vacuum problem

[chrisfullwood]

i have a 90 galant gsx, with a vr4 turbo motor, 2g mas, 550cc injectors, safc2. set at zero correction. it has a 255 walbro pump, and stock FPR, till i have the cash for a good AFPR. so burns alot of fuel.
egt gauge. at idle has always been 750-800 degrees F. never overheated, has an oil leak around the oil pan, but its never gone below the mid point for more than a day.
out of no-where the headgasket went
have previously had problems with the timing, and the tension adjuster etc. but that was 2 months ago, re adjusted the tensioner everything seemed fine, it ran good, i checked the compression back then and it was 145 across the board.
dont have any way of checking the knock on it, i can only assume with the amount of fuel its been burning, that it should be ok, the engine hasnt seen more than 12 psi boost. the vacuum used to be about 16" at idle.

The compression prior to replacing was
1-145
2-145
3-120
4-100

replaced head gasket now, it has fluctuated which i find odd, previously cylinder 2 was 150
1-150
2-125
3-125
4-150

car will start and if given gas will run fine. at 2000 rpm it has 10" vacuum.
i had problems aligning the cams, it seems where the alignment marks are dont line up, if the belt is off and you try to line them up, there natural resting point is 1-2 teeth off.
i tried lining them up properly and got compression readings as follows
1-120
2-120
3-90
4-30
so i put them back, and they are the same as above.
ive tried messing with the timing and it is jumping around, in a regular pattern to try to get a good idle.
it needs about 4-5% throttle to keep the car running. ive set the idle previously and it hadnt changed.
plugs were out of gap, so i fixed that. i cant find any apparent vacuum leaks, but i dont have anyway to do a boost leak test.
any help would be awesome. im trying to get it running for tomorrow (2nd day, no car. wife and 2 kids...... this is my daily driver sadly. idiot crashed into my old daily.

 

[Bodack]

Your "vacuum leak" could be a faulty IAC valve. I know what you mean about the cams turning when you pull the belt off though. I thought I was at TDC when I pulled mine, but I was wrong. I had a friend help me hold them in place while I put the belt back on. Good luck.

 

[chrisfullwood]

i got the cams re-aligned, it was a nightmare getting it all done. but its done. had to tweak with the timing a little to get a good idle out of it. still seems to have a vacuum leak, the engine tries to die with the brake on hard when slowing down.
also the egts are higher than they used to be. ive started messing with the safc2 correction settings which has helped, i need to pull more fuel though i think. currently at 8% at 1000rpm (doing this gradually as i never got to tune it before it was built with all its goodies)

 

[freshlane]

+1 on the IAC. Yea the timing is a pain in the az also

 

[chrisfullwood]

i checked it a few months ago, i guess its time to check it again, what sucks with mine more so is that the previous owners hacked the harness to pieces and trying to find the connector that you use to reset the idle ...so far ive been unsuccessful. i have a knock sensor wired to some wire...... and another connector hanging. and because i dont have a logger i really cant tell what the timing is doing, as im experimenting....
quick question
since the headgasket went...my turbo timer doesnt keep the engine running. everything else works on it, but as soon as the key is turned its all off.
any ideas as to why? havent started tracing the problem yet, just curious as to ideas.

 

[toybreaker]

It's interesting how your compression numbers fall in the order you're checking them.

Did you re-check the low cylinders?

Either your battery is running down...

Or, you're washing the cylinder walls down with fuel.

You can unplug the injector resistor on the firewall to prevent fuel from being injected while cranking. The fuel will wash the oil off the cylinder walls, leading to lower compression readings on the gauge.

 

[chrisfullwood]

i rechecked the low cylinders and generally they were 5 psi higher.
while i was cranking i removed the mpi fuse so it shouldnt have been putting any fuel into the cylinders. i did the add oil trick, and my compression went up to like 160 psi in each cylinder. so i figured it might be because the cylinders were dry. im going to work on it some more this weekend to try to get the idle better.
so ill check the compression again. given that its had some drive time.

 

[chrisfullwood]

just checked the isc. pins 2-3 and 4-5 show nothing at all, pins 1-2 showed 27.8 and 5-6 showed 27.5 ohms.
so i guess i need one of these huh.

interesting update.
put the isc back on, replaced the turbo outlet gasket, found one ic hose was a little loose, fired right up, held at about 1100 rpm, tinkered with the biss screw, idles aroubd 800, drive it, i gave it about 75% throttle in 3rd gear, got 15psi boost, egt temp didnt go above 1200°F im messing about with my safc2, currently if got it starting at 12% correction at 1000rpm, then tapering down. im having to do this as i go, i never got to do this from a stock turbo car, it came with all the goodies, so
what i really need is a logger, but to broke right now.

any other suggestiongs or ideas are always welcome.
thanks

 

[chrisfullwood]

New issue same type of thing...

previous, less than 500 miles ago the head gasket went.
was fixed.
Now Acting as though the headgasket has gone...but

compression
150+ psi in each cylinder.
was blowing lots white/blue smoke.
car didnt overheat at all.
have checked the exhaust manifold and there doesnt appear to be a whole lot of moisture, maybe a little in the 2nd runner. but not for as much coolant had to have been burnt.

any ideas.?
i found quite alot of oil from in the intercooler piping, from the compressor out to the in side of the intercooler. would the turbo going out burn coolant?

thanks.
Chris.

 

[dieseltech]

are you using synthetic oil? If you are and your turbo seal is going bad, the smoke produced could be white in color. There are many other indications. Remember antifreeze smells sweet even after it's past the engine. So sniffing around the fumes may lead you to the answer. Obvioulsy don't stick your face in the tail pipe.

 

[chrisfullwood]

i dont think im using synthetic, im just using regular 5w30.....
i think the turbo seal might be whats wrong. ive already got the engine partly tore apart.....i think im going to get my head skimmed and the valves and stuff all checked to make sure. its only like 50 bucks.....
seeing as i dont have enough for a turbo i might as well get it done.

 

[1gdsmraider]

Stems/Seals are a good culprit of this, glad you're having it inspected as for the turbo... You'll know when it goes... I was a moving smoke screen for a good 15 seconds before I noticed it after I stretched the clips' legs awhile back

 

[chrisfullwood]

yeah i was laying down a smoke screen the whole way home, maybe 2 miles...
it was awesome....if it was summer there would be no mosqitoes here.
anyway i guess ill have to go with the head and maybe a new turbo....
unless anyone has any suggestions.

thanks
Chris