I decided to post this here cause it probably has to do with the TBI ECM. First for a run down. After I dropped in my 350, I overheated it shortly after and started burning serious coolant. So I pulled the motor back out and had the heads checked and they were fine. Put everything back together and in and luckily I nailed the problem with the first shot (bad stat), then I cooked the trans. I put a new trans in with a trans cooler in series with the stocker in the radiator and now I seems to want to hang around 140-150 degrees. I'm sure the guage is probably accurate cause I popped the hood after about 30 minutes of driving and could hold my hand on the upper hose for about 30-40 seconds so I know that the motor is definately not getting that hot. But to my problem, what temp does the ECM go into closed loop? That controls TC lock up right? When I was out tonight, I felt a small bump while cruising at 60mph and noticed that my revs dropped from 2000 to about 1400. Then I got on the gas and then came back down to 60 and couldn't get it below 2000rpm for the rest of the night. Is this my TC not locking because of the low engine temp? Any suggestions or if you think a different board would be more helpful, please let me know.

Tom

 

Yes, you need to get your engine up to at least 160 degrees...mine will go into closed loop and lockup at that temp range. Below that I have no idea.

How does the car run with the Vortec heads and 454tbi? What have you used for a cam?
Sounds like it might be good for ~260hp.

 

I'm guessing that the HP is a little over 300. I know the compression is up there cause I can't run anything less then 93 octane and I'm running Comp's XE262 cam which has 218/224 dur. @ .050 and .462/469 lift with 110 lsa.

 

Some of the bins used in the 747 ECM will go into closed loop at 90*F provided the O2 sensor is warmed up all the way.

The TCC lock-up is not dependant on closed loop tho. There is another value in the PROM for TCC enable temp.

 

Do you know if the 747 supports 8192 baud mode?
And what variables does it display? I think it has injector pulse width...my 93 9C1 doesn't. It's also 160 baud. Really sucks. I am looking to replace the ECM with one that has the 8192 baud ALDL rate as well as a full array of variables...any ideas?