Jump to content

1990 TSTE Grand Prix not right/boost prob


SVOSTE90

Recommended Posts

hey guys,

 

not very familiar with the 3.1 turbo setup, but i acquired this car 2 years ago and just had a chance to start tinkering. new battery started her up. ran fine and pulled hard with partial throttle, turbo seemed to boost. got back home and checked fuses and accidently put one of the ignition fuses in a blank spot. ran down the road again, car ran sick. rechecked my fuse tampering and plugged the fuse back in. she leveled off and ran fine, but under boost it backs up at any positive boost on the gauge and tranny won`t shift until i let up. keep in mind when the fuse was out the car ran sick and sparks shot out of exhaust when reving up at idle before fuse correction. maybe i should reset the ecm? seems that boost control not working or something in that line. thanks for any tips. would like to get this 1990 turbo ste/red running like new again.Edit/ after reading some here on the site, with no answers or suggestions yet, i figure i need to look at what is called a crossover pipe. maybe a crack there will keep the turbo from waking up. eitherway, i`m just not accustomed to the v-6 turbo gms, been around 2.3 turbo svo`s and turbo birds all my life, inline 4`s.

still any suggestions will be appreciated,today changed the front 3 plugs, next, the back while checking underside of drivetrain .

 

 

 

Link to comment
Share on other sites

by the way, since my beginning with the car, the tach always shows more than double the actual rpms she`s turning and the speedo does the same. i thought the rev limiter could be the prob if it runs off the tach..... not allowing boost to come up due to shutdown of fuel etc., or timing retard

 

what do you think?? i think code scan first......

Link to comment
Share on other sites

Every turbo cluster has these issues for some reason. It is the cluster itself though, everything else (rev limit/fuel shutoff etc) run directly from the ECM, so the cluster is not causing any other problems. I wouldn't take any stock in what the stock boost gauge is telling you either.

 

The crossover pipe can cause some serious boost leakage, depending on how bad the cracks are.

 

I don't know if it's a common problem on the turbo trannies as well, but the N/A 4T60's have a shitty valvebody design and with age most of them won't shift out of first unless you let off the gas a little (if it's floored). Could also be something like your tranny's vacumm modulator going out, of maybe the check valve is missing before it's connection. Check to make sure there's a vacumm line that's plugged into the front of the tranny (I think it's about in line with the turbo about halfway down the tranny casing) and make sure the check valve is in place.

Link to comment
Share on other sites

Thanks for the info, changing fuel filter and back plugs today with further inspection of other components mentioned. Also have a friend with snap on code scanner that will run scan soon. again thanks, will keep updating post as we go.

Link to comment
Share on other sites

well, the car runs great, but still appears to have no boost and it won`t shift at all unless you let up alot in any gear. i believe the cat has to come off to check for partial blockage as it runs well until turbo goes to positive boost then whoosh like a bov, then hangs in that gear until backing off. i may have clogged/ melted the cat in previous tinkering/ mistake above.(when sparks were coming out of exhaust.) very frustrating, as everything worked great until i checked and misplaced an ignition fuse for 15 mnutes of running.

it`s bad when my 88 turbo 4 cylinder t-bird will smoke this v-6 turbo. all the t bird has above stock is a gillis valve turned up to 16 psi and a cold air kit. and my 97 sho will smoke both of these stock. got to get the ste turbo right or die trying, that garret is not pulling in and boosting as it should like a t-3. thanks

Link to comment
Share on other sites

If it still has the factory air box, the hose that connects to the turbo inlet can collaps. Also, check the Trottle cable that connects to the Trans. Make sure its not stuck. It should return when you pull on the cable. It should have some slack. If its fine, try loosening the cable by pushing on the ajusting tab to losen the linkage.

 

You might also wanto check the vacume hoses under the intake and around the map sensor, around the trottle. THey can come loose. Some might even be cracked.

 

Where exactly did the sparks come from? tail pipe, crossover pipe to turbo?

Link to comment
Share on other sites

sparks came out of tail pipe when i had misplaced one ignition fuse in a blank spot at night. and i do realize now so many things that could be wrong after one of these sits for a while. it`s just that it pulled so well on the first drive with the turbo, shifts, everything. then the boost and shifts went downhill. i`ll keep checking as i go and correcting. i`ll find another air inlet hose to the turbo, all my k & n`s r to big to go there. thanks for the pointers. alan

Link to comment
Share on other sites

it`s bad when my 88 turbo 4 cylinder t-bird will smoke this v-6 turbo. all the t bird has above stock is a gillis valve turned up to 16 psi and a cold air kit. and my 97 sho will smoke both of these stock.

 

Well now I definately know you have a problem. :lol: This TGP will walk both of those cars easy. Without the car sitting in my garage I really can't pin point it. But what I do have is a shop manual for this vehicle. So if theirs any certain pages you want for me to copy and paste on your webmail I'll be glad to do so.The only other thing that I can remember is when mine did'nt boost, I found that my knock sensor was bad. good luck! Jimmy

Link to comment
Share on other sites

Well now I definately know you have a problem. :lol: This TGP will walk both of those cars easy. Without the car sitting in my garage I really can't pin point it. But what I do have is a shop manual for this vehicle. So if theirs any certain pages you want for me to copy and paste on your webmail I'll be glad to do so.The only other thing that I can remember is when mine did'nt boost, I found that my knock sensor was bad. good luck! Jimmy

 

The late 80's Turbo T-Birds are not exactly slow, don't pay attention to the shitty ET's the magazines got out of them back in the day. A good running stock turbo Bird is on par with a stock TGP(the T5/stick version at least...190hp/240 ft-lbs in a car that weighs very close to what our cars do...~3400lbs).

