I opened up the exhaust and now the air intake. my new problem is, now at a quick rev up to 35oo rpm, I get a backfire that just about breaks windows. Would this be a timing issue or what? I was going to check the timing this weekend but, figured I would ask first. thanks.

 

bonestock,

As a new owner of a '97 F-250 SCLB 4x4 with a 460 with 5spd ZF, who wants to do headers eventually, I'm interested in your problem.

I understand that the vast major of our 460 F-250s were SD, not MAF, and that SD has a limited capacity to adjust to breathing mods., as compared to MAF.

So...I'm wondering if you've exceeded the injectors' ability to add enough fuel for the proper air/fuel mix? Is it a backfire on the "overrun" (after you let off the gas) or just as you wind up to 3,500? If it's on the overrun, I'd suspect a lean condition.

Does it also stumble upon accel? If so, again, I'd suspect a lean condition.

Does your engine temp. run higher than normal? When my tank selector valve was starving my '88 Big Six for fuel, the temp. went from a low (normal) temp to almost maximum temp--while attempting to idle in a parking lot!

Keep an eye on the temp for unusual behavior--if it's a lean condition, don't drive it--only damage can result, IMO.

I should add I am not a tech--this is just my "shade tree .02"--value accordingly.

Best of luck,

BigSix1

 

BigSix1,
first of all, thanks for your intrest. I've had some backfiring issues in other vehicles before and was able to fix them rather easily. This one, stumps me. Temperature runs just above half way religiously all of the time, unless I'm pulling a load up a long, long, long hill. the back fire occurs after leaving off the gas and the rpms are allready half way back down. what stumps me, is after it backfires, it hesitates to idle very well until you low rev the engine a few times. I run this truck as a semi daily driver and also run in a few truck pulls through the summer, so I am just looking for a few easy slightly off stock mods to do to it, just to compete a little more. Cost wise, I am guilty of running 87 octane in it a lot. My truck is also an automatic, which I'm still deciding if I like. I don't think it is a lean issue but, I could be wrong.

thanks