cracked turbo? and a crazy ecu...

[Lasertown]

i didnt know anything about dsms when i bought my 92 laser. it has the 4g63t

the guy i bought it from told me:
it has a bigger fuel pump, doesnt remember size/brand
it has bigger injectors, doesnt remember the size. the brand is on there i can look if it matters
it has a "chipable ecu" and the stock boost gage under the tack is "a rev limiter" after getting a palm logger i found out the stock boost gage shows the knock sensor output. it jumps to around 40 knock when im in first if i dont rev the engine and let off the gas before i start. cel is 43 egr but its not on all the time i read somewhere thats a sign of different ecu?
it has a apexi safc


when i got this car it had a few minor problems, a leaking head gasket, and ran 18 psi. i blew a ring on a piston and took the head off replaced the one damaged piston and had the head rebuilt (all though it still has some valve clatter so i think the guy didnt replace the adjusters)
now i have a boost leak... i think. it only goes to around 14psi and it gets there slower then before. i made a boost leak tester but i have to turn the compressor up to 25psi to get the system to have fifteen pounds and i cant hear or find the leak. oh and now when i go wot a huge puff of light gray smoke come out of the tail pipe but only when i first hit the gas then there's no smoke keeping it in the turbo through the gears.
ok sorry i know this is long. one last thing.
i didnt touch the safc before taking the head off and i dont know if it got reset some how. it wasnt running very good after the rebuild and it showed half the rpms (im 90 percent sure it had the correct rpms when i bought it) found out it was set to 4 cyl instead of two when i set it to two it would barely run so i got a logger and tuned it to run better ( but not great considering the boost leak ) i wrote down the original numbers that were in the safc before i changed anything.

im thinking the smoke is from a crack in the turbo? could that be my boost leak that i cant hear? pieces of piston ring probably shot through my exhaust... i dont know where else they wouldve gone.

whats up with the ecu/knock sensor?

is there a way to figure out how big my fuel pump and injectors are?

Thank you for reading my post any help or insight is greatly appreciated

-Morgan

 

[JusMX141]

Possible damage to the turbine inducer tips, resulting in slower boost being built or less peak boost.

Doubtful there could be a crack in the turbine housing large enough to make a significant dent in your turbo's ability to generate boost. More likely a wastegate issue causing the flapper to hang open a little which results in a pressure loss between the manifold and turbine wheel.

 

[Lasertown]

ok that makes sense. i had a hard time getting the manifold bolts back on, the posts wouldnt stay in the head very well on some of them. ill try new post or maybe a thread repair kit.

is it normal for me to have to turn the compressor up to twenty five psi to get fifteen tho? ive read people using bicycle pumps and that would be impossible in my case.

is the throttle plate right before the intake manifold supposed to hold the pressure? for my leak test i take the maf and the piece between the maf and turbo off and put my hose on the turbo.

thank you so much
Morgan

 

[99gst_racer]

Lasertown - Please use proper capitalization and punctuation when posting in the tech forums. Thanks.

 

[rizzzo29]

ok that makes sense. i had a hard time getting the manifold bolts back on, the posts wouldnt stay in the head very well on some of them. ill try new post or maybe a thread repair kit.

is it normal for me to have to turn the compressor up to twenty five psi to get fifteen tho? ive read people using bicycle pumps and that would be impossible in my case.

is the throttle plate right before the intake manifold supposed to hold the pressure? for my leak test i take the maf and the piece between the maf and turbo off and put my hose on the turbo.

thank you so much
Morgan

You should for sure do a boost leak test, also check the exhaust manifold itself, if it is badly cracked it can cause you to lose some psi as well. Turn the boost down to where its boosting to about 10 lbs right now. Double check that your boost controller is properly installed.

It's better to play it safe until you have it running right.

 

[hubz91talontsi]

Possible damage to the turbine inducer tips, resulting in slower boost being built or less peak boost.

Doubtful there could be a crack in the turbine housing large enough to make a significant dent in your turbo's ability to generate boost. More likely a wastegate issue causing the flapper to hang open a little which results in a pressure loss between the manifold and turbine wheel.

This happened with my brothers aluminum rod 14b car. Took us forever to figure out the problem. Its hard to find a 14b without cracks in the casting in the inside, but this crack was terrible.

 

[AlaskanDsm]

ok that makes sense. i had a hard time getting the manifold bolts back on, the posts wouldnt stay in the head very well on some of them. ill try new post or maybe a thread repair kit.

is it normal for me to have to turn the compressor up to twenty five psi to get fifteen tho? ive read people using bicycle pumps and that would be impossible in my case.

is the throttle plate right before the intake manifold supposed to hold the pressure? for my leak test i take the maf and the piece between the maf and turbo off and put my hose on the turbo.

thank you so much
Morgan

Make life easier to find those boost leaks. Take off the hose that goes to your throttle body and start your boost leak test there. This will help to eliminate a lot of additional possibilities so youcan focus directly on the throttle body, intake manifold, and injectors seals. Then move back to in front of the BOV. If everything is good at the throttle body, then you will have less to worry about. and finally move to the turbo to test the turbo and the intercooler.

 

[Lasertown]

I'm sorry about the lack of punctuation and capitalization.

Well my water pump died today. I have to deal with that first so I can go to work ...not looking forward to putting the timing belt on again.

I will try the leak test starting at the manifold, thanks for the great idea. I don't know how to turn the boost down the controller doesn't have a screw or anything to turn. It's a turbo xs. I think it's hooked up right I put it back the way I got it, one side goes to the waste gate the other is t'd in to the bov and intake manifold.

 

[ChiTownHussla]

No bov should be teed for vacuum. take that out and run it from the waste gate to the j piipe at least for now. that will give you stock boost levels again