Link to comment
Share on other sites

And their collectables too. But my neighbor has one and it has nothing on my TGP. I smoke him from the start, and all the way to finish, and yes he also like me is working on the damn thing and also has a few mods. Well actually I do have a few more mods, But going back to stock yes, I do beleive it would be a better race.

 

If theirs no trouble codes popping up than you just need to stick your head down there further and find that trouble maker its got to be something dumb. what did you find on the scanner anything?

Link to comment
Share on other sites

my friend with scanner out of town right now, but i bet it`s something dumb as said previous. replacing air box to turbo hose today, appears hose trys to suck shut just on motor/in park reving up without turbo engageing. like my turbo coupe the ecu on these probably doesn`t let boost occur unless rolling in gear. and by the way the 88 tc 5speed is no slouch, from 60 on they fly(1st and 2nd gear likes to spin), and the 86 svo`s are real fast. the sho v-8`s with the new program from doug lewis ford motorsport specialties in atlanta unleashes the detuning on the factory ecm`s. but still i know the way this pulled the first time i drove it and it`s capable if modded to boost more and flow the air in and exhaust out for a heavy car. i appreciate the tips, i want to restore this car to factory condition with some mods, there`s nothing like turbos pulling you back in the seat. i drove an 87 GNX one time modded right and it was scary. thanks and will update soon. alan

Link to comment
Share on other sites

guys, got the boost up. broken vaccum line left side under turbo inlet, could not see the break until i moved the line. then hose sucked shut even without a filter in the box(tried that to see what would happen), had to snatch the the hose off , it had collapsed going down the road and shut down. then after new autolite 103 platinum plugs, a new oil change , a small filter on the valve cover to air box hose, a short k&n on the turbo inlet.( not a ru 1910 but half the length) i got a universal k & N for a motorcycle/4 wheeler. i still believe the short k & N is lacking the airflow i need but couldn`t get anything else in stock in this town. i think i`m gonna get some hose that won`t collapse and put a long cold air duct to a large k&n type filter outside the engine compartment. she runs 100 percent better, but i still think she`s not able to pull the air she needs thru this small filter.

same size around as the ru 1910 but half the length.

also, the tranny shifts fine now, guess the collapsing hose caused that.

any ideas guys on the air filter type /location? and what about exhaust ideas?

do these cars flow/ perform better with a cat or without?

thanks for all help and advise, i caught holy hell getting those back plugs out and new ones in, but it runs like a naked ape now, although don`t believe she`ll get the 5 speed turbo t bird or the v-8 sho. but we will see when i can figure where the fluid from the rear of the brake fluid reservoir is going with a quickness.

i can go fast now but need to be able to stop quick LOL!!!!

again thanks guys and i`m sure i`ll need more help, my push fan works but my big fan has never came on, any tips there also? alan

Link to comment
Share on other sites

if it won't shift until you let off then its probably the TV cable. I am surprised nobody mentioned that

 

Posted by: TurboGTU

Also, check the Trottle cable that connects to the Trans. Make sure its not stuck. It should return when you pull on the cable. It should have some slack. If its fine, try loosening the cable by pushing on the ajusting tab to losen the linkage.

:mrgreen:

 

The problems you described are verry commen on the TGP.

The hose collapsing is one of the ones I told you about. It doesn't have the steel spring like the TC has to keep it from collapsing. The brake fluid leaking is the commen Power Master III brake system leak, Its cracked.

 

Unplug the big fan plug from the fan. Grab you volt meter or a test light. When the car is up to temp with the AC controlls at ON, both fans should be working. Using a volt meter/light probe, it should read battery voltage or light on. If not, check fuse box or fuse links. Also check your relay out. Last but not least, coolant temp sensor.

Link to comment
Share on other sites

As far as the air filter goes, here's an air filter topic from the TGP board.

http://www.tgpforums.com/index.php?topic=225.0

 

I have the RU1390 on my TGP and it fits great.

http://i2.photobucket.com/albums/y33/mfewtrail/1990%20TGP/IM002048a.jpg

 

 

About those autolite 103 platinums, some people here are probably going to tell you to ditch those in favor or copper cores. They will say this based on the old platinum plugs that could potentially cause problems(platinum tips breaking off). I don't think that's an issue now as OEM's install platinum plugs in their forced induction engines.

 

More power can be had from removing or gutting the cat, turbochargers like as little restriction to flow as possible. :wink: There's a post somewhere around here from a guy with a stock TGP exhaust and a cutout placed in front of the cat, his car showed very nice gains with the cutout open vs. using a completely stock exhaust system.

 

 

Link to comment
Share on other sites

thanks a bunch guys for the tips and advice, i guess i`ll be putting in a new break booster etc., if it leaks there and not at the lines or wheels. also i`ll be installing a cut out for the exhaust or putting in a new hi flow cat. in my experience with turbo`s you need some back pressure to spool up quick, maybe not with the turbo grand prix, but with some applications.

i just know it runs alot better now, although i hear it stumble thru the exhaust sometime when watching my son come by under boost. that could be the need for new wires at the plugs. every little thing i`ve done with everyones help has been a large improvement over the way it ran before each step. thanks again and " May The Boost Be With You!!!"

update as i progress or to replies.... alan

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...