turbo spools but no pull

[tsi8503]

hey i have a 90 talon tsi with a newer turbo. the problem is that sometimes when i go to hit the turbo, it spools up and whistles but the car doesn't pull. its like the turbo stops pushing air into the intake. But then other times it will pull ike normal. any comments would be greatly appreciated.

 

[c_riggan]

Same problem here... Most of the time it pulls nice and hard.. every once in a while, it pulls like crap.. feels like it is trying but holding back. the turbo spools much quicker than normal when it does this, hitting 15psi waste gate fully open and no pull (even at low low RPM).. this happens at WOT or at normal throttle.. I used to have a fuel cut problem, but it vanished and now does this instead. The car runs extremely rich too (All the time), enough that my room mate mentioned it cause he could smell raw fuel when he was behind me on the freeway. Hope somebody figures this out.. I have run a boostleak test it charged up to 30psi (dropped in mere seconds) but can't find the source of the leak anywhere. I think it is probably Phantom Knock or timing pull due to overfuel..

 

[MitsGray97]

I have a 90 tsi with the same problem, good boost (14psi) but no power. Pressure test was ok…could it be the throttle position sensor?

I was wondering the same thing? I just barely started having this issue after i tweaked with the tps and cas. And it was a sudden thing. Car was boosting fine then i
Turned it off, messed with the sensors. Turned it on and vaccum was low and car didnt pull. Gauge reads accurately and it reads boost and i can hear the turbo spool and bov work. I would really like to figure out what is causing this issue.

 

[Joethefallen23]

I was wondering the same thing? I just barely started having this issue after i tweaked with the tps and cas. And it was a sudden thing. Car was boosting fine then i
Turned it off, messed with the sensors. Turned it on and vaccum was low and car didnt pull. Gauge reads accurately and it reads boost and i can hear the turbo spool and bov work. I would really like to figure out what is causing this issue.

Absolutely! An old saying I was taught is K.I.S.S. (Keep It Simple Stupid). The car ran fine before hand and not so much after? Get your hands on your voltmeter and re-adjust that TPS!

 

[MitsGray97]

Absolutely! An old saying I was taught is K.I.S.S. (Keep It Simple Stupid). The car ran fine before hand and not so much after? Get your hands on your voltmeter and re-adjust that TPS!

Well I know what you mean.. after that happened i immediately adjusted the tps with the voltmeter. I thought it would go back to normal but it stayed that way. I put both the cas and tps back to how they were. but the "full boost no pull" issue persists.. any ideas? It used to pull hard even when it had bent valves. and like others say.. its embarrassing

 

[crand]

just had a buddy have this same problem and sure enough it was his plastic bov,

 

[Bouche Dag]

I was a freshman in H.S. when this thread was started.

Sounds like you all need to do BLTs

 

[MitsGray97]

So ive fixed a couple of boost leaks... last one to do is an injector o-ring.. but the car still develops full spool no pull and low vac. No difference whatsoever. The only upside is the faster spool. But i rather have the pull over fast spool any ideas other then blt's? Maybe its not mechanical? I really need some insight..

 

[GSTurbo1]

could your clutch be slipping?

 

[alphamythos]

Boost leak with high fuel , probably getting the timing pulled .the car is ecu is compensating for the fuel getting close to fuel cut often and air volume . You find out what's wrong with a log . Evoscan could help you figure it out .

 

[MitsGray97]

Well the clutch slipping wouldnt make the vacuum drop. And I am getting some knock. so it could be that but i would really like to know is if anyone knows if the cas and tps could have anything to do with this, and if so how its related to it directly. Those were the last things i messed with before this happened. the source of the problems has to be there somewhere.

 

[jasjasbinks]

maybe your wastegate is stuck open?

 

[curt-s]

could your clutch be slipping?

A slipping clutch would also be most often evident by engine RPMs racing up but no real extra speed being gained, as gear and engine RPMs (along with tire diameter, etc.) are a function of vehicle velocity. A test of this could be finding a bridge or steeper grade incline, and driving up in at lower speed with the throttle mashed in high gear -- 4th or 5th. Should be able to see the clutch slip by doing that.

maybe your wastegate is stuck open?

A wastegate stuck open would cause the turbo to not spool as much, or at all.


Have you verified both mechanical and ignition timing?

.. you really need to check a logger

 

[MitsGray97]

Hmm ive already had my clutch slip on me before so i know how that feels. Ive checked base timing and its at 5 grounded and about 8-13 at idle ungrounded. Ive also redone the exhaust gaskets. Checked turbo and it checks out fine. Ive done a couple of boost leak tests, fixed them. But with the blt issue. Ive always had boost leaks and it boosted fine and pulled hard. Even when it had low compression due to bent valves and riding on only 3 cylinders. It pulled hard. You can kinda see my frustration im honestly not sure its mechanical.. so what effects does the cas have if its rotated without the pin being grounded?


