I just got my car tuned using Crome last Monday. Almost everything went well and I made 291whp. The only thing we had trouble with is the idle. I have a Venom IM. Since it has no provisions for an IACV, we had to open the throttle plate a little using the allen screw on the bottom, by the rotor, to get the car to idle. We got the idle to stay steady around 1300 rpm. According to my tuner, for some odd reason the injectors would sputter when the TB opened up 3-10%. It would act like a mini Crome launch control, jumping 500 rpm or so back and forth. My tuner thinks its either the injectors (brand new PTE 1000cc), the Blox 68mm TB, the lack of an IACV, or combination of the three. Its good to race (WOT) but a hassle to drive on the street. Has anyone experienced the same thing before?

<U>setup</U>

fully built d16
sls topmount with sc6152s
venom intake manifold
blox 68mm TB

<U>dyno sheet</U>

 

If you disabled the IACV in crome it is probably fuel cut. Does it happen around 1900 RPM?

 

get an IACV on there or have ur tuner retune the part throttle areas where the car is stumbling. i have tuned a few cars on crome where there was no IACV motor. the car ran fine and clean throughout the RPM, but some cars would want to shut off when coming to stop if the TB wasnt opened up a bit

 

Have him enable the iacv code & simply plug-in an iacv to see how it effects the partial throttle.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">If you disabled the IACV in crome it is probably fuel cut. Does it happen around 1900 RPM?</TD></TR></TABLE>

It happens throught the PRM range. Once that TB is opened up that 3-10%, it'll sputter.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">get an IACV on there or have ur tuner retune the part throttle areas where the car is stumbling. i have tuned a few cars on crome where there was no IACV motor. the car ran fine and clean throughout the RPM, but some cars would want to shut off when coming to stop if the TB wasnt opened up a bit</TD></TR></TABLE>

Well upon startup, the car will hold idle at 1300rpm but once it warms up good, the motor will have a suging idle and slowly idle itself down until it dies. If i adjust the allen screw under the rotor to open up the plate, its gets close to the 3-10% range and starts to sputter. Did any of those cars you tuned on crome have a sheetmetal intake manifold?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mtber &raquo;</TD></TR><TR><TD CLASS="quote">Have him enable the iacv code & simply plug-in an iacv to see how it effects the partial throttle. </TD></TR></TABLE>

Correct me if I am wrong, but isnt it the IACV's job to supply the motor with enough air to idle when the throttle plate is closed/idle? My sheetmetal intake manifold only has the one hole for the TB opening, which is portmatched to my 68mm TB. If i were to plug in an IACV, wouldn't I have to somehow attach one hole to the IM and supply a pre throttle plate source of air for the other hole on the IACV?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by peiku &raquo;</TD></TR><TR><TD CLASS="quote">
It happens throught the PRM range. Once that TB is opened up that 3-10%, it'll sputter.
</TD></TR></TABLE>

Adjust the fuel/map cut settings.

 

I'll have my tuner take a look at those again. I'll see if he can chime in on this thread. He's doesnt frequent HT much.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by peiku &raquo;</TD></TR><TR><TD CLASS="quote">

Correct me if I am wrong, but isnt it the IACV's job to supply the motor with enough air to idle when the throttle plate is closed/idle? My sheetmetal intake manifold only has the one hole for the TB opening, which is portmatched to my 68mm TB. If i were to plug in an IACV, wouldn't I have to somehow attach one hole to the IM and supply a pre throttle plate source of air for the other hole on the IACV?</TD></TR></TABLE>

Yes, but I suspect the issue may have something to do with the iacv delete code. (Just throwing it out there). Try enabling it & let the iacv dangle until you get the bypass kit. (Just a thought....)

Before you have him do this, try making sure the tps is properly calibrated.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mtber &raquo;</TD></TR><TR><TD CLASS="quote">

Yes, but I suspect the issue may have something to do with the iacv delete code. (Just throwing it out there). Try enabling it & let the iacv dangle until you get the bypass kit. (Just a thought....)

Before you have him do this, try making sure the tps is properly calibrated.</TD></TR></TABLE>

That was the very first thing that I did before I started the car up. With the throttle plate closed, I adjusted the TPS exactly to 0.5v. We havent touched it since. Currently, the reading is sitting at 0.65v because we had to open the throttle plate a little for the car to hold an idle. I will have to wait until tomorrow to try it with the IACV enabled and dangling.

 

still try to adjust the TPS with the car running. that might help out a bit.

one of the cars i did had a Venom IM which has no IACV support. car ran good but sometimes it would stumble when coming to a stop.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote">still try to adjust the TPS with the car running. that might help out a bit.

one of the cars i did had a Venom IM which has no IACV support. car ran good but sometimes it would stumble when coming to a stop.

</TD></TR></TABLE>

Right now the TPS reading is 0.65V because we had to open it up a little to hold an idle. Should I re-adjust the TPS so that it reads 0.5V with the current throttle plate posistion? This was also one of my concerns. Wouldn't the TPS have to read 0.5V to tell the ECU that its idling or can you adjust the TPS reading in Crome?


Modified by peiku at 4:18 AM 10/18/2008


Modified by peiku at 5:51 AM 10/18/2008

 

make sure the tps is calibrated.....