dbtk2 Posted September 17, 2003 Report Share Posted September 17, 2003 So I have been having a lot of problems with my TGP since I got it. We have fixed all the problems except for the boost, and that is what I want to be fixed the most. When we got it it overboosted and now it doesn't get any boost (or at least not very much if it does get some). So I have replaced the Boost Control Selenoid and had the Turbo rebuilt (which includes rebuilding the wastegate actuator so it is good also), and no, I probably didn't need the turbo rebuilt but it was pretty worn once I got it out of the car and actually looked at it closely. I also cleaned out the vacuum lines that run to the turbo so they are like new, and I cleaned out the air intake before and after the turbo except for the intercooler because I am too lazy to pull it off to clean it. So basically the only problem that I think could be the problem is either the intercooler is clogged or there is something bad in the exhaust. (like the cat is plugged) So, can anyone here think of anything else that would make the car not make any boost or at least not a significant amount. (if it gets boost right now it gets MAYBE 1.5psi) I am going to unbolt the exhaust before the cat to see if it is an exhaust restriction, but I need to know if I will need a gasket for that or can I do it without a gasket first. As soon as I know that I will rip it right off. If it isn't the exhaust and it isn't the intercooler I really have no clue what it could be, so if there is anything else that could be causing the problem let me know because I really want this problem solved ASAP. Thanks, and I hope you guys can help, Shawn Quote Link to comment Share on other sites More sharing options...
z24 turbo 93 Posted September 17, 2003 Report Share Posted September 17, 2003 check for leaks in your piping. i also found it wierd that the foreign cars have to reset there computer if you over boost.....maybe we do also.....i was just wondering? Quote Link to comment Share on other sites More sharing options...
Jeff M Posted September 17, 2003 Report Share Posted September 17, 2003 I am going to repeat myself on this but this time follow closely IF you want to check things out! I assume you never even spike above 1.5!? Pull off the boost hose at the wastegate actuator, go for a drive, got big boost then something is not controlling the wastegate solenoid, electrical problem. DO NOT run big boost for more than a few seconds, stock you will hit the fuel cut but if your low boost is caused by another problem, you can make things worse so just need to see if you can get more than the 1.5, even a quick fuel cut if you can get it is all the indicator you NEED! If yes boost and even a fuel cut/SES Light then trace the wires for a cut or short!! You have seen pics of the hoses so you know how they are routed. To test a cat, one only need to note the vacuum reading at idle, then rev the engine and hold it there, if the vacuum drops then cat is probably good, if vacuum comes up/moves toward the boost side of the gauge, then most likely plugged cat. Jeff M Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted September 17, 2003 Author Report Share Posted September 17, 2003 I assume you never even spike above 1.5!? No, it never goes higher than that, and I am not so sure it gets any boost because I don't have a gauge for it, I am using the factory gauge for boost. Pull off the boost hose at the wastegate actuator, go for a drive, got big boost then something is not controlling the wastegate solenoid, electrical problem. DO NOT run big boost for more than a few seconds, stock you will hit the fuel cut but if your low boost is caused by another problem, you can make things worse so just need to see if you can get more than the 1.5, even a quick fuel cut if you can get it is all the indicator you NEED! If yes boost and even a fuel cut/SES Light then trace the wires for a cut or short!! You have seen pics of the hoses so you know how they are routed. Done that a few times....gets the same amount of boost, sometimes it even gets less. To test a cat, one only need to note the vacuum reading at idle, then rev the engine and hold it there, if the vacuum drops then cat is probably good, if vacuum comes up/moves toward the boost side of the gauge, then most likely plugged cat. So you use the boost gauge for that? Just rev the car in park and if it goes up then it is probably a plugged cat? I can pull off the cat easily, I just need to know if I need a gasket for that. Thanks. Quote Link to comment Share on other sites More sharing options...
