Looking for input on my current problem.
Have a 93 class A moterhome, (Coachman) w/ 460. Installed the Banks Power Pack, (Headers, exaust (no cat) ram air intake) When in cold weather, and I let of the gas I get a very impressive backfire through the exaust.
The Banks guys said to look at the air diverter valve ??
Any thoughts??

 

look for any sort of exhaust leaks... like header gaskets, collector gaskets, egr, etc.....

 

Still looking for answers, I have a bit more data now.
460 in a class A RV, Banks ram air intake and exaust system. back fires when decelerating, burns very rich when started (more when cold).
Found the EGR tube (from the exaust man.) cut off and crimped shut.
What effect will this have??

 

Scott,

I'm a little late in this response as I haven't been on the boards for awhile, but the EGR tube being "cut and crimped" is going to give you some big problems. In fact, I'm suprised you didn't describe driveability issues (surging, bucking, hesitation) in addition to the backfiring. The computer is modulating that (EGR) valve to try to blend exhaust back in with fresh intake air for emmissions and warm-up purposes, but in your case it's not doing anything and as such the mixture going into the cylinders is not at all what the computer thinks it is.


Having just recently put Banks headers on my truck I have a pretty good feeling your EGR tube was ruined in the process of removing the original exhaust manifolds - I know mine was despite tons of penetrant, heating things cherry hot, etc. You will be happy to know, however, a replacement tube was only $23 from Ford, and it only took a day to get one. It's still going to be a tough job, though, just because all the fittings are rather large and inaccessible -- Maybe an RV will be better access than a pickup though.

I have to wonder what's plugging the hole in your Banks header where that tube should be connected?!?!?

Hope this helps - Good luck!

 

My 93 460 runs great with the EGR not hooked up, Just make sure you unplug the vacuum hose from the EGR and put a bolt in it.

 

Has your gas mileage dropped? Are you running rich all the time? If so, you may want to check for a bad ECT sensor, bad fuel pressure regulator or leaky injectors.

-john

 

if that egr pipe isnt crimped off tight it will cause vary impresive backfires. But if the motor is computer controlled rather than bandaiding things, it would probly be easier and better to get a new egr pipe.