Need help with my GST

[clipse4u2c]

I am having a horrible time with my 97 GST and really just need some help. I bought this off a kid and drove it home but it had some major issues. It wouldn't boost over 10 psi or so. It has 680cc injectors and only tuned by a safc which wasn't really even done properly. It was running REALLY rich. It had horrible i/c piping (pvc, etc.) and a beat up evo 3 front mount. I also had a tial BOV to atmosphere. It had a breather filter over the valve cover vent hole dripping oil everywhere and the pcv valve was capped so it wasn't doing anything at all.

Now that you know how this started i'll get started with the problems. I knew i needed a new FMIC so I bought a SSAC with short route. I also bought a HKS SSQV to recirculate in exchange for the Tial. I have been battling boost leaks pretty much this whole time. It has a Venom Intake Manifold that was warped badly at the head and throttle body. I got the head flange machined but couldnt machine the throttle body side so i finally got it to seal there pretty good. I bought new shaft seals for the throttle body and now it doesn't want to go all the way closed (thorttle sticks) I think I may have the plate in it wrong because the springs are on the right way and tight. I also bought an eprom and dsmlink from a guy and basically got ripped off. He sent me an eprom and chip but he later sent me the cable and it was off a pocketlogger! I finally got ahold of him and he SAYS he'll give me the money back but we'll see. Anyways i put the eprom in the car with the chip (set to 720cc) injectors and tried to start it. Hoping if it ran it would be easy to adjust the 40cc injector size difference with the SAFC. Well the car will not start. I put the stock ECU in and it will run but not good. It WILL NOT boost over say 8 psi with the mbc cranked all the way up i double checked that it is hooked up right. Also at about 5k rpm it starts to stutter really bad. I did a compression test and they are 161,152,150,170 so not that bad really are they? Also i dont think it's fuel cut because it has a 255, AFPR, and 680cc on a 16g. I'm totaly lost on what to do. I want to roll this thing down a hill! Sorry for the long post but PLEASE HELP!

 

[SanTa_]

Boost leak test?

 

[crimsondragon]

Ouch. Sounds like it went through hell and back. Check the plugs, wires, etc. Do a tune up and oil change and all that good stuff. Then fix the PCV valve, as well at the VC vent. Do more boost leak tests. I would check around the throttle body area. Get rid of the PVC piping and get some real piping. Check the shaft play of the 16g and yeah. That's off the top of my head at the moment.

 

[knochgoon24]

Yeah, PVC piping may be pretty nasty looking ,but if it's holding, then that's the least of your worries.

If it ran rich for too long, the CAT may be clogged.

 

[vancitydsm]

bad cat , put a straight pipe and try it out. Are you getting alot of backfire? I'm sure this retard messed something else up somewhere. But ya start with basics get things off the list, do another boost leak for good measure, try getting a test pipe on to replace cat for now, or just take it off and take it around the block for a test drive. Check the turbo for play like stated above. If none of those work, check the plugs and replace if needed. It could be a tuning problem as well I'm an idiot when it comes to tuning but seems like you have quite a bit of fuel upgrades you think your afc can manage all that?

 

[clipse4u2c]

I have checked the turbo which i will do again to make sure but I remember there was no shaft play but i didn't try to spin it. What should i look for in the turbo test. Just make sure it has no play in and out or side to side and spins ok? Anyways as far as the plugs I have new ngk bpr7es that I put in but i'm thinking I made have needed the 6es. What are your thoughts? I know the boost leak test needs to be done some more. I just ordered a tester because the one i made was crap and this one has a gauge on it. I never thought about the cat I actually have a test pipe I haven't installed yet i'll try. It does need tuned REALY bad that i do know for sure!

 

[dsm_Prince]

Yea i say you need a tune up, also thats right on checking for shaft play side to side and in and out. Is the pvc holding tight if it is that shouldnt be a problem and just test for boost leaks.

Good Luck

 

[clipse4u2c]

the pvc piping is gone. I upgraded with the short route kit with the SSAC FMIC.

