Do I have a bad fuel distributor..? - PeachParts Mercedes-Benz Forum

mauka · #1 09-02-2003, 08:50 PM

1991 300SL about 117,000 miles. Basically a cold start problem. In the morning, or after it has sat awhile, I've found that if I turn the key on and wait a moment untill all the noise stops, (I don't crank the engin) and then turn the key to off position and back on one more time...the car then will start upon cranking the ignition. However, sometimes starts at high idle and sometimes starts at normal idle. Starts great when hot. Mechanic wants to replace fuel distributor, and injectors. I would really like to be sure before I spend the money on a fuel distributor....? Thanks for any thoughts or suggestions...I know this subject gets a lot of attention, but I haven't been able to navigate through the searches to pin point my problem....

Thank you,

sbourg · #2 09-03-2003, 01:33 AM

Are you saying it sometimes starts at warm idle speed and sometimes at high idle? Is that a problem? If you DON'T go through the on-wait-off-on-start routine, what happens?

Steve

mauka · #3 09-03-2003, 11:34 PM

If I don't go through the on-wait-off routine it takes a long cranking time for it to turn over and when it does...it sort off stutters and misses before warming up to normal.

No problem when the engine is hot...

Thanks...

jeffmg1 · #4 09-04-2003, 08:05 AM

I am not a mechanic, and know nothing about your engine, but before you let one change fuel distributor and injectors ask what about cold start is different than warm run or warm start for those parts.
I know of no part of the fuel distributor used specifically for cold start. Leaking injectors cause warm start problems. Bad injectors should cause cold or warm problems.
There might be parts on your engine used for cold start such as the Thermo-time switch, Cold-start injecter, Auxiliary air valve etc.

Turning the ignition on turns on the fuel pump for a couple of second to build fuel presssure. Since that helps cold start you could have fuel delivery problem. For example if the fuel accumulator is not fuctioning after the car sits you could get vapor lock.

I think if you deal with a good mechanic, he should have the knowledge and test equipment to check all engine systems, and give you definate reasons to replace any part!

Jeff

mauka · #5 09-16-2003, 06:28 PM

Still looking for any suggestions on this problem...?

mauka · #6 11-28-2003, 05:37 PM

Hello all....still have the cold start problem..just been living with it.

Fuel accumulator was check and it's OK. I just leave the ignition on for about 30 seconds and then crank it...and it starts pretty good.

The mechanic has suggested replacing the fuel injectors...that may help cold start....car has 110,000 miles....I'm told these should be replaced at this time anyway.

Still hoping to avoid replacing the fuel distributor...

Any other suggestions would be helpfull.

thank you

mike690003 · #7 11-28-2003, 06:41 PM

maybe it is the coolant temp sensor, that sensor causes warm start problems.

Mike Murrell · #8 11-29-2003, 12:39 PM

There was a recent question about CIS high idle.

idle speed high?

Look at what Steve Brotherton had to say. The comment above about a faulty coolant temp sensor is a possibility.

You may also wish to go to the search facility and key in HIGH IDLE and do this search against titles only. Yes - a long list, but cheaper than allowing a hit-n-miss mechanic the opportunity to shot-gun parts that may not solve your problem.

I doubt that you need a new fuel dist. AND new injectors.

Personally, I'd do some reading, then maybe you'll be able to do some diagnosis on your own or at least be better equipped to understand the possibilities.

I would also get a second opion.

Cigar Havana · #9 12-01-2003, 05:50 PM

A bad fuel accumulator usually causes problems for warm starts, not cold starts. Have you ever replaced your fuel check valves? They should be preventing the fuel running back into the tank and if they malfunction then your fuel line may be out of fuel.

Have you checked the O2 sensor? I had a long crank and a rough idle until 60c. Replacing the O2 sensor worked for me.

The fuel distributor is over $1,000. I would need serious proof before replacing it.

engatwork · #10 12-01-2003, 06:02 PM

yea - I am not exactly sure about your model but there may be a cold start valve in there that has some issues. I suspect if it was the fuel distributor it would do it all the time.