newtgp Posted May 2, 2006 Report Share Posted May 2, 2006 Hi everyone...new to the forum as I just purchased a '90 TGP off of ebay item#4631025345. Unfortunately I'm having some issues with the car that were not disclosed by the seller so I've got a few ?'s. Here's the scoop: '90 Red 150K in decent shape. Tranny recently replaced, shifts very strong. Turbo rebuilt by Garrett, sounds fine. New fuel tank, pump, water pump, thermostat. K & N air filter. When I bought the car I was told it needed a new fuel pressure regulator and it would be fine as it was running rough and had been checked out by a mechanic. I replaced the fuel pressure regulator and that helped somewhat. Also, the car had no mufflers when I got it it (surprise!) so I had a new exhuast system installed as everything that was on there before was leaking like crazy, hoping this might help. The car runs and sounds much better, but a slight miss at idle, and when I accelerate it hesitates until I press on the gas harder. Haven't driven it much since the repairs, but I took it out and drove it hard and at higher RPM's runs tough and strong. Not sure if it's still a fuel or vacuum issue? Any of this sound familiar to anyone? And to make the purchase more interesting the car needs new calipers and pads all around, along with the proportioning valve as it's leaking too. Might be looking for some parts soon.... Filed a complaint with e-bay, so can't do anymore altering till I find out what's gonna happen. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
kuntzie Posted May 2, 2006 Report Share Posted May 2, 2006 a slight miss at idle could be caused by the leaky crossover... good luck, i ruled out plugs arnd wires as he said he just replaced them... the link for anyone..... http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ru=http%3A%2F%2Fsearch.ebay.com%3A80%2Fsearch%2Fsearch.dll%3Fcgiurl%3Dhttp%253A%252F%252Fcgi.ebay.com%252Fws%252F%26fkr%3D1%26from%3DR8%26satitle%3D4631025345%26category0%3D%26fvi%3D1&item=4631025345 Quote Link to comment Share on other sites More sharing options...
newtgp Posted May 2, 2006 Author Report Share Posted May 2, 2006 Would the crossover have been something that would have been noticed in the exhaust replacement? Thanks Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted May 2, 2006 Report Share Posted May 2, 2006 there should be a red plate on the turbo, read it and type what it says. the crossover can be rebuilt, its what bolts to the turbo and connects the headers, in case you didnt know. I got my turbo from Garrett and it says Garrett Factory Overhauled on that red plate. Quote Link to comment Share on other sites More sharing options...
TGPilot Posted May 2, 2006 Report Share Posted May 2, 2006 Alot of driveabilty issues can be tracked to the cross-over. Like you said that at wide open throttle (WOT) it runs good because it is in open loop. Well the ECM is still looking at the 02 sensor for A/F levels, but it is in fuel tables that are pretty well set by the chip. If you are driving around out of boost you are in closed loop and the ECM is constantly taking readings from the 02 sensor and adjusting/trimming the fuel for optimum fuel use. Now with a cracked cross-over you will allow in fresh air that the 02 picks up and tells the ECM to richen the mixture to compensate. Well it will never compensate for the fresh air and thus you have problems with normal driving performance. If your pipe has a heat shield surrounding it or it looks like this...it is a stock cross-over and most likely cracked. If it looks like it has a braiding around the bellows than most likely it has been repaired by someone. If it looks similar to the top picture then it will need to be repaired and if you follow the link in my signature we can get you setup to run much better! Quote Link to comment Share on other sites More sharing options...
newtgp Posted May 3, 2006 Author Report Share Posted May 3, 2006 Thanks for the advice so far. The crossover pipe has been replaced/repaired at some point as it has the braid, (who knows maybe it's bad again). Something I noticed while checking that out is 2 sets of wires that are not connected to anything...hhmmm. The first one is a single red wire with a gray single pin connector coming from the lower side of the fuel pump relay. Too dark to see where the others were coming from but they were a black and orange bundle (and I think I saw a white as well cut partway down) with a black 2 pin connector; these were routed on the top left of the engine compartment near the shock/strut. Any ideas? Thanks again Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted May 3, 2006 Report Share Posted May 3, 2006 The single wire is just the fuel pump test wire. Don't worry about it. The other kinda sounds like the underhood light connector? not really sure on that one. The problems still sound like they're crossover related, but you said you saw braid on the pipe.. then again, in the ebay pics it looks like it still has the heatshield on (though they could be old pics). I'd definetly keep a look out for vacumm leaks however. I was going to say check the vacumm plug on top of the throttle body (they usually tend to pop out under boost), but amazingly enough yours still has the stock holding clip. I'd say next step could be coilpacks. Quote Link to comment Share on other sites More sharing options...
