I Have Owned A 1982 Corvette With The Crossfire Ing. For Several Years I Have Restored It To Mint Condition And Have Had No Problem With The Crosfire Ing. A Friend Of Mine Told Me This Weekend That The Crossfire Had A Problem And Alot Of Them Caught On Fire And That Is Why It Was Only Offered 2 Years. Have Any Of You Heard Of This Fire Hazard And What Are The Pros And Cons Of The Crossfire ?

Thanks,
Mike

 

That's plain crazy!

The Crossfire lasted only 2 years because it was replaced with a more advanced technology: Tuned Port Injection.

When properly set up, Crossfire is very good indeed.

 

I dont really see how the crossfire could catch fire. I always thought they produced them for so short of a time becuase they produced very little hp.

 

The HP isn't much lower than the first TPI systems and the only major difference is throttle body injection versus port fuel injection, TPI is batch fire so not a true sequential system and it's very similar in it's working (the computer control) to the CFI...maybe not what most cfi bashers want to hear but it is true. No way a CFI will catch on fire just for no reason..it's bull poopie. The low HP is for the most part a result of the cam and the heads, even with the stock heads...just drop in a better cam and you can easily run with the tpis.

 

I heard the factory crossfire injector control modules had bugs in the programming and crossfire was the least fuel efficient method of fuel injection, thats why they got a bad reputation.

Modern aftermarket control modules have the programming figured out quite well and the fuel efficiency of crossfire is still much better than a carb.

 

my 84 crossfire gets horrible gas mileage, I wonder if I need a tuneup. It gets about 14.6mpg, and that is when I am nice to it. And its stock!

 

There is nothing wrong with a Crossfire. It is 2 throttlebodies instead of 1 like the 87-95 TBI pickup/Suburban and Impala/Roadmaster through 92 I think. Much misunderstood is the Crossfire, mostly by people who tried to "make it better" who didn't know what they were doing. Do not be afraid of a Crossfire.

 

The CFI can get some good mileage, usually the poor mileage is a bad CTS, an out of synch system, bad O2 sensor, worn throttle body housings (loose shafts) or something like hat...

There's no such thing as an injector control module, the ECM has a set of injector drivers (peak and hold or saturated circuit for TPI), and they ground the injector and make it fire, the TPI one fires 4 smaller SD injectors at 1 time, the CFI fires 1 P&H one ...both do the same thing, the difference is in design, opening/closing time accuracy and the ability to hold the driver open...the prom only has coding for the base pulsewidth (inj. open time), in closed loop (normal driving, warm engine) the standard tables are altered by correction factors depending on map, throttle position, coolant temp, lambda signal...and so on..and so on.....nothing there to cause increased gas mileage as the system is self regulating for holding a value close to Lmabda =1 (stoichiometric a/f mixture of 14,7:1) The only major difference w/ tpi is the idle smoothness because of fuel injected above the throttle plate cauysing bigger droplets to be sucked past the gap between throttle plate & housing and mixture distribution problems associated with every wet flow system (like a carb)....as said before, it's more similar than you think..if you've seen 1 SD EFI OBDI system you've seen em all... Mass Airflow system is real similar also, just the means of measuring/determining incoming air volume is different.

 

TT, what is a cts? I assume when you say out of synch system you mean the 2 TB arent synched together right?

 

coolant temp sender, yes out of synch means someone messed with the adjustment of the TB's or removed them from the lid, isntalled new gaskets and dumped them back on. Any difference in vertical position will upset the delicate synchronisation of the 2 units.

 

lost patrolman,my 82 gets over 21mpg and thats with the bigger than stock cam .if your motor is running good is your overdrive trans lockingup ?

 

Mike,

First and foremost, TT is ‘da man when it comes to the cross-fire system. To borrow from an old investment ad slogan; when TT talks about the cross-fire system, CFI owners listen!

…he could defiantly write a book.

As for your question on the system (I know just enough to be dangerous…like that kid at the bus stop with one day of karate under his belt) I’ve driven two 1982 Corvettes, had one for over five years and my present car for just over a year. My first car had 120K on it when I bought it; original CA car with “extra” smog stuff for CA emissions. That car saw over 150K miles and still turned 24 MPG on the highway when I sold her. My new ’82 has just over 25K on it. She turned over 25 MPG on a highway trip this summer…with the A/C on. While gas mileage is not on the top of the list of why I own an ’82 it is important as prices hover around $2.00 a gallon. Also, I think gas mileage is a pretty good indicator of how healthy the car is running. Bottom line is both of my CFI cars have given me no problems what so ever.

