Hello Everyone,
I recently performed an auto>manual transmission swap on my 93 FD. Car was automatic with working cruise. I performed all the various splices and such outlined in the other threads. Everything works fine...all gauges working, driveline is functioning properly, but my cruise control doesn't work now. What I mean is that I press the button on the dash to turn on the system (Button light lights up), and when I press the set button on the steering wheel, the cruise does not engage. Can anyone help me figure out how to get this back or is this a sad byproduct of doing the swap?

Current Setup:
93 FD Auto - Power FC with Auto ECU w/ Banzai plug adapter - original engine harness- All splices made were at the transmission sensors - original dash harness - OEM 5 speed trans

Thanks in advance!

 

You don't need our adapter anymore as you should have pulled out the auto trans ecu.

 

So I should be able to run solely on the Power FC now, and my cruise control should function again?

 

You do not need the stock ECU or the Auto trans ECU anymore. I can't tell you that your cruise will function.

 

Could be a problem with the brake switch. I have a thread on troubleshooting cruise control, hands down that's the most common problem I've seen. Since you probably swapped the pedal assembly out that's most likely what's going on.

The cruise doesn't do anything with the ECU. The cruise computer in the driver's side gets a speedo signal input that goes to the actuator under the hood.

Dale

 

Thanks for the input. Gonna try doing this and see what happens with the cruise. Thanks again for the input!

 

Dale, thanks for commenting. Have you done the trans swap as well? Perhaps we can compare notes to find the solution. I did swap the pedal assembly but I swapped the switch from the old pedal to the new one. I did the wire jump for the Auto trans inhibitor rather than use a clutch pedal switch and spliced the wires to have my backup lights work in reverse. The wiring diagram looks like it sends or receives some sort of signal with the AT trans ECU. Maybe since the inhibitor is permanently jumped rather then the clutch switch, maybe the cruise computer "thinks" the clutch pedal is depressed??? Any thoughts?

 

The clutch pedal does have switch that disables cruise when it is pressed. It acts just like the brake pedal.

 

I wonder if I were to disable that input wire going to the cruise computer that it would trick the computer to think that the switch is no being depressed but still all the starter circuit to operate as normal. Because my thought is starting to become that if I want cruise, I may have to install and wire the clutch switch into my car if I want my cruise back. Gonna do some testing this weekend.

 

Yeah, I think you can jumper the wire (or leave it unplugged, not sure if it's looking for a complete or broken circuit) to test out.

The brake switch is the one that's gotten me in the past. There are 2 sets of wires going to the brake switch, one for the cruise and one for the brake light itself. The beginning of the switch travel is for the cruise switch, then the brake switch. If the switch isn't adjusted right on the pedal so it's pushing in the brake switch all the way it will think you're pressing the brake and not engage the cruise.

I've actually not done an auto-manual swap, I've read up on how to do it in the past and I know the principles, but never done the job itself.

Regardless I'm convinced that it's in the pedal switches. I would completely rule that out before going further. Good thing is it's easy to get to that stuff to test out.

Dale

 

Check out section Q in the body troubleshooting manual. There’s a TON of good info on shooting wires and there is even a built in diagnostic mode with codes to assist.

http://www.wright-here.net/files/man..._tshooting.pdf

Matt

 

FD Auto > Man Trans Swap Update: As mentioned in one of my previous posts, after doing my transmission swap I noticed that my cruise control no longer was operating properly. The system would turn on, but not set the speed. After reading Dale Clark's notes on the RX7club.com page about diagnosing the cruise control system, I determined that the only possible explanation why it wouldn't set was that the inhibitor switch was jumped as part of the conversion and was telling the cruise module that the the clutch switch was closed rather than open (clutch pedal not pressed). So after verifying there are no codes, I cut the wire telling the module the status of the clutch switch and voila! Cruise works! If I ever want to cancel the cruise by pressing the clutch, I'll just need to add the clutch switch back on to the pedal and splice it into the one I cut.

 

Nice! Glad you sorted that out!

I had a feeling it was related to the pedal side of things.

Dale