JamesRS

I just took a look at the injector part numbers on my CFI and wanted to make sure they were the right ones. The car doesn't seem to run well when the fuel pressure is set to 14PSI. When I back it down to about 11 it runs okay, but that makes me wonder if the injectors are the correct ones. The part numbers that I have are 5233775 on the front Injector, and 5233770 on the rear. Does anyone know if those are the correct injectors for an 84 crossfire Corvette?

brian84

I dont know if those are the right injectors or not, but im giving you a free bump, and a question,
the car re sets the settings for idle control at 45 mph?
did you try ajusting fuel preassure to 14psi and go for a quick drive to re set the computer?
maby you could do it in series, going from 12.5psi - go on a short drive get up to 50 and let computer re set, and then dial the fuel up little bits at a time and "re set" the computer along the way by taking her out on a spin.

id like to know where to get some replacment injectors as well. mine are working fine, but you never know when one is going to conk out

JamesRS

Well I received this information from another forum, so I thought I'd post it for any else that may be interested.

L83 injectors (350 Cross-Fire)
GM5233770*RPD (rear)
GM5233775*RPD (front
LU5 injectors (305 Cross-Fire)
GM5234255*RPD (front)
GM5233765*RPD (rear)

Thanks for the reply Brian. When I did fuel pressure testing, I started with about 15psi, test drove, then 14psi, test drove, then 13 and so on until I found the best response and performance which was 11psi. After each test drive I would reset the ECM by disconnecting the battery.

James

69427

What is your reasoning for running 14 pound line pressure? Is there some reason you suspect that you're getting insufficient fuel delivery?

trackman44

If you go to the scrap yard and find any 85 to 92 GMC or chevy truck or van with 350 TBI i'm sure you could use those injectors as replacement.

CFI-EFI

The 2 bbl TBs on the TBI 350s use two of the same injectors. The Crossfire uses two different injectors. By the same token, you could go to the scrap yard and find any gen I, sbc V8, 265, 267, 283, 307, etc to replace your 350 Corvette engine. Physical fit doesn't necessarily mean a satisfactory replacement.

RACE ON!!!

Rohn

What do you mean by not run well? If you have a stock fuel pump not sure if it can sustain 14 lbs at WOT anyway?

The stock .bin is calibrated for 11-13 lbs FP. Closed loop operation will correct to stoich but it will take awhile to adjust to the higher FP but eventually should do so. The PE will most likely be enriched and that will not be corrected. Is that what you want? Cold start will be rich as is operating under 165F on coolant temps and that may affect drivability. A datalog will tell you the effect on the higher FP.

CFI-EFI

Mine can, and does. At least through 2 1/2 gears, shifting at 6000 rpms. As a test I ran the 1/4 mile at 17 psi fuel pressure. The gauge needle never even wiggled, all the way down. It ran way, way, too rich, and it blew black smoke the whole way, but the fuel pump kept up. Now I just keep my fuel pressure at 14 psi for daily use and racing.

RACE ON!!!

JamesRS

I'm a member of the crossfire injection vault and several people over there indicated that 14PSI is the best pressure for a crossfire system. I had replaced my stock fuel pump with an 85 pump because they can handle the higher pressure better from what I was told, but the higher pressure made my injectors act up.

trackman44

I understand that, but if your willing to experiment why not try it? GM always used the corvette as a test bed for new designs before implementing them the next model year on other products that they offered ( for example, almost all the wiring harness and emissions equipment and computer that was used on the 84 corvette was carried over to the 85-92 GMC and Chevy vans and trucks, except were the corvette had the crossfire intake, the vans and trucks had the TBI). Just a thought.

CFI-EFI

But not much of a thought. If that was your intention why wasn't that mentioned here? "If you go to the scrap yard and find any 85 to 92 GMC or chevy truck or van with 350 TBI i'm sure you could use those injectors as replacement.." One CAN go to equal sized injectors if they parallel plumb the fuel lines and add a regulator. That must be what you were thinking HUH?

RACE ON!!!

trackman44

Yes, that would be a good idea. parallel plumbing with a regulator. Then you can use similar injectors and not only that, you could adjust pressure with an external regulator.

CFI-EFI

Why is that a good idea? Why would you want to use similar injectors? From your earlier post, you suggested same sized injectors WITHOUT parallel plumbing. Why is parallel plumbing is such a good idea, now that you thought of it? Does that provide an advantage? What is the big deal in adjusting the fuel pressure with an external regulator? Is that better, for some reason, than adjusting it with the stock regulator?

