Ok, I have an 1989 IROC with a 100,000+ mile 350, with TPI setup. It has a rebuilt 700-R4 with corvette servo and a wider 2-4 band. 3.23 or 2.27 rear end gear in back, which ever it is, I can never remember.

I have new spark plugs correctly gapped, new ignition wires, new cap, new rotor. Fuel PSI set to 47 PSI, Throttle Body cleaned... has an air foil in the throttle body and a home made ram air setup. Also has a gutted MAF sensor, with wire still intact. Ohh, yeah, and an open cat, which I have been driving on for about 3 months.

It also has some type of computer problem w/ something, when I start it up, it stumbles for a second and then idles at about 900 RPM, when I first shift into reverse in the moring, the tranny will enguage and begin to roll but the engine will stumble again down to about 300 RPM until I tap the gas and it returns to normal. What could this be?

Sometime over the past week, I have begun to notice a huge lack of power under 2000 RPM. If I slam the gas from a stop, the engine bogs and then slowly takes off. Sounds like a timing issue to me, but I have adjusted it with the computer controlling it and it not, neither seems to work. I set the base timing with the computer not controlling it to 6 degrees.

My first and only run with the car was a disappointing 15.471. 87 octane gas, engine temp was around 200, the outside air was about 45 degrees. Tires didn't spin at all, didn't have the power to do it... any ideas?

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Owner of a 1989 IROC-Z Camaro, a.k.a. "The Babe Magnet". Painted a cheap metallic blue that chips off all too easily and covers over the IROC-Z decals on the doors, also has non-leaking T-tops, ps, pw, power rear hatch, working A/C. Mods: SLP intake runners, gutted MAF sensor, adjustable fuel pressure regulator, modified air spoil, 3.27 posi rear end.
Broken stuff: rear spoiler brake light, driver side lock, power antenna, tilt steering, rear end bushings, cracked passanger side ground effect, washer fluid tab, leaking exhaust and a rotted through muffler that sparks when the car bottoms out while driving like any 17 year old does.

 

I'd say its the 87 octane gas. An engine with 100,000 miles on it may have carbon buildup in the combustion chambers, causing knocking, pinging and detonation. What was your mile per hour on that run? Try again with 92 octane, or better.

Your 89 should have a 3.27 9-bolt if its dual cats, and a 2.77 9-bolt if its single cat.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

2 THINGS I NOTICE TEMP OF CAR AND THE GAS. GET SOME 93 AND OUT A BOTTLE OF OCTANE BOOST IN AND COOL THE CAR DOWN FEFORE YOU RUN SHOULD BE AROUND 150 FOR GOOD RUN.

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91 camaro RS
- 305 TBI
Mods: Performer TBI intake, 1" TBI spacer, K+N, jet fan switch ,160 thermo,Accel control module, Jet Stage 2 chip, edelbrock TES headers, Compleate 3" Flowmaster exhaust, Edelbrock springs, KYB struts and shocks, 700R4 built by TSI, SLP tq converter, b+m trans cooler
Soon to come .SLP Posi 323,Spohn LCA's and panhard bar,Ascd ram air hood, Z28 spoiler and grille,white guage faces.

 

what about the exhaust leak...when my pipe came apart at a weld, the car felt like ****.
that's pry not the only prob, but might wanta get it fixed

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90 IROC 5.7l (L98)
ram air, K&N's, air foil,Flows

LIKE A ROC

 

My 305 is that hot and outside 72 I still run 15.1's. Post the hole time slip. 60', 1/8, and 1/4 times and your 1/4 speed (trap speed). Something isn't jiving here.

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87 Z28 305 TPI, Auto, LT-1 cam (@.50 418/430, 194/199, LSA 111), roller timing set, 2.73, Gutted air boxes, K & N fillters, Dyno Max 3" cat back, 8.8 mm spirals, air foil, BFG Drag radials, and 170* Stat.
Old Best 15.414 @ 87.47.
new best 15.006 @ 89.55.

“Fallen But Not Forgotten”

 

Exhaust and vacuum leaks will have a big effect on performance!

My STOCK 305 TPI with over 200,000 miles and 2.77 rear gears ran a best of 15.6 last summer!!! You need help....BAD! I feel for ya!

[This message has been edited by 86TpiTransAm (edited April 28, 2001).]

 

47 psi may be a little high for those few things, your car may be running rich, which would cause it to bog and have a lack of power

 

I don't think it's it's the gas, my '89 has 110K on it, 2.77's, and will still spin both tires from a dead stop...I run the cheapest 87 I can find.

I'd take a look at the TPS setting, make sure you're in spec (.54v) and have a clean sweep though WOT to 4.2-higher voltage.

Then look in Tech Central for the IAC reset procedure...BTW, when you cleaned the TB did you dissassemble it and clean the IAC passage as well? Or just clean from the TB bores?

 

Don't use octane booster, and get some much higher octane than that.



[This message has been edited by IROCZTWENTYGR8 (edited April 28, 2001).]