i recently purchased a 82 crossfire injection model. motor has 72k miles. the idle jumps between 600 and 1200 rpms and the car hesitates upon moderate acceleration. ive already replaced the fuel filter and plugs. any suggestions? ive also noticed both injectors misting fuel, but also a trickle of fuel down the center of each cone. is this normal or are the injectors plugged up?

 

we need more information.
my guess is that your fuel pump is not putting out enouph pressure.

 

Sort of O/T and no help here, but saw my first Crossfire "in action" this Saturday. All I can say is that system is a rolling flame bomb just waiting to happen especially when the air cleaner is off. My urge for a smoke while we were chatting immediately disappeared

 

Could be a number of things, but first check for vacuum leaks. The tb lid perimeter bolts tend to come loose, make sure they are all snug. That's a start for you, if that checks out then check your fuel presure. FP should be between 9-13psi, the closer to 13 the better. Check those out first then from there the; TPS, IAC's...

Are you pulling any codes?

 

what other info do you need? let me know!

 

There is so much that could be wrong, you can chase grimlins for weeks on that setup. I gave up, pulled the intake, added a carb and new distributor, viola, picked up an easy 150 HP and it runs great, starts every time.

Contact my IDRIVEC5 on this forum, he has been through every aspect of the XFire.

Best to you,

tt

 

no codes and found no vacuum leaks. havent checked fuel pressure yet. engine doesnt hesitate while in park or nuetral only with light pressure on gas pedal. i have no experience with the crossfire injection. if its a fuel delivery problem, why does it only happen upon first stages of accelleration? also do you know why fuel is dribbling down center of injectors cone? is this ok? i thought injectors only should be a mist of fuel. please help!

 

Hi,
The best source of information for this motor is the crossfire injection forum, those guys know everything about the crossfire.
Good luck with your Vette,
Tom

 

Actually the CF is a VERY realiable system if you know how to set it up properly... thats the key to a CF motor. Once you sort out all the things that others have done to it wrong it will run rather well. like mentoned, go on over to the crossfire forum and get your vette fixed.
The CF is very sensitive to FP, if you don't know what the FP is set to, you are shooting in the wind.

http://www.crossfire.homeip.net/

 

It should not be dribbling out of the injector, should be a nice cone shape. Suggest you check your FP, 9-13 PSI spec but I believe 12 bare min is best with a strong pump, and go from there, you may need to pull injectors if FP OK. Vacuum leaks can cause erratic idle also, you may have multiple issues, good hunting!

 

Go after the TPS. If this is the original on the car it is going. Make sure you set it to the proper voltage.

 

When I got my 82 it had an ok idle and sluggish performance so I read up on the CFI setup...including all the bad stuff. Almost replaced it with a TPI setup but did the following and it runs like a champ:

1. Had the injectors professionally rebuilt...there are many places that will do this online. You should see a cone shape fuel delivery.

2. Replaced stock fuel pump with 85 corvette version. That was a huge difference and I dialed my pressure in to 13.5. You can get the setup information from the crossfire homepage. I'm at work and don't have the link but someone will post it.

3. Replaced fuel filter - just because there was no way to know how long the existing one had been in place.

4. Replaced the plugs - same thing as far as knowing how long they were installed.

5. Checked all the vacuum lines one by one.

6. Checked the torque and seal on the intake manifold...several of my bolts were not torqued at all...almost finger tight.

7. Set and checked the TPS.

8. Set and checked the timing.

9. Had the throttle bodies sleeved around the shafts...they leak.

10. Balanced the throttle bodies.

Sounds like a lot but after doing what I believe is really making up for neglected maintenance, it ran great. It continued to get better as the computer stored the optimal settings.

 

It's just a dual monopoint TBI system...all TBI cars are prone to burning to the ground aren't they. probably why they still are being produced today.

 

My avatar is what used to be my crossfire. I suggest you pull it all, box and store it and put a nice intake with a car. on it. Keep in mind that you may have hood clearance issues.
Before I did the heads and put in the air gap manifold I had about 1/128clearance with the air cleaner in the baffled air channel.

 

Change your 02 sensors if still in place.

Tommy

 

The biggest single problem with the crossfire is the amount of inaccurate information that is all over the place. Get a GM factory shop manual and always confirm any advice you read before you act on it.

