Idle stall and no restart problem
Discussion
Hi,
Another one of those annoying idle cutout problems.
Car has been doing this for the last couple of years and only really occurs when left idling for more ten minutes or so. General driving around is ok, but it is denting my confidence in wanting to use it more.
Engine dies pretty quick and will often not restart for several minutes (turns over fine)
Things I have looked into so far :
1 There is still a spark when it wont restart (did replace coil and amp)
2 Fuel pump still primes and runs normally when it wont restart
3 Rovergauge does not show anything untoward before or after the stall, no error codes logged.
4 Swapped the relays but noticed one in black socket gets quite warm
5 Today after a lengthy investigation had the MIL light come on a few times whilst it was not restarting
6 Could be related to under bonnet temps, fuel temp got up to 42deg
Any help appreciated. I suspect it can only be the injection system or associated wiring breaking down.
Another one of those annoying idle cutout problems.
Car has been doing this for the last couple of years and only really occurs when left idling for more ten minutes or so. General driving around is ok, but it is denting my confidence in wanting to use it more.
Engine dies pretty quick and will often not restart for several minutes (turns over fine)
Things I have looked into so far :
1 There is still a spark when it wont restart (did replace coil and amp)
2 Fuel pump still primes and runs normally when it wont restart
3 Rovergauge does not show anything untoward before or after the stall, no error codes logged.
4 Swapped the relays but noticed one in black socket gets quite warm
5 Today after a lengthy investigation had the MIL light come on a few times whilst it was not restarting
6 Could be related to under bonnet temps, fuel temp got up to 42deg
Any help appreciated. I suspect it can only be the injection system or associated wiring breaking down.
If you've had the MIL light on re-check rovergauge for error codes.
Are the fuel/ecu relays the original metal top/red stripe type, if so worth swapping them out for the newer brown plastic ones.
you can swap the relays from black/blue socket around to see if the hot relay stays hot when in the other socket and vice versa.
What do the spark plugs look like black & sooty?
Are the fuel/ecu relays the original metal top/red stripe type, if so worth swapping them out for the newer brown plastic ones.
you can swap the relays from black/blue socket around to see if the hot relay stays hot when in the other socket and vice versa.
What do the spark plugs look like black & sooty?
Edited by ukdj on Monday 4th April 18:05
Relays are both the original red stripe ones. ECU is the one that always gets warm, but that could be normal.
Rovergauge still says no errors logged.
Looking through the rovergauge logs it confirms my feeling that the engine always stalls just after the cooling fans kick in as the ECU volts drops from 13.63V to 13.2V. Even when it does not stall I have always noticed the engine has to trim the idle slightly when the fans kick in. Still confused why it does not restart straight away, perhaps it floods.
I think my next thing is therefore fuel pump voltage and maybe fuel filter as that has not been changed for a while
Rovergauge still says no errors logged.
Looking through the rovergauge logs it confirms my feeling that the engine always stalls just after the cooling fans kick in as the ECU volts drops from 13.63V to 13.2V. Even when it does not stall I have always noticed the engine has to trim the idle slightly when the fans kick in. Still confused why it does not restart straight away, perhaps it floods.
I think my next thing is therefore fuel pump voltage and maybe fuel filter as that has not been changed for a while
Edited by dogbucket on Monday 4th April 19:23
from memory The ECU has a trick up its sleeve when the fuel rail gets hot- it runs a longer injector pulse on start up to clear any vapour in the rail- but for it not to start is pretty major. If you can do it Id drop a plug out when it wont run and see if its wet- it will stink of fuel if the engine is flooding. Good time to check the plug colour and condition as well.
You could strap out the otter switch to turn the fans on to check is not the fans turning on that causes the problem.
It sounds like a heat issue, ignition amp, plug extenders are susceptible to heat. The temp sender for the ecu that is by the dizzie is also worth checking/changing. Cheap to do at around a tenner.
My own Chim ran rough intermittently until I got rid of the extenders.
It sounds like a heat issue, ignition amp, plug extenders are susceptible to heat. The temp sender for the ecu that is by the dizzie is also worth checking/changing. Cheap to do at around a tenner.
My own Chim ran rough intermittently until I got rid of the extenders.
Hi,
sorry i have a completely different TVR (S-Series) but i had exactly the same issue last winter & it drove me mad!! Within first 5mins of my journey usually moving in slow traffic or waiting at a set of lights my car would suddenly cut out & not start back up again for a good few minutes.
I tried new ignition leads (and spark plugs whilst i was at it) was told to check the ignition coil too.. which had already been replaced, in the end there was a split in the 'air flow meter cap' & the air flow meter itself was in a bad way the plate inside had dropped screwing around with the mixture & causing it to suddenly cut out.
For good measure the distributor cap was checked & points were badly corroded so replaced that too, its been running fine ever since, hope this helps
Steve
sorry i have a completely different TVR (S-Series) but i had exactly the same issue last winter & it drove me mad!! Within first 5mins of my journey usually moving in slow traffic or waiting at a set of lights my car would suddenly cut out & not start back up again for a good few minutes.
