Temporarily possessed!
Discussion
Jumped into the car to drive home from the office, started it and it stank of fuel and could not idle for more than 10 seconds. Ok, let it warm up I thought (it is still over 28 degrees here) but still it was idling like a dog 5 minutes later.
Got it out onto the road, above 2000 rpm was OK and hard acceleration it was pulling as usual and no apparent lack of power, but on half throttle, it was hiccupping and coming to a stop, it would not idle at the lights. So heeled and toed it at every junction to keep the revs up with the help of the handbrake (useless at anything over 1mph) and got it home 20 minutes later, car fully warmed up, not holding the idle at junctions.
Turned it off and 10 minutes later, started it to let the wife out of the drive, and it purred beautifully again, no sign of whatever had possessed it. I was thinking stepper motor (it was out and cleaned about 2 months ago), or a dodgy HT lead (again, about 5 months old) so no clue what it could be.
My car is on Map 2 so can't check RG for faults, can put it back on Map 5 to check, but what the hell was that all about?
Got it out onto the road, above 2000 rpm was OK and hard acceleration it was pulling as usual and no apparent lack of power, but on half throttle, it was hiccupping and coming to a stop, it would not idle at the lights. So heeled and toed it at every junction to keep the revs up with the help of the handbrake (useless at anything over 1mph) and got it home 20 minutes later, car fully warmed up, not holding the idle at junctions.
Turned it off and 10 minutes later, started it to let the wife out of the drive, and it purred beautifully again, no sign of whatever had possessed it. I was thinking stepper motor (it was out and cleaned about 2 months ago), or a dodgy HT lead (again, about 5 months old) so no clue what it could be.
My car is on Map 2 so can't check RG for faults, can put it back on Map 5 to check, but what the hell was that all about?
I can't help thinking that had I pulled over turned it off for a few minutes and then turned it back on again, would it had reset itself?
It has been running without fault for weeks as a daily driver, this problem has just popped up out of the blue.
I'll start it again tomorrow morning, it will probably idle perfectly again but if not apart from checking if there is a loose plug, what else should I be looking for?
I'm handy with spanners but electri trickery is not my strong point.
It has been running without fault for weeks as a daily driver, this problem has just popped up out of the blue.
I'll start it again tomorrow morning, it will probably idle perfectly again but if not apart from checking if there is a loose plug, what else should I be looking for?
I'm handy with spanners but electri trickery is not my strong point.
As it "clears itself" its probably going to be difficult to pinpoint. (See the other thread going at present on rough running) as you have similar situation.
I would get a can of spray electrical contact cleaner and clean the contacts both male and female on all main inputs that control fueling
ie the AFM and the plug on it
The TPS and plug
Engine temp sensor
Fuel temp sensor
Disconnect each spay inside and pkug em and unplug em a few times to ensure good contact.
Make sure all ignition component connections are good ie distributor coil cap rotor arm leads plugs.
Do you have rovergauge ?
I would get a can of spray electrical contact cleaner and clean the contacts both male and female on all main inputs that control fueling
ie the AFM and the plug on it
The TPS and plug
Engine temp sensor
Fuel temp sensor
Disconnect each spay inside and pkug em and unplug em a few times to ensure good contact.
Make sure all ignition component connections are good ie distributor coil cap rotor arm leads plugs.
Do you have rovergauge ?
Using map 2 Frank.
Rovergauge should show you the stepper position in numbers if it’s anything like Ecumate. I used to watch those numbers when it was working correctly, those numbers changed quite dramatically when a stuck stepper then started working again but out of sync and you can see the Ecu trying to address it.
Often turning car off for a few moments or maybe minutes will be enough to re set stepper position. Mine would stick randomly and display similar signs of very low or erratic idle. When stepper worked the car drove perfectly again.
Rovergauge should show you the stepper position in numbers if it’s anything like Ecumate. I used to watch those numbers when it was working correctly, those numbers changed quite dramatically when a stuck stepper then started working again but out of sync and you can see the Ecu trying to address it.
Often turning car off for a few moments or maybe minutes will be enough to re set stepper position. Mine would stick randomly and display similar signs of very low or erratic idle. When stepper worked the car drove perfectly again.
Rovergauge (RG) still works with map 2. Its just the lambdas are not used in map 2 where they are in map 5
Run RG and record data whilst the car is running good this will become your reference data set. Then run RG and collect data until it starts running badly again. Then make a note of the time so you can then look at the data to see whats going on in comparison to your reference data.
Run RG and record data whilst the car is running good this will become your reference data set. Then run RG and collect data until it starts running badly again. Then make a note of the time so you can then look at the data to see whats going on in comparison to your reference data.
It’s entirely possible it gets out of sync.
Usually goes something like this,,, starts fine, heats up, stepper momentarily gets stuck then carries on working, trouble is Ecu can’t detect the sticking so now the stepper is not in the position the Ecu thinks it is so goes round in circles trying to resolve the inconsistent air supply, turning ignition off over pulses the stepper plunger to ensure it starts from zero next time round which is why it’s often resolved by simply turning ignition off.
Sounds very similar to your symptoms but checking all connections as Frank mentions sounds like a first move.
I spent months trying 3 steppers once mine failed regularly.
I eventually noticed when stepper motor was removed from plenum that by manually adjusting stepper with Ecumate it would randomly stick for a second or two then work again, this was all it took to make the car run rough as hell until it was re set again. After market ones were worse as the plunger was never really in the correct position to start with.
Usually goes something like this,,, starts fine, heats up, stepper momentarily gets stuck then carries on working, trouble is Ecu can’t detect the sticking so now the stepper is not in the position the Ecu thinks it is so goes round in circles trying to resolve the inconsistent air supply, turning ignition off over pulses the stepper plunger to ensure it starts from zero next time round which is why it’s often resolved by simply turning ignition off.
Sounds very similar to your symptoms but checking all connections as Frank mentions sounds like a first move.
I spent months trying 3 steppers once mine failed regularly.
I eventually noticed when stepper motor was removed from plenum that by manually adjusting stepper with Ecumate it would randomly stick for a second or two then work again, this was all it took to make the car run rough as hell until it was re set again. After market ones were worse as the plunger was never really in the correct position to start with.
Nope.
Not in my experience but hopefully someone will come along and prove me wrong
Good second hand ones would be my guess. Joolz and other mappers sometimes have spares from Ecu installs but probably keep them for their needs.
What you really need is a spare that’s known to work or just do as Blaze away says and check your data to confirm if it is the stepper!
Not in my experience but hopefully someone will come along and prove me wrong
Good second hand ones would be my guess. Joolz and other mappers sometimes have spares from Ecu installs but probably keep them for their needs.
What you really need is a spare that’s known to work or just do as Blaze away says and check your data to confirm if it is the stepper!
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