PaPaPooh Posted September 17, 2003 Report Share Posted September 17, 2003 I can pull off the cat easily, I just need to know if I need a gasket for that. if you do that and the cat is good i would recomend a new gasket good luck in finding one you may have to get a multy kit of dognut gasket to get the right size good luck hope this helps Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted September 17, 2003 Report Share Posted September 17, 2003 Tried the vacuum trick. It wasn’t conclusive enough for me to go to all the work and expense of replacing the cat. Removing the down pipe was. Your gasket should be fine. Iv'e had mine of quite a few times and reused the gasket. Go do it. Jud Quote Link to comment Share on other sites More sharing options...
Jeff M Posted September 17, 2003 Report Share Posted September 17, 2003 I assume you never even spike above 1.5!? No, it never goes higher than that, and I am not so sure it gets any boost because I don't have a gauge for it, I am using the factory gauge for boost. Stock will work fine for the tests here. Pull off the boost hose at the wastegate actuator, go for a drive, got big boost then something is not controlling the wastegate solenoid, electrical problem. DO NOT run big boost for more than a few seconds, stock you will hit the fuel cut but if your low boost is caused by another problem, you can make things worse so just need to see if you can get more than the 1.5, even a quick fuel cut if you can get it is all the indicator you NEED! If yes boost and even a fuel cut/SES Light then trace the wires for a cut or short!! You have seen pics of the hoses so you know how they are routed. Done that a few times....gets the same amount of boost, sometimes it even gets less. Now we are getting somewhere. Check the easy things first (a list of how you are setup would of skipped some of these). Take off air inlet hose to turbo, air filter may be choking things, while it's off check turbo wheel spins freely and coasts for a second or more if you are lucky. Test boost levels while driving with air filter hose off/brief trip around the block/no dirt roads. Make absolutely sure all your intake hoses from the turbo outlet to the throttle body are in place, and not leaking, the main culprit is the one at/under the throttle body. Make sure this is no hole in the intercooler, or in any of the rubber intake unions between hard pipes. To test a cat, one only need to note the vacuum reading at idle, then rev the engine and hold it there, if the vacuum drops then cat is probably good, if vacuum comes up/moves toward the boost side of the gauge, then most likely plugged cat. So you use the boost gauge for that? Just rev the car in park and if it goes up then it is probably a plugged cat? I can pull off the cat easily, I just need to know if I need a gasket for that. A $15 vacuum gauge is worth the cash if it gets you running proper. I have 4 of them, 3 w/boost as well. I have not used the stock gauge for a vacuum/cat test but it is an indicator enough it should work, yes!! Let the engine warm up then note vacuum reading at idle, then rev to 3K and hold, vacuum reading should get higher/drop lower on the gauge meaning it shows something like 10 (the notch about there) at idle, and then when it revs goes to 13 or 14, then that is a gain in vacuum and says the cat is most likely just fine! Jeff M Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted September 17, 2003 Author Report Share Posted September 17, 2003 Now we are getting somewhere. Check the easy things first (a list of how you are setup would of skipped some of these). Take off air inlet hose to turbo, air filter may be choking things, while it's off check turbo wheel spins freely and coasts for a second or more if you are lucky. Test boost levels while driving with air filter hose off/brief trip around the block/no dirt roads. Make absolutely sure all your intake hoses from the turbo outlet to the throttle body are in place, and not leaking, the main culprit is the one at/under the throttle body. Make sure this is no hole in the intercooler, or in any of the rubber intake unions between hard pipes. I have already tested it with the intake hose off and it didn't change it at all. The turbo spins freely as it should since it has about 5 miles on it because it was JUST rebuilt as I said before. Since the turbo was just re-installed after the rebuild we were very careful to make sure every line was installed properly, and the only leak could be at the intercooler and it didn't appear to have any holes in it, and it runs exactly as it did before the rebuilt turbo. I have tried just about everything I and others can think of other than removing the exhaust and doing anything with the intercooler. That is why I came here. A $15 vacuum gauge is worth the cash if it gets you running proper. I have 4 of them, 3 w/boost as well. I have not used the stock gauge for a vacuum/cat test but it is an indicator enough it should work, yes!! Let the engine warm up then note vacuum reading at idle, then rev to 3K and hold, vacuum reading should get higher/drop lower on the gauge meaning it shows something like 10 (the notch about there) at idle, and then when it revs goes to 13 or 14, then that is a gain in vacuum and says the cat is most likely just fine! I will go try this is guess. So if the boost gauge goes up the cat is good, and if it goes down or stays the same it is bad, correct? If I can't figure it out with the boost gauge I may bring the car to school and use a vacuum gauge there and test it. (Because i am cheap and don't want to buy one) If I do end up using a vacuum gauge, where would I connect it at? Thanks for the help so far. Shawn Quote Link to comment Share on other sites More sharing options...
