Ford 460 timing

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Jul 3, 2015 | 03:16 PM

#16

Tkc432

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From: Windsor, California

Here's a thought .... could all this be caused by a faulty EGR valve? Seems to happen only after I have taken the truck up to hwy speed for a while. No issues if I just drive the truck around the block staying under 30mph.

Jul 3, 2015 | 03:42 PM

#17

Brnfree

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Quote:

Originally Posted by Tkc432

Yes. Like I said, could be EGR is hanging open or its getting vacuum when it shouldn't.

Simple enough to disconnect the EGR vacuum line, cap it, and take it for a test run. Only down side is it might ping a little under light acceleration at highway speed. But if that eliminates your idle problem you've isolated it down to the EGR.

Jul 5, 2015 | 11:38 PM

#18

Tkc432

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From: Windsor, California

Back from my trip to the hills for the 4th. I like to be as far from town as possible on this particular holiday.
Anyway ... I disconnected the EGR line and capped it prior to heading up and low and behold the problem disappeared completely. So .... I have a faulty EGR valve. Now .... my question is how long can I drive around without it connected before I replace it? Will it cause any issues? I am way short on funds at the moment after the new carb so it will likely have to wait for a month before I can replace it so just wondering if I will do any harm driving around with it plugged. Truck runs great without it .....but I need to pass smog in October so gonna have to replace it before then.

Jul 6, 2015 | 06:50 AM

#19

Franklin2

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From: Virginia

How do you know the valve is faulty? You unplugged the vacuum line and it shut and it runs fine. You plug it in and apparently it's opening when it shouldn't. That's not necessarily the valve's fault. Could be but maybe not.

Jul 6, 2015 | 02:05 PM

#20

Tkc432

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From: Windsor, California

Hmmm now I am even more confused. I thought I had it figured out. What else could it be then if disconnecting the EGR cleared up the problem?

Jul 6, 2015 | 03:06 PM

#21

ctubutis

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From: Denver Metro Area, CO

Could also be a plumbing problem to the EGR valve, something might be/might not be telling it to open/close at the right time... those VCVs play an important role in that...

Jul 6, 2015 | 03:17 PM

#22

Tkc432

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From: Windsor, California

Well ... sounds like I have more diagnostic work to be done. Can't work on it today ... busy with other things. However, anybody know the answer to my other question .... will leaving the EGR disconnected until I can afford to fix the issue cause any harm? I doubt I will be able to tackle the repairs (cost) for at least 2 weeks. Don't want to cause more damage to the truck in that time frame while running with the EGR disconnected

Jul 6, 2015 | 06:14 PM

#23

ctubutis

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From: Denver Metro Area, CO

The EGR is supposed to operate a 2,000+ RPMs only when the engine is warm; with it disconnected, you may experience pinging under loaded acceleration e.g. climbing a hill in top gear.