BenzWorld Junior Member
Date registered: Sep 2005
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89 300E, Rough Idle, hard start, stalling solved, thank you all
Thank you to all that helped out with my 89' 300E idle, start, stalling problem.
I will outline all that I did in the hope that it helps someone else, I spent over 12 hours
working on it and hours reading on the net.
Here was the problem:
89 300E, 62K, regular service:
Car started hard, hot or cold, need to give it gas to keep it running. Then once I put it into gear it wants to stall. Once it was running, say a mile or so, car was fine. I started having this problem when my dumb head put 87 octane in it. Since then I have ran cleaner and 5 tanks of 93. Still was happening. I start the car it runs real rough, shaking at idle and at 3000 RPM for a minute then once I take off smooth. But when I come to a stop, it idles a little eratic, 500 - 700 rpm, almost like the AC is kicking in, but it is not.
Anyway, it seams to get worse with the more days that go by.
More: Violent, one time, shake on cold start is a product of a low idle.
When the car stalls in D while driving and then stopping is a result of low idle. It drops to 600 RPM at a stop then will just shut down, like I turned the key off, no rough idle then stall. I simply double foot it and gently press the accelertor to maintain 600 RPM.
It starts easily but idles rough, need to flutter the accelerator to keep it going then brake and accelerate at the same time to put it into Drive or Reverse. Once rolling though, from 600 RMP and up, the car runs great.
OK, here is what I did, in sequence.
- Replaced Distributor and Rotor since it had some erotion in it. Didn't help much.
- Went to Bosch Platinum 4 spark plugs. Didn't help much.
- Tested ignition wires. Fine.
- Cleaned throttle body and butterfly. Helped idle some.
- Tested OVP relay. Tested fine.
- Checked all vacuum with Starting fluid, found hose off Fuel Regulator Valve to Air cleaner housing, easy to accidentally disconect
if not carefull in removing the air cleaner. Check this!
- Tested O2 sensor. Tested fine.
- Ran Chervron Techron complete fuel cleaner. Helped some.
- Replaced fuel filter. Helped a little.
- Cleaned ICV. Helped start problem.
- Cleaned the fuel injectors offline. Smoothed idle out some.
- Adjusted Idle up a hair. Helped start and smoothness.
- Lubed all the throttle linkage and springs, it appeared they were sticking a little causing idle to be eratic some. Helped some.
- Adjusted CO adjustment. With all above and this the car runs perfect.
Starts cold/Hot fine now, idle in P, D, D w/AC, etc. at 600-700 RPM. No
more surging, stalling. Can't tell car is started when at idle in D.
All the above is outlined in various places in this forum, so search for it.
All of the above was just routine maintenance that was needed. Just
bought the car a month ago but with 62K it sat a bunch. 3 last things to check,
for that I see can easily occur: Check for fuel leaks, especially at the
filter and fuel pumps. Check to make sure fuel pumps humm and function, this includes
checking fuel pump relay. Check your injectors offline. On my car they were
part mechanical assist and on one the ball valve was not seating properly causing
a injector leak.... this contributed to hard cold start.
My problem was a combination of things, all stemming from what I believe was crappy,
dirty fuel. Car sitting a bunch before I got it.
Hope this can help someone as you all helped me!