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3" blow through setup, idle problems

Posted by Ludachris, Dec 17, 2004

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  1. 91 white tsi

    91 white tsi Proven Member

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    That is what i was going to say. I have installed about 8 superchargers on my friends mustangs, if the maf is not in the correct roatation it will not read right and have the stalling affect as well. I dont belive it matters where the arrow is due to the fact that every innercooler creates a different turbulance pattern so the maf needs to be adjusted different in ever situation. I recommend marking part of it or remmebering where the connector is and try rotating it a quarter each time and drive and see if it acts different. rotate it all the way around till you find the perfect spot. I know that works on mustangs and could see it helping but i could be wrong. Also my TPS reads 6% at idle and 100% wot good luck
     
  2. Ludachris

    Ludachris Founder & Zookeeper

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    Interesting, I'll try this. I currently have the connector on the side... please let this be it! Please!!! OMG
     

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    1997 Eagle Talon TSi AWD (sold)
    manual · 2G DSM

    Road Race Build 7K  10  23

    1991 Mitsubishi Eclipse GSX
    435.0 whp · 399.2 lb/ft · 1G DSM
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  3. Ludachris

    Ludachris Founder & Zookeeper

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    Rotated the MAF around a little bit and drove the car around - didn't make any difference.
     

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    1997 Eagle Talon TSi AWD (sold)
    manual · 2G DSM

    Road Race Build 7K  10  23

    1991 Mitsubishi Eclipse GSX
    435.0 whp · 399.2 lb/ft · 1G DSM
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  4. ViciousVendetta

    ViciousVendetta Proven Member

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    ,
    Tough problem... I went with the 3in blow thru setup, I also have an Xact flywheel. I dont have the idle problem you do, just another one ive had forever hehe. The only thing I could think of is check the plug from the MAFT that plugs into the cars harness... As the instructions say it is very picky, and even if it looks like its plugged in correctly it might not be. Id try unplugging it and plugging it back in with a good bit of force and try starting her up again. That and the throttle cable might be slightly off... Sorry I cant be of more help. BTW your setup sounds kick ass, good luck getting her running solid!
     
  5. RED&BlackGSX

    RED&BlackGSX Proven Member

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    u put the arrow on top?
     
  6. Jshaorn1

    Jshaorn1 Proven Member

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    The rotation on a Gm sensor will not make a difference because of the style of sensor it is. A mustang sensor is a sample tube sensor and only get a fraction of the air sensored that goes into the tube and if it's not rotated correctly not enough air will get into the tube making the reading inaccurate. GM sensors don't have this problem since they use hot wire instead of sample tube. Where did you source you gm sensor? is it brand new or is it a junkyard pickup? I have my car setup with blowthrough and the same flywheel just not larger cams. When I installed the act flywheel the car kept stalling out on me also and how I fix that was installed the gm maft on my car. Apparently my stock 1g sensor wasn't metering correctly and once I got the maft on and drove it for about an hour it went right away and felt exactly as stock without the stalling issue. Why I asked if your gm sensor was new or used was because I have seen people get bad junkyard mafs and the car never ran correctly and had a few issues. If you got a buddy that has a working 3" that you could borrow from them give it a shot I've seen a good sensor fix a few problems people were having with the maft setups.
    -Jay
     
  7. RED&BlackGSX

    RED&BlackGSX Proven Member

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    www.Teamnabr.com says otherwise. If it did'nt matter, then why do all GM maf sensors on GM cars are rotated in the same direction
     
  8. Jshaorn1

    Jshaorn1 Proven Member

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    I've run my gm maft with the connector facing up down and to the one side since i do'nt have enough clearance to run it on the other side. Currently i have it with the connector facing up and out at an angle. I have never had any problems in any config and i was getting the same gram/rev with the exact setup. just had to take it off a few times to fix a hard to reach blown intercooler hose. You might want to check out the old maft yahoo group if it's still up cause it had some very good information about the gm unit. i'm not here to start and argument just relay what's worked for me.
    -Jay
     
  9. ViciousVendetta

    ViciousVendetta Proven Member

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    Just my 2 cents about the MAFT issue... It doesnt matter how the maft is roated really, but you must make sure the arrow is pointing the way the air is flowing. Having the MAFT in backwards will be an issue, so make sure the arrow is pointing toward your throttle body. From every GM MAFT thing ive read it doesnt matter if its slightly off, just have the connector part of the maft facing left toward the battery if you have clearnance, thats how mine is now.
     
  10. 92awddsm

    92awddsm DSM Wiseman

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    I dont have a maft but I do have larger cams, lightened flywheel, 750cc injectors, and a dsmchips.com stage 3. I had an Idle problem also and chased it for a while. First, I had idle raised to 950rpm with no avail. Next I played with a/f and it seemed to help a little. I actually richened it up 4-5% at 1k and leaned it 2-3% 2000-4000 low throttle and eliminated about 50% of the stalling problems.

    The real problem ended up being my fiav. I disabled it and all problems went away but then I was plagued with cold idle problems. I found another fiav, installed it and hooked coolant lines to it and the idle was great afterwards. Now I need to replace the ISC to eliminate the idle surge Ive developed in the past month or 2.
     

