engine running very weak since turbo swap

[dsm2012]

hey guys im new to this website a buddy of mine turned me onto it i am having some problems with my recent purchase of a 1990 talon tsi awd 1g as it says in the description i was pulling boost at first when i got the car but it had a bad aftermarket manifold cause it was cracked but the crack developed and the manifold had eventually so i swapped the manifold back to stock and then the turbo stopped working all together so it ran like a regular four cylinder, like crap, so then i figured the wastegate was stuck open on the 16b turbo so i played with it a little and got nothing after that fail i swapped the turbo to the stock rebuilt 14b turbo because i took apart the 16b and found a chunk of manifold stuck in the blades of the turbo so i knew the turbo was done after swapping my turbo bak to the 14b my car wont pull any boost instead its actually pulling a vacuum and i am 99.9% positive that ther is nothing wrong with the turbo itself sinve i can hear the turbo spool and the wastegate is fine but i have spent the past five days on it and cant figure it out i have had a couple of friends even check it out and even had a 1g GSX next to mine and compared the vacuum lines and they r all hooked up the same heres the main issue my car wont go over 30 mph and wont pull any boost its creating a vacuum instead and also the car wont go over 2000 rpms while driving and wont go over 4000 rpms while in neautral and giving it gas im thinking its a fuel to air ratio like a clogged fuel filter or bad injector but the problem is unknown i am just looking for a few suggestions please help it would be appreciated

 

[kccombs]

Blt (boost leak test)

 

[xyexz]

Welcome to the forums, what you'll get from most people on here is to do BLT (boost leak test, or bacon lettuce tomato).

Boost Leak Testing 101: Building the tool. - YouTube

Boost Leak Testing 201: Using the tool. - YouTube

 

[dsm2012]

Yeah thats what everyone has been telling me and im not losing boost anywhere. Plus I thought I might have had a clogged catylaic converter but I checked and its not plus I have even replaced the intercooler and bov (blow off valve) and nothing has changed it was idling rough. So I cleaned the throttle body but still didnt fix anything except the rough idle any other suggestions?

 

[Boostdriven]

Sounds like it could be something with your MAF (mass air flow sensor) check the connection and make sure its plugged in all the way. If you have another maf sensor try it. Like mentioned before check for boost leaks, a small vacuum line shouldn't cause that much issues but a torn coupler will. Also I would recommend getting a new o2 sensor if the one you have has a lot of miles on it.

 

[jacobgsx]

just a couple of questions first
are you running stock mas(mass air flow sensor)
what happens after two thousand rpm while in gear.. shuttering... stalling?
do you see any boost?
and is it throwing any dtc's (diagnostic trouble codes)?

 

[NOSLO2PT0]

hey guys im new to this website a buddy of mine turned me onto it i am having some problems with my recent purchase of a 1990 talon tsi awd 1g as it says in the description i was pulling boost at first when i got the car but it had a bad aftermarket manifold cause it was cracked but the crack developed and the manifold had eventually so i swapped the manifold back to stock and then the turbo stopped working all together so it ran like a regular four cylinder, like crap, so then i figured the wastegate was stuck open on the 16b turbo so i played with it a little and got nothing after that fail i swapped the turbo to the stock rebuilt 14b turbo because i took apart the 16b and found a chunk of manifold stuck in the blades of the turbo so i knew the turbo was done after swapping my turbo bak to the 14b my car wont pull any boost instead its actually pulling a vacuum and i am 99.9% positive that ther is nothing wrong with the turbo itself sinve i can hear the turbo spool and the wastegate is fine but i have spent the past five days on it and cant figure it out i have had a couple of friends even check it out and even had a 1g GSX next to mine and compared the vacuum lines and they r all hooked up the same heres the main issue my car wont go over 30 mph and wont pull any boost its creating a vacuum instead and also the car wont go over 2000 rpms while driving and wont go over 4000 rpms while in neautral and giving it gas im thinking its a fuel to air ratio like a clogged fuel filter or bad injector but the problem is unknown i am just looking for a few suggestions please help it would be appreciated

Holy shit! Pat Sajak, I'd like to buy a PERIOD!!!

 

[Strobe]

I had this exact same problem with my car when I was changing to hard piping and was cleaning up my fittings (corroded I.C flanges of course). I stuffed a rag into my IC to make sure filings and junk didn't get in there and forgot to pull it out. Ya I know Im a dumbass. My car ran exactly like what your describing. Any chance at all you have something stuck in your piping from when you did the swap?
If for sure not, when you have the car running, try unplugging the maf to see if the maf is actually functioning.

 

[dsm2012]

Yes I am running a stock mas(mass airflow sensor and it stalls after 2000 rpms and I have swapped the mas with a known working one. No I know that nothing is clogged I have even swapped everything to a known working intercooler and bov...could the fact that the bov(blow off valve) is crushed be an issue? And when I say crushed I dont mean its been stomped on im sure all of you guys kno what I am talking about. One last question if you notice I said that the aftermarket manifold had shattered is there anyway that it could have damaged the oxygen sensor but did it to where my check engine light isnt on?

Oh one question I forgot to ask. Where might I have a torn coupler cause I believe that I dont have any on my car but I could be wrong.

 

[MunkyX69]

Pretty sure you have couplers man. Unless the whole intercooler piping system has been welded. If everything is bone stock, then replace all the rubber pieces that connect the intercooler pipes. A crushed BOV could be a sorce of a leak, I had this happen on my car when I first got it, but I could still build boost. You can hear the BOV leaking air when just reving the motor.

Like everyone else says, do a boost leak test. Easy enough to make one, and you'll find out if you have any vaccume or boost leaks.

If the turbo was rebuilt and your IC system is good, the only thing I can think of is that someone put the compressor blade on backwords and the vaccume of the turbo is over taking the vaccume of the motor. Doubtful though.

 

[1983gsp]

the only thing I can think of is that someone put the compressor blade on backwords and the vaccume of the turbo is over taking the vaccume of the motor. Doubtful though.

WTF

Check the compressor for shaft play and that the turbo isn't seized. Go back over everything you've touched or replaced.

A restriction in the exhaust gives the same symptoms. Disconnect the downpipe and see if the problem goes away.

A disconnected coupler also gives above mentioned symptoms. BACON LETTUCE TOMATO!

Have you recently changed the fuel filter? If not, change it. Check the fuel pump sock and make sure its not clogged, or worse, torn/ripped. If it is ripped, pull an injector to see if trash has made its way to the injector inlet.

Check fuel pressure to make sure the regulator didn't give out on you, not likely, but possible.

 

[dsm2012]

Ok I will try the fuel filter and its all bone stock