Surging Idle
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Joined: Oct 2000
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Surging Idle
I just replaced my old 4.9L six ('82 F100) with a rebuilt that I bought at a parts store. The engine is now surging during idle and I am not sure how to track down a vacuum problem.
What I know is:
1. Remove the vacuum line from the EGR and it stops surging.
2. I can see the EGR valve stem move in time to the surging.
3. Replaced all vacuum hoses per the sticker under the hood.
What I don't know is:
1. How much vacuum should I be seeing from the vacuum ports on the engine?
2. How do I test the EGR?
3. Where can I get some more of the hard plastic color coded vacuum hose? Ford dealer said they don't carry it.
Thanks for any help
Monte
What I know is:
1. Remove the vacuum line from the EGR and it stops surging.
2. I can see the EGR valve stem move in time to the surging.
3. Replaced all vacuum hoses per the sticker under the hood.
What I don't know is:
1. How much vacuum should I be seeing from the vacuum ports on the engine?
2. How do I test the EGR?
3. Where can I get some more of the hard plastic color coded vacuum hose? Ford dealer said they don't carry it.
Thanks for any help
Monte
Posting Guru
Joined: Jun 1999
Posts: 1,083
Likes: 1
Surging Idle
One way to test the EGR diaphragm for rupture/cracks/leaks is to stick a plastic bread bag over it and twist tie the end closed...tightly. If your EGR diaphragm is shot, it'll start drawing the bag in, just like if you were drawing air from the bag with your mouth. Not real technical, but it works as a quick diagnosis.
