Ok i just bought an 82 z28 with the crossfire injection, it has 96k and a newly rebuilt trans. ok the problem with it is that the car floods out after running for a minute. it backfires through the intake and seems to be missing. i have an new o2 sensor so its not that and I dont get any codes. does anyone have any ideas? or have the same problem

 

what does the fuel delivery look like? are the injectors dripping or anything funky?
when was you r last complete tune up?

start with the little stuff liek your tune up and stuff. move along from there. there are several sensors that can cause an overly rich condition, but they shoudl all pitch a code out. one thing you shoudl do is get a scanner hooked up to the car so you can see what is really going on.

later
tim

 

try here
http://www.crossfire.webhop.net/cftest

 

Make sure that ALL of the vacum connections( hoses , caps) are in place , the best thing to do is buy a kit of assorted vacuum caps and replace all of them.



Also check your timing , backfiring throug the intake is a sign of retarded timing.

 

ok this weekend i fianally get a chance to work on my car. But im still not sure what needs done or what should be done. Ive been told that the injectors might be bad but i dont really know how to check them and that vaccums might be bad but i dont know how to check those either. I was also told that my return line might be messed up. Another possibilty is changing the intake to a carb or TPI with a carb i was told i could just use a regulator to control fuel instead of changing the brand new fuel pump. Well i have about $300 to spend to get this car going so if you have any ideas/ suggestions or comments please post them.

 

i seem to remeber camaros having backfiring problems with bad ignition modules.

 

Oh yeah.

 

Well today i got to work on my car. I decied to unhook both injector and i tried to see what would happen. well the front injector just started pouring gas without being connected while the back injector didnt spray at all. So im pretty sure the front one is bad considering it poured gas when it was disconnected. Is there any difference in front and back injectors? I went to autoZone today and there were 2 types... one was 100 the other was $120 so i want to make sure i get the right one instead of blowing $100 on the wrong part.

 

yes they are different, i think the rear one is smaller, im not sure of the sizes on a 305, i do know the 350 is 60# and 66#

you must maintain the proper stagger, best bet would be to take the defective one to the store and check it with the 2 in stock.

 

You don't need to run the stock "stagger". Two like injectors will work just fine. They do on my 310 hp engine!

You also do NOT need to replace your injectors. THe one that is dumping fuel while disconnected has a bad O-Ring.
1. Remove the top of the housing.
2. lay a screw driver or wrench across the top of the housing.
3. using another screwdriver, pry the injector up and out, using the first tool as a fulcrum.
4. replace the bad O-Ring. Any properly sized O-Ring will work; you don't need to get this specific one from a Chevy dealer.
5. reassemble and test. You probably wont be able to get the injector to "seat" fully in the body. Don't worry about that. Screwing the top of the housing back on will do that. A bit of lube on the new O-Ring will help with re-assembly.

 

you may want to go ahead and do a minor overhaul on the whole thing. i got a rebuild kit from autozone for about $30. it has filters and all the gaskets found in the throttle body. this worked for a similar problem on my tbi.

 

tom, dominic sorreso and grumpy both say you have to maintain a stagger, or plumb them in parallel. They both werent able to get it tuned properly with identicle injectors.

I sure it'll run fine and most people wouldnt know the difference, but im inclined to believe grumpy.

 

I guess, but I'm not sold. I have been running identically paired injectors for the last 10 years, on three different sized engines; the original 305, a 350, and my current 400. That was three different pairs of injectors too, so it isn't jus a "lucky" set that I may have gotten.

Using improperly matched injectors would be most noticeable at low throttle openings; idle and part throttle cruising. My car idles VERY well(smooth), and pulls 24 mpg+ cruising on the highway, so getting the proper "injector stagger" is of very little concern to me, and I have a tough time buying into that philosophy. My Opinion.

 

yes they mentioned its only noticible at idle, and low throttle.
Fair enough, my car isnt optimized and its fine for me.

 

btw tom, i havent seen you on the crossfire forum recently. Are you still having problems with the port 81 link?

 

No problems with the link, but my I forgot my password. I did the email thing several times to retrieve my PW and never got a response. I'm not sure why. Anyway, if you can get on there, maybe you could get Ken to email my my username/password @

tkendrick@thecanyons.com

I definitely would love to be back on there. That is one of the best technical boards I've been part of, and I enjoy the discussion. BTW, thanks for noticing my absence on the board, Nick. Later.

 

i just left a post in off topic for ken, he'll get that. For some reason he doesnt get half his email.

 

Cool! Thanks alot Nick!

 

Ok i took apart the injector and the bottom O ring was almost cut in half so i went on the search for matching o rings and cant get them anywhere ive tried autozone, a dealer, and napa. A hardwear store had the right sizes but the gas would eat through those. where can i get these without having to pay 44.99 at autozone for the rebuild kit, or if anyone has some that would work and could mail them to me post it here and ill get back to you.

 

Let me guess - the rear injector on the CFI is the smaller one...am I right?

 

did you try the ones from the hardware store? or did you just guess they would get eaten by fuel? o rings are pretty standard.. most autoparts stores (discount autoparts for instance - a chain i worked at big in the south east) have a big box of o rings under the counter that you just match to. Call around, they arent that hard to find. If worse comes to worse find any place that deals in aircraft parts.. small airports etc. Planes use o rings like its cool

 

Two places you could check, An hydrolic hose company or an industrial bearing dealer. Both should have the size and material needed to work.

 

The 350 crossfire injectors are 66pph in the rear and 64pph in the front.


Nick isn't the only one to notice.

 

Tom,

You have mail