My 1986 300E, when the weather is cold, starts for a second and dies. I have to try it as much as 18 times before she idles. If I try to give it gas, even after she runs, it dies, unless I let her warm up first. New plugs, fuel filter, and air filter. Any Ideas?

Perhaps the Dist Cap & Rotor. My camshaft seal failed recently which caused the dist. cap to be filled with oil/dirt grime which led to hard start problems.

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1991 190e 2.6 190,000mi

Once it finally runs, does it do so well? How is the gas mileage? I guess it could be the cold start valve that does not inject fuel long enough after cold starts. Or it could be a faulty KE temp sensor that signals higher than actual coolant temperatures.
If "cold" starts includes ambient temperatures above about 60 of even warm starts after some waiting period there could also be a problem maintaining the fuel pressure with the engine shut off. This may be due to a defective fuel accumulator or leaking fuel injectors.
Good luck, Bruno

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1992 300TE 160 kmiles

having the same problem i,ve changed the cold start valve, check valve on the fuel pumps, water temp sensor, cleaned the idle control valve, also have check for leaks found non if you are anyone find a solution for this headache
please post it

is your abs light on

I am having the same problems, runs fine when warm hard starting, abs light only flickers every once in awhile and only at hyway speeds, I have changed Idle aie valve and hoses, check valve, accumulator, temp. sender and all this after valve job, but had none of these problems before only oil usage and fouled plugs

This same topic has been covered about 6 times in the last week!

Whats going on?

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

I just replaced both hoses and idle air valve, and bothhoses to valve cover

The OVP relay provides power to BOTH the ABS and "E" portion of the CIS-E, and the "E" portion of the CIS-E has all the cold start and idle speed control functions.

If you have cold start or idle speed control problems AND an intermittant or steady ABS light, the most likely culprit is the OVP relay.

Understanding this point will possibly save you the cost of replacing a lot of good parts and chasing your tail.

Duke

I have this same issue and checked both fuses in the ovp and they were fine. I even pulled them and the the car wouldn't start without them. ABS is still on and the thing won't start and stay running. It dies after a few seconds.

The OVP is more than a couple of fuses.

The external fuse(s) protect against shorts downstream. The internals of the relay protect against overvoltage from the vehicle electrical system.

Many OVPs fail due to cracked solder joints inside, which means there is no power to CIS-E and ABS, so cold starts are problematic and the ABS light will be on if you can keep the engine running. Some have been able to repair them. You can remove, disassemble, inspect, and possibly repair the relay. Or, you can just buy a new one.

If you search you will find extensive discussion of the OVP relay, but little system knowledge on what it does or how it works. The service information schematics basically tell you what it does and how it works.

Duke

I hate to tell you this. Its the CPU. I just spent $600 buck on the same problem. I also changed the OVP realy while I was at it. I'll start from the begining. It started when the temp started to get cold. I have a 90 300E 3.0. It wouldn't start for the life of me. After 15 times it would idle and when warm, it ran fine all day until it sat for 6 to 8 hrs in the cold then same problem. I looked here and they said to change the OVP and I did....nothing. They said that the hoses going to the Idle control valve. Did them both. Still same problem. Then they said the cold start valve. Got that. Still started after the 15th time. I then looked for a vacuum leak. Nothing. Changed the temp sensor that tells the cold start valve and idle control valve. Still same problem. I broke down and sent the car to Mercedes. It was the computer. (ECU) I then went out and found a used one and it starts like a charm. So for all of you with that problem, its the ECU. its behind the battery next to the OVP. I changed everything and should have just taken it to mercedes in the start. Would have saved alot of cash. This sight is great but still not as good as a good mechanic. Good luck.

Add info. They way they found out it was the ECU was they checked the sensors, i watched, it was a BOSCH unit that plugged in to a round connection on the car and it had a guage on it that read from 1 to 12 and it read a steady 9. He then said that it was running lean and checked each sensor and found that they all were reading fine and sending the right signal. He said that at that point it had to be the ECU and put a new one on it a in two seconds the car started up. He said that he could sale me a new one for $1000 bucks or I could find one in a junk yard. I picked the junk yard one.

Also Ikchris, don't get so angry at people asking question, this is a forum, so if alot of people are having the same problem then they ask. I search and found all the wrong answers. Your post is right on how a Mercedes engine runs, but there are alot of inbetweens that need to be addressed. So if people are having problems let them ask and maybe it would be something as simple as a hose, or a CPU.

I bought these injectors cheap from eBay and fixed my idle irregularities !
They came with seals and free shipping and they're original BOSCH . I waited
for years to find cheap injectors and by chance checked with eBay . See for
yourself at eBay # 8031671714 .

my problems were the ovp and the new hose on the idle air valve, the hose kept aplitting after a couple days so I made my own, I also took the linkage completly apart and cleaned running great, thanks for the help