I have taken the old crossfire injunktion of my 83 z28 went to a weiand action plus spreadbore intake and a holley 650 spread bore doublepump. I also used a accell ehidist with adjustable vacum advance. I am prety sure i will need a fuel pressure regualtor. but does the computer control the intank fuel pump and is there a way to make it so the computer doesnt run it if it does?

 

Welcome aboard.

The CFI computer isn't involved in the fuel pump operation, from what I understand. That came later in the TPI era.

 

Thank you for the welcome. Does the fuel pressure regulator need to be a return style? I have had everyone tell me that the timeing is off but i have checked ti 5 times already and the car is acting like it wants to start it sputters a bit then shuts down. I have been told the the lack of the regulator is the problem cause the carb is flooding out. does this sound like it could be the cause? or is the regulator the key to my success? thanks again

Steven

 

Steven, to the best of my very limited knowlege about CFI engines they ran at a fuel pressure comparable to later TBI engine- about 12 PSI, regulated internally inside the TBI units themselves (with return lines to bleed off the excess back to the tank). The pumps can supply even more pressure than that.

If that's the case you will need a return-style regulator. I used the Mallory 3-port on my 92 Camaro that I converted from TBI to carb, still using the stock pump.

 

so i am takeing it that the fuel pressure reg is the way to go..? Is your ECU still hooked up? Went out and checked it a bit ago and it seems like the ecu is controlling the feul pump. i checked on the mallory pump not badly priced but it doesnt have a port for the guage. So how would i go at hooking that up?

 

www.summitracing.com p/n MAA-4309. It doesn't have a gage port, but it has two regulated outlet ports. If you do the standard fuel line to the carb, which splits to the two bowls, you'll only need one of those regulator outlet ports. You can use the other outlet port for your gage.

 

so is the regulator the only thing i will need to make her purr? thanks for all the help. I guess what i was meaning to ask is will this solve my problem of it not wnating to start? thanks so much to all of you.

 

Did you happen to see this? https://www.thirdgen.org/newdesign/tech/carbswap.shtml

 

No i did not see that but thats very helpful
thanks again
steven

 

shaolin524ad,

I would strongly suggest retaining all of the Cross-Fire equipment. Someday the Cross-Fire (a.k.a. CEASE-Fire) will be a collectible. It's performance was definately sub-par (185hp) but they were only made for slightly over one (1) year before they were discontinued. My son's '82 Z-28 was a Cross-Fire. When we bought it, we thought it still was (e-bay). Unfortunately, all the cross-fire items had been removed and were long gone.

If I ever see a Cross-Fire in a Junk Yard I'm going to grab every part and set them aside for the future. IMPO - find a quiet corner of the Garage and store ALL the parts for the future. I would also STONGLY suggest not hacking up the original fiberglass hood and functional scoop assy. The Cross-fire may be the only Third Gen collectible since it was made in such small numbers for such a short period of time.

You are going to have issues making clearance between your carb and the functional hood scoop assy. We are using a Q-Jet and a Low-Profile GM air cleaner modified into a dual-snorkel. We made a few very minor "Adjustments" to the Scoop assembly to make it fit.

OFF TOPIC:
My son wants his original scoop to function (or look like it does anyway). We have been unable to determine how it was wired originally. If there is anyway you could follow the original wiring and snap us a photo or two of any switches etc. we would appreciate it.

Sincerely,
Kurt

 

Well its a little to late to save anything its already on the way to someone that bought it for 50 bucks on ebay i was so fustrated with it i put it on eaby to get it out of my sight i highly doubt it will be worth anything in anyones lifetime nobody really kne enough about them t make them work right. hence the 2 years they put them on the car. I do belive that the induction hood was controlled by the ECU and the TPS switch so i belive that switching it to a carb setup renders it useless. No i didnt hack the hood up i just got a drop base air cleaner from K&N and a 2 inch air filter and it fits perfectly. Not sure if the hood does work or not as i need a fuel presure reg to make it go. I wil go out and see if i can get any decent photos on the wireing if i can i wil post them. How did you get the 700r4 hooked up to work properly??

 

shaolin524ad,
WOW! That e-bay guy got a heck of a deal. I would have paid much more than that amount for the cross-fire parts. There are MANY people who know how to make them run "Like-New", although that's not saying too much performance wise. There are a few web-sites dedicated to Cross-Fire. I've had several people offer to sell me the missing cross-fire parts. Never has anyone asked for less than $300. Oh well... Too Late Now!

As far as the TH700 is concerned we've replaced the ENTIRE engine and dash harness with a 1986 LG4 system. The ECM, CCC-Carb, CC Dizzy, and all other Stock GM LG4 parts are completely functional. The only missing piece is the Air Pump which I really don't want to install. The car runs VERY VERY well and the LG4 system needed no modifications (other than the Knock Sensor) to operate the 350 C.I.D. engine properly. The standard LG4 computer and wiring harness handle the TH-700 lock-up perfectly.

I know it's not the choice many folks would make but I personally felt that the LG4 system was a good choice and would be a better choice [IMPO] than going non-computer and ending up with a variety of non-functional items or having to add work arounds for things like the TH700 Lock-Up. I haven't seen ANYONE get EVERYTHING working properly when they do the rip it out routine. Also [IMPO] the ONLY guy that will ever figure out what the owner was trying to do when there is a problem is the guy that made the modifications (i.e. wiring, etc.). As far as the engine or wiring is concerned, my son's car is now a Nearly Stock '86 LG4 Camaro.

