ernielist Posted February 8, 2009 Report Share Posted February 8, 2009 Heres the deal, I picked up my quest with 20k on a rebuilt motor. When I got it it had a bucking problem which occurred around 3-4 k and it only happened when the car was hot. Recently the problem has been getting worse. Heres what I have done to correct it and it hasn't worked so far: Replaced the ignition wires, coil, cap, rotor, and plugs with the recommended stuff. Replaced the fuel filter, dropped the tank and inspected it for corrosion (clean) checked the strainers and replaced the fuel pressure regulator. Checked the injector clips, cleaned the clips (which are relatively new anyhow) and the injector connections. I also had the injectors ultrasonically cleaned. I have tested the engine collant temp sensor and the injectors and they ohm out to be normal. The 02 sensor is good as well. I have no cat or precat so I know they are not clogged. I have cleaned and checked all the fusible links and the sensor connectors. I spoke witha friend of mine who runs a shop and described the problem. He told me that he would bet money on it that my turbo was bad and it was binding up. He told me to look at the hose going from the turbo to the intercooler to see if there was oil in the hose going to the intercooler. I pulled it and I noted a minimal amount of oil, maybe enough to wipe out with one pass of a rag. I couldnt feel any shaft play either. I will check to see if the compressor wheel is binding on the housing and update yall. Link to comment Share on other sites More sharing options...
ernielist Posted February 8, 2009 Author Report Share Posted February 8, 2009 Update to my first post - Once the car cooled down I checked the turbo for shaft play and to see if the impellar spins freely within the housing. The impellar spins fine, but I did note some shaft play. I am not sure how much shaft play is too much? I can move the shaft up and down pretty good...can this cause the turbo to bind up and cause the bucking problem when the turbo bgins to spool up since it is restricting exhuast flow? The bucking only happens under boost and it is worse when the turbo first spools up and starts to go away as it boosts further? Any ideas? Im about to give up on this car lol. Link to comment Share on other sites More sharing options...
vettekiller593 Posted February 8, 2009 Report Share Posted February 8, 2009 Stick a vacuum hose on you distributer vacuum advance and suck on it and see if its holding. If not its a bad vacuum advance. Link to comment Share on other sites More sharing options...
MadMax Posted February 9, 2009 Report Share Posted February 9, 2009 Check for scratches inside the turbo housing and check for bent blades on the wheel. unless that turbo has been recently rebuilt it will have shaft play, come to think of it Ive never come across one with journal type bearings that doesn't have a little play. I second the vac advance check, also check the rubber boot before the turbo and the flexible boost pipes for cracks. Maybe a vac line collapsing? Link to comment Share on other sites More sharing options...
Dad Posted February 9, 2009 Report Share Posted February 9, 2009 My vac advance passed all those tests. But I still had a "hicup" on hard accel about 3500. That hicup went away after I put a new Vac advance on. Dad Link to comment Share on other sites More sharing options...
ernielist Posted February 9, 2009 Author Report Share Posted February 9, 2009 My vac advance passed all those tests. But I still had a "hicup" on hard accel about 3500. That hicup went away after I put a new Vac advance on. Dad My vac advance is good and this isnt just a little hiccup. My friend who told me I had a bad turbo came by and checked it out for me and told me that my shaft play is excessive and that when he turned the impeller in its housing he felt it bind up due to the shaft play. He said that he has seen it alot and that on a 19 year old car thats probably the culprit. Ernie Tsi said that a rebuild kit is available on ebay and the rebuild is pretty simple and cheap. Link to comment Share on other sites More sharing options...
Starwolf Posted February 9, 2009 Report Share Posted February 9, 2009 i figured you would really hear the noise of a bad turbo...or notice smoke from your exhaust (sorry if i didnt read all the posts and missed something) Link to comment Share on other sites More sharing options...
tsiconquest88 Posted February 9, 2009 Report Share Posted February 9, 2009 Yea funky, i wouldnt be surprised if u still have the buck after a new turbo though lol. I dont think thats ur prob but hey its prob part of something. You technically wouldnt get a buck from such a thing you would be under boost and if the blades touching the housing you should definately be hearing soemthing and feeling a lack of power possibly, a buck? i wouldnt think so. If its hitting the housing that bad that shaft would (shoulda be) broke by now. Link to comment Share on other sites More sharing options...
tsiconquest88 Posted February 9, 2009 Report Share Posted February 9, 2009 my 2.6 cents lol Link to comment Share on other sites More sharing options...
ernielist Posted February 9, 2009 Author Report Share Posted February 9, 2009 my 2.6 cents lol Thats what I thought as well but my friend used to own an import tuner shop and did specifically turbo work. When I described the problem to him he bet me money the turbo was bad. He also took a listen as it went down the street. The compressor blades arent hitting the housing, the shaft is just binding up under initial boost due to the shaft play and as the turbo spools up its spins better. Thats why you get the initial buck at 3-4k rpms when the turbo just starts to spool, due to it binding up the exhuast gases cant get past the turbo impellar as efficiently and it makes the car buck. Thats not exactly how he explained it, but I think he's right, I have gone through everything else in the car and the car idles fine and drives fine when if I stay out of the boost. The turbo spools with no problems in neutral under no load as my friend predicted. He basically explained it as a large exhuast restriction. I had hoped he was wrong, but...I would like to get Indianas opinion on this however if hes reading this thread. I found rebuilt 12as for $160 bucks, so its not like its that bad and I also found rebuild kits for 110. Its a 19 year old turbo, what can ya expect. Link to comment Share on other sites More sharing options...
