I HAVE HAD THIS PROBLEM FOR ABOUT 2-3 MONTHS AND I AM TIRED OF THIS PROBLEM NO 1 SEEMS TO KNOW WHAT IS IT SO CAME HERE

SMETIME WHEN I COME TO A COMPLETE STOP AT A TRAFFIC LIGHT AND THEN WHEN ITS TIME TO TAKE OFF THE CAR WILL HESITATE TO GO AND THEN BACKFIRE IN THE AIR INTAKE DONT KOW WHAT TO DO HELP PLEASE !!!!!!!!!!!!!!!!!

85 Z28 305 TPI 103,000MI
MODS K@N'S, TB AIR FOIL,AIR BOX SILENCERS REMOVED SOON TB COOLANT BY PASS AND FLOWMASTER

 

Make sure your timing's OK, and check for the presence of fuel in the intake. It shouldn't be there. Could be alot of things, but I have never personally experienced this problem. It doesn't sound good, though.

I wonder if it may be loading up with fuel at idle. I also wonder where it's coming from. If you find some in the plenum, not good...does it smell like you're running rich? How does it idle otherwise? Is the charcoal canister full of fuel (sholdn't be)? Vacuum lines? Crankcase(really bad...)?

 

I know this sounds simple but check your plug wires as soon as one goes bad thats what happens...I know cause it happened to me last year!

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85T\A 305 TPI Auto WS6 3:43 Edelbrock TES headers Jet Hot Coated,Air Foil,Hooker CatBack,SFC's,STB,AFPR,B&M Mega Shifter Ported Plenum&Manifold,High Output Coil,Accel 8.8 wires,53000 org miles

 

I ONYL HAVE BLACK SMOKE IN THE MORING START THATS ALL

 

I am also experiencing this problem. The timing is set to 7* btdc. It's got new plug wires, new plugs, MSD6A. I don't see how fuel could get into the plenum. But it's really scaring me cause I don't want to hurt my car. Any other suggestions? What vacuum leaks should i look for and where?

Wally

 

My dad's GN did this a long time ago. It turned out to be a defective injector. It still idled fine, but when you would start getting into it, the thing would pop back through the manifold.

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82' Z-28. 327" w/ flat tops. 216/228/112LS. Pocket ported 041 heads 1.94/1.50 SS valves. World Class T-5 from a 91'. Best run? Runs with 2001 vette to 150mph! Soon to be converted over to TPI w/ supercharger.

 

fuel can get into the plenuim by a faulty fuel pressure regulator diaphram. It gets torn and the engine vacumme suckes the fuel into the intake. Since the regulator vacumme line goes directly into the plenum. I seen this happen on a 98 buick park ave. ultra, IT BLEW THE INTAKE COMPLETLY APART, but it was made of plastic.

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89 Iroc 350 TPI,
Forged pistions
Comp roller Cam .510 lift 230dur
Flowmaster exhaust
Dart Iron Eagle heads 200cc runners 64cc chambers
MINI RAM SOON!!!!!
stock TPI for now 24# inj

 

Someone has suggested pulling the throttle off and cleaning out the IAC. Would this help at all? Would it be worthwhile to do it?

Wally

 

I had the same problem and I fixed it by cleaning my AIC and while doing that I noticed almost all of my runner bolts were loose. Fixed it....

 

Just a month ago, my '85 TPI done nearly the same thing. I had just got through cleaning the injectors with a Motor-Vac machine. When I went to start the car, it wouldn't rev up and would backfire through the intake at lower RPM's. I was just about to order new Injectors cause I though the cleaning had stopped them up. The car never through a code except lean exhaust until that last day when I was just about to order the injectors. It finally threw the code 34. I then swapped the MAF out of my '87 and the '85 cranked up and ran like a new one. But as soon as the old MAF was put back on, it would go back to caughing. It would run with out the MAF plugged up, but it wouldn't idle. I eventually had to go buy a rebuilt MAF from Carquest for $162. But now it runs wonderfully.

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1987 IROC
305 TPI Slush box G80,G92
139K +
Mint condition
K&N Filters, ADS Superchip.
Stock Exhaust, Virgin Engine and transmission.

1985 Z-28
305 TPI Slush box
161K+
Not the first Mod. Completely Original and Virgin Engine and Transmission. Not so great body or interior.

1984 Z-28
305 H.O. Q-Jetted Slush box
Future Drag Car.