Discussion
I have a '96 500. Standard set up - no mods.
Has been running fine for the 2 years of ownership.
Today, whilst underway, it stalled. Maybe a coincidence, but simultaneously, the speedo stopped working, as did the odometer.
Ran the ecumate and it showed a fault code 48: stepper motor. Removed the stepper motor, which wasn't that sooty, so just swept residue away with terps. Also cleaned inside where stepper motors lives. Ecumate still says fault, so tightened idle screw per Bible. Also reset the stepper motor position back and forth via the ecumate. Ran ecumate again, and fault disappears.
Gave the car a short blast. Was fine for a while, then just before test drive over, she stalls again. Per ecumate, no faults.
When idling, she runs sweet, at about 900/950 rpm.
Ideas welcome!
Has been running fine for the 2 years of ownership.
Today, whilst underway, it stalled. Maybe a coincidence, but simultaneously, the speedo stopped working, as did the odometer.
Ran the ecumate and it showed a fault code 48: stepper motor. Removed the stepper motor, which wasn't that sooty, so just swept residue away with terps. Also cleaned inside where stepper motors lives. Ecumate still says fault, so tightened idle screw per Bible. Also reset the stepper motor position back and forth via the ecumate. Ran ecumate again, and fault disappears.
Gave the car a short blast. Was fine for a while, then just before test drive over, she stalls again. Per ecumate, no faults.
When idling, she runs sweet, at about 900/950 rpm.
Ideas welcome!
if its stalling when you dip the clutch and come to a halt and the speedo is not working it will be the speedo signal not telling the engine to idle. I had this problem it is quite common. The most likely fault is the adjustment of the sender gap between the sensor and the toothed wheel on the propshaft which is located above the rear of the propshaft in the tunnel. see photo - I have a hatch over my diff so access is easy - in a standard car its a pig to get at from below to set the gap. 
When you have exhausted all other possibilities, like I did a couple of years ago, and are dreading stopping anywhere for fear of stalling, then try this:
My stepper motor had become temperature sensitive.
No idea why, or what bit of it was affected, but the issue only happened with the engine warm and drove me to distraction. I tried all the suggestions from PH, no change.
I had to take it to Mark Adams anyway for a remap, and mentioned this issue, but it didn't do it while it was with him, and he didn't have any idea what it might be.
But it did it all the 130 miles home.....GRRRR......and spoiled my enjoyment of the now correctly mapped engine.
I ended up taking it to the guy who built the engine for me. I had phoned him first, to find out what injectors he had fitted, and he said "bring it over, I will see if i can find it". An hour later I arrived, having stalled every time I stopped on the way over, and he spent an hour checking and resetting everything - throttle pot voltage, return springs and butterfly movement, base idle, fuel pressure, coil etc etc etc.
Under his breath he said "it MUST be the stepper", so I asked him if he had an old spare, one off an original TVR engine and so not a cheap Lucas copy. He rummaged around in his stores and found one, fitted it to the hot engine without removing the plenum (huge respect) and bingo - problem solved.
But do check everything else first.
Good luck
My stepper motor had become temperature sensitive.
No idea why, or what bit of it was affected, but the issue only happened with the engine warm and drove me to distraction. I tried all the suggestions from PH, no change.
I had to take it to Mark Adams anyway for a remap, and mentioned this issue, but it didn't do it while it was with him, and he didn't have any idea what it might be.
But it did it all the 130 miles home.....GRRRR......and spoiled my enjoyment of the now correctly mapped engine.
I ended up taking it to the guy who built the engine for me. I had phoned him first, to find out what injectors he had fitted, and he said "bring it over, I will see if i can find it". An hour later I arrived, having stalled every time I stopped on the way over, and he spent an hour checking and resetting everything - throttle pot voltage, return springs and butterfly movement, base idle, fuel pressure, coil etc etc etc.
Under his breath he said "it MUST be the stepper", so I asked him if he had an old spare, one off an original TVR engine and so not a cheap Lucas copy. He rummaged around in his stores and found one, fitted it to the hot engine without removing the plenum (huge respect) and bingo - problem solved.
