'82 hesitation at 1/4 throttle after tune up
 

On the forth of July I was happy as a clam cruising the whole day. I put 150 miles on the '82.
In my opinion, the only opportunity for improvement was to eliminate the hard start and rough idle.

Next day, I decide to change the spark plugs to AC Rapidfires and distributor cap/rotorto NAPA Gold. All seemed to go smoothly. I did disconnect the battery due to the heat shield bolt being so close to the starter solenoid. I also removed the wiring from a couple of non-functioning fog lamps from the previous owner. The lamp wires were strung from the dash, along the drivers side fender and to the lamps. I also spayed some thottle body cleaner in and around the TB's. I also noticed that the previous owner cut and rewired the orange wire from the HEI to the ignition coil. The new wiring led to under the dashboard where it dead-ended and was shorted together. Therefore, whatever purpose it may have had was no longer being performed. After this discovery, I cut this wiring out of the circuit and return the orange wires back to a straight connection (together). The final change was that I removed some sort of performance add-on that was inserted between the stock wiring harness and the thottle position sensor. I may have bumped a couple of sensors that are near the spark plugs, but I didn't smack them any harder than what they experience during normal vibration. At the most, I may have disturbed the sensors' wiring connection.

When I start it up, after putting it all back together, the hard start and idle seems much improved. Of course, I am excited so I jump in and take her out for a spin. It all seems good on a short run around the neighborhood. I didn't get on it at this time. An hour goes by and I take her out for a serious ride. This time I stop on a deserted road and floor it. She lays a ten foot patch, but the acceleration doesn't feel as powerful as yesterday. I shrug it off as my imagination or the fact that I removed the performance device. I keep the thought of re-installing it in the back of my mind. As the night continues a 1/4 throttle stall starts to develop and has continued to get worse.

The basic problem: Idle and start are smooth both when cold and hot. It may be a little harder to start when hot, bit not significant. At a stop, wide open thottle results in a lurch forward for about one second, two seconds of stall, a recovery lurch forward and constant performance from this rpm to redline.

In summary, o throttle to 1/4 = Good running, 1/4 and up = stall or near stall, after stall recovery wide open up to 5500 rpm = Fair running.

What I have eliminated:
Checked all of the spark plug wires and they appear to be OK. Again, idle is smooth in drive (600rpm).
Replaced the fuel filter.
Checked the distributor cap and rotor to make sure I did not screw up the installation.
Replaced the performance add-on between the wiring harness and thottle position sensor.
Checked the distributor cap wiring change to make sure the butt connector is a solid union.
Checked the battery connection to make sure that both were clean and tight.
Looked for vacuum leaks and found none.

Please help. Sorry for the long-winded description, but I wanted everyone to have all of the information. I did search this forum and the CrossFire Injection forum and did not find similar posts.

RE: '82 hesitation at 1/4 throttle after tune up
 

Hey Batmobile, this one sounds like the TPS to me but go to your other thread for more info.

RE: '82 hesitation at 1/4 throttle after tune up
 

I am an idiot. I have only had the car five days and the previous owner didn't tell me the fuel gauge didn't work. The tank was empty.

Having run it lean and hard while trying to diagnose this problem, does anyone think I may have damaged something?

It seems less peppy, but it may be the eighteen and a half gallons of gas it is now hauling.

RE: '82 hesitation at 1/4 throttle after tune up
 

I need to add that after driving 150 miles and the gauge only dropping a little over a quarter tank, I thought this car was getting exceptional gas mileage. DUH!

RE: '82 hesitation at 1/4 throttle after tune up
 

:DOuta gas? I'm sorry, that's funny! [sm=icon_rofl.gif]
I been there, done that too. :D

RE: '82 hesitation at 1/4 throttle after tune up
 

Hi Batmobile, and again welcome to the forum. You ran out of gas! You made me laugh too. My car has a carb so I don't no about TPI but there might be some info at CorvetteFaq.com . Enjoy your new ride, PG

RE: '82 hesitation at 1/4 throttle after tune up
 

So this ain't an ongoing problem???

I really wrackin' my CPU here, and you're outta' gas?[sm=icon_beat.gif]

Here I was thinkin' your vacuum timing advance was off, or the little centrifugal distributor weights for timing advance were hangin'...

[sm=chairshot.gif]


[sm=laughat.gif]

RE: '82 hesitation at 1/4 throttle after tune up
 

Oh man, does Batmobile owe us big-time on this one, all the blood, sweat, and tears, not to mention our many years of exceptional motor head experience almost going to waste, I think I'll make a trip over to the west side of the state just to slap him. We'll try real hard to forgive ya Batmpbile.

RE: '82 hesitation at 1/4 throttle after tune up
 

Im glad it was that simple.
I was going to add a comment about a possible bad coil. I had a very similar problem, all be it on a boat engine, but it was a 350 Carb'd engine....not all that different from the Vette engine. I went crazy trying to fix a similar problem, tune up's, rebuilt carb, fuel filters, etc. At the end it was a bad coil causing very similar symptoms.

Im glad you found the problem...silly or not, it is a huge relief to finally find it, and fix it.....I hope to be 'there' shortly myself....

RE: '82 hesitation at 1/4 throttle after tune up
 

So now with a full tank, does it run OK?