Sincerely,
Kurt

 

I dont understand what everyones problem is with Cross-fire. All you need is a water manometer and a basic understanding of how it works and how simple it really is. Ive had my fair share of CFI cars and I never had any problems whatsoever with working on them or adjusting them, etc. Also, they didnt just make CFI engines for one year. They had the 305's in 82-83 Trans Am and Z-28, and the 350's in the 82 and 84 Vettes. Id take a Crossfire car any day of the week over a newer LO3 car. Also, the fuel pump has everything to do with the ECM. No ECM...no pump operation.

 

I rebuilt the whole unit and it never would run right new gaskets vacum liines everything and it never would run right they put that junk on the cars for 2 years for a reason from what i have heard. Like you said you HAD the CFI fi it was so simple why did you keep it? Even whit the thing totally over hauled includeing the injectors it still wouldnt run right. So tell me what did i do wrong and yes i had an experinced mechanic look at it and still it wouldnt run right to save its life. Not tring to be a smart *** but tring to figure out why 1 in literally 100 people i talked to would say its worth keeping even GM junked the idea.

 

Im not at all saying I think its a better system than the newer TBI or TPI setups...because its not. I just prefer CFI over them. I am fan of the 82-84 TA's, I dont really care for the 85-92's. But thats neither here nor there. I honestly couldnt tell you what was wrong with yours. I do know that they are prone to vacuum leaks and can sometimes be next to impossible to track down. For some reason, a vacuum leak on a CFI has a far worse effect than a TPI, TBI or carb setup. They were equipped with prehistoric, archaic ECM's, and were basically an all around bad design. But like I said, everyone has their own preferences. I just have too many cars as you can see in my sig...so some of them had to go.

Anyway, everyone is entitled to do what they want with their cars. I didnt mean for my post to look as if im flaming you. I wasnt. Anyway...in answer to your question, you will need a fuel pressure regulator. The CFI ran at a pressure of 9-12psi. Also, you will need to find the fuel pump power wire and wire it so the pump has power when the key is in the on position. I dont remember what color the wire was in your year, but it should be fairly easy to track down. Anyway, good luck with your car.

 

Good to know. I've never heard the guys who've done the CFI-to-carb conversion mention it.

 

Correction.. Slightly over one year for the Z-28.
According to GM (via - ) the Z-28 Crossfire was discontinued in mid-production of the 1983 model year.



84L69TA,
When we made the switch to Carb my son and I removed the tank and the fuel pump and installed a block-mounted pump. There are several folks that prefer NOT to remove the tank. It IS a major PITA.

One SMALL advantage is cost. A standard duty block mounted pump is about $12 and guaranteed for life at AutoZone, a regulator is normally a good bit more expensive and you still have to get the original pump wired to work without the ECM. It's still more work to remove the tank/pump but you'll never have to do it again. If your block-mounted goes bad, it's less than 30 minutes to replace. Eventually, the electric pump will go bad (maybe a few years down the road) perhaps that's a better time to make a switch to a block-mounted pump.

Kurt

EDIT: Spelling.

 

No need for an apology I didnt think anyone was flameing me what so ever thats quite an impresive list of cars. I was aware that they put that crossfire injunktion on other cars and most that i have talked to took it off. I kinda figured out the other day that the ECM controlled the fuel pump when i unhooked it and tried to get fuel out of it and got nothing. So the question is how do i convert the tank to work with a mechanical fuel pump??? I think the electric pump took a dive on me anyway cause it only pumps the fuel when you turn the key on. You all have been excellent to me with the change over. Does anyone know how to make the TV cable work with the carb???

 

Shaolin524ad,
The standard CFI TV cable is about 2 miles too long to work properly on the carb. I purchased one off a J.Yard LG4 car.

The electric fuel pump should only work with the key on, sounds like it's working to me. If you want to eliminate it just remove it from the pick-up assy. and replace it with a piece of fuel line of equal length. You'll want to reuse the sock from the end of the pump. Just attach it to the end of the fuel line.

Kurt

 

Ok from my understanding the TV cable for the tranny goes on the same side as the throttle cable. Mine is falling abot 2 inches sort of the linkage on the carb. Excuse my ignorance but what is a LG4 car???. Thanks for the diagram for the fuel tank greatly appreciated!!!!!!! and for the mechanical fuel pump wont i need to get the lobe that goes on the cam to drive the fuel pump??

Thanks again

Steven

 

An LG4 low-output, run of the mill 305 4-barrel. Your 305 will have the lobe on the cam for the mechanical fuel pump. All you need to do is buy a pushrod for the mechanical pump.

 

Opposite. The throttle cable goes on the top, the TV cable to the bottom of the throttle shaft.

 

Ok how to i make sure the thing is hooked up right its falling about 2 or 3 inches shourt of the linkage is there anyway to fabricate something to make sure the 700r4 is hooked up right i heard that they are very imparticular in how they are hooked up

Thanks again
Steven

 

Ok heres an update on the swap after a weiand spread bore action plus intake a holley DP spread bore carb and a accel dist some new plug wires and plugs. and a few vacum l;eaks that i had to fix she's running nice surpriseingly quick for a 305 practially stock shes running mid to high 13's. well now the delema is trying to clear up all the wires from the cfi system. i already unhooked the ecm from under the dash but there is 3 plugs one black one and two white ones that look to be connected to the ecm but they run under the dash.

 

heres the pic of the wireing

 

Mid to high 13's? Track slips? Thats VERY impressive for a 305. I think Dewey316 is running a completely worked over/ported/cammed/nitroused 305 and the best he's gotten is 14.1

 

most of it is the driver and how the car is tuned i know a old guy around here that has a 72 skylark looks like **** but runs 13 virtually stock no nos tothing. he know his crap and tunned the car for me he wount tell me what he did to it he told me that he will take his tuneing secrets to the grave with him. How can you argue with that. Not to menchon it was a ideal night to run in the 60's low humidity and a sticky track.