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-   -   Rough idle at startup, smooths out after 10 seconds.... (http://www.peachparts.com/shopforum/showthread.php?t=283470)

Diesel Dawg! 08-23-2010 04:57 PM

Rough idle at startup, smooths out after 10 seconds....
 
When you start the car for the first time after it has been sitting for a while, it fires right up but has an intermittent miss at idle that clears up after a few seconds. It doesnt seem like it misses at any rpms above idle. I initially assumed it was a leaky injector losing prime, but that would still miss at any rpm. MAybe a bad glowplug? My glowplug light does not come on, but the car fires very easily. Ideas?

andrewjtx 08-23-2010 05:08 PM

Check your glow plugs.

You have a lot of posts for a new member. Welcome. But please remember that the search function, given a little effort and time, will answer most of your questions.

Diesel911 08-23-2010 05:16 PM

Check the Glow Plugs and you could have a small Air leak.

The Air leak would be in the Fuel Supply system.
The Injectors are in the Highe Pressure part of the system and there would be high pressure Fuel sprayed from an external leak.
In order for the Injectors to lose their prime so to speak the Nozzle seats would have to be badly worn or the Delivery Valves in the Fuel Injection Pump would have to be letting the Fuel seep past them.

If you are running the Stock Bosch Fuel Injection Nozzles there is tiny drilled passages in the Pintel of the Spray Nozzle. And, they can get plugged with Carbon and cause a rough idle.
Look in one of the rough idle threads where I have pic/s.

MW Fuel Injection Pumps do not hav the Delivery Valve Holder O-rings. But, some had similar symptoms when their Delivery Valve O-rings started to go bad. The claim is that somehow Air is pullled past them.
There are some threads where changing the O-rings solved the Problems.

NoSparkNeeded 08-24-2010 08:46 PM

Mine did this for a short time
 
Only the first start of the day, no matter the ambient temperature. Had to give it a bit of throttle to smooth it out. Only for about 4 seconds. After it was warm it idled perfectly. Turned out to be #5 glow plug. Now I can startwithout touching the throttle, even on the coldest day. (hehe, where I live,that might be 32 at the most bone chilling :>) ). Glow plug was an easy quick fix.

Craig 08-24-2010 10:02 PM

Definitely, check the glow plugs. One cylinder is missing until it warms up a little.


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