bagged36

iTrader: (1)

I have an intermittent problem with my car. It is a 1936 Ford with an ls1 and 4l60 out of a 2000 Camaro. Sometimes when it down shifts from 2 to 1 the rpm's will jump up to 5000 and stop for about 5 seconds then climb. Also, it will occasionally get stuck in 3rd gear and wont shift at all, not matter if I'm pulling away from a stop sign or going down the highway, but I can manually shift it. Another thing that it has been doing is when you floor it, it wont down shift but it does climb through the rpms very slowly. The guy that tuned the car is excellent at what he does and has spent a lot of time with my car. He has even loaded my tune in another car with a similar set up and it had no issues, so I know it is not in the tune. I have even tried two different computers. The transmission was rebuilt when I got it, but I had it rebuilt again to make sure and it still acted up, so I tried a totally different transmission and it did the same thing. I also called and talked to Yank, because I have a Yank converter, and they said it did not sound like the converter. So then I then pulled the harness out of the car and had it gone through, but it still acted up. Can anyone please give me some new suggestions on where to start?

Thanks

bagged36

iTrader: (1)

I forgot to mention that it also goes through the gears really fast and locks up around 35 mph

Sharpe

iTrader: (7)

Moved from Advanced Tech to General Maintenance and Repairs.

LS6427

iTrader: (2)

Damn!! I'd try the "Auto Tranny" section.

So when it jumps to 5,000 rpms when down shifting from 2 to 1...does the car just launch forward, or does it not move?

If it doesn't move, that would be an engine issue, no?

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bagged36

iTrader: (1)

No it launches hard and then hits a brick wall. Its wierd. Any advise you might have will be welcome.

Thanks
TJ

LS6427

iTrader: (2)

Cool *** ride.........

I'm no expert, but I don't see how a tranny can make an engine rev hard like that. Maybe free spin and cause an increase in engine rpm's because the tranny has a slipping issue...YES. But not rev it under hard acceleration just like you are hitting the gas pedal.

Maybe your IAC (idle air control) valve is wigging out on you and opening up all the way suddenly, that would certainly cause an acceleration of the engine. But it probably wouldn't be able to rev that high to 5,000.

Or maybe a massive vaccum leak opening up suddenly.

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LS6427

iTrader: (2)

Maybe something going on with the throttle cable allowing the throttle blade to snap open suddenly.

SOMEHOW....you are getting a blast of air into the intake....its the only way your engine can accelerate HARD like that.

Fuel dumping in there would stall it out and more spark would do nothing at all.

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bagged36

iTrader: (1)

Thanks guys but I checked everything and it still acts up. Another thing that it did to me yesterday was as soon as I pulled off the highway it tried to die on me, so I had to two foot it all the way to a parking spot. If I took my foot off of the gas it would die. I came back a couple hours later and it acted fine. When we put it on the dyno everything read perfect just as it should, but it was way low on power so something is binding somewhere. I did a compression check and it reads 150 across all cylinders plus I pulled the motor out of a very low mile car so I know its good. So where do I go from here?

LS6427

iTrader: (2)

This sounds like one of those simple things your missing. The only way the engine can accelerate is by getting a big gulp of air. Someone awhile ago was having both jumps in rpm's and loss of power...I think it was a crack in the intake that was almsot impossible to see. When the engine torqued around it opened up the crack and would cause his problems. Something like that.

But your engine is getting a gulp of air somehow when it revs on its own. Only possible way that can happen.

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