Numerous issues 1G.

[English_Rugby]

My 91 DSM has been giving me issues for a while now, they are as follows: 1 - sounds like it is missing slightly at idle as if there was an injector issue. 2 - when running, won't boost at all (it cuts out when you rev it to the point of boost) 3 - when running, heats up very quickly.

What I've done so far: - did a compression check, 150 - 155 psi across board, although, the pressure leaked out of the tester at a uniform rate down from this point (I figured a bad tester). checked for combustion pressure in cooling system, there is none, however, the coolant bubbles/appears to boil at idle when it is not hot. The coolant has no oil in it. If it was a HG causing the bubbling, then it'd also have oil - so no HG? I really need to find out what goes on, and my posts keep getting linked to other ones which are beyond the point of useless. Please help me out - I need this to get me to work. Thanks.

 

[Deadspool]

Have you inspected the turbo itself? Perhaps try isolating its coolant lines .

 

[EGLTAWLN]

the bubbles concern me....
do you have to replace coolant after going for a drive? 4g63 can blow headgaskets WITHOUT mixing oil and coolant. if you are replacing coolant after a drive, it is the headgasket or heater core. and a bad headgasket will blow a heater core if not fixed in time.

 

[EGLTAWLN]

you should probably try a boost leak test as well.

 

[English_Rugby]

the bubbles concern me....
do you have to replace coolant after going for a drive? 4g63 can blow headgaskets WITHOUT mixing oil and coolant. if you are replacing coolant after a drive, it is the headgasket or heater core. and a bad headgasket will blow a heater core if not fixed in time.[/QUOTE

The coolant seems a bit lower after I drive, but to be fair, I haven't driven it with the issue apart from to get it home. The coolant color is fine, but it behaves very strangely like there is a ton of air getting through a gasket or just leaking into the system: [ame=http://youtu.be/b0cXz_dpOlE]DSM issues. - YouTube[/ame] I would expect oil in the coolant if this air was coming through the gasket? Thanks for your help again - I really appreciate it. Also, I inspected the turbo - it's fine. Also, what is your opinion on the missfire - could this be caused by the HG or would it be a bad injector or something?

 

[92AWDHX40]

Spark plug wires or coil pack for misfire.

 

[5150DSM]

Looks like the HG to me. I've lost a couple recently and my car acted pretty much the same. Didn't show up on a compression test or combustion leak test at first. Turned out the gasket was blown in between cylinders in one place and straight into a coolant port in another. I chased this for weeks before I finally pulled the head and discovered the truth.
Link to my situation.

http://www.dsmtuners.com/forums/cylinder-head-short-block/447491-another-bhg.html

 

[Techmonster23]

Sounds like a HG to me.

As stated above they can blow between cylinders and other than a bit of coolant burning off through combustion there's no clear symptoms other than overheating. Just helped a friend with a '97 GSX diagnose a similar situation.

 

[Deadspool]

I'm willing to bet a hole has been poked in a fire ring. I'm going to call cyls 1 and 3. Exact same thing happened to me twice. Turns out the ecu that came with my car did not have knock sensing abilities.

Not a horrible job to do at least.

 

[Wildside22]

you can rent a tester from autozone to determine if those bubbles are indeed exhaust.

it looks like this one....

Combustion Leak Detector Kit LIS75500

 

[English_Rugby]

Yeah I am really willing to bet it is an HG now seeing as cooling system holds pressure, each piston holds 155 psi, and the block only has 5 k miles on it. Especially after 5150DSM's post which states about the blown coolant line to turbo which happened to me also - thanks for all the suggestions, guess i've got to open her to see.

 

[English_Rugby]

Okay, so I removed my head and my headgasket is fine... I was able to just take the studs right out with my fingers though... I know ARP say finger tight when putting them in, but this seemed strange - could this have been causing a 'hg leak' without it being a BHG? - they weren't re-torqued after 500 miles of installation either. Another idea, and this is just an idea, my water-cooled turbo - is there any way that internally a seal could have broken, allowing compressor discharge into the coolant return line to my thermostat housing? I am not a turbo tech, but this would explain the mass of bubbles, very rapid gain in heat (my heat temp. sensor is on t-stat housing, where the return line is) and also this would explain why I couldn't boost? (also why my turbo coolant line burst) Thanks for your help and opinions. John.

 

[EGLTAWLN]

what foot/pound number did you torque the ARP nuts to?
when i install my ARP studs, i use an allen key to make sure they are firmly set in the block. i don't torque them down, but i make sure they don't move. sometimes, unless you have completely cleaned out the threads, they will appear to be snug, but actually they are caught on crud in the threads. after you install all the studs, eyeball the top of the studs inline to make sure one is not higher or lower than the others.
what type of headgasket are you useing?

 

[Rsawd95dsm]

what type of headgasket are you useing?

The million dollar question...

 

[yhype]

Able to post pics of both sides of the gasket? unless the head is slightly warped still betting on the head gasket had failed.

 

[English_Rugby]

It's a cometic mls gasket - I'll post pictures, but it really looks as good as new. The whole build has only 5000 miles - the turbo more. The head studs were torqued to 70 ft/lbs - I was tired and just wanted get the damn head off, so I didn't check the torque before I took them off, I just took them off (stupidly). It'd have been nice to know where they were sitting at - oh well.

 

[English_Rugby]

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Looks like the head studs weren't torqued properly - to me it seems like there was pressure flowing between cylinders and into the coolant passages?

Sorry - try the hyperlink to the photos:
John Wynne-Irvine's Photos | Facebook

John Wynne-Irvine's Photos | Facebook

 

[curt-s]

Another idea, and this is just an idea, my water-cooled turbo - is there any way that internally a seal could have broken, allowing compressor discharge into the coolant return line to my thermostat housing? I am not a turbo tech, but this would explain the mass of bubbles, very rapid gain in heat (my heat temp. sensor is on t-stat housing, where the return line is) and also this would explain why I couldn't boost? (also why my turbo coolant line burst) Thanks for your help and opinions. John.

Even if there were a seal, you're not producing positive pressure at idle, just vacuum.

It's -possible- that removing the head stud nuts caused the stud itself to loosen, though based purely on statistics, you'd think some of them wouldn't do it themselves and you'd have to resort to the allen key. However, it still is possible.

That much air getting into your coolant line screams head gasket sealing issue. Oil doesn't absolutely *need* to be coolant (or vice versa) to indicate this, it's just one of the common signs of a catastrophic failure. You could have a ever-so minute sealing problem that allows combustion gases to escape. Too easy for that to happen.