86 300e - OVP Relay - PeachParts Mercedes-Benz Forum

AzizSFH · #1 10-20-2005, 03:03 PM

Hi
I was wondering if someone can tell me:
1. Where the OVP relay is located
2. What it looks like
3. Where I can buy a replacement from.

Thank you in advance, please let me know soon if you can

Aziz

A264172 · #2 10-20-2005, 03:32 PM

1. -Behind the battery behind the black plastic splash cover.
2. -Silver relay with red top, Clear plastic lid with a 10amp fuse.
3. -Top of this page click on Fast Lane tab,

yal · #3 10-20-2005, 03:54 PM

May also be black top.

AzizSFH · #4 10-20-2005, 04:46 PM

Thanks all,

I found it, but mine is not bad.

Trying to diagnose poor running when engine is warm.
Hard to start, idles very rough, accelarates with extreme hesitation and power-loss. This does not happen at all first thing in the morning when the car is cold. Only once warm.

Previous owner tried several things
1. Cap rotor wires plugs
2. EHA
3. o2 sensor
4. checked fuel pressure and it was ok

And now I see the OVP is ok,

any other suggestions?

momentum1 · #5 10-20-2005, 05:03 PM

Im having the same exact problem with my 87 300e. I read it may be also a vacuum leak. I tried spraying wd40 on the hoses for leaks. No leak found. Are you also getting bad gas mileage and low idle when you come to a stop?

AzizSFH · #6 10-20-2005, 05:20 PM

Mileage is worse and yes it idles low at a stop and the idle is much worse in general when the car is in gear as opposed to park.

I see posts about the TMS and ICV but I am not sure if those would match the symptoms of having such a dramatic difference in behavior from when the car is cold to when it is warm

Anyone that knows please reply!

mctwin2kman · #7 10-20-2005, 05:49 PM

Most likely a vacuum leak. But also could be a craked AFM Boot! It sits between the AFM and the throttle body. When craked it sucks in outside air and bypasses the AFM plate so fuel is not metered properly. Also check your O2 and basic mixture settings. My 190E had similar issues, vacuum leaks, cracked boot fixed most of my issues when replaced. Also look at your Water Temp Sensor. It tells the CIS-E controller your engine temp so that it can tell the EHA what to do.

AzizSFH · #8 10-20-2005, 06:08 PM

Is the Water temp sensor the same as the 'Water temperature Sender' which I found for sale in fastlane section of this site? Since I did not find anything else I assume that is it, but please confirm. There is just one right? Where is it located on the engine exactly?

Thanks

mctwin2kman · #9 10-21-2005, 08:49 AM

Under Fuel Injection and Water Temp Sensor!

Test it first!

MacGyver · #10 10-21-2005, 11:00 AM

I've had it with this problem, (87 300E, 195K miles) I have an OVP relay on order, when it gets here, if it doesn't fix the problem, I'm about ready to take it to the dealer to diagnose what is causing the hesitation and rough idle! I've replaced:
Plugs, wires, cap, rotor, fuel injectors, fuel filter. Each item improved the performence a little, but the hesitation still exists.