Need Procharger High Idle Help

gsjohnson

New Member
Nov 21, 2007
81
0
0
Woodland Hills, CA
Hello-I'm new to your forum and I was referred here by a couple of friends who stated that there are some pretty sharp members here. I have a 2004 GT, 5 speed with 15,000 miles on the clock. Last weekend I completed a Procharger P1SC with a 3 row intercooler install and took it to the Dyno/Tuner after I completed it. I'm very mechanically savy, although this was my first centrifical super charger install and I thought that it was quite simple. The other associated adds were:
Focus SVT fuel pump
#42 injectors-Green
NGK TR6 spark plugs gapped at .035
Trick Flow Upper Plenum
70 mm throttle body
Lightning MAS
Diablo 2 stage chip
I bought the Procharger used and then sent it back to ATI for an inspection & overhaul just to be safe. Upon completion of the install, I drove the car 6 miles to the Dyno/Tuner. He reflashed the Diablo 2 stage chip for optimum performance keeping engine longevity in mind. This was done because he found that the supplied chip did not match my ECU tag #. No biggy. When I picked up the car it ran beautifully and very strong. The only problem was the idle was very high (between 2000 & 2500 RPMs). It would occasionally idle down to 1100 RPMs, but then it would start crawling back up to 2000 RPMs. The idle was irratic, but smooth. I called the Tuner and he asked me to bring the car back & he would fix the problem. I waited for the car while he reflashed the chip. He must have reflashed the chip at least 6 different times, but couldn't get the idle to go down. He asked me to drive it for a day and give him a call back to report how it was. Well, I still had a high idle problem, but this time it was more predictable. The idle was always at 2100 RPMs, but when I come to a stop, in 5 seconds, the idle would come down to 1100 RPMs and stay there. If I run the car down the road & put it in nuetral, the idle will stay at 2100 RPMs until I come to a stop. The Tuner was suggesting installing a smaller orfice in the IAC valve. I called ATI & they stated to check the surge valve. It was operating as designed. I was also asked to check for any intercooler/plumbing leaks. I found none. Now, I'm being suggested to replace the IAC valve, but I never had this issue previously and the car has low miles. Any ideas???
 
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SVT32VDOHC

waiting for the next hack atta
Founding Member
Nov 22, 2001
3,501
27
119
Motor City
I had this exact problem with my 96 Cobra Vortec. I had it installed and tuned and at the time my tuner used Autologic chips. Car ran great, reliable, and fast. High/eratic idle. There was really nothing he could do about it. 1 year later he started using SCT Tuning software. He called me...I came down, and my car was a new animal. Stock like idle, and even better driveability.
 
Jul 3, 2005
159
2
18
39
Va Beach, Va
I think that this may be very common after the first re-programming....it has something to do w/ the engine computer learning the new air/fuel, throttle response, and intake temps...people have said that you may have to put upto 200miles on the new setup for most of the kinks to work themselves out....I remember mine doing that back when I installed a new throttlebody/plenum...but it stopped after a week or so really gradually...I just kind of stopped noticing it
 

Killa

Active Member
Jul 9, 2007
1,006
56
49
This is very similar for my sistuation, after I did the PI intake swap my car high idle and car run like crap, but after a month car run fine , idle is fine too, alot people say the car need time to learn new setup.
 

2002BLGT

Well-Known Member
Dec 18, 2003
2,945
4
59
Bedford VA
www.dirtydirtyracing.com
Hello-I'm new to your forum and I was referred here by a couple of friends who stated that there are some pretty sharp members here. I have a 2004 GT, 5 speed with 15,000 miles on the clock. Last weekend I completed a Procharger P1SC with a 3 row intercooler install and took it to the Dyno/Tuner after I completed it. I'm very mechanically savy, although this was my first centrifical super charger install and I thought that it was quite simple. The other associated adds were:
Focus SVT fuel pump
#42 injectors-Green
NGK TR6 spark plugs gapped at .035
Trick Flow Upper Plenum
70 mm throttle body
Lightning MAS
Diablo 2 stage chip
I bought the Procharger used and then sent it back to ATI for an inspection & overhaul just to be safe. Upon completion of the install, I drove the car 6 miles to the Dyno/Tuner. He reflashed the Diablo 2 stage chip for optimum performance keeping engine longevity in mind. This was done because he found that the supplied chip did not match my ECU tag #. No biggy. When I picked up the car it ran beautifully and very strong. The only problem was the idle was very high (between 2000 & 2500 RPMs). It would occasionally idle down to 1100 RPMs, but then it would start crawling back up to 2000 RPMs. The idle was irratic, but smooth. I called the Tuner and he asked me to bring the car back & he would fix the problem. I waited for the car while he reflashed the chip. He must have reflashed the chip at least 6 different times, but couldn't get the idle to go down. He asked me to drive it for a day and give him a call back to report how it was. Well, I still had a high idle problem, but this time it was more predictable. The idle was always at 2100 RPMs, but when I come to a stop, in 5 seconds, the idle would come down to 1100 RPMs and stay there. If I run the car down the road & put it in nuetral, the idle will stay at 2100 RPMs until I come to a stop. The Tuner was suggesting installing a smaller orfice in the IAC valve. I called ATI & they stated to check the surge valve. It was operating as designed. I was also asked to check for any intercooler/plumbing leaks. I found none. Now, I'm being suggested to replace the IAC valve, but I never had this issue previously and the car has low miles. Any ideas???


is it set up as a blow thru ?
 

gsjohnson

New Member
Nov 21, 2007
81
0
0
Woodland Hills, CA
Update:
I returned to my Dyno tuner for the third time on Friday. After calling ATI, I really was not satisfied with the responses. My tuner in the meantime called Diablo. After they reviewed the tune, Diablo believes the problem is in the throttle body. Since I have a 2 stage chip, they suggested that a second tune should be setup as it was with the high idle problem. They further suggested that I then install the original T/B back onto the car and then flip my switch over to the new stage 2 tune. Then see how it runs and observe the idle quality. If the problem is resolved, then I need I new and different T/B than the 70 mm unit I had on the car. We are reinstalling the OEM T/B because we know we didn't have a high idle issue when utilizing that T/B. Diablo further stated that they have seen numerous high idle issues and that 90% of them have been atributed to aftermarket throttle body replacements. I won't have a chance to make these changes until Saturday. I'll keep you posted. Thanks to all who have responded so far.

I'm not sure what you mean by "Blow thru" when referring to a Procharger.
 

mklovell

New Member
Jun 19, 1999
29
0
1
Fremont, Ohio
Visit site
Ditto on the IAC Restrictor plate. Worked for me as well after I installed my P1SC. The only thing is that it helped but didn't fix. I ended up going to Lowes and picking up a couple of hose clamps and one of those copper plumbing end caps (1/2 OR 3/8 not sure) that would fit snugly in the hose between the IAC and the inlet tube. I ended up drilling about a 3/16's hole in it to restrict the air flow further.

That was the ticket. I started small and kept opening it up until it idled right. The only side effect is if it's really cold out I have to crank it a little before it will start. But don't be alarmed. I'm talking about it cranking for 3 seconds instead of the quick twist of the key and it firing.

So, I ended up with the IAC restrictor plate as well as my home made restictor. I'm assuming you could just get away with the home made job. You won't be risking anything except for cutting the hose and some low cost pieces like hose clamps.

The other side effect this fixed was it would take it's good ole time winding down. Now when I pop the gas it rev's and then drops to normal idle rev's like it should.

I hope that helps since it seems you are experiencing the same thing I was.