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  11. Ludachris

    Ludachris Founder & Zookeeper

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    Well then, it must be so :)

    I have a few good friends that know their LT1/LS1 tech. One buddy is running low 11's and comes from a family of Vette owners. He's been working on them most of his life. I trust him when he says that he's seen these sensors mounted at different angles from the factory. Sure, the airflow must be flowing in the correct direction, but the angle the sensor is mounted shouldn't cause any major problems - at least not the problems I'm having. The readings are more likely to be skewed by leaks or pressure surges.
     

    Street Build 9K  0

    1997 Eagle Talon TSi AWD (sold)
    manual · 2G DSM

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  12. yugotdonkey

    yugotdonkey Proven Member

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    I second the FIAV check. That seems to give alot of people idling problems.
     

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  13. 98spydert

    98spydert Proven Member

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    What happens to the FIAV to make it screw up? I started having an idle problem today and I'm replacing my leaky seals shaft seals and I've got an extra ISC if mine is bad. Should I do anything to the FIAV or can I do anything? Thanks for any info...
     

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  14. yugotdonkey

    yugotdonkey Proven Member

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    Anyone please feel free to correct me if I'm wrong, but the FIAV is used for aiding in cold start-up conditions. It can cause a vaccuum leak, and many people have found that blocking the FIAV off with JB weld or making a plate to block it off helps idle problems. Here's a few links on it.

    http://www.dsmtuners.com/forums/showthread.php?t=23185&highlight=FIAV+LEAK
    http://www.vallotton.com/fiavblockoff.asp

    Either blocking off/replacing the FIAV, or like the person above said checking your shaft seals could possibly help the problem.
     

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    1992 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  15. Mr.Tao

    Mr.Tao Proven Member

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    My car idled fine with stock flywheel, when i installed XACT flywheel, stalling issues came up. At this time, i also did the did the catch can mod. I tried rerouting the lines back in, but they didnt work so well. And if they were the lines, shouldnt they idle like crap right from the start? My car stalls most when i clutch in. I'm positive it's the flywheel. ECU cant compensate. Like DSMJIM said, gonna have to raise the idle to 1000 or more.
     
  16. hose101772

    hose101772 Proven Member

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    Gona throw this out.

    Ever try cleaning the air passages in the throttle body?Carbon buildup in the passages cause most cars to have stalling problems,light flywheel or not.
     
  17. RED&BlackGSX

    RED&BlackGSX Proven Member

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    I was going to suggest that too, but I ASSumed that they tried that already. But however, some of the simplest things are overlooked.
     
  18. Scrymerr

    Scrymerr Proven Member

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    Ludachris-
    Although I cannot help you much with one of the problems in your original post (the stalling one), I have had the same problem with hot starts. I do not know why the car cant be shut off, and then turned on 5 minutes later and still hold idle. To me this is a bigger problem than the stalling out. In order to correct the stalling out I just increased the idle and put a bit of tension on the throttle cable leaving the throttle plate open a tiny little bit. I wonder what would happen if I just drilled a tiny hole through the throttle plate?

    I know your biggest concern has been the stalling, but have you figured anything out with the hot starts?
     

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  19. missouri_dsm

    missouri_dsm Proven Member

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    I would try cleaning the throttle body with carb cleaner. After a while it will build up carbon around the throttle plate and air can barely get through. I have seen this problem on many cars and it seems to help, if not fix the problem 95% of the time. I could be way off, but I just like to try the cheapest and easiest solutions first. It would'nt hurt to try, and a can of carb cleaner is less than $10. :thumb: Beats changing flywheels any day.
     
  20. ISUJakey

    ISUJakey Proven Member

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    Did troubleshooting this issue evolve any further?
     
  21. jeremy0203

    jeremy0203 Proven Member

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    cleveland, Ohio
    had similar problem my mechanic just figured it out yesterday, my engine fuse kept blowin and also the car would stall when rpms dropped from a good number. got bad readings from front 02 sensor so he went to replace it and found it rubbing against the alternator. replaced it and made it so it didnt touch and what do you know, no more blown fuses and car no longer stalls
     
  22. TransAmConvert

    TransAmConvert Proven Member

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    Pittsburgh, Pennsylvania
    I'm just thinking aloud....

    I wonder if you could dial up the deceleration value on the AFC? I remember everyone says set it at 10% and forget about it. Im not even totally sure what it does, but theres a chance...
     
  23. kristmen

    kristmen Proven Member

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    Southwestern, Michigan
    This thread scares me. I finished a major project on my car. Did a a/t to m/t swap, rebuilt engine, rebuilt head, fidanza flywheel, maft/afc2 combo with some 650's.

    Few other things done too.

    Anyway the idle is WACK. it bounces between 800~3000 rpm's. Does not stall too much. Sometimes when I try to take off but that just due to the idle making it hard for me to drive.

    If I pull the wire off the idle switch, it idles at 3k steady.

    Boost leak tested fine. ISC tests in spec too.
     
  24. ITSME4G63

    ITSME4G63 Proven Member

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    chicago, Illinois
    if its causign you all these headaches, I mean whatever you do doesnt seem to be working. Try adjusting your throttle cable, so that the throttle plate stays open at like 1% throttle, youd have to mess with it back and forth, checkign the afc. It would cause your car to idle higher, but will fix the problem of your car dying when coming to a halt.

    Your car dying problem - trust me, your not the only one, theres tons of us!
     
  25. kristmen

    kristmen Proven Member

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    Joined Oct 26, 2002
    Southwestern, Michigan
    Thank god mine doesnt die. I just cant handle this ####ing idle. It's embarassing. People look at my car like I'm driven a ghetto hoopty.
     

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