Starfighterpilot Posted February 11, 2009 Report Share Posted February 11, 2009 I have not read that you did a TPS sweep test. That may be your problem if you have not done it. See the below on how to perform the TPS test and reset. http://starquest.i-x.net/viewtopic.php?t=907 For What It's Worth. KEN Link to comment Share on other sites More sharing options...
Hoosierquest Posted February 11, 2009 Report Share Posted February 11, 2009 (edited) when you got your injectors cleaned were they tested to assure there was no leakage and a proper spray pattern? Also have you removed the dist. and checked the VA linkage for freedom of movement? Make sure its not gummed up and that it moves smoothly as you add pressure. How did you check the VA? Edited February 11, 2009 by Hoosierquest Link to comment Share on other sites More sharing options...
ernielist Posted February 11, 2009 Author Report Share Posted February 11, 2009 when you got your injectors cleaned were they tested to assure there was no leakage and a proper spray pattern? Also have you removed the dist. and checked the VA linkage for freedom of movement? Make sure its not gummed up and that it moves smoothly as you add pressure. How did you check the VA? I checked the vac advance with a might vac, I also checked to make sure I was getting vac from the TBI its all good. It was also explained to me that our 12a turbos have shaft play when they are cold and as they come up to op temp the shaft play goes away. I think I found the problem however, I think my mas air unit is bad, I got a friend coming over tommorow with one to see if that fixes the problem. The only thing wrong with my distributor that I can see if a little shaft play, ill address that later, but I think the mas is gonna be the culprit. Link to comment Share on other sites More sharing options...
Ernie88TSi Posted February 13, 2009 Report Share Posted February 13, 2009 Just a quick little update on Ernie's behalf... (heh, what's the odds of two Ernie's owning StarQuests in Jacksonville). I went over to Ernie's house today and went thru the car a little bit. MAS is fine. The primary and secondary injectors had been in the wrong positions (primary closest to firewall). On top of that, the pigtails were also swapped... the primary injector plug was running the secondary injector. I'm actually surprised that it idled without being pig rich. It defiantely was running rich at idle, but not pouring out black smoke. Anywhoo... Once we got everything where it should be, I diagnoised it to be a bad primary. I'll yank one from my car or one of my spares. They do ohm out ok, but the car did a lot of sitting previous to Ernie purchasing it. Secondary appears to be in excellent condition. It actually idles like crap running on the primary... idles pretty close to perfect on the secondary. Another issue that is magnifying the problem is his base timing is out of whack. Vac advance is working just peachy, no vac advance hiccup. I went over his car pretty well, and this Sunday I'll run back out to his place and get everything straightened out. Overall his car is pretty nice and clean, he'll be ready to take it out and enjoy it soon enough. Link to comment Share on other sites More sharing options...
ernielist Posted February 13, 2009 Author Report Share Posted February 13, 2009 Just a quick little update on Ernie's behalf... (heh, what's the odds of two Ernie's owning StarQuests in Jacksonville). I went over to Ernie's house today and went thru the car a little bit. MAS is fine. The primary and secondary injectors had been in the wrong positions (primary closest to firewall). On top of that, the pigtails were also swapped... the primary injector plug was running the secondary injector. I'm actually surprised that it idled without being pig rich. It defiantely was running rich at idle, but not pouring out black smoke. Anywhoo... Once we got everything where it should be, I diagnoised it to be a bad primary. I'll yank one from my car or one of my spares. They do ohm out ok, but the car did a lot of sitting previous to Ernie purchasing it. Secondary appears to be in excellent condition. It actually idles like crap running on the primary... idles pretty close to perfect on the secondary. Another issue that is magnifying the problem is his base timing is out of whack. Vac advance is working just peachy, no vac advance hiccup. I went over his car pretty well, and this Sunday I'll run back out to his place and get everything straightened out. Overall his car is pretty nice and clean, he'll be ready to take it out and enjoy it soon enough. Yea ernie, thanks again for coming out and checking out the car. I really appreciate it. Heres a lit fo what has been done with the car for everyone to peruse, if anyone else can think of any other maintenance type items I need to do on the car let me know: Cap and rotor replaced Ignition wires replaced All fuel filters replaced, strainers checked, gas tank checked, fuel pump checked. All intercooler hoses checked for cracks and tightness. Valve lash adjusted to .006 for intake and .009 for exhuast BSE kit complete JV Kit complete FPR replaced Plugs replaced with NGK BPRES-11 (think 11, whatever the ngk stuff is supposed to be for out cars) KN cleaned and oiled. Rag joint replaced Winshield fixing to be replaced. Ernie fixed my third brake light and rear wiper motor. Injectors cleaned and flowed Vac advance checked for proper functioning, distributor cleaned. Vac advance signal from TB checked and verified. Verified 10.5 psi of boost coming from turbo with mechanical gauge Shaft play checked in turbo, all good. Iginition coil replaced with new stocker (will upgrade to MSD once car is running right.) Cleaned all fusable links except for the main link which I will be replacing. Cleaned all relays under hood. Checked alt for good voltage and amperage. Removed ac compressor and associated belt. Repaired engine collant temp sensor connector and checked sensor for proper operation. Checked wastegate for proper operation with might vac. Oil and filter change Vac lines checked and replaced. Interior professionally cleaned I cant think of anything else at this time. If anyone can think of anything else I need to do let me know. Mods I am planning - 3 inch downpipe with associated exhuast Increase boost pressure from 10.5 to 15 psi. MSD coil 8mm wires Hardpipes for IC lines Link to comment Share on other sites More sharing options...
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