HELP! 86 16V MYSTERIOUSLY SHUT OFF

Recently when starting my 86 190e 16v, as soon as it starts, it will die. After a few more starts, it will idle. It's been getting worse. Also when driving, it will mysteriously shut off. Sometimes it will come back on and sometimes I'll have to turn off the ignition and turn it back on and it will run. I don't think it's the fuel pump because it will start. Maybe it's the filters? It doesn't smell like it's running too rich. Any thoughts? Help!

[stevebfl]

Sounds like the infamous OVP relay. (Overvoltage protection relay). Easy to test least expensive problem if your rolling the dice.

Be sure to check the fuse, but the fuse won't be intermittant.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

[Benzmac]

More often than not, I have seen the fuel pump relay cause this...Try one or the other and see. Let us know of the outcome.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I agree with Benzmac. My 1984 190E started doing the same thing -- it was the Fuel Pump Relay (about $125.00 a few years ago). Seems the original units were not hermetically sealed and moisture tended to corrode the contacts. I'd try replacing this unit first.

Good luck!

Brian

[This message has been edited by Brian16V (edited 04-21-2000).]

MY 190E 16V IS GIVING ME THE EXACT SAME SYMPTOMS AS DESCRIBE BY DC + LAST WEEK WHEN I STARTED THE CAR THE IDLE WHEN ALL THE WAY UP TO 2000RPM AND I HAVEN'T BEEN ABLE TO BRING IT BACK DOWN.
WILL THE ADVICE YOU GAVE DC, WORK FOR MY SITUATION?
THANK YOU!, FOR YOUR RESPONSES...

[stevebfl]

Not sure whose advice you are looking at, but I would try disconnecting the idle valve to see what happens. If I recall the idle valve on the 190s goes limp home at a moderate idle. If the OVP relay is involved there will be no control to the valve and there will be no fuel enrichment, usually not something that makes the engine idle high.

If the valve does different plugged in than disconnected, then it has some control and has the ability to move (they can stick). I would worry that air leaks combined with cold fuel enrichment allows the high speed. I would also go straight to the valve and monitor the signal three ways: current, duty-cycle and scope pattern.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

Here is a bizzare twist - I was in the garage and decided to spray some contact cleaner on the pins of the fuel pump relay. It ran fine for a couple days after that, but after that, it went back the normal. I've done that cycle twice now because I didn't have time to get a new fuel pump relay nor did any dealers around here have it in stock. ????????????? I am baffled. Any suggestions? Thanks.

[Benzmac]

By removing the relay, you are disturbing the internal crack that is going open. This will seal for a while, then fail again. If this is the case you could open it and see if you can find the crack and solder it.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

DC:

My 2-cents, I'd order a NEW Fuel Pump Relay (partsshop or ************************). The $125.00 or so you'd be paying will more than make up for the embarassment of stalling your 16V in the middle of an intersection.

My opinion.

Brian

Gang:

I'm reviving this post 'cause I may have to take a dose of my own medicine. My car has performed *flawlessly* since purchased in February (1986 2.3-16V). That is until last Friday afternoon. Here's what happened:

[1] Drove 50 miles on the freeway to San Francisco; some stop-n-go; drove 50 miles home -- no problems whatsoever (drove next to a CLK 430; we were both eyeballing eachother's cars ).
[2] Drove to the local mall and was parked approximately 30-minutes (outside temp around 75-degrees).
[3] Started my car and (out of habit) feathered the gas pedal as I turned the key. The RPMs rose to 2000, the needle dropped and the car died. Started on the second try.
[4] Stuck it in 1st (5-speed manual) and proceeded to pull out of the parking space. Drove 25-feet, pushed in the clutch, lifted off the gas and the car died -- STALL #1.
[5] Started up (no problem), stuck it in 1st, proceeded to the main street, pushed in the clutch, lifted off the gas and the car died -- STALL #2.
[6] Pushed in clutch (still in 1st) started up (no problem), proceeded to the next intersection, pushed in the clutch, lifted off the gas and the car died -- STALL #3. Still rolling, so I bump-started it.
[7] Took some back streets home and it never died; got on the freeway -- no problems.

Questions: Did feathering the gas pedal on startup do *something*? Vapor lock? Bad gas? OVP Relay? Fuel Pump Relay?

I have the means ($) to purchase the two relays, and am thinking of doing it anyways. Is replacement a pretty easy proposition? Just remove the battery, then unplug/plug the relays?

"DC" and "gill" -- what was the final resolution on your problems?

Thanks in advance for any/all advice (man, I LOVE this forum !!!).

Brian

My problem went away by itself until I plugged in my new fuel pump relay. Then the very next day, it happened again until I plugged in the old one. Nothing has happened since (knock on wood). Strange huh?

DC
86 190E 2.3-16

"this is gill again" okay, i've found the time in my schedule to work on my 16v. now this question is for all the technicians' that give advice in this web site. how do you check the over voltage relay & the fuel pump relay? if a device is needed, will purchasing it be cheaper than taking it to a tech.? my car is dying on me all the time now, it happens more frequently on days like today...VERY HOT 105F IN THE NORTHERN CA. VALLEY