No OVP...what happens? - PeachParts Mercedes-Benz Forum

JohnEspeed · #1 09-09-2002, 10:12 AM

My '87190 E 2.3 cuts out when the engines gets hot.It then only starts after it cools down (15or 20min).When it happened last week, I was just putting up the hood when an off-duty Mercedes Road Side Service truck pulled up. He quickly identified that I was getting no spark, but couldn't tell the exact cause. I Figured it might be the coil,and checked it with a Volt/Ohm meter. It didn't give me the specified #s so I changed it. The problem however persists. I read a few threads about the OVP, so I when out to take a look. Turns out that mine is missing! What affects will a missing OVP cause on my car? Could this be my problem?
Thanks for any input.

pentoman · #2 09-09-2002, 01:46 PM

Yes, a missing OVP will definitely cause starting problems!

When I had mine out recently for a few days (to disable ABS - found out after that its not good for the car to run without OVP), the car was very difficult to start when cold, wouldn't idle etc. etc. Once it was warm it seemed fine. I don't remember it being a problem on a hot start, but I don't think I ever tried it.

Does your car have ABS? An ABS light on should have given away that there was some problem.

later!

Mick J · #3 09-09-2002, 02:14 PM

OVP has nothing to with the ingition system on that model. It's failure (or removal!) will cause illumination of ABS light and may cause rough idling, stalling and poor starting. However it does not usually prevent starting.

JohnEspeed · #4 09-09-2002, 02:17 PM

The car doesn't have ABS, but I figure the relay missing can't be good.
Anyone else know about this?

pentoman · #5 09-10-2002, 10:01 AM

Didn't notice the bit about no spark - a missing OVP won't cut spark to your engine, but *definitely* get one before you start any other diagnostics - Fix what you know is wrong before you dig for other stuff

later!

JohnEspeed · #6 09-10-2002, 10:08 AM

Put in the newer(2fuse on top) OVP last night. Problem Persists. Can this be the crank sensor being affected by heat and cutting the signal to the EZL until it cools down again?
I am almost ready to take it to the mech to diagnose.

pentoman · #7 09-10-2002, 10:23 AM

Just read the other post in different thread where you said you installed a new OVP.

As the problem is ignition related, I presume you have new plugs and leads? Or at least, they were done quite recently. They would make more sense to change than the coil, IMHO, and even when looking good can need replacement.

Otherwise, your mech may beckon. Shouldn't be a problem for him, the engines are quite simple, and nothing unusual about them for a knowledgeable mech.

later!

jay123 · #8 09-10-2002, 03:00 PM

Had the same problem on my dad's '93 190E 2.3. Took us a while to figure things out.

It was a bad crankshaft/reference sensor.

Check the following thread on this:

Checking EZL ??? 190E 2.3 won't start...

Keep us posted.

JohnEspeed · #9 09-10-2002, 04:10 PM

Thanks. It also sounds like the sensor to me. I will have it checked out at the end of the week hopefully.
Know where I can get one cheap?Parts are anything but from dealers here in Montreal. Paid $130 Cdn for the OVP relay!

JohnEspeed · #10 09-26-2002, 06:21 PM

So the problem seems to be solved. As I thought it might be, it turned out to be the crank sensor.
Thanks for all who gave me their input.