 

[clipse4u2c]

Well I took the cat out and it didn't help. It will not go past like 5500 rpm? It sounds like fuel cut in a way because it's like i hit a wall when i get there. I'm still waiting on my blt gauge to arrive which should be in the next few days. With my previous blt I was able to get it to hold some air. It does still ahve some minor leaks but nothing where air is rushing out so as I know this is a problem i'm not sure it is the only culprit here. Until my new gauge arrives i'm thinking it could only be something to do with my ignition or fuel? How do i test these? Also could it be a timing issue? As far as ignition i have new ngk bpr7es plugs and for fuel i have walbro 255, AFPR, bullit rail, PTE 680cc injectors. Your thoughts

 

[clipse4u2c]

I checked the wastegate to make sure it wasn't stuck open and it was not. Today I should have a new BLT gauge to test for leaks. I'm also going to test the shaft play in the turbo. Can you guys think of anything else I should check? Thanks

 

[Splitpi]

You should be using the stock BPR6ES or BPR6EKN spark plugs (I believe the EKN are dual prong... just get the single prong ones) gapped between 0.028 to 0.030.

Consider taking the 680's out and replacing with stock 450's till you DSMLink and zero out the SAFC. Inspect the Cat and ensure it is not cloggged. Also the engine compression values while above the minimum our still out of spec because they very too much from one another.... however, I think you are still ok... just need to watch it (I'm in the same boat on one of my cylinders). As mentioned check and recheck the turbo shaft play after the engine is warmed up (some very small amount is acceptable... and if there is no oil in the turbo it may feel loose when in reality it is not). Boost leak test.

My list of routine maintance to perform as I prefer to do it:
Get a new mitsu PCV valve (every 3rd oil change)
New BPR6ES plugs (every 5th oil change)
Inspect the wires... if questionable then replace
Change the engine oil (every 2-3k miles)
Inspect air filter... if looks dirty either clean (k&N) or replace
Get the tires balanced and rotated.

Also consider the following maintance if you feel the maintance was scetchy or work questionable by previous owner:
Change the transmission oil (every 30k miles)
Timing belt job
- New Timing Belt
- New Balance Shaft Belt
- New Timing Belt Idler Pulley
- New Timing Belt Tensioner Pulley
- New Balance Shaft Tensioner Pulley
- New Hydraulic Tensioner
New Water pump
New Thermostat kit
New Fuel Filter
New Battery
New Accessory Belts (AC, PS, Alternator)
New Vacume lines (see RRE Larson Kit for example)
New Front O2
Radiator Flush

Edit: My boost leak tester cost me about $1.20. I bought 2.25 inch rubber cap and a clamp. I put the cap over the turbo. Put rubber caps over PCV valve exit, and any nipples on the valve cover/IC pipes. Then I put a T in the BOV line and pressurize the engine through the BOV line. This way I'm not hitting the turbo seals with 90 psi of pressure. Works great this way. I then watch my Boost gauge and count to see how long it takes to drop.

 

[clipse4u2c]

thanks splitpi that helps alot. I did check the shaft play and there was none and it spins freely so I don't think its the turbo. I had made a boost leak tester but it leaked and was junk so I just bought one with a gauge. I don't have anybody to help me and it's hard to run back and check the gauge. Also I plan on checking it to around 20 psi how long should that hold and how slowly should it drop. Thanks alot!

 

[drewvr4]

Man you have so much that needs done to that thing. The method of running between the hood and boost gauge is unnecessary just put pressure threw the piping and listen for leaks, you don't need but 20 or so lbs of pressure not 90 and you will be amazed where leaks will come from.

And get a good tune with that dsmlink, that will help out alot of your kinks and with the handy error code reader built in can give you a hint where some problems might be

 

[demografik]

uh, your compression is horrible. minimum compression before a rebuild is necessary is 160. you should start there and fix all the other problems while the motor's out. good luck.

 

[Splitpi]

uh, your compression is horrible. minimum compression before a rebuild is necessary is 160. you should start there and fix all the other problems while the motor's out. good luck.

No...

~178 psi is standard
~133 psi is the lower acceptable tolerance
~14 psi is the acceptable max variance between any two cylinders.
- From page 11A-12 of the Factory Service Manual.

160 psi is perfectly fine.

 

[demografik]

No...

~178 psi is standard
~133 psi is the lower acceptable tolerance
~14 psi is the acceptable max variance between any two cylinders.
- From page 11A-12 of the Factory Service Manual.

160 psi is perfectly fine.

my mistake. maybe i was thinking of the minimum, assuming one cylinder was at normal. regardless he's got more than a 14psi variance.