Backfiring after new headers
 

Just installed Edlecbrock TES Headers and Y-Pipe... 3inch catback already on car. I don't think its the headers fault, but, the car runs VERY VERY rough... Idles very very rough and backfires like popcorn even at idle. Sounds like it is coming out of the driver's side header but i could be wrong. Any ideas? also installed new spark plugs Bosch Platinum (same as was in before the install) and I also have accel 8.8 wires and accel cap and rotor (also previously installed) After checking the firing order i yielded no results.. if anyone has a diagram of that or any other great Ideas I would appreciate it... 88 IROC 350 TPI. Had headers on it before but they were leaking badly.... Please send any ideas... Car is rendered useless for now =(

AceIROCZ

If it's backfiring through the exhaust then you need more fuel. I tried explaining this to some other guys on here, but they refused to believe me. You are running too lean.

You've increased the airflow through the engine, but not the fuel. You have to maintain at least a 14.7:1 mixture, or a lower ratio such a 13.8:1, etc.

Whenever you lean out the mixture, the plugs, valves, ex. manifolds/headers, etc., become very hot. This is what causes backfiring through the exhaust.

If it was backfiring through the TB/Carb, then it's running too rich. That's what I couldn't get the other guys to understand. And some of them have probably never touched an idle mixture screw. :rolleyes: Let alone changed jets.

AJ

not to sound like a total idiot but would that do it constantly even pretty much during cranking when the motor starts... shouldnt the tuned port provide enuff fuel to not do that or atleast close.. i had header on it before and all the other parts.. is there an ything i could have knocked off the side of the motor that could be doing that.... Still learning about a lot of this stuff.. many knowlegable friends. When i say backfiring like when u make popcorn im not exaggerating...

hey have u ever thought it could be the plug wires. becuz u said u replaced the plugs. maybe u crossed 2 wires. becuz when me and my brother did a tune up on a neighbors vette. we did the plugs and my brother crossed the last 2 wires on the passenger side.(even though i had them layin at the right plugs). go thru thew plug wire order and see if u mixed 2 up on the drivers side. maybe that will help.

AJ_92RS would a inconsistent fuel flow rather then a lean problem cause that
this way you have it running lean to make things hot but then have a little rich in htere to give some unburnt fuel in the exhaust?

other things you can check is for exhaust leaks.

hey have u ever thought it could be the plug wires. becuz u said u replaced the plugs. maybe u crossed 2 wires. becuz when me and my brother did a tune up on a neighbors vette. we did the plugs and my brother crossed the last 2 wires on the passenger side.(even though i had them layin at the right plugs). go thru thew plug wire order and see if u mixed 2 up on the drivers side. maybe that will help.

Can i get a good description or diagram.. i went over them and i think they are right.... i have the firing order but not sure as to the layout on the distributor.... i assume it goes counter clockwise from the bottom right...
350 TPI 88 IROC w/ accel cap and rotor

did u take any plug wires off of the cap? if not then just get a chiltons or hanes book i think. and they should have the correct firing order on the cap. then just trace each wire to each cylender. and each plug wire should go to each cylender and if any r messed up then theres ur problem.

I would agree with everyone else get a Chiltons and check for crossed wires, also have you checked for a bad wire?

Hmmm... checking them now.. will tell u the results.. i think the sides are mixed up.. .strange how it may have started... going out now to retry the wires... Brrrr.... 5 degrees in the yard is not fix your car weather.. thanks a lot for the replies all... Haynes does NOT have the diagram by the way =(

make sure u find the right plug wires that r mixed up. becuz i did a tune up on my car while ago and i had plugs crossed and it started but after i figured out which plugs went where , sum how i shorted out the entire distributor andhad to take itto a machanic becuz i didnt know when happened. i replaced everything to find out that i shorted the entire distributor and it costed me about $500 to get it all fixed.

i had same problem...had a vacuum leak... running lean..but....before that ..the car would run like it had a lumpy cam ....it was awsome..but.....i was stumped.. days of work...............finally the LAST thing i checked was the firing order....number 2 and 4...switched..................i've learned from that to check the small stuff...first.....

Rob.... mine still does it on the down rev..but... lack of backpressure blah blah blah