90TGP Posted May 3, 2006 Report Share Posted May 3, 2006 Might have a bad fuel pump too. I had similar symptoms when my pump was dieing. Quote Link to comment Share on other sites More sharing options...
newtgp Posted May 3, 2006 Author Report Share Posted May 3, 2006 The fuel pump has been replaced, and can hear it run when I turn the key. I bet the loose wires are for the light....Thanks Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted May 3, 2006 Report Share Posted May 3, 2006 "Brand new Fuel Tank, ACDelco Fuel Pump and Filter. " supposedly. Quote Link to comment Share on other sites More sharing options...
newtgp Posted May 3, 2006 Author Report Share Posted May 3, 2006 I can tell the tank has been replaced because they forgot to reinstall the black plastic fitting around the filler neck, its sitting in the trunk now... Quote Link to comment Share on other sites More sharing options...
Pontiac6KSTEAWD Posted May 3, 2006 Report Share Posted May 3, 2006 Sounds like he needs some injectors to me. Mine had the same problem and some new 96+ injectors corrected most of it, I still had a bad x-over soo.... Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted May 3, 2006 Report Share Posted May 3, 2006 Thanks for the advice so far. The crossover pipe has been replaced/repaired at some point as it has the braid, (who knows maybe it's bad again). Something I noticed while checking that out is 2 sets of wires that are not connected to anything...hhmmm. The first one is a single red wire with a gray single pin connector coming from the lower side of the fuel pump relay. Too dark to see where the others were coming from but they were a black and orange bundle (and I think I saw a white as well cut partway down) with a black 2 pin connector; these were routed on the top left of the engine compartment near the shock/strut. Any ideas? Thanks again Just to clarify, are you sure the crossover had braided bellows? Or did you get confused with the braid on the downpipe. Not trying to doubt you, just making sure we aren't looking over the obvious. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted May 3, 2006 Report Share Posted May 3, 2006 Thanks for the advice so far. The crossover pipe has been replaced/repaired at some point as it has the braid, (who knows maybe it's bad again). Something I noticed while checking that out is 2 sets of wires that are not connected to anything...hhmmm. The first one is a single red wire with a gray single pin connector coming from the lower side of the fuel pump relay. Too dark to see where the others were coming from but they were a black and orange bundle (and I think I saw a white as well cut partway down) with a black 2 pin connector; these were routed on the top left of the engine compartment near the shock/strut. Any ideas? Thanks again Just to clarify, are you sure the crossover had braided bellows? Or did you get confused with the braid on the downpipe. Not trying to doubt you, just making sure we aren't looking over the obvious. thats what I was thinking looks like a heat shield. Quote Link to comment Share on other sites More sharing options...
newtgp Posted May 8, 2006 Author Report Share Posted May 8, 2006 You guys are correct; in the dark I was looking at the downpipe. So it now appears that the crossover may be the culprit. Garrett I might be in contact with you...... Happen to have just a few days off, so I'm gonna limp it up to my Dad's place, he's got the facilities to get more in-depth. It's an 800 mile trip so hope she holds up alright. Thanks again for all the help![br]Posted on: May 03, 2006, 01:01:32 PM_________________________________________________Well the TGP made the long trip with no additional issues so that was nice. But it turns out I'm not gonna have as much free time as I would like to get this fixed all the way so it looks like I'm gonna sell it; makes me mad as I've always wanted a TGP... There are a few pics on the e-bay link and will be taking a few more after I finish the brake work. I've got well over $3,000 invested so far, and would like to recoup as much as possible. The previous threads give a pretty good description of everything I know. In addition it now has a brand new exhaust, new catalytic converter, new rear rotors/calipers. Am not gonna have time to get to the crossover issue, as discussed in the previous posts it appears to still have the factory crossover. Has a very slight miss at idle and when geared low and given gas the car will hesitate until the accelerator is pressed harder and shifts out of overdrive. When the Turbo is engaged it runs excellent and has a lot power. The transmission has been rebuilt and does shift very strong. If anyone is interested or has questions let me know...Thanks Quote Link to comment Share on other sites More sharing options...
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