Keep in mind that i got a 6 bolt swap. I also got ecmlink to log and keep things under control

 

[jrohner]

Phantom knock will cause the car to not accelerate with boost. Check the condition of your knock sensor. If the end is all gooey get a new one.

 

[MitsGray97]

Yeah i thought it could be phantom. I checked my knock sensor a couple of days after screwin my car up. It was gooey and i also had found that one of the wires had ripped out at the connector so i went to the junkyard and replaced the pigtail. But unfortunately it didnt fix anything. Now my question is if it was knock.. how could that drop my vacuum from about 18 to 10?

 

[Slightlystoopod]

Boost leak test (obviously). Check your intake gasket. It could've gone bad and there is a big boost leak. Also, check your BOV to make sure that it isn't getting stuck open and constantly dumping boost. Another thing, if your turbo is internally wastegated, make sure the wastegate isn't stuck open. Only things I could see. Maybe the throttle body not opening all the way and the boost pressure is getting hung up on the throttle body plate.

 

[MitsGray97]

Ive already performed severals blts. Ive fixed the leaks. Bov isnt sticking.. But like i stated before.. ive always had boost leaks and its always pulled hard. I adjusted the throttle plate after redoin the shaft seals. Ive also checked the timing belt for slippage and it was good. Turbo has an external wastegate and its working properly. To those who just tuned in- this instantly happened after i messed with the cas and tps. Turned the car off.. messed with both the sensors(rotated the cas without grounding the pin-not sure if it does anythin when ungrounded). Started it up and the vacuum had dropped and had no pull. I put them both back in place but the issue persisted.

 

[gotclutch23]

Make sure the vaccum line to the blow off valve has no cracks and make sure its hooked up ive forgot a few times also sounds like boost leak just check all your piping for any holes cracks ect.

 

[MitsGray97]

yeah ive done blts, but still have the issue. kinda getting sick of the non turbo feel with a turboed car i checked the bov several times, connections and such, the only thing that i could think could be wrong would be my egr, i get the dtc for it but i just ignored it with ecmlink. if the egr isnt working properly could that give me boost issues?

 

[gieri002]

My vote is boost leak. At least do a blt, it will narrow the options down immensely.

 

[Cool09]

Wow, another person suggesting a BLT. Somehow I don't think people are actually reading the thread.

 

[Spyderman7]

On all the 1g cars i have owned that boost but dont pull I check the timing and it is always wrong so I just advance the timing with timing light and they come back to life.Usually it is because who ever played with the cas doing a head job or something never set it back in the right place using a timing light.

For those that this comes and goes I would think phantom knock is causing the ecu to pull timing or something.I believe someone has already said this in this thread

Check your base timing with timing light and make adjustments. To advance go clockwise and to retard counter clockwise with the CAS

And my thoughts on a boost leak just doesn't sound like it is the case.A boost leak will usually cause the car to break up under boost.

 

[MitsGray97]

Wow, another person suggesting a BLT. Somehow I don't think people are actually reading the thread.

Haha for reals

On all the 1g cars i have owned that boost but dont pull I check the timing and it is always wrong so I just advance the timing with timing light and they come back to life.Usually it is because who ever played with the cas doing a head job or something never set it back in the right place using a timing light.

For those that this comes and goes I would think phantom knock is causing the ecu to pull timing or something.I believe someone has already said this in this thread

Check your base timing with timing light and make adjustments. To advance go clockwise and to retard counter clockwise with the CAS

And my thoughts on a boost leak just doesn't sound like it is the case.A boost leak will usually cause the car to break up under boost.

Thank you ive been looking for this kind of answer. Ive checked base timing and it seems to be at 5° Now my question is what happens when the cas is rotated without being grounded? I have rotated the cas back and forth and it affects it for a couple of seconds and them it goes back to normal.

 

[redheadbov]

Same issue, but will not pull at all I did a blt to 15psi and held nicely except for a single injector o ring leaking. What i recently did was put a rebuilt throttle body on, and messed with the cas...... Now it has no pull but full spool and too quick spool on a .70 compressor housing. I have a 6 bolt swap,660 denso injectors, 2.5 dsmlink, large fmic, 1g bov, smp exhuast manifold, and 3in downpipe with cut out right below the driver seat. I have yet to check base timing again, which I know I should. Im running a little rich as of right now because of no wideband which im getting as soon as i can afford it. If someone actually fixes this please put a detailed post of what you did.

P.S. I DID A BOOST LEAK TEST THANKS

 

[awdtalon4451]

Haha for reals



Thank you ive been looking for this kind of answer. Ive checked base timing and it seems to be at 5° Now my question is what happens when the cas is rotated without being grounded? I have rotated the cas back and forth and it affects it for a couple of seconds and them it goes back to normal.

Not sure if this is the case but mine did something similar when I installed the CAS 180* out. MIne ran lIke poo cause of It. Something worth looking into.