2G Need help with 2G GST cutting out under boost

taz2016 · Jul 22, 2016

I have a 1996 GST mild tune (275 whp) that I am getting out of storage after 7 years. At the time I put it away it was in driving rotation with my 2003 Evolution which I recently sold. It had developed a problem I couldn't solve at the time and could use some help with. It has a 16G turbo, upgraded side mount intercooler, manual boost controller, full 3" turbo back exhaust, K&N open air filter, upgraded fuel pump, aftermarket pressure regulator, and was tuned with an Apexi AFC at Buschur Racing on their dyno. It ran well for many years until it started cutting out on boost. It would start fine and run normally until the turbo started to build boost. Any ideas?

lasershark · Jul 22, 2016

Have you done a BLT?

taz2016 · Jul 22, 2016

Thanks, other than a minor throttle body leak all was good.

Ferp · Jul 22, 2016

You could check your spark plugs/wires, maf, o2 sensor possibly, and take a serious look around your upgraded intercooler, make sure they are snug.

lasershark · Jul 22, 2016

To narrow this down, what have you tried?
Is that your full mod list?
Injectors? Boost level? what spark plugs/gap? Fuel pump? <Rewired?
Can you describe the "cutting out" a little better? Is it breaking up, stumbling, going lean, going rich, ect...
Also what psi did you BLT at? For example I run 25psi so I test at 30psi

If you plan on sticking around (on dsmtuners)
http://www.dsmtuners.com/threads/welcome-to-dsmtuners-now-go-create-a-dsm-profile.499707/

2gmitsueclipse · Jul 22, 2016

I am not sure if you have gotten it running yet or not, nor how you stored the car, but I would first ensure:

your fuel tank is clean
fuel pump filter (in-tank)
Change fuel filter (engine bay)
Have injectors cleaned and flow tested.
Flush coolant system.
Change oil
If it were me, I would consider changing the timing and balance shaft belt (if you have it).

Then, you are ready to tackle the issues which caused you to store it.

taz2016 · Jul 23, 2016

Thanks for all your ideas. To clarify a few things, the car also has 550 cc injectors, 1G BOV, chipped computer, NGK plugs, and Accel wires. The fuel pump is rewired. I'm not quite ready to start it yet. I don't have a lot of time to work on it and need to find a way to pump out the old fuel and put new in. As best as I can remember I was running 18 or 19 PSI before and then it just would not run under any boost. As stated before the car ran perfectly for many years until it suddenly would not run under boost. I was hoping that something that specific and sudden would point directly to the most probable cause.

pauleyman · Jul 24, 2016

sudden symptom id lean to ignition. I had a 1g that arced through a spark plug wire at the boot. difficult to see. ran great until under boost. put a piece of tape around the boot until I purchased new wires

chrysler kid · Jul 25, 2016

Probably a fouled plug or wires if a boost leak test came back ok. I would also check for evidence of wires being chewed through if the car was in storage and put a full tank of 93 in there too

TehRiceBandit · Jul 25, 2016

Spark plugs

taz2016 · Jul 28, 2016

Time for an update. It's running but unfortunately on 3 cylinders. #2 has very low compression. A little oil brings it back up some so it looks like the rings. I'm trying to free them up by soaking with Marvel Mystery Oil and running one a day. If that doesn't work it looks like it will be time for a rebuild. I don't feel like doing it myself this time. Any suggestions on a good shop in N.E. or central Ohio?

95REGF150 · Jul 28, 2016

I doubt its stuck rings. What were the numbers on the compression test? How much does it come back up with a little oil? I wouldn't completely rule out a valve being the issue until you do a leak down test. That will tell you for sure.

Tiki2777 · Jul 28, 2016

taz2016 said:
Time for an update. It's running but unfortunately on 3 cylinders. #2 has very low compression. A little oil brings it back up some so it looks like the rings. I'm trying to free them up by soaking with Marvel Mystery Oil and running one a day. If that doesn't work it looks like it will be time for a rebuild. I don't feel like doing it myself this time. Any suggestions on a good shop in N.E. or central Ohio?

If you mean Nebraska (NE) then look at 3D motorsports on the Iowa-NE border. Chad does awesome work and mainly works on DSM's and evos. Another great shop is RG (Russ' Garage). His specialty is subies but he is no stranger to 4g's.

taz2016 · Jul 28, 2016

Compression was 180, 30, 165, 175. After an ounce of MMO #2 went to 75 PSI.

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2G Need help with 2G GST cutting out under boost

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