still trying to figure out the lack of power and hesitation problem with my 82 crossfire. have replaced plugs, fuel pump, map sensor and cleaned the idle air control valves. no codes stored, but problem still exists. also found no vacuum leaks. im about to give up! was told to check balance of throttle bodies, but still dont understand the procedure. any more suggestions?

 

The Crossfire is sensitive to vacuum leaks, that’s why people probably had you checking for them. Does the computer give you any fault codes?

Have you checked for wear in your throttle body shafts. It’s real common over 70k miles for them to wear. Open the throttles by hand part way and see if you can move it in the forward-back direction or up-down. Any play/rattle is too much, they will be leaking which usually causes idle issues. Many people get bushings put in the Crossfire TBs. If the TB shafts are leaking it will be difficult to balance them.

The hesitation could also be that one of the sensors is bad or corrosion on a connector. How old is the O2 sensor? Another thing that can cause erratic part throttle accels is a worn Throttle Position Sensor (TPS). If you have a Ohm meter or DMM you can check it.

Do you have the GM 82 Vette shop manual? There are some pretty good experts over at the crossfire forum if you can get it figured out.

crossfire forum

 

I would go to the Crossfire Injection Vault forum, register, and start looking through the forums there. There is soo much info and it makes the unknowns of the CFI engine much more clear- including TB balancing.

Sanity check these:
-good fuel pressure at the throttle bodies (meaning you also replaced the fuel filter)
-good Coolant Temp Sensor (known to go bad over time-buy the newer 2 wire style) made a big diff for me.
-no vacuum leaks (intake upper plenum-TB bolts, lights vacuum lines, brake power booster) Mine were tight at 84K miles.
-correct base timing 6 BTDC with advance wire removed I believe.

All else fails, you may need to do the throttle body balancing bit. This is done by adjustment of the linkage betwen the throttle bodies. It must also be tight with no play.

There is also some stuff about throttle bodies in balance at idle, but not in balance once you start to step on the throttle. You can build a water manometer for $6 with Home Depot items to check for this. Simpson36 has some pics and a write up how he did it. Pretty amazing I thought.

I didnt see how many miles you have on your engine, but you may also want to check your shafts for wear by pushing on them and see if this affects the idle speed.

Its probably just maintenenace items like this that may cure your hesitation

Good luck, Brent...

 

Here's a thought for you.
I had a power problem a few years ago and it turned out that a peice of the converter broke loose and was plugging the exhaust. I used a bore scope to look in there and voila, there it was.
Just a thought for you.

 

Hi,
I was thinking restricted converter also.
Good luck,
Tom

 

You can hook up a vacuum guage, and check for a plugged exhaust. I would replace the O2 also.

Tommy

 

I found most of the roughness in my engine was from a dirty fuel filter. I spent a lot of time monkeying around. The dirty filter was restricting the gas flow.

 

1st thing to check when soemthing's amiss w/ FI engine. Fuel filter & ACTUAL fuel pressure