Getting into boost and sputters/back fires

[izzyrslaser]

I have a 90 laser rs turbo fwd 74k original miles. When I get into boost slowly or fast it gets choppy then backfires and bucks the car. It's all stock except a header. Stock boost pressure around 7-9 lbs. Any suggestions? Looked it up on here and got a lot of different threads. Also I have the good olé idle surge but don't know what's causing it for sure. Iac, isc, maf? When I got the car it was running really well for a stock car, now it doesn't boost like it should and won't get out of its own way. Thanks

 

[codym]

I have a 90 laser rs turbo fwd 74k original miles. When I get into boost slowly or fast it gets choppy then backfires and bucks the car. It's all stock except a header. Stock boost pressure around 7-9 lbs. Any suggestions? Looked it up on here and got a lot of different threads. Also I have the good olé idle surge but don't know what's causing it for sure. Iac, isc, maf? When I got the car it was running really well for a stock car, now it doesn't boost like it should and won't get out of its own way. Thanks

Boost/ vacuum leak.

 

[Jazz]

Check your plugs and wires. Make sure the plugs are ngk

 

[Daveregs]

Boost/ vacuum leak.

Yea Im going to have to agree.

Also check your plugs and wires

 

[dsmotors95]

spark plug and wires

 

[DEADKITTY]

+1 to boost/vacuum leak also as stated above check plugs and wires. Also make sure your Wastegate is functioning properly.

 

[izzyrslaser]

I put new plugs in it and noticed the wire must rubbed the timing belt so I'm picking them up tomorrow... anything else it could be? Also someone put the full 2g head on it, should I throw the 1g intake manifold on?

 

[boost97gst]

2g head/2g intake. Dont put a 1g intake on it. The runner ports are different shape. It'll flow like shit

Speaking from experience, bucking, sputtering can be caused by a lot of things. Plug gap, afr, coils, wires, adn even compression. Thats what eventually led me to do a comp/leakdown on mine. i couldnt figure out why i was sputtering in 3rd gear pulls. Afrs were good, new coils, tried many dif plug gaps. You probably dont have a ring or valve problem but that IS one culprit that doesnt get mentioned as much because its much more rare and most people check compression frequently on built engines. It will cause misfires under heavy load in the higher rpms if you have low compression on 1 cylinder compared to the other 3.

Boost leak goes without saying, thats usually what causes it. Im just coming up with things off the top of my head. Theres more im sure.

 

[codym]

I put new plugs in it and noticed the wire must rubbed the timing belt so I'm picking them up tomorrow... anything else it could be? Also someone put the full 2g head on it, should I throw the 1g intake manifold on?

Had that happen before I learned to get a timing cover.
Ate through half of cyl. 4 wire, and I noticed it rather quickly.

If your taking the intake off its a good idea to check the vacuum lines to and from it and the throttle body. A good piece of maintenance to do while you're at that is the intake and t/b gaskets.

Do a proper boost leak test , and make sure all the clamps on the couplers are secure.

 

[Dueydog]

NGK BP6ES plugs and wires gaped at .0028 sounds like the fix. Then leak test if persist.

 

[jbus]

ive had the same problem before with my 2g, she would sputter and back fire and kinda cut out around 7-9 lbs of boost, and i couldnt find any boost leaks. turned out to be my waste gate.