive. I'm not sure it applies to the 1990 300CE:
There is a tech service bulletin, which may be applicable. Text is as follows:
03/95-2 M104 WITH HFM INJECTION SYSTEM
In case of customer complaints of high idle (approximately >2200 rpm) for a very short period of time (< 1 second) immediately after cold start, an updated EA/Idle control unit is available from our PDCs. The updated control units can be identified by a software production date of "SW 43/94" and higher stamped on the housing in the area of the barcode label. The following control unit part numbers are affected:
Electronic Accelerator Control Units
Part No. 124 545 65 32 - E320
Idle Control Units
Part No. 124 545 55 32 - E320
__________________
This message written with 100% recycled electrons.
So I installed the new MAS Control Unit. The car has never run better. Before going out and buying one (since they are very expensive), do extensive searches on mercedesshop. I'm not sure how much info you'll find, but you'll definitely find a long thread that I created about my idle issues, what I replaced, and what fixed it in the end. I'm still not 100% sure that the problem will stay away permanently... only time will tell. But for the time-being, I am very relieved.
So I installed the new MAS Control Unit. The car has never run better. Before going out and buying one (since they are very expensive), do extensive searches on mercedesshop. I'm not sure how much info you'll find, but you'll definitely find a long thread that I created about my idle issues, what I replaced, and what fixed it in the end. I'm still not 100% sure that the problem will stay away permanently... only time will tell. But for the time-being, I am very relieved.
The word on the net is to stick with Bosch brand units. Other units for sale - such as on eBay - are cheaper, but they are remanufactured units using some type of Volkswagon sensors, which are not fully compatible with Mercedes ecu's.
I am also having the Anti-Lock light coming on along with the high idle issue. I took out the ICV and cleaned it and it worked fine for about a few weeks. I tap on the OVP and it corrects the idle for a minute and it goes back into the high idle. I see a bit much of play in the socket where the relay goes into.
Linear Mode
