not boosting like it should!

[Angus]

hey i have a 1990 GTR running 2 GT2540R's normally at 20 PSI of boost, it went to the paint shop and all that was parked all winter now today took it out and for some reason it wouldn't boost past 10PSI under load, i fixed the coilpack harness the other day fixed any broken wires and is running on all 6, but for some reason it still back fires and you can here like a small back fire every 4 - 6 seconds when it idles so all in all its running like a p.o.s. and i wouldn't mind knowing why i checked vacuum lines checked for boost leeks, it sounds like they are spooling normally. so other then that can a blown engine cause a turbo not to spool half as much as it should? i should also mention i have an hks electronic boost controller, tried unplugging the vacuum lines that go to the wastegates but gave the same 10 PSI. Also i guess running with half the boost its normal that its slow as hell? input would be great, thanks alot!

[Daryl @ RightDrive]

did you check the intercooler piping?

[Angus]

did you check the intercooler piping?

no...would that explain the the missfires and the backfires?? but it actually makes alot of sense, because at the body shop they removed the like wannabe skid plates or w.e. they are.

[mcfly]

skylines quite often have a stumble on idle without a leak in the piping.

Either way that's you best bet to begin with.

[Angus]

skylines quite often have a stumble on idle without a leak in the piping.

Either way that's you best bet to begin with.

ok i will check it out first thing tomorow...but how about before the engine boosts there is like no torque? or is that just me not used to the turbo lag since its been parked for like 8 months? or that like a sign of boost leak..anyways if the leak isn't there is there a way to check where it is?

[MUNDA]

No, just ceheck the IC piping, im sure you will find one thats popped off.

[Angus]

No, just ceheck the IC piping, im sure you will find one thats popped off.

ok cool...my friend lent me a fog machine...im going to run it threw the intake system and find the leak, if i don't find a leak are there any other sugestions?

[NismoS-tune]

Plugs.

[Angus]

Plugs.

well i just put in 120$ worth of plugs can we rule that out?

[NismoS-tune]

I guess lol. I just tossed it there since I had a similar issue once but slightly different symptoms. The plugs had fouled...

[mcfly]

have you checked the compression yet?

[Angus]

have you checked the compression yet?

nope...i think im going to go "rent" one from canadian tire...

[MUNDA]

It not very hard to take the bumper off, check all the pipes, tighten all the claps... it's a 30 minute job... Skylines are very very prone to haveing IC pipe leaks.

[Angus]

ok so i got a buddy to come by and help me with everything, fixed alot of the problems, still only boosts to 16PSI runs smooth, but almost stalls on a 5000RPM clutch drop in RWD, right now his stock GTS-M is faster on take off then my "500HP" gtr... obviously something is still up, last thing it could be is compression i had access to my friends compression test but when he tested his 4 wheeler is was giving whack reading so i don't want to take a chance with it. so if its compression...how do i narrow it down from there?

[mcfly]

what ecu are you running, injectors, air flow meters, fuel pump?