Problem with trans shifting early
11-17-2004, 08:27 PM
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Problem with trans shifting early I resently put in a custom grind cam, it is pretty big... high 230's intake and high 240's exaust. This is the only thing that we changed on the car, so it has to be part of the problem. Now for some reason the car is having the following problems:
1. If I launch the car the converter will flash but as soon as it does the car shifts immediatly into 2nd gear, and the car just falls on its face. If I let off the gas and roll for a little bit then slap the gas again the car seems to act normal. I used EFIlive to lock the trans into 1st and the car takes off as normal.
2. I will be crusing with the converter locked usually around 45-50 mph and then stomp the gas to pass someone and the car will not unlock the converter nor will it downshift. The converter just stays locked and bogs the motor again. Then 2 minutes later I go to do it again and everything acts as normal.
The car is not throwing any codes.... does anyone have any idea what this could be?
Thanks in advance
Wes
1. If I launch the car the converter will flash but as soon as it does the car shifts immediatly into 2nd gear, and the car just falls on its face. If I let off the gas and roll for a little bit then slap the gas again the car seems to act normal. I used EFIlive to lock the trans into 1st and the car takes off as normal.
2. I will be crusing with the converter locked usually around 45-50 mph and then stomp the gas to pass someone and the car will not unlock the converter nor will it downshift. The converter just stays locked and bogs the motor again. Then 2 minutes later I go to do it again and everything acts as normal.
The car is not throwing any codes.... does anyone have any idea what this could be?
Thanks in advance
Wes
11-18-2004, 08:29 AM
#3
I've been thinking about this one since I read the first post, but nothing is coming to me. Sounds like something electical, since it's intermittent. But I don't know why it would have started when you did the cam swap... Unless the map, vss, or tps connector is loose or off, but that should set a code. You wouldn't have been around the vss anyway. MAP sensor or tps might be a possibility.
11-19-2004, 06:10 AM
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Thanks for the replies... we are leaning towards the MAP histeria (sp). Because the cam has big lobes and and a tight lsa it is causing a loss in vacum at lower RPM's. This could cause part of the trans problems from what I am told. My tuner said he has already changed the MAP values but the problem is still there. He is going to bump them up some more, and hopefully that works. Oh and I found out that my preload on the exaust side was too much, so I am putting in a shorter pushrod today.
