I'm not sure if this is a transmission problem or not. I recently replaced my Q-Jet Carb with a re-built one. Every since then, I've been getting variations in RPMs while driving at steady speeds. In other words, while I'm driving the engine RPMs goes up and down, but nothing major. I didn't notice this problem until after I replaced the bad Carb. I also must point out that this is the first TH 200 transmission I've dealt with, and this may be normal. It's a three speed automatic, with no overdrive. What are your thoughts?

Jeffery Morgan
82 firebird S/E
LG4-305
Everything original

 

how much are the rpms varying ? can you tell in the sound of the exhausdt that its doing this ? maybe the tach or a connection for it somewhere is loose intermittent or a part is defectove for it

does the tranny shift quick and tight on each shift for each gear, or is it sloppy and rpm spike increase each shift ? tranny bright red clean smelling or ?

 

Randy,

The RPM variation only happens at high speed. Not during gear change out. I can hear the variation in the engine compartment. Like I said, it only started this after I installed a re-built Q-Jet. Not sure if that has anything to do with it though. Do you currently have a TH 200 in your 82 TA?

Thanks for your help..

Jeff

 

Jeff, if it only happens at high speed 45mph+ its probably the tq converter locking and unlocking. Swaping carbs can lead to line pressure variations also, no carb linkage is exactly alike so re- adjust the tv cable to make sure. The procedure can be found in the tech articals in the main page. Just for kicks theres a 4 prong plugin on the DS of the transmission, very easy to get to on the 200c, unplug it and see if the rpm still bounces around at high speed but try the tv cable adjustment 1st.

One of the best mods I made was swapping the 700r4 in my 82.

 

Thanks SSC. You're the second to mention vacuum problems relative to the Torque Converter locking and unlocking after a Carb change.. Yes, I'd like to change to the 700R4. However, I've got a brandnew TH 350 in my wrecked 86 Firebird, so if anything I'll put the TH 350 in my 82 once the 200 craps out.. I'll put a vacuum gauge on, and figure out what I need to do.

Thanks

Jeff Morgan