Ok, here's the latest installment for those of you keeping up with my 355 swap. I have stabbed the distributor and adjusted the heck out of it over and over, and my car keeps backfiring. Actually, I'm not sure if that's what it's called, but I keep getting a big ball of flame shooting out of the throttle bores. At first I thought I was 180 degrees out, but I rotated the distributor and the same thing happened. Also, when the injectors pulse, it seems like it really sprays hard. It makes sort of hissing noise, and fuel shoots back up out of the engine bay like a geyser, hence the fire. These are 65# injectors (AC Delco), I am running a hypertech fuel pump, but keeping the stock regulator (I replaced the diaphragm today). My chip is a hypertech thermomaster made for the Caprice cop car. I figured this would be ok, but I'm running into problems and thinking that it might be the chip. My stock chip got fried with the old ECM (long story) so I don't have anything to compare to. My cam isn't too radical: .480 lift on intake and exhaust, low duration. Please help me. I'm getting very frustrated. This is my only vehicle and it has been down for 8 months. I could've gone carb and driven it for the past 6 months instead of it sitting in my parents' carport, and for a lot less money, too, which I am running out of. This scares me because custom chips are upwards of 300+ bucks, and no telling what else I'll have to buy. I need my car back. Getting desperate. Make me a believer that this project is still worth it!

 

By the way, I DO plan on burning my own chips eventually, but I just need something to keep this car running for now.

Hmm... Just read a post on the carb board. Some guy was having the same problem I was. His timing was out 90 degrees. Could this be it?

[This message has been edited by JRoy91RS (edited July 22, 2001).]

 

Have you checked to make sure the intake valves are closing all the way. If the valves arn't ajusted correctly one or more could be staying open causing the backfire. It's just a thought.

Steve

 

Hmmmmm.... will check that. Didn't even think about it. Thanks!

 

A lot of people are having problems with the 350 TBI swap. It definatly sounds like either an intake valve or distrib problem. If it were a fuel problem it would either die and backfire with a pop OR make you cry like a baby. 8 months!!!! Took me 1.5 weeks, half of that waiting for parts and finding that the starter was wired up wrong. Definatly don't go with carb, I have a strong feeling it isn't going to solve the problem. I have a feeling it's the distrib.

------------------
, Jon (350 TBI!)
91 Red My website

 

(Sigh). Yep 8 months. This is my first real attempt at something like this. I first tried a TPI swap but that didn't work (long story), so I waffled for a couple of months trying to figure out what to do and decided to go with TBI. When you say it is a distributor probelm, do you mean that the distributor is bad, or that it is just in wrong?

 

try tearing down the front ofthe engine, and double check the alignbment on the crank and cam gears, also make sure you done have one of the 3 keyway crank gears, also pull out the dist, and put it back in with the alignment dots aligned, i got confused when i did my 91 bird, although it wasa 305 but whenever the dots aligned the dist always pointed at 6 not 1, after a little reading i found out it was supposed the be at 6 on tdc when the dots align for that car, so it could just be something simple like that.
--Stormr

------------------
"If its in my way-It gets run over"

--'91 firebird
305 TBI
Hypertech chip-thermomaster
Edelbrock performer intake
Crane compucam 2010
B&M shift kit
straight pipe exhaust-with resonator tips
160 thermostat
open element