Please tell me this isn't the wiring harness!
 

Hey Guys/Gals:

I've had an ongoing problem with my E-320 that I can't seem to get fixed. I recently replaced the throttle actuator (I know it was bad, though because it was making a lot of noise), but the problems persist.

Here are the symptoms:

• random ticking from underneath passenger side of dash
• slight engine surges that coincide with the ticking noises
• abrupt hesitation upon hard acceleration
• cruise control fails to work

These symptoms are much more noticable until the engine has been running for several minutes-- even after it's warmed up. Once past a certain stage, the clicking noise goes away along with all the other symptoms and everything runs fine.

Also, but not necessarily related: sometimes when I arrive at my destination and place the gear shifter in any postion other than D, the dash lights and center consol lights flash rapidly. Maybe that's related?

Thanks for any help!! I'm trying to determine it's NOT the wiring harness before replaceing such an expensive item. My mechanic examined the harness and says it looks fine, no cracks. I'm pretty sure it was replaced before I bought the car.

SfloriII
I'm 100% certain that your records (you do still have them don't you) state that the engine wiring harness had been changed by the dealer under warrenty. Not sure of any of the other wiring harnesses though. Off the top of my head I can't think of any relay located underneath the passenger side dash that could be ticking and causing your issues. I would suggest looking for the wiring schematic in the CD and see what all is tied into the cruise control circuit and start from there.

Thanks, Jim. I was pretty sure the harness had been changed out.

I'll see what I can find from there. (But you have the CD schematic, remember? :) )

I'll look - I thought they were with the records in the folder I gave you. I'll look for them this weekend.

HAHA!! Age is affecting your memory!! :P

They were included in the packet when I bought your car, but I mailed them to you a few months ago.

Nobody has any ideas?

Have I actually STUMPED the forum?? :P

Examine the wiring harness for crumbling insulation.

rotflmao:D.

I have a copy of them sitting right here - next to the puter and I could not remember for the life of me where they had come from:eek: cause I knew I had put them in the folder.

I'll nose around in there here in a little bit and see what I can tell and will advise accordingly.

thanks

I've heard of the OVP from others' postings. Would that also be the cause the slight engine surges?

Thanks, Warren. The harness does looks good with no cracking-- per my mechanic.

One of the control modules powered up by the OVP is E-GAS. E-GAS is responsible for idle speed control, cruise control, and throttle intervention during wheel spin. It's located beneath the floor carpet in the passenger side footwell. E-GAS can be scanned for trouble codes. For what it's worth, I've seen faulty OVP's cause the symptoms you describe many times.

Don't know if your model has the 'ice cube' relays or not, but the clicking and engine surge you describe sounds like the problem I've traced to one of these particular relays in my SL. I ran it down in the passenger footwell on the right side by feeling for it with my hand when the clicking occurred.

I ordered one and then pulled the cap off the one I removed. The right arm (contact) on the removed relay was offset and only making partial contact. I realigned the contact, slipped the cover back on it and stuck it back in the car. It has run fine for several months now, but only a couple days ago I noticed the clicking again. Could be the same relay or perhaps another. I'll use the same technique to isolate the problem again.

Just called my mechanic and he says you're probably right. I'm ordering a used on from Potomac German to swap it out.

Thanks for the help! This forum is invaluable! I'll post results after the swap. :)

Do you mean you are replacing the e-gas moduel or the OVP?

The ovp is so cheap and the original part was defictive, I think I'd swap out the OVP first.

Hi Paul,

I was replacing the E-GAS thingy that's under the passenger floor carpet.

Would you recommend replacing the OVP first, then move on to the E-GAS?