back firing at idle

[kccombs]

Well guys id like to figure out what is goin on with my 92 nt to turbo talon. Just got done with my turbo rebuild and put a new frount mount on that was dif size of piping then what i had before. I have 2" going from the outlet of the turbo to the intercooler and the 2" out of the intercooler to a reducer going up to my 2.5" piping that was originally in my talon before the tubro rebuilt. I adjusted my idle on the bracket attached to the intake manifold since before my turbo rebuilt it idled way high and turned my boss screw out alittle bit since it seemed like it may have been in to far but not bottomed out. Could you guys give me some advice on what to look for. Thanls for anything.

 

[92AWDHX40]

Sounds like wires maybe bad check that out. backfiring was my issue with crossed wires.

 

[skatershawn]

Can you give us some more information on your car?
Did you just turbocharge the n/t motor? or swap everything over from a turbo model?
How are you tuning for the additional air thats getting metered?
And im assuming since you rebuilt it, you have new plugs gapped properly?
Also check for a boost leak.

 

[kccombs]

I beleive i need new spark plug wires and it ran good as turbo before just high idle then blew the oil seals in the turbo from my return line being kinked. I still have the nt motor. Just all the sensors and wiring from a turbo and turbo ecu. I think it may have something to do with the biss since i turned it out but im not sure what the stock setting for the biss would be as in how far it should be turned in. Im only running a 7psi spring in my waste gate but since i have a t3t4 turbo i have the boost turned down to about 3 to 5 psi since at 7 on a t3 t4 is alot more air flow and dont have the injectors, afpr and tuning means to boost more.

And it will idle right around 1400. Cant get it to go down and now i have a cel on. And as it was running i pulled each wire off at a time of the plugs and it will get worse. So i dont think the wires could be to bad. But they are about 2 yrs old.

 

[skatershawn]

Has the cars base timing been properly tuned?
Bypassing the ECU, turning the CAS to adjust the timing.
That will effect the idle alone with the biss. You have to kind of play with it to find its right spot.
I'm not sure where the biss was located from the factory, but mine is down pretty far in order to keep my idle about right. But then I also think I have a bad FIAV.

 

[sparky1987]

An exhaust leak could cause back firing too if your running rich.

 

[kccombs]

Thats the only thing that stumps me. It was set right before. I had it at 5 degrees btdc. Then the seals in my turbo went out so pulled it and replced it. But also instead of 2.5" intercooler piping like i did have before i put on 2" intercooler piping. Then after my intercooler i have my 2.5" piping still to the intake mani. Thats all i changed.

 

[skatershawn]

Can you Give more information on the car? Reread my first post (#3) and answer some of those question please.

 

[kccombs]

Can you give us some more information on your car?
Did you just turbocharge the n/t motor? or swap everything over from a turbo model?
How are you tuning for the additional air thats getting metered?
And im assuming since you rebuilt it, you have new plugs gapped properly?
Also check for a boost leak.

Well i had everthing transfer over besides the non turbo block and head. I got the engine remained and bored 50 over. But swaped the resister pack. Ecu. Turbo maf. Gaped plugs. Throttle body. And the fpr selenoid but then unhooked it since its not nessecary to have it. Havent done a boost leak test just yet. I work for the union and been working alot of over time and havent had the time to do it yet. Hopefully this weekend. What do i need to set the timing at so air does get by the valves?

 

[Eeeeky]

Replace the plugs, and possibly wires first and foremost. I had the same issue after a 6 bolt swap, this cleared the issue.

 

[4G63LOVE]

I got the engine remained and bored 50 over.

i ran 20 psi on my stock block with stock injectors, fuel rail, and intercooler. the only problem i had was hitting the factory fuel cut since i dont have engine management. i would ask the machinist what all he did to your engine as far as did he order new valve train components such as cams, lifters, etc. if it has forged internals and if he reused the stock crank. im actually a machinist so im also curious as to why it was bored .050 unless the engine was in really bad shape because thats quite a bit bigger than stock and that changes your displacement alittle. that and the machinist or whoever built your engine should have timed it correctly before it left the shop. also is it backfiring out the exhaust or intake? intake is lean, exhaust is rich AFR

 

[kccombs]

Replace the plugs, and possibly wires first and foremost. I had the same issue after a 6 bolt swap, this cleared the issue.

Plugs are brand new but i dont mind changing them regardless and i know the wires are atleast 2 yrs old. I wanted to upgrade to 10 mm wites anyways.

i ran 20 psi on my stock block with stock injectors, fuel rail, and intercooler. the only problem i had was hitting the factory fuel cut since i dont have engine management. i would ask the machinist what all he did to your engine as far as did he order new valve train components such as cams, lifters, etc. if it has forged internals and if he reused the stock crank. im actually a machinist so im also curious as to why it was bored .050 unless the engine was in really bad shape because thats quite a bit bigger than stock and that changes your displacement alittle. that and the machinist or whoever built your engine should have timed it correctly before it left the shop. also is it backfiring out the exhaust or intake? intake is lean, exhaust is rich AFR

There isnt really a machenist i can ask. I got it remained there auto zone. They go thru a company in cali. Cant remember the name of the company. I would have to double check me warranty paperwork. I know that all they do is rebuild the cores they are sent. My bottom end is 50 over with stock size cams, lifters. Head wise is stock size. How do you gind out the new displacement from how much your engine is bored?

 

[4G63LOVE]

volume = 3.14 x radius of bore squared x stroke

also if you want to spend the extra money and upgrade Street Tuned Motorsports offers a coil-on-plug setup which is way better than just running bigger wires.

 

[kccombs]

Ive hear of the coil on plug set ups. I was goin to look up the kits for them sometime. Now may be a good time to do that...

 

[kccombs]

Found out my high idle issue. Mbc was turned up to high and must have affected it while idling. So turned it down and the idle dropped

 

[kccombs]

So i was wondering if i have something wrong. Should it make the idle run high like that if you turn the mbc up to high or is something else wrong?