This is probably all tied to my IAC problems, but who knows.

Here's the deal. My 5-speed 350 IROC has ran a best of a 14.3@97 with a lousy launch in 80 degree weather. This tells me it's 13 second capable as-is. The car won't even chirp 2nd when I shift. It is a pig at low rpm, and builds power gradually. It *feels* slow.

Then there's my 6-speed 91 vette. That ran a best of a 13.8@102, so obviously it's more powerful than the IROC, but the way that thing hurls me into the seat is just night and day compared to the IROC. Hell, that chirped 3rd at the strip all night long.

Hell, even my LB9 5 speed GTA, and friend's LG4 5-speed cars hurl me into the seat a little bit when I shift during agressive driving.

But my IROC doesn't. I looked at my BLMs, and at low load, low rpm, they sit around 118,114, 120, etc. Once I get on it hard, they come up to 124, 128, 130, etc. I realize that I need to lean out the low rpms a little bit, but they don't seem to be so far off that they explain my lack of low rpm power.

It seems to be down on power at low rpms both at part throttle and at WOT. It seems to me that my motor isn't really radical enough for a nearly-stock APYP bin to be too far out of line. As long as my injector constant is set right, I've got to think that although not completely optimized, an APYP bin isn't going to be a total mess. It's got to be something mechanical and not in the programming... I think.

Can this be all related to my POS non functioning IAC issues, or do I have something else going on here?

 

well my first guess is with it running rich, then flooring it gives you an overrich condition until it can lean out. IAC should be near 0 when running. things to consider there would be the idle screw not far enough open. so the IAC is maxing out. but i don't know what the problem is with your IAC.

 

my IAC issues have been a long-standing problem that I've made a bunch of threads on. So far, no solution at all. I've set the idle & iac a million times, replaced the throttle body, iac (twice), ecm, harness plug, and tested the wiring a bunch of times. I start the car and the IAC stays pegged at 160, then gradually works its way down to 0 where it stays. Sometimes it'll start to drift back up slowly. I've tried setting the idle above the "desired" idle, I've tried setting it below it. Hell, I can unplug the IAC at any time and never notice a difference.

 

mine does that. until it gets to operating temp it'll stay up. what about when you turn on the AC? or give it some throttle?

 

I don't have a/c anymore. The last time I screwed with it, as it started to drift up, it was at around 32 when the fan kicked on. When the fan kicked on, it jumped to about 55, then my scan tool quit communicating with the ALDL and that's the last bit of info I could get.

 

ok. so it is working. now onto the next problem. why did you lose communication when the fans came on? maybe you have an alternator with 1 diode not working. the alternators have 3 inline. so, one may go bad and never know it. works. just barely keeps a charge. then when a load is suddenly put on it, can't keep up. hell, i had one with 2 out. with only engine running showed fine. got AC on, lights, stereo, etc... and couldn't keep up and kill off the battery.

 

it doesn't have anything to do with the fans coming on. My ALDL on the IROC is just another thorn in my ***. The scan tool communicates beautifully with every one of my other cars, but with the iroc, as with everything associated with the car, there's always got to be complications.

Generally I've got to scan anywhere from 2 to 20 times before the scan tool will communicate with the ALDL, and then sometimes it loses communication at random times.

 

Same problem I'm having. I'm trying a different laptop tomorrow. Our cars must've been built next to each other.

 

Have you tried just setting the idle and leaving the iac unplugged?

 

Yeah. Since the IAC isn't doing a damn thing, it's more or less the same as having it plugged in. I want it to function properly, not to put a band-aid over it.

 

Could be a timing issue. Is this the 461 headed motor? Curve the PROM to avoid knock..might add that you should be able to run 14-16 with EST connected..minimum

I wouldn't be too concerned about "chirping" gears, clutch peformance, RPM's, speed, gears..yada-yada..all play into that, just be concerned on the power, or lack of, when going through the gears.

Heck, back in HS with my '63 Bug and race clutch, I could chirp all 3 shifts...bet it still wouldn't turn a 20sec 1/4.

 

I just commented on chirping to try and illustrate the lack of low rpm grunt it has. It doesn't bother me that it doesn't chirp, it bothers me that it's slow.

My timing is set conservatively at 6* because the APYP uses an agressive timing curve for the L98 aluminum heads. I get no knock counts and no audible knock with the car.

 

Hell then, increase the base timing for good lowend, curve the advance to suit you needs througout the RPM range....assuming increasing the base helps.

Never know unless you try it.

 

I guess I just can't convey how bad it is, because although a lot of these suggestions would be great if I was just off a tad, I'm off way more than a "tad". 6* is stock timing, and is perfectly adequate until I iron out my problems. Running stock timing isn't going to cause anywhere near the sort of low rpm bog I've got, especially considering the agressive timing of the APYP bin.