7M-GTE runs hot but does not overheat

bsupra

Member
Oct 1, 2006
140
0
16
California
I know this question may have been posted a while back. I have 1991 supra turbo everything stock. If compared to my old 89 turbo, the 91 supra seems to go up in operating temperature half the time of the 89, both at idle. Also, I know the fan should disengage at some point after it cools down but on the 91 it does not (even the small electric fans running also non stop) even AC not running. Myold 89 only only engage for a short time and disengage. That is why every time i drive the 91 on normal operating temperature, it sounds like a driving a big rig just because of the fan engaged the whole time but car does not overheat. NO CODES

Also, when the car reaches this operating temperature, the runs sluggish (hesitates/poor acceleration). It has a really bad jerk went you let your foot off the gas pedal (specially on freeway).

Checked timing,TPS, and AFM and both seems to be fine according to TSRM. All the sensors around thermostat seems intact but have not inspected it with multimeter. Just gave the forums a shot first maybe somebody can pin point issue to save time and money.

Could the car be running lean? What could it be?

Thanks
 
Last edited:

Poodles

I play with fire
Jul 22, 2006
16,757
0
0
42
Fort Worth, TX
If the fans are on, the temp switch kicked on and it think it's overheating. Stock gauge has a terrible dead spot, but it could also just be a bad sensor (there's a ton of temp sensors, and if it's sluggish and the fans are on, I'd bet on the gauge sensor being bad and not telling you that you're actually overheating).

Test/replace t-stat, could be stuck closed. After that, well, there's always the dreaded BHG...
 

MkIII FTW

New Member
Aug 31, 2009
401
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0
Huntsville
My brother's car seems to do the same thing and the motor was freshly built ( like has only 4 miles on it). When we drove it, the temp gauge shows the car is running warmer than normal but it never oveeheats. I suspect the gauges may be incorrect. Part of the cluster already doesn't work..