Member

Registered: Jan 2002
Location: fla
Posts: 43 vapor lock & new exhaust

Hi

i had a new cat back exhaust installed on a 92 rs w/ 305 tbi 150 k miles about 1 month or so ago.

its not performance just stock replacement.

i began having/noticing stall problems and rough idle lately.

incident 1; out from work, car sat 8 hrs, started right up, rough idle kinda stalled but didnt. turned it off, could not restart for 10 min. battery goor got goos crank no turn over.

incident 2 driving home same night, about 30 miles high speed on i95 70 mph + /- for about 1/2 hour get to exit ramp, uphill, car runs rough at stop light, stalls cannot start for 10 min. good crank as above.


incident 3 get home, park in drive, return to move car wont start . repeat above.

i csan smell gas outside car.

take to dealer in am, techie says vapor lock after running car 2 hour in lot, it will not start, when it does its rough.

he says the new exhaust is boiling the gas in tank or lines causing vapor lock which is the problem.


ok, any one have same problem ?

if this sounds right any suggestions?

i will take it back to exhaust shop, i would just like some info to tell them.

dealer said runn exhaust closer to factory spec, i thought it looked rather close to original route.

help is appreciated

thanks john


sorry for the novel

 

That sounds about right. Alot of our cars have vapor lock issues especially after exhuast mods. Go here...
Thread on intank pumps and vapor lock!!
That should give ya some good info on what causes vapor lock and why. Find out where the exhuast route and fuel line routes come close and wrap the fuel line with heat protective tape or wrap. That will help.

 

I have had the same problem on warm days, it is a problem with our lovely cars. I re jetted the carb a bit, the 750 we have is way to rich for our motors, and too big. I re jetted it down a bit and made it run a bit leaner and the problem went away.