converter?
 

I 've been having a issue with my car when it takes off. When I watch the playback on the tach the car intial hit is good but it doesn't seem to flash to the correct rpm(5100) it goes to 3200 and then it seems to lag to the fist shift point then it seems to labor the the last shift point. Plus the car has slowed from 6.80s to 7.00s. When we first saw this we fiqured the converter was broke and swapped it out took it back out and it keeps doing the same. Also the 60 ft has changed from low1.4s to hight 1.4s-1.5s. We have tried other things ign box, fuel pump, fuel reg, carb. Still now luck. The car is a 86 transam ihra gt stocker 70 lt1 combo and a turbo 350.

Any ideas on what to do next
thanks
Andrew Mylin

Re: converter?
 

It's no fun being in a situation such as yours. I would do an actual fuel flow test, run the pump for 30 seconds pumping fuel into a jug (thru the regulator) and be sure you have close to a gallon, minimum. Check the voltage right at the pump with the motor running. How old is your battery? Is there any chance that the harmonic balancer has slipped and you're getting a bogus timing reading? I'm sure others will chime in as issues like these will really try your patience and pocket book. Good luck.

Re: converter?
 

The battery is new I changed it out thinking it was that as well. How would I know if the balancer has slipped?

Re: converter?
 

Sounds like something has gone sour in the engine. I would leak check and do a compression check first. Check valve springs and look for a bad lobe on the cam.

Re: converter?
 

I did a leak down and a compression check everything there looks good. I'll will have to check the springs and the cam for any issues there. It doesn't skip or "load up" when it is running at a idle or down the track.

Re: converter?
 

We also changed the msd box, coil ,timing computer, checked fuel pressure. checked the timing ,the distrbutor. We went through the car but we could have missed something. haven't changed the tach which is a newer tach haven't seem to have any issues with it. Thought it might be a trans issue pulled the pan no debri in the pan and the fluid looks good and doesn'r smell burnt. It's a auto 1-2 shift looked at the govener seemd to be moving free the weights and the springs look good.

Re: converter?
 

With the stall speed that low, you might have a broken or slipping sprag in the torque converter. If you have a spare converter, you might want to make that swap and do a test.

Re: converter?
 

I changed it to a 5600 stall converter and had the same result

Re: converter?
 

I had similar problems and it turned out to be a stator support on the trans.
At first it was intermittant, usually happening when I used the 2 step. Then it wouldn't go above 1800 in gear under any circumstances.
I fought this problem for 8 months. Changed converters, ecu, coils, head, everthing but the trans and short block.
Was going to change short block but decided to change the converter again. That's when I was able to spin the stator support by hand. Changed front pump, fixed problem.
Stator support broke means no torque multiplication.

Re: converter?
 

Similar problem also, a few years back. Stator support was the problem. Tony