ZachW04Stang

Do you still have you smog pump? Theres something in the smog pump that will cause the car to backfire if it fails. Its some kind of check valve. I can't remember what its called.

91RedGT

got a link on how to do that?

91RedGT

^

aode08

just a second,

i removed my somg pump and no pops, but let me dig in the old books

aode08

You have a roller block meaning you need to adjust the valves right or the pushrods for the lifters will go flying through the valve covers, and or the setup will make no power/ or pistons hit valves


, but you did it wrong yes and I wouldnt drive until you fix this.





A. Starting with #1 cylinder, turn the engine over until the exhaust pushrod just begins to move up.(its the one , right on the exhaust port of the head, yead where exhaust exits into the header).

B. At this point, stop and adjust the intake valve on the same cylinder.

1) Tighten the rocker until you can roll the pushrod between your thumb and forefinger with the SLIGHTEST bit of resistance.

2) At this point tighten between an additional quarter to half of a turn ONLY

C. You have now adjusted the #1 intake valve PUSHROD.

You will now want to turn the engine over while watching the SAME intake pushrod that you just set, it will go full open and then BEGIN to CLOSE. When it is ALMOST closed, stop and adjust the exhaust rocker arm on that particular cylinder. By following this procedure, you are assured that both of the lifters PUSHRODS are at the base circle of the cam and that there is NO additional pre-load applied to them from cam lift at this point. IN OTHER WORDS UR SET

D. You are now able to repeat this procedure on the remaining cylinders.

91RedGT

thanks, have you had this problem before? and can it be anything else besides having to adjust that?

vristang

There are other things that can cause backfires.

Are you running adjustable rockers?
I thought the stock 302 rockers were bolt downs?

I assume you have checked for diagnostic trouble codes?

What modifications have been done to the car when the problem started?




jason

91RedGT

Changed upper and lower intake gaskets, nothing else besides that.

Stanger90

When does this happen? Part throttle or full throttle? Is the engine hot or cold, need a little more info. Also, what type of a setup do you have (heads, intake ect..?

91RedGT

It happens in part throttle, at full throttle u dont feel it at all, it happens when its cold or hot, my car motor is stock besides the mods on my sig.