Cross Fire Injection- Bad Idle

I have had this problem since I bought the car 4 years ago, but never this bad.

The most obvious things to check are the fuel pump and  injectors, the fuel pressure regulator, vacuum leaks.  And the next is the fuel return line.  I have seen cars with that return line plugged, and it makes for all sorts of annoying problems.  Another possibility is the Throttle Position Sensor. 

Some more obscure ideas:  a leak where the two halves of the unit mate, or worn throttle shafts, coolant temp sensor,.

Corvette Fever mag had an article about tuning the Crossfire.  I found it online at: http://www.corvettefever.com/techarticles/4688_chevrolet_corvette_efi_system_tuning/index.html


Good luck

Larry

When all tune up items are okay and there is no vacuum leaks the throttle bodies are out of adjustment.  Don't forget the PCV valve, use an AC delco valve, NOT and aftermarket.  These are very touchy.

Dave, you have a PM

Dave, do you have the '82 service manual? It has pretty good instructions with lots of pictures on the Injection system.

When my X-Fire refused to idle, the fix was to reseat the prom in the computer seat.  Maybe I had a bad contact at a pin.  I haven't had a single episode of poor idle or cease-fire ever since I did that, two years ago.

To balance the throttle bodies, you won't need to reinstall the original chips.   I don't have a picture, but if you take one and post it, I will grab it, apply the proper arrows, and repost with the information.

With all the sensors being up to spec and running as they should, make sure the front trottle body isn't resting on the idle stop before the rear throttle body does. They should both be resting on the respective stops at the same time. The main reason being important is that the front throttle plate will be closed and the rear will be slightly open. Then the idle control motor can't react fast enough to adjust air, hence the up and down rpm until it stalls. My CF did this and I found the long linkage rod from the front TB causes the bracket connecting it to the rear TB to bend. Try holding the rear TB still at idle and put forward pressure on the front linkage rod and see if it doesn't smooth out! If it does, take a pair of pliers to the bracket holding both linkage rods (looks like a "C" shape) and slightly bend it forward. Over the years of motion, the front rod puts so much pressure on the bracket causing it to bend. TB's won't be out of sink unless modified or removed. In that case, they have to be timed together. 

The question was asked somewhere above about how to find a vacuum leak.  Another of my "Old Guy" easy tricks is to let the engine idle, and spray suspect areas with starter fluid or Gumout spray.  If you hit a leak, the engine will rev for a second.

Larry