god910 Posted September 18, 2003 Report Share Posted September 18, 2003 Why even screw w/ it. NIX the damn thing. (Unless you need it for emissions, I can't remember if MI is one of them tree hugging-dolphin fucker states) My TGP runs w/ no kat, no mufflers. As soon as I can get the red TGP here I am going to remove the exh. and make a mandrel bent version (2.5" or 3" don't know yet.) Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted September 19, 2003 Author Report Share Posted September 19, 2003 Why even screw w/ it. NIX the damn thing. (Unless you need it for emissions, I can't remember if MI is one of them tree hugging-dolphin fucker states) My TGP runs w/ no kat, no mufflers. As soon as I can get the red TGP here I am going to remove the exh. and make a mandrel bent version (2.5" or 3" don't know yet.) MI doesn't have that stupid emissions crap, but why remove the cat if it isn't bad. I am going to test it first. Then if it is bad...straight pipe here we come! Its just that if it isn't bad, I don't feel like wasting my time messing with it. Quote Link to comment Share on other sites More sharing options...
4PASNU Posted September 19, 2003 Report Share Posted September 19, 2003 So if the boost gauge goes up the cat is good, and if it goes down or stays the same it is bad, correct? Reading Jeff's quote below your gauge should go down if the cat is good. If it's an analog gauge your needle should go counter clockwise (more vacuum). If your cat is bad, the back pressure would cause your gauge to move clockwise, giving you less vacuum. then rev to 3K and hold, vacuum reading should get higher/drop lower on the gauge meaning it shows something like 10 (the notch about there) at idle, and then when it revs goes to 13 or 14, then that is a gain in vacuum and says the cat is most likely just fine! Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted October 11, 2003 Author Report Share Posted October 11, 2003 So, this morning my dad and I dropped the exhaust off of the TGP, and drove it, and right away it got boost. So the problem was definately in the exhaust. We drove the car around for like an hour with no exhaust, because we were enjoying the power so much! So then we took the exhaust into a shop and had them replace the cat and mufflers because the cat was what we figured was the problem, and the mufflers had holes in them (they are the only things on the car with rust on them). So they took out the cat and it was all busted up. The pipe behind the cat was filled with pieces from the cat, and that is what was clogging the exhaust. So they welded on a new cat, and some turbo mufflers. The car sounds and drives GREAT!!! It's so nice to have a TGP that runs as it should. I find it a weird coincedence that the cat plugged the exhaust the exact time we brought the car into the shop to get the turbo fixed though. Anyways, just thought I would let you guys know that the problem we have been having with this car for 10 months is finally resolved. One thing I want to check though is if I stop the car completely and nail the gas as hard as I can the tires will not even chirp, all they do is stick, and the car seems kinda wimpy until about 15-20mph, when it wakes right up. I am assuming it is supposed to do that, and the computer is just not allowing the turbo to spool until then? I know the Jeff M. chip quickens up the "ramp rate" of the when the turbo spools, but is the stock chip supposed to be that bad? I don't have a problem with it like that, just wondering if that is how it is supposed to be. And if I nail the gas from like a 20mph roll it gets boost right away, so its not like it takes the turbo that much time to spool. (And I would hope it wouldn't, seeing it was rebuilt only a few weeks ago.) Thanks, Shawn Quote Link to comment Share on other sites More sharing options...
