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Discussion Starter · #1 ·
Hey guys whats up. I got a quick question. I've seen posts like this a million times, and im guessing my problem is pretty common, although the fixes listed in previous posts didnt help my problem
I have a single turbo setup still utilizing the stock maf. Yes I know its not the ideal setup but its gotta stay like this for a little while.
The car runs perfect, its boosts perfect everything is good.
The only small problem I have when putting the car back into nuetral and rolling to a stop.
If im driving steady at like 2000 rpms and have to stop at a red light, i hit the clutch, put the car in nuetral, then roll to a stop.
When the rpms drop it goes to around 200 rpms bounces a little and tries to catch its self, some times it does...and sometimes it stalls.
I've read alot of times that this is caused if the bov is not rerouted. So i rerouted the bov back into the intake pipe and that didnt do anything. Do i maybe need to adjust the bov soft or hard? i tried messing with it a little but didnt really get any results.

I also thought maybe i just have to slightly raise the rpms? At idle my car is at like 500-550rpms which i thought is a little low. Maybe if i raised it to like 700-800 rpms I wouldnt run into this because when it drops after coming out of gear it would only go down to like 400-500 and then catch its self back up to 700?

Any input would be greatly apprecaited.
Thanks Alot
John
 

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You need to raise your idle.
 

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Captain Cool
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idle rpm's seem kinda low,,,normal should be around 750-800
 

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you routed the IAC hose to the filter from the turbo right? me and freidn put a filter over his, setup and it did the same thing so we routed it back to filter from turbo and it worked fine.. Also sorry to jack your thread but is the stock preasure tank in use when you go single?
 

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Boost Junkie
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Pressure tank is no longer used. Did you reroute the BOV behind the MAF? If so you should be golden. If not, move it. What device are you using to tune with?

Steve K.
 

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Discussion Starter · #6 ·
Yes, the BOV is routed right behind the stock maf. Its between the stock maf and the turbo.
Im not using any tuning device, im using the stock maf, with the stock obdII computer.
I had this problem once in a while with the stock twins. Perhaps it is just the idle like many of you said.
 

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Discussion Starter · #7 ·
d0cktor said:
you routed the IAC hose to the filter from the turbo right? me and freidn put a filter over his, setup and it did the same thing so we routed it back to filter from turbo and it worked fine.. Also sorry to jack your thread but is the stock preasure tank in use when you go single?
Yes I have the IAC routed correctly. If you dont have that, the car wont even idle.
 

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Don't forget the dashpot as well. I adjusted mine and my car doesn't stall nearly as much as it used to, and I'm running an atmospherically vented bov. Adjust your idle and your dashpot and see if that doesn't fix the problem.
 

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Hey bro...Heres your solution:

There technically is none that I know of, UNTIL you get rid of your stock maf. The thing is no matter how you adjust your BOV, open and close the valve behind it, the stock MAF is getting the wrong "air pressure" signal due to the atmospheric BOV. I had this problem ALL the damn time with my old car. The only way to get rid of it is to either get HKS VPC, which will complete your single setup, together with a fuel controller of course, as well as get rid of maf. OR go AEM, MAP ECU.
 

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^^^ agreed. i was having the same problems, so i just decided screw it n went VPC/SAFCII, there will be no more problems after they go in, and plus you will be able to tune it to make alot more power.
 

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Oh yeah, almost forgot i have a good condition HKS VPC with the "B" chip for single turbos for $390 shipped to your door.
 

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Supra Owner Since 1996
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I had the same problem and always had to feather the RPMs when coming to a stop until the ECU caught back up. It's habit now and I do it in everyones car. Raising the idle will help catch more of the stalls. Car is currently in for AEM install.
 

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Discussion Starter · #14 ·
I understand what you guys are saying about the vpc etc, and I do plan on doing something to that nature in the near future. But im tryign to make the car as best as i can for now.

Sorry, but what is the dashpot?

Thanks for the responses.
John
 

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pane2k said:
I understand what you guys are saying about the vpc etc, and I do plan on doing something to that nature in the near future. But im tryign to make the car as best as i can for now.

Sorry, but what is the dashpot?

Thanks for the responses.
John
Your best bet is to either feather the RPM's when you shift to neutral, like stated above, OR keep the car in gear until you are almost at a complete stop, then you can shift it to neutral. Its annoying but basically something you will have to live with, and cant really further "improve", you can try to raise idle, but you will still run the risk of your car stalling out, sometimes it can be annoying, until you go the other aformentioned routes.
 

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'95 TT
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In my NA-T, I had this problem when venting the BOV to the atmosphere.

I found that there was a "sweet spot" that I could push the clutch in when coming to a stop. That spot for me was at about 1200 rpm. I would leave the car in gear, and while slowing down, as soon as i saw the tach hit 1200 rpm, i pushed in the clutch and the car held idle. If i didn't do this it almost always stalled out.

With your idle being lower than what mine was, that advice may or may not help, but give it a try.
 

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Alpine Hardtopper
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The dashpot is located on the throttle body. It's a little damper that slows the closing of the throttle in the last bit of travel. First, check if yours has been removed. If it's still there, test it with the engine not running by opening the throttle 1/2 way by hand, and letting it go. It should hit the dashpot and slow way down before closing.

For an image of the dashpot location, see here:
http://www.its2.uidaho.edu/cordon/dan/automotive/Cars/Supra_Images/Supra_dashpot.jpg
 
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