View Full Version : need help, poor idle after turbo install

09-23-2007, 11:49 PM
Over the course of the past month, when I've had times in the evenings and on weekends, I've been upgrading my SR. I added a GT2871R, new hotpipe, downpipe and elbow, stainless lines, 740cc injectors, new plugs, z32 maf and got an enthalpy tune.

It finally ran today. I drove it around the neighborhood and it's a monster. But.....it doesn't idle worth a damn. We cranked it the first time and it ran fine for about 3 minutes, then I began losing vacuum, and the car died. So...we checked for leaks and fired it up again, it look longer to turn over and idled very rough. We tried and tried, checked and rechecked, the finally let it sit and cool down. I came back to it a few hours later and it started right back up and ran fine for longer...about 5 minutes, then idled roughly but never cut off like it had before; it sputtered and then caught itself, and regained vacuum pressure.

It continued to do this, even when i drove it around a little, cutting off occasionally when I would let off the gas. Anyone have any ideas what this may be? Nothing's leaking that we can tell...

09-24-2007, 12:53 AM
car running rich?

09-24-2007, 02:18 AM
I have been having this issue as well and after playing with my fuel and timing and a few othr maps in my EMS it is better. The only thing I can advise is a piggyback to tune with, cuz the only way I fixed mine was in the software.

Verify timing of CAS, I know you didn't touch it right, but I haven't touched alot of things after upgrades, yet somehow they change.

Now my idle sits stable between 850-900 with cams and built motor at ~300mmhg vac. I have a feeling this will change when I reshim my SLA though.

09-24-2007, 08:12 AM
yes,you need fine tuning since you've changed bigger injector and z32 maf.

09-24-2007, 11:49 AM
the ecu has been tuned by enthalpy...I dont see why I would need anything else

09-24-2007, 12:59 PM
Although enthalpy has really good tunes, all engines are different, and will benefit from fine tuning with a piggyback. Also pull IACV, clean and re-install as a preventative measure.

09-24-2007, 08:36 PM
None of my enthalpy tunes have ever idled ok, it all depends on the car. If you email chris or scott they will usually try to lean out the idle for you and send you a new tune, but its easier if you just grab a rom reader and fix that **** yourself. Safc should also do the trick.

Oh and I hope you have a wideband, trusting a tune to be spot on without checking AFR's is a bad gamble.

09-24-2007, 10:12 PM
nope, no wideband. Will probably hook it up to a wideband and see if everythings good with it this weekend. In the next few weeks I should be able to get an AFC. Gotta buy a new bed first.

Figured the issue out, messed with the idle a little bit, found a vacuum leak from the boost gauge. Car ran beautifully. With the boost controller off it held at 12psi and pulled really really hard at 1/2 throttle. I won't be pushing it real hard until I can get an afc, wideband and a new clutch.