Bare with me, I've searched for related articles, but haven't had much luck. I'm new to the forum and at my wit's end.

I have recently adopted an 82 Vette with the crossfire injection setup.

When cold, the car will barely hold an idle or even drive for that matter. It seems at 1/4 throttle or higher it falls flat on its face. If I let up, it smoothes out, but only slightly. At full bore(when cold), it will stumble to the point of stalling.

After it warms up, however, it'll idle like a dream. But when driving it still wants to bog. A fellow tech thinks the engine is starving for fuel. Full throttle application is moderately smooth, but still lacks the punch a vette should have.

Here is a list of what's been done:

Fuel filter
Fuel pump
Spark plugs
Plug wires
Dist. cap
Rotor
De-carbonizing top engine
Rebuilt both throttle bodies with new diaphragms(no springs)

The spray pattern out of the injectors look ok. I hooked up a fuel pressure gauge, but it was a modified set up, so I don't believe the readings were accurate(6psi old pump, 6psi new pump). I am about to verify timing, but in my opinion, if the timing was off, my problem would be more consistant.

Please help! I am running out of options, and I don't have much more time with the car.

Jim

 

You haven't mentioned anything about the ECM or whether the Check Engine light was on (or not), whether there were any trouble codes thrown on the ECM, nor whether all the sensors in that system are hooked up or not. The CrossFire system (when working properly) is about as smooth as it gets. I had a new '84 and never had a moment's problem with it. But, if the ECM is not really controlling all that stuff (not hooked up or running in 'default' mode), the engine will do all kinds of 'funny' things.

 

Verify that fuel pressure first, it should be 12-14psi for good operation. After that, check for vacuum leaks around the top plate. If you can eliminate those two as problems, then start looking at the coolant temp sensor and work your way thru. Its a good idea to start with the least expensive, most obvious possibilities and go from there.

 

I too had similar issues with my '82 crossfire. They are great when operating properly, but a PITA when they're not. Sounds to me at idle you may have issues with the IAC's and driving with the TPS. Any codes?

 

We need more info. Are you getting any codes?

Where did you check for fuel pressure? Between the TBI's? This is where you should be checking. It should be 12-14 psi between TBI's.

Don't start messing with other setting just yet.

Jim

 

The fuel pressure, when I tested it, was before the first throttle body. I'm going to test it again with a different method, but I keep getting side tracked. Posting results soon.

There is no check engine light illuminated at all. I was unable to find any codes, seeing as my Tech II only goes back to 1991 and the Tech 1A we have won't power up. Isn't there two pins I can jump the get the engine light to flash?

 

If there is no check engine light staying on don't bother. Make sure the light works though. Does it come on when you put the key to the on position then go off when youstart it?

Under the ashtray. Two pins furthest to the driver side. Use a paperclip or something similar. Insert it touching both pins with the key on. Light will flash "12" three times then the codes come out. When done it flashes "12" three times. You have to watch carfully. Engine light flashes once for 1 and twice for 2 followed by a brief pause then the codes.

If it flashes 12 six times there are no codes. Make sense? codes are between the 12's.

You can clear codes by pulling the fuse for 30 seconds in the battery compartment with the wire going to the ECM.

Measure fuel presssure between the TBI's.

If no codes it sounds like a fuel pressure issue. Maybe a CTS (Coolant Temp Sensor) going bad. Cheap to replace.

The TBI with the spring is on the driverside right? Only one TBI has a spring. The TBI's look different....passenger side does not have a spring. No one switched them? Anyone tamper with theTBI settings?

Jim

 

Not to sound cocky but everyone jumped over the obviouse
All of us who worked on the crossfire will tell you to do two things.
1) check your fuel pressure or switch to the 85 vette pump. (I still have my stock 13PSI pump in mine)
2) All 82 Crossfire Vettes have a half assed gooped up plenum seal that alway causes a vaccuum leak driving mechanics crazy
Felpro sells a real gasket to seal the plenum and you will never have a problem again. It's easy to fix, about 2hr labor if you work fast and you don't find a silicon/permatex mess that has to be scraped off!
When you finally get it fixed. I strongly suggest gettin a $160.00 Hypertec chip. Takes less than 5 min. too replace and the car will drive like a dream

 

I agree check your codes then check your, gaskets, seals and fuel pressure, between the throttle bodies- start at 13 to 14 lbs and go from their, you will need to adjust the rear throttle bodie from underneith, crossfire injection forum has a step by step write up on how to do this. check your tps (.54 I believe) setting and go on the Crossfire injection forum, join if you have not already, they have a lot of good write ups on the crossfires. I finally got my 82 up and running right with help from this forum and that one, plus their is an 84 crossfire forum that has some usefull information on it.
good luck, these crossfires run great once properly adjusted
marcus

 

Here's the latest update.

There is no check engine light on. I jumped the two pins at the DLC, and the light did not flash. However, it IS illuminated during the bulb check.

We do not have the proper tool to accurately measure fuel pressure between the throttle bodies. I had to make my own adapter and was rather successful. With only a couple drips, I measure 6 psi. I know that's below spec, but I am not sure where to go from here. I adjusted the spring on the rear throttle body to make it tighter, but there was still no change.

I tested the CTS for proper resistance. My measurements were within spec according to the resistance/temperature table I got off of AllDATA. Also, I readjusted timing within 2* (I think it's 1-1.5* retarded).

So, she still runs rough on cold starts, hard to hold an idle, and has terrible throttle response. But again, when warm, most problems seem to dissipate.

My question, I guess, is what to do about the lack of fuel pressure.

Thank you for your help so far. I greatly appreciate it.

Jim

 

It shouldn't be 6 psi. There is no sensor that has an effect on fuel pressure. Sounds like the pump or the in tank rubber hose.

No flashing light from the check engine light is another mystery.

Pull the pump again it may be bad. Replace with a 1985 pump. Replace the hose and sock. If you are lucky it may only need the hose and/or sock. Off chance it's the gas cap.

 

I completely agree with everything you said. 6 psi is way too low.

I did what you said, and miraculously enough, the hose connecting the pump to the line was all dry rotted and cracked. I replaced it with a new one, and pressure shot up to 14 psi.

The car starts right away and idles like a dream...cold AND hot.

Thank you all very much! This was an endeavour I would not have accomplished without your help! If there's any way to repay, please let me know.

Jim

 

I'm glad you got it figured out Jim. No problem just sharing the knowledge I have picked up over the years. For the most part from this site. Thats what we are all here for...to help.

Jim