RACE ON!!!

trackman44

All i'm saying is that if you want to replace two parts that were only used in two model years of corvette (82 and 84) that your best chance to get similar replacements is thru the 85 to 92 chevy or GMC truck or van with 350 TBI, if you didn't want to order such parts because they would be expensive and hard to find and if you were willing to find a cheaper alternative thru a scrap yard. That's what i'm saying. Maybe one cylinder bank will run richer than the other, maybe it wont. How would anyone know if they never considered it before or at least tried it. Heck, if anyone was so concerned about it, why not try and use a TBI intake from those vehicles ( 85 to 92 trucks and vans that i mentioned above). They only use one IAC valve motor instead of two and both butterflies are attached to the same shaft and there is only one fuel regulator, very simple and straight forward. All i'm saying is this is a couple of possible options to consider, either you think it would work or you don't. I like to experiment, that's my nature. All i'm saying is it wouldn't hurt to try. I'm not trying to put anyone down, i'm just throwing some ideas out there. Please be kind, rewind!

CFI-EFI

Feel free to experiment with your own stuff, but it is poor form to suggest that someone use mismatched, different, and incompatible, parts, when you have no clue as to the ramifications. It is obvious you don't have a clue as what is used in and how the Crossfire system works.Your original post didn't present these, different and wrong parts as an experiment. It was offered as a viable alternative to the proper parts with no cautions offered as to possible problems. Problems, of course you had no clue may exist. Once again, one should not offer solutions about which they have no knowledge.



How many "fuel regulators" does the Crossfire use? Are they adjustable?



All I'm saying is you didn't present these as "couple of possible options". You presented them as solutions All I'm saying is it COULD hurt to try. When you have no clue as to what you are talking about, you can do more harm than good.

RACE ON!!!

trackman44

Fine you have your opinion and I have mine. All I was trying to do was put some ideas out there that's all. I'll give you an example. Once I had a friend of mine who owned two different ford vehicles. One was the 91 Escort GT 1.9L and the other was a 88 2.3L ford Mustang. The Mustang had poor performance so I had a hunch. I took the fuel rail off and put a towel underneath the injectors ( while the fuel rail was still attached to the fuel line) and asked my friend to crank her over. Sure enough all four injectors had different spray patterns. My friend just happened to have a spare set of injectors for the Escort, so i replaced the ones in the stang with the escort set and performed the same test. These other spare set from the escort performed flawlessly, all four had same spray pattern, so i installed them in the Stang. It started up fine and idled great. He took the Stang out for a drive and ran better than before. This is why I don't think putting injectors from one GM vehicle into a different GM vehicle that are similar is such a big deal. The L83 CFI 350 and the 85 to 92 TBI 350 are identical when it comes to ECM and harness and emissions equipment. That's all I have to say, take it or leave it. It's up to you (forum members) to decide if you want to take this route or not.

calpbs

I removed a crossfire in liew of a Carb (Oops I know the purist hate that) but I could be easily convinced to relinquish ownership if needed.

CFI-EFI

It isn't a matter of opinion. Either you are not reading what I'm writing or your comprehension is weak. You didn't just "put some ideas out there". You offered up a solution, a cure, as if it was tried, and was proved to work. You even end your recommendation with "i'm sure you could use those injectors as replacement.", proving you've never tried it and that you don't know that it works. It's fine to suggest something as a possibility, but to recommend something as a cure, that you know nothing about, is criminal. Somebody that doesn't know better, may follow your advice and have it end up costing him a bundle, all because you felt the urge to purge.



That doesn't sound like a suggestion for experimentation.



"don't think" being the operative phrase.

I didn't notice where you answered the regulator question. "How many "fuel regulators" does the Crossfire use? Are they adjustable?"

RACE ON!!!

trackman44

What harm could there be if you try putting a pair of TBI injectors into a crossfire setup? I must admit I haven't tried such a thing. The worst thing that could happen is that it would probably run richer on one bank and leaner on the other. But i have a hard time seeing this because the crossfire intake plenum is huge, both throttle bodies go into a shared plenum (before they go into the individual intake runners), so if one injector fired more fuel than the other it would even out in the plenum area. This is why I suggested this possibility as a solution to the forum member's problem. How can one know if it hasn't been tried?

lance m p

the 1st # is the front rated at 67lbs/hr the 2nd # is rear rated at 68lbs/hr