Stuttering and backfiring

[Twinturbo120]

Well today my car decides to stutter and backfire, I got ####ing scared as shit. It was working fine the past could of days, until today. I checked my plugs and they are fine (gap is fine too) I don't know about the wires though, could this be the cause?

The car would work for a good 10 mins and then out of nowhere it would stutter and backfire, doesn't matter what gear I'm in either. I noticed it happens a lot above 1.2k RPM.

 

[98420a]

have u checked ## injectors. sometimes the can clog and cause a misfire. check to see if u hear all of them opening and closing.... u can also unplug one at a time to rule out if one is bad. same with the plug wires. id invest in a good spark checker, got mine from matco, but the sell em at the parts store to. then ull know what you are getting for spark. oh and check fuel pressure. if its doing that at a higher rpm(other than idle) could be a pump or blockage issue aswell

 

[Twinturbo120]

have u checked ## injectors. sometimes the can clog and cause a misfire. check to see if u hear all of them opening and closing.... u can also unplug one at a time to rule out if one is bad. same with the plug wires. id invest in a good spark checker, got mine from matco, but the sell em at the parts store to. then ull know what you are getting for spark. oh and check fuel pressure. if its doing that at a higher rpm(other than idle) could be a pump or blockage issue aswell

It wants to stall in idle (like I said not all the time), guess I'll have to check the injectors.

 

[romeen]

I agree that it sounds like a fuel issue. Compression test and verifying correct timing are also a good idea and they are easy to do.

 

[Twinturbo120]

I agree that it sounds like a fuel issue. Compression test and verifying correct timing are also a good idea and they are easy to do.

I did a compression test already, apparently its good. I'll have to check timing tomorrow >.<

 

[98420a]

Im not the best with turbo builds, but it may be a slight boost leak aswell. It would probly be more present durring a cold start. I would do a leak down test just to be on the safe side.

 

[Twinturbo120]

Im not the best with turbo builds, but it may be a slight boost leak aswell. It would probly be more present durring a cold start. I would do a leak down test just to be on the safe side.

I already found a boost leak but it didn't fix the problem.

 

[98420a]

Then I would say look into the fuel and spark side. And as mentioned above make sure timeing is still right. Skipping one tooth can cause this aswell. And if u skip one tooth you can skip more... Im sure you know what that means..

 

[Twinturbo120]

Then I would say look into the fuel and spark side. And as mentioned above make sure timeing is still right. Skipping one tooth can cause this aswell. And if u skip one tooth you can skip more... Im sure you know what that means..

Yeah But if I skipped timing wouldn't my vac be 10 or less? I'd have pretty bad compression too, which I don't. We'll find out tomorrow

 

[98420a]

Depends, do you have adjustable cam gears or the stockers? If yours are aftermarket then it may only be a few degrees at most. SO you might not notice and vac advance. and compression can go both ways depending on the tune and cam timing. Let use know what you find tomarrow. Id be glade to help.

 

[Twinturbo120]

Depends, do you have adjustable cam gears or the stockers? If yours are aftermarket then it may only be a few degrees at most. SO you might not notice and vac advance. and compression can go both ways depending on the tune and cam timing. Let use know what you find tomarrow. Id be glade to help.

Stock cams, I checked the timing and its fine. I took the liberty of getting new plug wires and still hasn't changed. I need to check my injectors now. Gosh I finally put in a new water pump and now this shit happens. I can never drive my baby

 

[fonzi90Tsi]

I know how you feel. I finally got my car all out together to fnd out I am having some sort of clutch problem. :-(

 

[Twinturbo120]

I bought a stethoscope to listen to the injectors. Haha #4 injector is being very very bad. It didn't "click" as nice as the others and sometimes it would fade and even stop clicking for a brief second.

 

[98420a]

Im glad you found your problem...

 

[Twinturbo120]

Im glad you found your problem...

Yeah, should I buy new 450cc's or used one guys?

 

[fonzi90Tsi]

I would get used if its from someone you trust. Otherwise new.

 

[Twinturbo120]

I would get used if its from someone you trust. Otherwise new.

I don't know how reliable people on these forums are >.>

Anyway, I checked the primary and secondary coils just to make sure they are good, and they are. Except the "primary" doesn't give me any readings, maybe I'm not probing it right

UPDATE: I got my injectors back from being cleaned. They gave me a chart with how they performed before and after and all four are running great. So now I have to check the fuel injector connecter itself to see if there's a possible issue there. And there's a tuner challenge tomorrow (-.-)

 

[Twinturbo120]

Hi everyone, I would just like to report that it wasn't the injectors. It is in fact the backplate of the crankshaft sensor. It was bent and damaged the sensor itself, causing me to backfire and stutter like a bi*** Anyway, test drove here today and shes better then new! Even idles better =D