95 GST Missing Exhaust Manifold Bolt

[Schwebe101]

Hello everyone, although I have left the DSM scene my roommate just picked up a 95 GST with a rebuilt 6 bolt engine and a new unknown 16g turbo with a open dump pipe and a walbro 255. (He bought the car for next to nothing). Anyway the thing barely runs, it idles rough and as soon as it sees any boost at all the thing cuts out and pops like crazy. I could barely drive it home, you can rev it just fine if you only put 1/4 of the throttle down in neutral. Previous owner said it ran perfect before putting the 16g on it but who knows.

Anyways my question is regarding the exhaust mani, there is a missing bolt in the upper left hand corner. I have check and the bolt is not broken off in there because I took one of the other bolts off and tried to thread it in there. The thing didn't grab on anything at all. I don't know if it's stripped or if a stud is supposed to be there? I've never had a 4g63 so I am definitely a noob at this. Picture included incase clarification is needed.

 

[TSiAWD666]

There should be a stud on which a washer and crimped copper nut goes. There shouldn't be any bolts on the manifold to head interface.

 

[Schwebe101]

So the current bolts that are in there are not supposed to be there? Also where can I get those studs?

 

[waterlance]

You could check out some OEM part sites for little things like nuts and bolts, but if not, junkyards have dsm's from time to time. Worth a check if you're worried about it

 

[19Eclipse90]

Even though original equipment is a stud and nut combination, using a bolt rather than a stud isn't a problem. If a bolt doesn't thread in, the hole is stripped and needs to be repaired.

 

[turbo6692]

The bolt or stud will be the same thread pitch so in order to fix that hole you will most likely need to use a tap and Heli coil it. For the other part of the running issue check the spark plugs and make sure they are good. I have had my 4g63 idle good but break up over 3000 rpm because of the plugs. Hope this helps.

 

[lasershark]

I would make sure the bolts are not a low grade bolt. If they are, I would swap them out with 8.8 grade or higher.

 

[Schwebe101]

The bolt or stud will be the same thread pitch so in order to fix that hole you will most likely need to use a tap and Heli coil it. For the other part of the running issue check the spark plugs and make sure they are good. I have had my 4g63 idle good but break up over 3000 rpm because of the plugs. Hope this helps.

It doesn't even idle that nice haha. Is it possible that there could be a big enough boost or vac leak to make it run that bad? I will have tools to test within a week but I am just worried that it is something bigger due to how bad the car is running.

 

[turbo6692]

Yes that is very possible and leak that is created after a maf sensor is unmetered air that the ecu can't compensate for with fuel so it creates a lean condition.