Engine/Transmission (1994 - 1998) Bucking after power mods

[ronco]

Last Friday I installed a TST 6 plate. Then, on Thursday, I had a new set of 215's installed. When my truck was stock, I had some bucking when the T/C locked up on level ground at 45 M. P. H. at part throttle. Now, under the same load conditions, my truck will buck like a manual trans. left in a higher gear too long. Have I decreased my power level at this shift point (about 1200 R. P. M. ) so much, that the engine is loaded heavily? Or, is this bucking the stock trans. telling me it is unhappy with the new power? I have tried to take it easy on the old trans. until a new convertor and valve body are installed, but I enjoy gouging the throttle and feeling the acceleration!



I am considering installing a switch to unlock the convertor until higher speeds, or lock the convertor to keep trans. temp down when towing.



Has anyone else experienced this problem after changing power parts? Any suggestions? I will be in contact with the mechanic next week to see what he says, just wanted to bounce this off everyone tonight.



Thanks, Ronco



PS, What kind of power will a #6 plate moved forward with 215 injectors make in this truck?

 

[Andy Redmond]

I'm guessing about 250 hp plate +30-40 hp . . injectors Is the prob. at 1200 rpm's in od lockup? Aren't you lugging it? Press the od off button.



I would swap your plate for a #10, then some 3k gov. springs, then you will smile. .



Do you have good fuel psi? At least 20 psi off idle?

 

[Andy Redmond]

Ok should have typed this too before clicking , ck. out the tsb's for 94-95, there is one on this very complaint. I remember it having to do with throttle linkage springs and maybe a "reflash"





TSB

21-04-95 Auto trans Vibration or perceived engine miss.

The symtom is a vibration or perceived engine miss at approximately 1100 rpm as the torque converter clutch engages. The condition occurs in fourth gear lock-up at speeds between 42 to 48 mph. Depending on year model the powertrain control module is either replaced or reprogramed.

 

[ronco]

Andy, the PCM is locking the convertor at 45 M. P. H. in OD and the tach only reads 1200 R. P. M. In the past, the bucking was minimal, but with the new plate and injectors, the bucking is bad. I think I will install a T/C lock/unlock switch and learn to use it! Thanks for your reply.





Ronco

 

[vssman]

TC is locking up at 45mph??? That sounds rather low. I believe it should be a bit higher than that - somewhere between 50 and 55 mph.

 

[JSmith]

Do you have an OD on/off button?

 

[ronco]

JSmith, I have an OD off button.



vssman, I suspect the PCM is programmed to lock the converter as early as possible to maximize fuel economy.



I am thinking about building my own converter controller. I need to find a programmable frequency counter and then learn what the frequency is at 50 M. P. H. to allow the converter to lock up.

Has anyone else done this?





Ronco