I tried new ignition leads (and spark plugs whilst i was at it) was told to check the ignition coil too.. which had already been replaced, in the end there was a split in the 'air flow meter cap' & the air flow meter itself was in a bad way the plate inside had dropped screwing around with the mixture & causing it to suddenly cut out.
For good measure the distributor cap was checked & points were badly corroded so replaced that too, its been running fine ever since, hope this helps
Steve
Edited by greyhulk on Wednesday 6th April 18:50
If the plugs are black and no error codes You could also try replacing the temperature sender for the ECU and installing warmer plugs like BPR6ES.
I had intermittent stalling problems and this fixed my issue.
Some information here
http://www.pistonheads.com/gassing/topic.asp?t=899...
And some really good information here
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
I had intermittent stalling problems and this fixed my issue.
Some information here
http://www.pistonheads.com/gassing/topic.asp?t=899...
And some really good information here
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
The MAF is about the biggest culprit for over fuling issues- problem is it gets really cooked in the TVR engine bay, and this can cause the output to go higher than it should do. This leads to more fuel and can flood the engine. As you have Rovergauge double check the MAF output at idle and make sure its within spec. Only thing to note here is "within spec" is with a stable idle- if the car is running rough and the idle is unstable, then getting a reading will be harder. You can run this basic DC test:
Most airflow meter faults will cause the engine to run excessively rich. However if the airflow meter remains connected whilst defective then the vehicle will probably not run. In most cases the output from a defective airflow meter will be in the range 2.0-2.5 Volts, which is a viable value. This represents a moderate load and will cause heavy over-fuelling without setting a fault code.
Testing is performed in the following manner. Peel back the rubber boot on the airflow meter connector and leave it plugged in to the airflow meter. Set up the digital multimeter to read voltage. Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal).
Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts after the initial "warm up" spike. Most defective airflow meters will overshoot to 0.8 Volts or higher, and take at least 2 seconds to come down to the correct voltage.
Now start the engine, and the reading should rise to 1.6 Volts (3.5 Litre engine) to 1.75 Volts (5.0 Litre engine) at idle.
With thanks to Mark Adams of Tornado systems.com.
Most airflow meter faults will cause the engine to run excessively rich. However if the airflow meter remains connected whilst defective then the vehicle will probably not run. In most cases the output from a defective airflow meter will be in the range 2.0-2.5 Volts, which is a viable value. This represents a moderate load and will cause heavy over-fuelling without setting a fault code.
Testing is performed in the following manner. Peel back the rubber boot on the airflow meter connector and leave it plugged in to the airflow meter. Set up the digital multimeter to read voltage. Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal).
Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts after the initial "warm up" spike. Most defective airflow meters will overshoot to 0.8 Volts or higher, and take at least 2 seconds to come down to the correct voltage.
Now start the engine, and the reading should rise to 1.6 Volts (3.5 Litre engine) to 1.75 Volts (5.0 Litre engine) at idle.
With thanks to Mark Adams of Tornado systems.com.
UPDATE
Still investigating this particularly as the recent MOT had to be abandoned as I wasted so much time trying to get it restarted after it stalled!
I am pretty sure it is fundamentally a lack of fuel problem as the plug are dry and there is a spark, but triggered by heat under the bonnet.
Looking at Rovergauge the normal startup sequence in regards to the fuel pump seems to be :
Ignition on
Fuel relay on for 2s then off (and priming sound)
Start cranking
Fuel relay back on and engine fires
When it stalled and failed to restart today :
Ignition on
Fuel relay on for 2s then off (and priming sound)
Start cranking
Fuel relay remains off (according to Rovergauge)
Using Rovergauge to run pump continuously it did restart, but I then turned run continuously off and of course it stalled and threw the MIL light. Had to wait a while for the MIL to clear before it restarted normally.
So my understanding is in the cranking sequence the ECU waits for a return signal from the ignition amp before running the pump continuously. Is this correct and if the ignition amp is still working in regards to triggering the coil that seems odd. Is there anything else that the ECU uses to decide when to turn on the fuel pump?
Still investigating this particularly as the recent MOT had to be abandoned as I wasted so much time trying to get it restarted after it stalled!
I am pretty sure it is fundamentally a lack of fuel problem as the plug are dry and there is a spark, but triggered by heat under the bonnet.
Looking at Rovergauge the normal startup sequence in regards to the fuel pump seems to be :
Ignition on
Fuel relay on for 2s then off (and priming sound)
Start cranking
Fuel relay back on and engine fires
When it stalled and failed to restart today :
Ignition on
Fuel relay on for 2s then off (and priming sound)
Start cranking
Fuel relay remains off (according to Rovergauge)
Using Rovergauge to run pump continuously it did restart, but I then turned run continuously off and of course it stalled and threw the MIL light. Had to wait a while for the MIL to clear before it restarted normally.
So my understanding is in the cranking sequence the ECU waits for a return signal from the ignition amp before running the pump continuously. Is this correct and if the ignition amp is still working in regards to triggering the coil that seems odd. Is there anything else that the ECU uses to decide when to turn on the fuel pump?
Edited by dogbucket on Monday 27th June 19:47
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