High CO at idle

Tiny
HEPFNER1
  • MEMBER
  • 1985 FORD F-350
  • 7.5L
  • V8
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
Checking the smog pump and diverter valve and check valve. The diverter valve (EITE-9B289-HA) rattles when I shake it after I removed it. Does this mean the diverter valve is bad?
Also, the check valve seems to be stuck in an open position. I'm still trying to remove it, frozen in place.
Thursday, April 28th, 2022 AT 2:02 PM

4 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,054 POSTS
Yes, the diverter valve should not rattle. Here are instructions on how the valves should work. Also does the truck have any codes? This guide can help:

https://www.2carpros.com/articles/ford-lincoln-mercury-obd1-1995-and-earlier-diagnostic-trouble-code-definition-and-retrieval

Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
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Friday, April 29th, 2022 AT 9:40 AM
Tiny
HEPFNER1
  • MEMBER
  • 3 POSTS
1985 E-350, No cat, No ob2 so no codes. First image without outlet b. This one rattles and seems to be stuck open, as I can blow through it. I would think it would be closed until needed. Also, took off the cross-member pipe that has the check valve frozen to it and I will try to heat that up to loosen the check valve. I can also blow through that. Another question is, how much air is that pump supposed to put out? Doesn't seem to be much coming out. Do you think this is the cause of the high CO at idle? Or the char- canisters being swamped. What else could cause high COs at idle? Passed smog test with flying colors 2 years ago?
Thanks in advance.
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Friday, April 29th, 2022 AT 12:38 PM
Tiny
HEPFNER1
  • MEMBER
  • 3 POSTS
I did not know about obd1, I will check it out.
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Friday, April 29th, 2022 AT 5:33 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,054 POSTS
The charcoal canisters being swamped with fuel will definitely cause high CO. The valve goes bad at the canister causing them to fill with fuel. Check the vacuum lines going to the engine and check the fuel.
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Monday, May 2nd, 2022 AT 2:14 PM

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