random bad contribution test
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Laughing Gas
Joined: Jan 2005
Posts: 920
Likes: 7
From: Mazon, IL
random bad contribution test
Any ideas what would cause a random intermittent bad cylinder contribution test? I installed new injectors, and it smoked like hell. Turned out 1 of the new (rebuild) injectors wss bad. Basically, I swapped the injector from the cylinder that failed the contribution test, and the problem followed. Replaced the injector, and the smoking has stopped, and only #8 failed the contribution test. Drove it home and it ran just fine. But I decided to run another contribution test after running it for an hour, and it failed on the cylinder with the new injector.
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Laughing Gas
Joined: Jan 2005
Posts: 920
Likes: 7
From: Mazon, IL
Yeah. #8 is always bad. I started with bad #4 then swapped injector to #2. All was fine, but now #2 fails
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Laughing Gas
Joined: Jan 2005
Posts: 920
Likes: 7
From: Mazon, IL
pretty much. It ran at high idle for about an hour after is warmed up, then actually got driven for about 50 miles
Former Vendor
Joined: Sep 2020
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From: Florence, MT
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Laughing Gas
Joined: Nov 2020
Posts: 988
Likes: 364
From: Republic of Texas
You just about need to drive it like you stole it for about 100 or so miles like the others have said. Clear the system..
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Thread Starter
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Laughing Gas
Joined: Jan 2005
Posts: 920
Likes: 7
From: Mazon, IL
OK, I finally had a chance to run around for about 150 miles. It seems to idle better, but it still smokes excessively at startup. (goes away after warming up). Still gives a code on the contribution test for #2 and #8. Also show P1316 for the IDM. All of the wiring to the valve covers has been tested back to the IDM
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Laughing Gas
Joined: Jan 2005
Posts: 920
Likes: 7
From: Mazon, IL
HA. My project keeps going. oil cooler blew today, so after I took care of that and degreased the cooling system, I messed around with more testing. Buzz test sounds fine. Drove another 100 miles or so, and #2 still fails. #2 perdels bounce between 1 and 4.5. I also have a miss that is easily noticable at high idle. Didn't notice that earlier, but it may have been there all along.
It's a Van Gogh
Joined: Feb 2010
Posts: 7,795
Likes: 1,326
From: Elk Grove, CA
What injectors did you install? Please give the details, not just "remans from Vatozone".
Also (what the hey) is the harness to the 42 pin connector rubbing on the driver side valve cover?
Also (what the hey) is the harness to the 42 pin connector rubbing on the driver side valve cover?