Stalling (not the usual stepper) advice needed...
Discussion
Hi all,
Griff has developed an annoying problem where it will idle rough and then stall. It starts fine but will then stall again. I have changed the stepper, which helped initially but then it has come back to haunt.
The stalling is fixed by resetting the ECU. This will usually work for the journey or even a couple of days but then it will start to act up again. It seems like the stepper is getting confused and not resetting properly when switched off or summat?? Any one had this? Any advice except to keep unplugging the ECU.
Cheers,
Lig.
Griff has developed an annoying problem where it will idle rough and then stall. It starts fine but will then stall again. I have changed the stepper, which helped initially but then it has come back to haunt.
The stalling is fixed by resetting the ECU. This will usually work for the journey or even a couple of days but then it will start to act up again. It seems like the stepper is getting confused and not resetting properly when switched off or summat?? Any one had this? Any advice except to keep unplugging the ECU.
Cheers,
Lig.
lig, this sounds familiar.
There's a whole host of possible solutions in my recent thread...
www.pistonheads.com/gassing/topic.asp?t=201032
There's a whole host of possible solutions in my recent thread...
www.pistonheads.com/gassing/topic.asp?t=201032
Oddly enough, I've not had alot of time to check the things that everyone recommended.
I just ensured all the leads were on (had to do some DIY to one of them) properly and had a thorough sniff under the bonnet. Its not missed a beat since I did this.
I have a feeling the problem will return and if thats the case, I shall go through all the options then.
I just ensured all the leads were on (had to do some DIY to one of them) properly and had a thorough sniff under the bonnet. Its not missed a beat since I did this.
I have a feeling the problem will return and if thats the case, I shall go through all the options then.
Hi there, sounds like you renewed the stepper motor for no reason! The stepper gets such a hard time by the TVR gassers! If you have idling faults like the one you have explained then remove the stepper motor and clean the conical end and also its seat in the plenum chamber. Refit the stepper and locate the idling bypass allen headed screw just right of the throttle butterfly, turn the screw anti clockwise one turn. Now start the engine, if the engine idles, fine, if not turn the screw one further turn anticlockwise. With the engine idling, SLOWLY squeeze the bypass pipe with a pair of pliers ( the wiggly looking pipe right of the throttle butterfly)at the same time turn the idling screw anticlockwise if the engine dies, or clockwise if the revs are too high. What you are looking for is an idle speed of 550rpm with the pipe completely compressed. Once achieved unclamp the bypass pipe and the revs should rise to 2000rpm + for a few seconds and then settle at the norm 850 to 900. If the revs stay high turn of the engine and restart. Pause for breath..... now with the engine off ignition on, measure the voltage at the throttle potentiometer, (the black plastic device clamped to the plenum butterfly spindle) your are looking to find 0.33 to 0.37 volts with throttle closed and 4.85+ with throttle wide open. If the voltage is wrong at idle then you can cheat by loosening the two flat headed screws and turning the pot left or right. If the voltage is still way out the call a mechanic!. Some vehicles from the factory have the plenum idle screw blanked off with an aluminium plug which should and can be removed easily. Hope that this fixes your problem.
Cheers TVR PRO,
I did try setting the idle speed but found that the engine would either idle at +1k revs or die, but i will try again... I assume you mean after cleaning stepper to turn the screw fully in clockwise then 1 turn anticlockwise?
Which colour wires on the throttle pot do i plug the volt meter in (its the newer type pot)?
When you say the plenum screw is blanked off do you mean on the inside i.e I will have to take the screw all the way out and look to see if its clear or blocked?
One thing I have tried recently which seems to have worked (but I am banking on it reverting to stalling soon) was to remove the vaccum advance lead and seal the plenum end?? what do you think???
Lig.
I did try setting the idle speed but found that the engine would either idle at +1k revs or die, but i will try again... I assume you mean after cleaning stepper to turn the screw fully in clockwise then 1 turn anticlockwise?
Which colour wires on the throttle pot do i plug the volt meter in (its the newer type pot)?
When you say the plenum screw is blanked off do you mean on the inside i.e I will have to take the screw all the way out and look to see if its clear or blocked?
One thing I have tried recently which seems to have worked (but I am banking on it reverting to stalling soon) was to remove the vaccum advance lead and seal the plenum end?? what do you think???
Lig.
Hi Lig. The wire to test voltage on the throttle pot is....off the top of my head, the middle one or green. If not keep your multimeter earth lead on an earth point and probe all three.. As for removing the vac advance tube from the plenum, dont, it will loose you engine performance and nothing else. Cleaning the stepper seat and refitting the stepper, could not be easier. You mentioned turning the idle screw all the way in and out one turn? thats the long way of setting the idle. Wind out the bypass allen screw until the engine idles then clamp the bypass pipe and wind the allen screw in until 550rpm. Job done. Does the stepper actually work? plug it in to the multiplug but do not wind into the plenum, now when you turn on the ignition it will move to its starting position for idle if not the voltages will have to be checked. Its worth disconnecting the ecu and checking the terminals for water ingress. Keep me posted. Oh nearly forgot the blanking disc over the bypass screw. Its about the same size as a half penny, if you have tried to set base idle then your engine doesnt have one.
THE TVR PRO said:
As for removing the vac advance tube from the plenum, dont, it will loose you engine performance and nothing else.
I thought the vacuum advance purely benefitted cruise economy - with no effect on power under acceleration as it is inoperative at full throttle ( = negligible plenum vacuum). So it's removal should only affect cruise economy?
Hi TVR Pro,
Checked out the TP and it was reading 0.55 when closed and 4.85+ when open as you stated. I have adjusted this to now read 0.35 when closed. Did the stepper bit aswell and all seems to be running OK. I will monitor this as this usually happens and after about 3 good runs it starts to act up. Heres hoping it was the TP set wrong.
Will let you know. Cheers for your help so far.....
Lig.
Checked out the TP and it was reading 0.55 when closed and 4.85+ when open as you stated. I have adjusted this to now read 0.35 when closed. Did the stepper bit aswell and all seems to be running OK. I will monitor this as this usually happens and after about 3 good runs it starts to act up. Heres hoping it was the TP set wrong.
Will let you know. Cheers for your help so far.....
Lig.
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