:mad: I am looking for help for my motor, problem I have a 383 stroker with 202 dart alum heads, a 282-290 cam with a accell linginfelter super ram air intake, and a msd ignition. my car runs but keeps trying to stall out it is also back firing but only when I let off the gas. when I get on the gas it stutters a little and then takes off like a rocket, but when I let off the gas it backfires and tries to die. any help on anybody who has seen this problem would be great.

Myabe a little more info! What carb are you running, has it been running like this since it was built or did it just start doing it, what is your timing set at? Did you set the cam to zero or is it advanced? (or retarded?) Is it backfiring through the carb or the exhaust?

whats your timing set at? both base and total
how have you adjusted the carb? do you have any vacuum leaks?

:mad: accell linginfelter super ram air intake.

why does that phrase throw me pictures of efi? Wut kinda car is this in anyway?
When guys don't tell us, we automatically assume first gen camaros with carburators and breaker points...lol.

Welcome to the best darned camaro site on the web, btw!

Sounds like my car when it had too big of a carb that was mistuned, no vacuum advance, and a bit too much cam for a stock stall torque converter. Back-fire comes from a lean condition. Vacuum advance will give you some idle / off-idle power without detonation when you accellerate.

Fill us in on the details.

Myabe a little more info! What carb are you running, has it been running like this since it was built or did it just start doing it, what is your timing set at? Did you set the cam to zero or is it advanced? (or retarded?) Is it backfiring through the carb or the exhaust?


car is a 1991 z28 camaro with what used to be a tune port induction intake, what I have now is the same thing just on a much larger scale. The timming is set at 18 degrees advance. It also started doing it after I built the new motor reall starting to drive me crazy.

I have no vacume leaks that I can fid I thought the same thing

an addition to my last thread

383 stroker
2.02 dart heads alum
282-290 cam
30lbs injectors
msd distributor
msd 8.5mm wires
bbk fuel pressure regulator
accell #5 spark plugs
bbk duel 58mm throttle body
lignenfelter (accell) super ram air intake and phlem
motervation racing computer chip built for engine
k&N air filter
3" flow master exhaust
flowmaster headers to match

Now with the problem I hope is a great discription for you all that can possibly help me.

When I step on the gas it idles up real rough like it is being flooded, pulled plugs and yep tons of charcole. so I turned down fuel regulator and put new plugs in. Same thing happens. Also when driving down the road the motor feels as if it is going to jump out of the car. when I let off the gas it will try to die but most of the time it will catch itself from dying, and also backfires out the exhaust. I have a leaking header but that is because every time I fix it the motor jumps around so much it wears it out and leaks. I then pulled the #1 plug got TDC again, redid the distributer and timed it at 18 degrees advance with a .40 gap on the plugs. Cranked up car drove down the road and what do you know--- same freaking thing. I checked for vacume leaks with a can of carb cleaner hoping that I would find one, but no matter where I sprayed no motor boging. Then I put a vacume gauge on it and read approx. 12psi but jumps around 2+lbs and 2-lbs around 12psi. I have tried advancing and retarding the timming with still no luck just sounds like it is missing a cylinder or two. Now here is the crazy thing O2 sensor was reading low so I changed it now reads low still but you can just smell the gas out the back side infact my bumper is black from it and wala ----- missing still and backfire on down shift with crappy acceleration. I hope that the info provided helps cause I sure could use some over here.........matt :(

I read your last post and this what I can see from the surface.

Wow - that is a huge camshaft for a computer controlled application. What are the exact specs on the cam? Fuel injected applications need lots of vacuum to operate properly, hence a smaller cam.

What size are the injectors? They may be to big causing the spark plugs to fuel foul.

What type of control are you using for the EFI? Stock, FAST, Accell?

Injector size was what i was thinking but this ram set up is supposed to be unitized? Right? I was thinking 24# injectors were more in line but this thing has a fuel map in the program logics ,,, doesnt it? If I recall correctly the injectors have to be tied to the intake duration of he cam on the fuel maps? Chemosabe here,,, I ran the Proflow eld 3500 so I guess the logic is the same??

I read your last post and this what I can see from the surface.

Wow - that is a huge camshaft for a computer controlled application. What are the exact specs on the cam? Fuel injected applications need lots of vacuum to operate properly, hence a smaller cam.

What size are the injectors? They may be to big causing the spark plugs to fuel foul.

What type of control are you using for the EFI? Stock, FAST, Accell?


the injectors are 30lbs accell injectors, as for the control I am using a stock gm computer with a motervation racing chip built for the motor. I think that I found the problem though. I figured that I tried everything else so I took it to a shop and and had the injectors tested and 3 of them are stuck in the open position, hence loss of power, stuttering, backfires. I just put in 1 bottle of chevron with techtron injector cleaner and the car is starting to run better. I still think I might have one or two still stuck open. hope that this info can help anybody out there with the same problem. (stupid injectors)

I was about to say you might have a leaky fuel pressure regulator. That too would dump too much fuel into the motor which would cause the problems you're seeing. If the regulator is leaking, you'll be able to pull the vacuum host off with the fuel pump running and see fuel dribbling out the vacuum port.

I'm curious how you discovered the dribbling injectors? That too sounds like a significant find.

30 lb/per hour is plenty big. I'd definately recommend an adjustable fuel pressure regulator. Plan on buying some basic tools like a fuel pressure guage. If that is a TPI injection setup, you'll find lots of interesting stuff on http://www.thirdgen.org. My friend is into a 383 TPI. He built a wide band O2 meter from schematics obtained on the net. He also has a modest laptop loaded with free software he got from thirdgen. The software allows him to read and adjust settings. Pretty cool stuff I always thought. Don't get frustrated, there is a great opportunity to become savvey with EFI systems - especially if it is a 3rd gen TPI setup.

the way that I figured it out was this
I took the vacume line off the adjustable fuel pressure regulator and no leaking then tested fuel pressure with the motor running----wala not good preesure took it to a buddies house and he had a tool that test if the injector is opening and closing, well what do you know 3 of my injectors are not firing, and stuck in the open postion hence all the mystery problems

it is offical 2 bad injectors caused all the problems, they were pulled and checked changing in procsss. :clonk:

Cool, sounds like you zeroed in on it. The right tools are great...I'm jealous of your friend.