I've done some more tuning on the 87 in an attempt to get it to run halfway decently. The problem was that the car would hunt at idle and stall, would miss really bad and bog on acceleration, and while driving at a steady pace the motor would NOT drive at a constant load. If you weren't on the gas accelerating...and you let off the gas the slightest bit...the motor would completely die. It wouldn't go dead, but it would be like you let off the gas completely even if you only eased off .5mm on the throttle.

Anyway, I reset the iac and idled it down to 600rpm. I checked the tps voltage & it was at .07! Ouch, maybe part of the problem so I adjusted it up to .35 (what I've been told will help the maf compensate for the mods). BTW, this was the max voltage I could get out of the tps. It wouldn't adjust any higher (it's brand new, second one).

This made a world of difference. No more "falling off" when trying to drive a steady speed. No more missing (other than a dead miss I can't seem to track down). However, as soon as I cranked it up the idle went straight to 1500! This was AFTER setting it to 600 per the usual method. This is playing hell on my ujoints!

I tried lowering the idle even further to 400-500. This helped the way it ran, but then I could only get .20v from the tps. Plus the car started running worse and driveability went downhill. So I'm in a catch-22 right now. I get the tps where it needs to be and the idle goes through the roof. I get the idle where it should be and the driveability goes to the toiled. HELP! P.S.- the chip is still the stock one...but I didn't think it would affect driveability this bad would it? See my sig for mods.

Once I get this solved then hopefully a chip will cure the complete LACK OF POWER. I think it was faster before I dropped all this $$$ into the engine. It will do a burnout, and will even spin the tires from a dead stop for about 5-10 ft...but that's it. Once it's out of that short 700r4 1st gear it won't do squat. Some loser in a prelude tried to race me today, but I was scared he'd win!


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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP cam, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax/Flowmaster catback
Coming Soon - Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - STOCK (for now)
SOLD ->91 Z28, 5.7, 3.23, Ported Plenum, Accel runners & lower intake, Accel distributor module, !dual cats, POS Edelbrock catback, K&N'S, ram air, tb airfoil, !tb coolant

 

I got the same feeling with my engine. After spending money on the heads getting polished, ported and stuffed a bigger cam in it, it didnt do squat ! I think I need a custom chip myself. Wait! Maybe that's why my chip burner came in the mail today... lol
Lemme know if you have any "chip" questions. As far as the idle stuff... maybe you got a bad IAC ?

 

I am not sure if this will help but the throttle position sensor should have an idle reading of .54 volts. The TPS should also be reset any time you reset the minimium idle speed.

Note: I have a 1987 GTA 350 with a ZZ-4 cam ported intake, plenium, and heads, 52MM throttle body, 1.6 roller rockers, Arizona Speed and Marine large tube runners, TES headers, and SLP 2500 stall speed, 2.77 gears, AFPR, stock chip. The car runs great but idles a little choppy at 600 RPM. My best idle quality is obtained when I set the TPS to .59-.60 volts. Best et 13.49 at 101 MPH.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

 

I would try setting it to .54 but the only problem is I can't get it! The new tps sensor (and the one before it) will only go up to about .35 at idle. And even then, when they get that high it is only b/c the idle stop screw has got the engine idling at around 1500rpm. The lower I idle the engine down the lower my max tps voltage at idle gets. I would try putting my stocker back on, but I robbed the base off of it for the new one. I wonder if I absolutely have to have that on there to use the TB?



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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224
.495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\
Flowmaster catback
Coming Soon (?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - STOCK (for now)
SOLD ->91 Z28, 5.7, 3.23, Ported Plenum, Accel runners & lower intake, Accel distributor module, !dual cats, POS Edelbrock catback, K&N'S, ram air, tb airfoil, !tb coolant

 

In case this comes up again...I finally solved the problem. Since the tps wouldn't adjust high enough w/ the idle adjusted correctly I took a soldering iron and opened up the adjustment slots on the tps until I could get it up to .35v. Now it idles perfectly, and there is no "dropoff" whenever I let off the gas.



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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224
.495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\
Flowmaster catback Coming Soon (?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 160,000 miles, K&N filter

SOLD ->91 Z28, 5.7, 3.23, Ported Plenum, Accel runners & lower intake, Accel distributor module, !dual cats, POS Edelbrock catback, K&N'S, ram air, tb airfoil, !tb coolant