Do everything Zixxer said and when you get to step 10 (your actual problem in all likelyhood) build or buy a WATER manometer to do the job right. Material cost is about $6 and it takes 15 minutes.



BTW it's easier to balance the TBs with the air cleaner off . . .

 

you have received some good advice and some bad...

Here is the deal my car did the same thing and it got progressively worse. The fuel pump on my car was the culprit. I would go ahead and change the fuel pump its cheap quick and easy. $50 bucks and 45 min later I was done. This cures the sluggish hesitation.

As far as the idle goes. this will take an afternoon to fix. You will have to check multiple things.

Tighten the Intake manifold bolts that secure the plate that the TBI units sit on. Make sure they are good and snug. Check your vacuum hoses for leaks, splits and cracks. If yout CTS (coolant temperature sensor) is original it is probably bad. $35.00 and 10 min...I chnaged mine and the idle greatly improved but was still not right.

Next my throttle bodies were way out of balance on at 15 and the other at 5. I had to balance the TBI units. I also advanced my timing from 6 degrees to 10 degrees past center. The link below will tell you how to tune the CFI system. Print it and read it several times before attempting. I did and then did it again. My car now Idles at 1200 rpm at dead cold start and the idle gradualy drops as the car warms up..takes about 2-5min depending upon outside temperature. My car Idles at around 700-750 rpm at operating temp in park and around 600-650 at operating temp in gear. The idle still fluctuates a little which I believe is due to slightly worn throttle shafts which will allow a vacuum leak.

Buy a year specific GM shop manual for your car. Its worth its weight in gold. You can pick one up off ebay or at many of the corvette prts shops.

Here is the link:

http://www.corvettefever.com/techart...ing/index.html

This article is fantastic and will take you through the process step by step. You will need a timing light and a manometer...spend the money on a digital manometer its worth it. once again I picked mine up used off ebay for $75.00. You dont need to buy the IAC plugs you can make them out of duct seal or or cardboard and electrical tape.

Also GM has discontinued the idle adjustment screw kit. Use your old one but becarefull grinding the weld off when removing. I would put a dab of caulk or JB weld on the screw once it is set to prevent it from moving over time.

This process took me about 1.5 hours the first go around and about an hour the 2nd go around.

Good luck and feel free to PM me with any questions.

 

Looks like you have her on life support. Give me a carb, STAT.

 

Now that was funny!

 

Follow on to some comments . . .

Kevenator . . too funny! I'm not gong to show you the Depends on the rear end . . .

The corvette fever article is the only accurate instruction I have seen other then the factory manual. There is a TON of bad info floating around, an example of which is that vac leaks at the shafts causes a problem. Total myth . . circulated by people selling re-bushing service.

You can get the factory manual cheapest from Helm.com as they are the OEM supplier.

Use only an AC Delco fuel pump.

If the lid is loose, often the gasket is shot. And the manifold bolts tend to come loose also, and they are under the lid. Crossfire troubleshooting should begin with a new FelPro manifold gasket set, loctight on the bolts and no more than 15-20 ft lbs on the lid bolts.

I do not reccommend a digital manometer unless it is a differential model and has a lighntning fast reaction time. Here's why:

ANY set of TBs can be perfectly balanced at idle no matter how bad a shape they are in. What matters on a crossfire is if they will STAY in balance when the throttle moves. With a water manometer hooked up to BOTH TBs at the same time, you should show balance. Now open the throttle and you may be surprised to see the balance change wildly. In my case the water instantly dissapeared from the manometer!

That deviation translates into an off-idle stumble . . . even with TBs that are 'perfectly balanced' at idle . . mysery solved.

A stock setup in decent shape will fluctuate as much as an inch. An excellent rebuild with new properly installed and reamed shaft bushings and proper balance should get you to 1/2" deviation. I use sealed stainless ball bearings on the ahafts and custim fitted plates to achieve 1/4" deveation . . and that's with a 2.125" bore.

Crossfire is a cobbled together Rube Goldberg with 4 banger TBs and a resurrected and neutered raceing manifold and a computer that could not power a pong game. OK, its wierd, but it can be made to work fine if you know how.