EGR Question

I have a 1986 Ford Econoline 350 with a 460 engine. It is a motorhome with approximately 37,000 miles. It starts good, it runs good most of the time but sometimes when I come to a stop the engine is shaking and rocking real bad, it feels like it wants to shut off. I ignore it and drive on and it seems to go away. Sometimes when I'm actually up to crusing speed of 55 mph I feel a slight surge. Lately it will idle ok and accelerate ok but when I'm driving between 10-20 mph I can now feel the surging has intensified. When I took the vacuum line off of the EGR valve and put another vacuum hose onto the actual hose that I took off of the EGR the engine RPM went up and smoothed out. Understand I was only touching the tips of the rubber hoses together when this happened, the EGR valve was not connected at all. I'm confused I'll take anything you got.
P.S. When I put the same live vacum hose to the EGR valve, it shut the engine off.
Do you
have the same problem?
Monday, September 3rd, 2007 AT 2:35 AM

1 Reply

It shuts the engine bcuz you have a full manifold vacuum -normally the EGR is provided with a ported vacuum. Meaning above the throttle plate and as you increase the throttle opening the vacuum will gradually increase.

To figure the correct vacuum above throttle plate you need a vacuum gauge-disconnect a vacuum hose above the throttle plate connect the gauge or use your finger and feel for vacuum-you shouldn't have a vacuum, if you got this Tee-in the vacuum hose at the EGR with this nipple and the disconnected hose this will solve your problem.

I hope its a Carb system that's what I gave you.

My type of engine 460 in an F250 75 body w/dual tanks.
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Monday, September 3rd, 2007 AT 3:53 AM

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