TBI Question:

[conoverbandit]

Hey Y'all,

i'm trying to fix my 87 R-30 tow rig.It has 7.4 (454) gas engine in it, the problem I got is it "high idles" real bad, I've replaced to date : Temp sensor,fuel regulator, all new gaskets, new IAC (idle air control). Still dumping way to much fuel into motor. I was wondering if a TBI would work on this thing from a 88 model 5.7? I had a fella tell me that the computer is what talks to the injector and tells it what to do and how long, so the 5.7 set up should work. But i'm not sure, I did raid the injectors from the mother in laws 91 caprice 5.0. It would run, but surged really badly, couldn't drive it. So called local shop, tell them what it's doing, and they say IAC is bad....Changed it out but did'nt know you were supposed to "reset" it before you tried it. Needless to say it did'nt work right either, so put old injectors back in it and by then I had learned what the "resetting" was but with old injectors it's back to dumping fuel again.....Wondering of I should try and swap those injectors again, just to see if.......Need help here y'all /forums/images/graemlins/histerical.gif Thanks,

 

[Rolled]

What does the injectors spray pattern look like? You should be able to see a cone pattern.

Also, are the o-rings bad? Did you lube them with vasoline?

I had similar problems as you. My first problem was a bad injector. I swapped them out and the orings were leaking and dumping way to much fuel. I put in 4 new o-rings and it was running smooth again...

Just a thought...

 

[conoverbandit]

O-rings........Hmmmmm,

Update: I re-installed the injectors from mom -in-laws TBI'd 305 caprice, and it seems to be doing better, but still flooding a bit, maybe just cause it's been flooding for a while and it might take a bit to get cleaned out right.But I used the o-rings from her car also, might explain part of it.I crossed the numbers on each other and they had same first 4 numbers and same last 3 ending, has a*rpd on the end of number, but the 454 injector has a 79 in between the numerals and letters, where the 305 injector does not. So I'm guessing won't work right?

Thanks,

 

[Rolled]

[ QUOTE ]
O-rings........Hmmmmm,

I crossed the numbers on each other and they had same first 4 numbers and same last 3 ending, has a*rpd on the end of number, but the 454 injector has a 79 in between the numerals and letters, where the 305 injector does not. So I'm guessing won't work right?

Thanks,

[/ QUOTE ]


I think I recall seeing specs on the injectors and thay are different... but, I have a 305 running 350 injectors and durring my experiments, I also used 454 and 4.3 (V6) injectors and orings.

The housing is the same and the rig *seemed* to run the same with all of them...