But do check everything else first.
Good luck
Thanks Andrew. Yes, a tad frustrating. It doesn't happen all the time as you say, but that doesn't stop you approaching a roundabout or junction, or coming to lights, dreading a stall and bump starting in 1st or 2nd gear!
Might go with having a feel around per Jez's description and go from there.
It doesn't help that the only other car in the house, a Golf GTi, has decided not to recognise the key, and now won't come out of the barrel; and a host of dash warning lights being displayed after the missus decided to drive over a storm drain! Two cars without ABS and ESP now!
Will re-post once I have hopefully sorted the issue!
Might go with having a feel around per Jez's description and go from there.
It doesn't help that the only other car in the house, a Golf GTi, has decided not to recognise the key, and now won't come out of the barrel; and a host of dash warning lights being displayed after the missus decided to drive over a storm drain! Two cars without ABS and ESP now!
Will re-post once I have hopefully sorted the issue!
Mines a toothed wheel on the side of the diff. I've not had to mess with it but I'm guessing the exhaust might not need to come off on the later BTR-diffed cars? Not sure what a '96 car would have - mine's a 1997/8.
eta this is the best pic I've got - you can just see the toothed wheel in the background /David Bailey
eta this is the best pic I've got - you can just see the toothed wheel in the background /David Bailey
Edited by andy43 on Monday 23 January 09:11
Edited by andy43 on Monday 23 January 09:12
Update as promised.
When I wrote the post, I was going to comment, more as humour than anything else, that coincidentally I had also that weekend spray dyed the carpets. Little did I know how this would come into play.
So, I put the rear end on axle stands. For the life of me, I couldn't find the speed sensor on the diff.
Took car to my V8 man. Luckily, he was prepared to come out to look, as it is Chinese New Year here.
Car on ramp and sensor was on top of diff. No wonder I couldn't see it whilst laying under the car. The sensor was totally gunked up. Solvent sprayed liberally, looking like new, quick test and ... Nothing.
Then cleaned cogs with a rag - not an easy job - need at least two more elbow joints. All shiny clean, quick test ... Nothing.
Got home, whilst gingerly approaching junctions and roundabouts. Ordered new sensor. Wallet £100 lighter. Noticed that on a photo of the sensor there is a connector on at the end of the lead.
Asked mechanic if he thought I could get my hands around exhaust system etc to play with existing connector. He says "the connector is in the cabin, under the centre console".
Brain skips back to spray dyeing. Erm, I removed the centre console. Did I disconnect the lead?
Two minutes with screwdriver, found that the connection has parted and, low and behold, all is well again.
Moral? Think of bloody everything you have done prior to an issue arising. However small or inconsequential it may seem!!!
When I wrote the post, I was going to comment, more as humour than anything else, that coincidentally I had also that weekend spray dyed the carpets. Little did I know how this would come into play.
So, I put the rear end on axle stands. For the life of me, I couldn't find the speed sensor on the diff.
Took car to my V8 man. Luckily, he was prepared to come out to look, as it is Chinese New Year here.
Car on ramp and sensor was on top of diff. No wonder I couldn't see it whilst laying under the car. The sensor was totally gunked up. Solvent sprayed liberally, looking like new, quick test and ... Nothing.
Then cleaned cogs with a rag - not an easy job - need at least two more elbow joints. All shiny clean, quick test ... Nothing.
Got home, whilst gingerly approaching junctions and roundabouts. Ordered new sensor. Wallet £100 lighter. Noticed that on a photo of the sensor there is a connector on at the end of the lead.
Asked mechanic if he thought I could get my hands around exhaust system etc to play with existing connector. He says "the connector is in the cabin, under the centre console".
Brain skips back to spray dyeing. Erm, I removed the centre console. Did I disconnect the lead?
Two minutes with screwdriver, found that the connection has parted and, low and behold, all is well again.
Moral? Think of bloody everything you have done prior to an issue arising. However small or inconsequential it may seem!!!
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