TBI 4l60e /drac problem (1 Viewer)

[Kurtis]

I put a tbi 4l60e combo from a 1993 suburban In my 85 fj60 and Have got it going and its running great except for one problem. The governer wants to kick in at 45mph. I pulled out the drac soldered on switches so I could program it for my tires and after wards I got a similar response. I then programed it to the highest ratio possible and now I am not goverened until 65mph. by governed i mean my speed is limited. I used advance adaptors 4l60e adaptor and they sent me a 40 pulse vss which should be right with the ring on a 4l60e as far as i know. I'm stumped I figured i'd post over here and see if anyone knew much about these. I have tried the original computer and a 7427 out of a 95 pickup, and both give the same result. Something isn't adding up but I don't know what.

 

[BRPRacer]

How did you end up solving your Drac problem? I have a 94 5.7 TBI with a 4L60E and it is also shutting down a 45 MPH.

 

[Kurtis]

The harness builder had the wrong input signal wired to the wrong pin. I looked up the wiring diagram and swapped the two signals. It was telling the ecm I was driving twice as fast as I really was. Its a little fuzzy but I believe the ecm uses 4k pulses per mile for the speedo and 2k for cruise control. So if you switch the wires you hit the governor at 48 mph.

I also modded my drac module using the method on this site http://www.tbichips.com/drac/ to make sure the shift points were correct after I got it working.

 

[BRPRacer]

Thanks for the quick response. I figured it was something simple. I just need to look up a wiring schematic or call the harness builder.
Thanks
Kevin

 

[BRPRacer]

The harness builder was stumped. I tried switching the two wires and it still does the same thing. Advanced Adapters said it was probably air gap between the VSS and the tone ring. I pulled the transfer case and made sure the gap was between .010 and .012. It was exactly .010. Its starting to get frustrating. Did you switch the wires on the ECM or the DRAC?

 

[Kurtis]

I think i switched it at the drac. it shouldn't really matter though. There is a few wires coming off to work with and the diagram can be a little deceiving. I actually swapped the wrong one first i think. Hook it up to a scanner and see what your speed reading is. Are you sure you have the correct drac?. Pm me who built the harness I'm curious if it was the same guy maybe it's the same wire. I'm at my place in kc right now working and the land cruiser is at my house in Arizona or i would go take a look.