power tr unit!?

[blackjdm90]

One day my 1990 AWD tsi started only running on 2 cylinders and mifiring pretty bad and all of the sudden i messed with my power transistor unit and started my car and it got all 4 cylinders running again. and when i hit 12 psi on boost or sometimes less it seems to blow out the spark and misfire. could this be caused by having a bad or weak power tr unit? thanks guys

 

[stevo911]

Got a bad ground? I would check all wires and grounds first chances are the boost has nothing to do with it but the engine moving when its boosted is throwing a wire loose.

 

[DSM1G90]

What you did was made a better connection with the power tr when you took off the plug to it and replugged it back on. Transistor has two sides to represent each side of the paired coils and with you repluggin it back on got that coil section back running again.

Spark plug gap should be .028 to .030. (I run .030 since .028 causes issues..) anything smaller or larger will cause blowout under higher compression.

 

[blackjdm90]

yeah when i started my car this morning it was sounding like a subaru haha so i started moving around wires and the idle sounded normal again. where should i look to check for loose wires of some sort?? thanks!

 

[DSM1G90]

Ignition coil runs in pairs since the each leg of the secondary winding runs each plug.

1-4 is run by one coil and 2-3 is run by the other coil ... and in series.

One plug will fire tip to ground, the other plug will fire ground up to tip and both at the same time.

They fire on both INT and EXH strokes - quite a simple firing operation being distributorless. Motorcycles uses the same paired firing system.

Thus if you got a faulty wire or sorts, the other plug will also be affected - mainly will be a dead plug.

What you did was got the two pair wires back on the correct coil side.

Wouldn't hurt to put new plug wires on your setup. AND to make sure that the coil end of the wire is definitely snug in the coil so it won't arc across to a ground.

Good luck-DSM

 

[blackjdm90]

so with bad spark plug wires it could cause it to make boost slow and have weak sparks? which end up getting blown out by boost around 8-12 psi?

 

[stevo911]

Bad wires cause low spark/no spark which can cause blow out. Think of it like this if you miss one fire you foul the cylinder so if at anytime during boost the spark isnt their that cylinder will flood causing no power to the cylinder.

 

[blackjdm90]

Bad wires cause low spark/no spark which can cause blow out. Think of it like this if you miss one fire you foul the cylinder so if at anytime during boost the spark isnt their that cylinder will flood causing no power to the cylinder.

sounds good to me. Also my spark plug wires are very old too so i am going to try some stock replacement ones from auto zone since i have little money at the moment. thanks!

 

[DSM1G90]

Then, after your Autozone experience, be prepared to buy 'real' plug wires down the road when you get enough cash up front.

Autozone="wal-mart of auto supplies"

If you had a NAPA around there, then you got a good parts house.

-DSM

 

[blackjdm90]

haha gotta love those autozones though? there is a NAPA around here and i was going to order some nice ones next paycheck!