I’ll take that back, I had a problem with the TPS once but that was my fault because I put the thing on wrong when I re-did the valve cover gaskets. After a simple adjustment/setting with a multi-meter everything was good.

 

i donno, how do i tell? It does have a rough idle though. I suppose I should start replacing the stuff TT mentioned.

 

You can feel it lock up, if you have an aftermarket prom, a later GM revised prom or some other gizmo it may only do it in 4th (which actually is nice since it will drive you nuts in lower gears), drive at a constant speed w/ constant throttle setting at low rpm and almost immediately you should feel a change and hear the revs go down, that's the lockup...if it doesn't do it, check the harness on the transmission, maybe someone disconnected it..or maybe someone installed (and removed?) one of those little switches to manually operate it, which is a bad idea because at highway speeds the lockup helps keep trans temps down.

The items I entioned do not do anything for the TCC, it's ECM controlled by grounding and it's just a little wiring harness that runs to the tranny.

You need to build a water manometer and check the synch, also check the IACs to see if the pintle & seat are dirty, check for vac leaks ..this can be in the most remote locations like the a/c control panel, the fresh air doors, cruise control disengage switch (brake pedal) and so on...the fact that everything on our cars works with vacuum and the CFI being a SD system is probably the #1 cause for poor running engines, SD systems aren't very forgiving when it comes to vac leaks since it uses the vac (absolute pressure below atmospheric -> hence Manifold Absolute Pressure or MAP) to determine incoming air volume and fuel needed.

 

I'll be of no help whatsoever here, but I love these crossfire topics. I read them just to see what Twin Turbo has to say about it. When TT talks about crossfire, you can be assured it's the final say. People who know EVERYTHING about a particular topic amaze me. Whatever TT says to do or check, by all means do it, you'll get your problem fixed.


-Justin

 

Crossfire injection is great for a daily driver where gas milage is a consideration, but they suck trying to get any performance out of them.

GM intentionally crippled the CFI with small runners and small TB's because of the upcoming release of the TPI two years down the road. They realized that with a few simple mods the CFI would outperform their new brainchild TPI drasticly. The years of R & D dollars that went into TPI would be lost to slack sales and because they were reworking the corvette as a whole, with a new body, new motor, and a new syspension, sales had to be high for a few years to recoup the money for the new tooling required to produce the C4's. They were very diliberate in their sabbotage, not only did they make the runners smaller they incorperated the water jackets too close to them, to rework them effectivley. The CFI could have been a definate performace peice in corvette history if they hadn't done this.

The long runners of the CFI coupled with good heads would produce an effect similar to a tunnel ram, only sideways instead of straight up. The longer runners would trick the motor into thinking the heads were larger, thus increasing airflow. More airflow equals more horsepower.

With the motor only made for two years, the market just wasn't there to support making aftermarket performance peices. Sure they came out with a few but they were expensive, complicated for the backyard mechanic that was used to dealing with carbs, and they came out too soon after the introduction of CFI. People with their new cars still under warranty didn't want to tear into the mods required to get any real performance out of them.

This is just my take on all of this, I might be wrong. It's just my 2 cents.

You can thank your C4 brothers for the anemic CFI.

 

lostpatrolman ,what is your rpm at 60mph?if you are over 1800 rpm then you have higher than stock rearend gears or the trans is not locking up.did your car start running rough all or a sudden or over time ?do your headlights work okay ?if not that can give you a big vac leak .how many miles on motor ?1982 had a soft cam would look into cam replacement on a high miler.

 

The car is an 84 so headlights are electric. I only bought the car about a month ago and I think it ran rough back then too. THe rpms seem low when driving around, i will have to look to make sure though.

 

TT,Ive got an 82CE.The guy I bought it from gave me an aftermarket alum intake for the CFI set up.It's made by wiend.Would this intake make much of a difference even without a cam swap?This intake is not for a swap for the CFI to a carb,

 

Sounds like an X-ram, http://www.x-ram.com it's a milled down Weiand Xcelerator with an adapter plenum for the TBs on top. I won't vent my opinion on it...it's not really positive