Low vacuum low compression ruff driving overworking the turbo

[clipto]

Friends car has about 10 vacuum and rides like crap had to drive 35mph on the freeway and won't go over 3000rpm. Did a compression check last night #1-3 cylinder is at 120psi and #4 is at 145. Was fine just a few days ago. What could it be? When going up hills the turbo gets worked really hard and causes temp to get to 220 degrees. No boost leaks timing seems fine up on the cams gears idk about down by the crank. Egr is blocked off and running a gm maf. Maf seems fine and cleaned it. Any idea's thx. Only check engine light was for coolant temp sensor we checked the wiring and it's good. Could temp sensor it self be bad but even still that wouldn't cause low vacuum. Only think really on vacuum is the bov and afpr. On a side note is it ok to run the mbc to the intake manifold or should it be on the compressor housing or lower intercooler pipe for positive results of boost control.

 

[BoostforBreakfast]

mbc is good on any possitive pressure source (comp housing, intake mani, etc). possible blown head gasket? have your checked the coolant while the engine is running.. is it bubbling? did you do the comp test with the engine up to operating temp? have the cams ever been swapped/changed/taken out? maybe it slipped the dowel. The dowel on the cams is ONLY to line them up, it cannot take a sustained load. He could of also damaged his woodruf key on his crank.

 

[clipto]

Stock 94 1g 7 bolt 106,000 miles coolant seems ok I'll check it. Cams stock not touched. You can hear a noise when the engine is running like something is loose spinning raddling.

 

[BoostforBreakfast]

u check for boost leaks also? try unplugging the MAF and see if anything at all changes. Is the engine vibrating at all?

 

[clipto]

zero boost leaks holds 20+psi been doing numerous boost leaks all week. Yes the motor is shaking bad it barly wants to run but it does.

 

[BoostforBreakfast]

does the loose/spinning/rattling sound occur all the time when the engine is running, or does it change/go away/get louder with different rpm/loads?

 

[clipto]

You hear it at idle from when the car first turns on and then gradually gets louder as the rpms increase.

 

[DeadlyScone]

does the loose/spinning/rattling sound occur all the time when the engine is running, or does it change/go away/get louder with different rpm/loads?

Yes to this. I tried starting it today ran 1 in/hg for 10 seconds and died. Doesn't start now.

does the loose/spinning/rattling sound occur all the time when the engine is running, or does it change/go away/get louder with different rpm/loads?

Yes to this. I tried starting it today ran 1 in/hg for 10 seconds and died. Doesn't start now.

 

[clipto]

...

 

[Spanky_DSM]

I know my input aint much, but what about balance shafts/ rod bearings?

I spun one about 2 weeks ago and it barley wanted stayed on and vibrated erraticly. Replaced them and it was smooth as butter..

 

[clipto]

I was thinking to look all at that but will just have to v wait to tare into it.

 

[Alpha]

I know my input aint much, but what about balance shafts/ rod bearings?

I spun one about 2 weeks ago and it barley wanted stayed on and vibrated erraticly. Replaced them and it was smooth as butter..

+1 seems legit

 

[DeadlyScone]

So the thing is, it drove and pulled fine. Then all of the sudden vacuum started getting lower and the car was a little jerky driving normally and got rich under boost. Re adjusted the tune a little and it felt better under boost but didn't pull like it did. Fast forward a week and now vacuum is at 12 in/hg and is bucking under normal driving and hits a wall under any boost. A few days later vacuum is at 10 in/hg and car is very difficult to drive and will not go past 3k rpm.

this sound like a spun rod bearing, hg, valves, valve seals, piston rings? Keep in mind I had 120, 120, 135, 140 compression. I don't know yet if my lower timing marks line up. Also iam going to be doing a leak down test when I can.

 

[Boostdriven]

If you have a bad coolant temp sensor it will make your car run rich and shitty but that still don't explain low vacuum. A broken balance shaft belt will make your engine shake but it should not effect the performance of the engine. It's possible that the timing belt skipped a tooth or two. You can check that without pulling the bottom timing cover off. Turn the engine over to where its at TDC so the mark on the crank pulley is at the TDC mark on the timing cover, then look at your cam pulleys and see if the timing marks line up there. Of course make sure that pin holes on the cam pulleys are to the top like you normally would have when you set timing. If the timing belt did jump a tooth that will also effect your base timing and in most cases it will jump in a way where your base timing will be retarded which will make your car run really weak and rich.

 

[GPTourer]

And you already ruled out a bad head gasket? Sounds like all the symptoms to me.

 

[clipto]

If you have a bad coolant temp sensor it will make your car run rich and shitty but that still don't explain low vacuum. A broken balance shaft belt will make your engine shake but it should not effect the performance of the engine. It's possible that the timing belt skipped a tooth or two. You can check that without pulling the bottom timing cover off. Turn the engine over to where its at TDC so the mark on the crank pulley is at the TDC mark on the timing cover, then look at your cam pulleys and see if the timing marks line up there. Of course make sure that pin holes on the cam pulleys are to the top like you normally would have when you set timing. If the timing belt did jump a tooth that will also effect your base timing and in most cases it will jump in a way where your base timing will be retarded which will make your car run really weak and rich.

Already checked the timing up top and is lined up, the dowel pins are in the cam holes.

 

[Boostdriven]

Already checked the timing up top and is lined up, the dowel pins are in the cam holes.

Timing belt will usually skip on the crank pulley and not between the cam pulleys so the cam pulleys will still line up but the timing in relation to the crank pulley will be off.

 

[clipto]

Timing belt will usually skip on the crank pulley and not between the cam pulleys so the cam pulleys will still line up but the timing in relation to the crank pulley will be off.

I know we will dig into it and look when have time to bust otbout to see what's going on down there.