Discussion
Stepper motor would be the first place to start.
http://www.parkersteve.dsl.pipex.com/stepper.html
Don't break it!
http://www.parkersteve.dsl.pipex.com/stepper.html
Don't break it!
None of the above, that's most definitely the TVR speed signal box not telling the ECU you are returning to idle.
If you take a Chim or Griff without the problem & disconnect the multi plug at the back of the speedo it will do exactly the same.
The signal ultimately comes from the diff mounted speed sensor then goes through (& drives) the speedo, then to the TVR speed signal box finally ending at the ECU.
Your fault could be anywhere within the above chain of components.
Remember, the 14CUX system is designed to cut fuel when you lift off the throttle, this both saves fuel and helps a little to make gear changes smoother.
If you rapidly return to idle say when you are approaching a junction from speed, your foot will be off the throttle and the ECU will have cut the fuel.
Clearly the result would be a stall, so to counter the stall problem the ECU recognises a below 7mph speed signal, ignores the throttle position and reinstates the fuel.
Result - no stall.
My first question to you would be, "is your speedo working?" not "have you cleaned your stepper motor recently?"
The stepper motor is wrongly blamed for almost every 14CUX fault it seems.
If your speedo is not working my advice would be to check the pick up at the diff and work your way forward to the speedo.
If your speedo is working, suspect the TVR speed signal box and generally all the associated wiring in that circuit.
The 14CUX ECU is typically extremely reliable and no more the source of this fault that the poor maligned stepper motor.
Steve Heath has been onto the faults in this circuit for some time now, he started early on by offering a speed pick up kit but has more recently begun offering a replacement for the TVR speed signal box.
He's not offering these parts for fun, they are a weak link.
Stalling at junctions and other related issues normally blamed on the stepper motor are way more likely to be the ECU not receiving the "rapidly returned to idle" signal during the fuel cut off condition.
You could fix it as simply as I did when I had this problem, in my case after a bit of thinking and some time with a multimeter I resolved the issue by disconnecting & reconnecting the speedo multi plug.
Hey presto the speedo came back to life and no more stalling at junctions.
Clearly I was lucky (hence my name), just a bad connection at the speedo multi plug.
If you take a Chim or Griff without the problem & disconnect the multi plug at the back of the speedo it will do exactly the same.
The signal ultimately comes from the diff mounted speed sensor then goes through (& drives) the speedo, then to the TVR speed signal box finally ending at the ECU.
Your fault could be anywhere within the above chain of components.
Remember, the 14CUX system is designed to cut fuel when you lift off the throttle, this both saves fuel and helps a little to make gear changes smoother.
If you rapidly return to idle say when you are approaching a junction from speed, your foot will be off the throttle and the ECU will have cut the fuel.
Clearly the result would be a stall, so to counter the stall problem the ECU recognises a below 7mph speed signal, ignores the throttle position and reinstates the fuel.
Result - no stall.
My first question to you would be, "is your speedo working?" not "have you cleaned your stepper motor recently?"
The stepper motor is wrongly blamed for almost every 14CUX fault it seems.
If your speedo is not working my advice would be to check the pick up at the diff and work your way forward to the speedo.
If your speedo is working, suspect the TVR speed signal box and generally all the associated wiring in that circuit.
The 14CUX ECU is typically extremely reliable and no more the source of this fault that the poor maligned stepper motor.
Steve Heath has been onto the faults in this circuit for some time now, he started early on by offering a speed pick up kit but has more recently begun offering a replacement for the TVR speed signal box.
He's not offering these parts for fun, they are a weak link.
Stalling at junctions and other related issues normally blamed on the stepper motor are way more likely to be the ECU not receiving the "rapidly returned to idle" signal during the fuel cut off condition.
You could fix it as simply as I did when I had this problem, in my case after a bit of thinking and some time with a multimeter I resolved the issue by disconnecting & reconnecting the speedo multi plug.
Hey presto the speedo came back to life and no more stalling at junctions.
Clearly I was lucky (hence my name), just a bad connection at the speedo multi plug.
Edited by ChimpanLucky on Saturday 5th May 01:44
ChimpanLucky said:
None of the above, that's most definitely the TVR speed signal box not telling the ECU you are returning to idle.
FWIW, I had a very similar problem (stalling on stopping but restarting straight away) and it was traced back to dirty ECU plug contacts. I've not had a problem with stalling since then.Gassing Station | Chimaera | Top of Page | What's New | My Stuff