Constint missing/backfiring/intake backfire.?!?

[stagefumer11]

my l20et is currently being a bit of a tempermental peice of equipment.

 

When hitting full boost. 10psi; the motor will miss. backfire. and backfire out the intake.

 

The backfires are happening at the same time. intake and exhasut.

 

I currently have minimal mods. noting major. and with these mods ive had them in the car over a year. and this problem has arisen a few months ago.

 

Ill start from the beginning.

 

 

Car W.o.f Ran out. so i parked the car up for 2 weeks. it was running fine before hand. 2 weeks later i set to work on fixing the rust problems.

I removed the battery and proceded into cut out major rust area's ( battery. drip rails. lower arches. )

 

i put it all together to go and get my patches welded in. hooked it all up.

Now this is where it started.... It didnt start freely. a bit hesitint. but then ideld fine. Let it warm up for 5 mins or so. then set off down the road. Now.... 3k bang car dies. 500rpm drop off and it comes back into life. at this point ive nearly had enough problems with the dam thing. one thing after another..

 

I limped it around to the welders place 40kmph was my top speed.

AFter welding in new plates ect. we both started to find out what the problem is. Noticed the B.o.v was to loose and was opening up under throttle. This moved the Cutting out problem to 5k.

 

after thinking it was a fuel problem, i went and got a second hand Fuel pump out of a late model Merc V8. A very high flowing bosh unit. unsure on what the flow rates are. but much higher that the original.

 

Replacing the fuel pump made no diffrence.

 

now this is what ive gone thru to try and find out.

 

Plugs been repaced 4 times. and gaped.

Leads tested and were fine.

All intake in front of throttle body was removed, cleaned and inspected. new clamps.

Turbo compressor housing removed. inspected turbo. "fine" for 20 years old

 

striped coil harness back and checked for any deterioation. all fine.

Removed all injectors. cleaned, cleaned plugs, and checked harness again.

Dizzy cap fine. rotor fine.

Umpluged o2 sensor. still the same.

Unpluged the knock sensor. still the same.

Unpluged the tps. still the same.

 

Got to the point. of not knowing what it was. so i sent it off to the local mechanic. he notied that my dizzy was advancing and retarding erraticly. and narrowed it down to a stuff water temp sensor.

 

they returned they car said it was running fine. which it was. but only running 5psi. which is dam SLOW!. wound it back up to 8 psi and it was better. but power was very uneaven. and missing,

timing was advancing and retarding.

Disconected the knock sensor to see what it would do.and it all came right. but then at 5k it has a miss and a backfiring problem.

 

Thinking it was overfueling up top i wound it up to 12psi. and then it continued to do what its doing now.

from 3k onwards on full boost it will miss, Backfire out the exhaust and intake. and run overly ritch. and hardly proceding anywhere.

 

after my mate had the same problem the other night. he thumped his ecu and moved the harnes around. and it ran fine again.

 

Ive just currently Resolderd all the soldir joint in the ecu. to see what would happen. and all i can say. is, its the same.

 

Currently all sensors are pluged back in. and nothing has changed.

 

My mods are.

 

2.5" exhaust.

Adjustable Acuator arm. Used to run 15psi no problem for over a year

Rebuilt head. (FActory settings)

pod filter.

Intercooler.

B.o.v in front of the throttle body.

 

http://img11.photobucket.com/albums/v35/Munkvy/?start=all

 

Thats currently what state it is in now. the bov has been moved with a larger outlet to stop backspooling. and thats it.

 

Ive been informed that i could have a Craked Compressor housing which has knowing to do these same symptoms on rb's but mine doesnt have a crack.

 

Any insite?