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  #1  
Old 08-31-2006, 11:41 AM
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Question Engine Misses ?????

I just got back from New York with a 83 300SD. The engine misses really
bad when cold. After it warms up it's not that bad. But still misses.
I am guessing its a bad injector, but thought I would ask you guys what
you think. It also shifts hard from 1st to 2nd and flares from 3rd to 4th?
Thanks. Jason

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  #2  
Old 08-31-2006, 12:05 PM
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Here is what my suspicions would be .........

"Misses" or nailing while cold, I would very much suspect a defective glow plug. And depending on how long it has been that way, may have caused some carbon build-up.

Changing out the glow plug(s) and cleaning the injectors in a dunk tank of carburater cleaner might be the ticket. That's what I would try first anyway.
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  #3  
Old 08-31-2006, 09:40 PM
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It misses. I think the fuel timing is off alittle too.
Thanks. Jay
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  #4  
Old 08-31-2006, 10:29 PM
t walgamuth's Avatar
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how long does it take to run smoothly?

tom w
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..I also have a 427 Cobra replica with an aluminum chassis.
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  #5  
Old 08-31-2006, 10:58 PM
KCM KCM is offline
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Possibly a broken prechamber ball. Had one break loose from it's mount inside the prechamber while driving and caused a miss at normal operating temperatures. This was on a '60's model but would think the same thing could occur with an '80's model as they are designed the same.
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  #6  
Old 09-01-2006, 03:08 AM
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how long ago since the valve clearences were last attended to ?
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Old 09-01-2006, 08:36 AM
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There are several things that could cause it. But I would test the glow plug circuit and ohm the plugs out first, valve adjustment, timing check. Then report back. Lets eliminate those items first.

http://dieselgiant.com/glowplugrepair.htm

http://dieselgiant.com/valveadjustment.htm
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  #8  
Old 09-01-2006, 10:28 AM
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Targa,

If the GP pass the resistance test, do the following:

Immediately after U start the engine and it is mis-firing, try to isolate a mis-firing cylinder by loosening the nuts on the top of the injectors one at a time.

If U don't notice a difference in the engine speed or sound when the nut is loosened, that is the cylinder that is mis-firing. A slight amount of fuel should leak out when U loosen the nut.

If you find a definite cylinder that is mis-firing, switch that injector with one from a good cylinder. If the mis-firing moves with the injector, its the injector that's bad. If the mis-firing doesn't move, then there is something wrong with the cylinder. It could be the ball pin or low compression from a leaking valve or rings.

If the engine mis-fires after its warm, is not a GP problem.

P E H
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  #9  
Old 09-01-2006, 01:09 PM
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Thanks everyone, I am going to try the things listed and report back.
Thanks again, Jay

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