Still more problems! Backfire only after driving

[mizuboi]

is their a disadvantage?
i did it actually to try and solve the original backfiring issues

 

[IJ.]

is their a disadvantage?
i did it actually to try and solve the original backfiring issues

Why would you think it would cause a backfire?

 

[mizuboi]

well initially the backfiring was during cold start idle so i thought that possibly it was bad and or leaking so was a source of the extra fuel hence causing the backfire but i've since been proven wrong

 

[IJ.]

Backfires usually aren't from a rich condition.

 

[mizuboi]

they are usually from a lean condition? is that why when i put on the lexus maf it stopped backfiring at idle? but what i don't get is why it fixed the stumbling at low rpms and made the intermittent misses farther and fewer between

 

[IJ.]

Usually a timing or vacc leak issue, sometimes tight valves will do it before burning them and doing it all the time.

 

[mizuboi]

so what do you propose i do? i know you are like one of the go to guys on this forum.

 

[IJ.]

Buy a can of aerostart and with the engine idling carefully spray some around the intake gaskets and see if the engine note/rpm changes that will confirm/rule out any leaks.

 

[mizuboi]

will do that tomorrow! and really thanks for all the info!

 

[IJ.]

Welcome!

It's just a case of thinking about what it's doing then doing the correct tests to diagnose it.

 

[jetjock]

A coolent temp sensor not being connected would cause this problem. Whats happening is the ECU is staying in warmup mode which is adding a lot more fuel then the engine needs when it is warmed up.

Not that it matters any longer for the OP but in the interest of accuracy, when using a stock ECU, that statement is wrong. The opposite is true.

 

[mizuboi]

well any info matters i think because what happens when i have to go back to the stock maf? and all my problems come back haha! hmmm

 

[mizuboi]

okay so changed to ngk vpower plugs and found a boost leak. Fixed those and then re set timing and now she runs like a champ! no hesitation, jerking, it still misses every once but very rarely now. time to get it taken to a ref to get my lights and brakes checked and registered finally and on the road! thanks for all the help guys!