z24 turbo 93 Posted October 11, 2003 Report Share Posted October 11, 2003 if you stop then step on it right away your going to be bogged down because of no blow off valve. Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted October 11, 2003 Author Report Share Posted October 11, 2003 if you stop then step on it right away your going to be bogged down because of no blow off valve. If I stop and sit and wait for a light for a minute or so it does that, it is not just stopping right away and taking off again, I stop and wait a while then nail the gas and the tires don't even chirp. Quote Link to comment Share on other sites More sharing options...
z24 turbo 93 Posted October 12, 2003 Report Share Posted October 12, 2003 okay in my cavy it is that way sometimes, it depends on how hard and fast you step on it, and then sometimes my car does what your talking about, but i have a big ass crack in my crossover i assume that is my problem Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted October 12, 2003 Author Report Share Posted October 12, 2003 Its not that it's a problem like that, I am just trying to see if it is normal to be like that. It will actually be very helpful for bracket racing because the car should be very consistant like that. I just want to make sure it is supposed to not be able to even chirp the tires. Because I can stomp on it as hard & fast as I possibly can from a complete stop and it will just take off normal and not break traction, then when it hits about 15-20mph it takes off like a bat outta hell. I don't have a problem with it, I just find it kinda odd, since I know it isn't turbo lag. Quote Link to comment Share on other sites More sharing options...
z24 turbo 93 Posted October 12, 2003 Report Share Posted October 12, 2003 you have the stock crossover yet? mine does what your saying, but with a cracked crossover so i don't get full boost till 3000 rpm, when i should have it at 1500 rpm Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted October 12, 2003 Author Report Share Posted October 12, 2003 yes, it still has the stock crossover. Thats probably what makes it idle rough too? Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted October 12, 2003 Report Share Posted October 12, 2003 yes, it still has the stock crossover. Thats probably what makes it idle rough too? yep, cracked crossover = poor idle quality and lower gas mileage, yours drinking a good bit of gas? Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted October 12, 2003 Author Report Share Posted October 12, 2003 yep, cracked crossover = poor idle quality and lower gas mileage, yours drinking a good bit of gas? I don't know what the gas mileage is. It was getting averaging about 16mpg, but I would have to guess a good bit of that was because of the cat falling apart and plugging the exhaust. After drinking a tank of gas I will see what the mileage is after the new exhaust, hopefully better, I don't think the crossover hurts the mileage THAT bad. Quote Link to comment Share on other sites More sharing options...
bumpin_z Posted October 12, 2003 Report Share Posted October 12, 2003 okay in my cavy it is that way sometimes, it depends on how hard and fast you step on it, and then sometimes my car does what your talking about, but i have a big ass crack in my crossover i assume that is my problem hey man wassup? so there are atleast 3 turbo cavi's on this board now? what crossover/trans bracket are you using? Quote Link to comment Share on other sites More sharing options...
god910 Posted October 12, 2003 Report Share Posted October 12, 2003 ...I don't think the crossover hurts the mileage THAT bad. If you are replacing the bad O2 sensor once a week or so it won't. Quote Link to comment Share on other sites More sharing options...
Chris A Posted October 13, 2003 Report Share Posted October 13, 2003 , I don't think the crossover hurts the mileage THAT bad. Hate to say it but think again. It can. Quote Link to comment Share on other sites More sharing options...
z24 turbo 93 Posted October 13, 2003 Report Share Posted October 13, 2003 bumpin_z...........i have stock tgp crossover, with grand am tranny mount ( uses original mount that is on the body and has a quarter inch steel plate that goes down to connect to the grand am tranny mount) Quote Link to comment Share on other sites More sharing options...
twalt13 Posted October 13, 2003 Report Share Posted October 13, 2003 Did anyone else catch this?..... Jay Warfel Muncie, IN 90 TGP Manual Estimated 4220 WHP (HP Yellow Corrugated tubing)" Thats two TGP's with a good tail wind right? Quote Link to comment Share on other sites More sharing options...
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