Stalling at rest when hot
Discussion
The car stayed in the garage over winter for a full rear axle overhaul. The exhaust pipe was dismanteled as well, therefore the engine hasn't been started at all between october and now.
Of-course the battery went down and has been recharged since.
But now, the car has developped a strange fault.
It starts ok, runs fine for a minute until water temp. reaches 70°C, then the engine stalls.
The car hasn't moved from the garage yet. I am just trying to operate the engine through a couple of heat cycles.
When I attempt to restart the engine, it fires ok but stalls shortly afterwards (half a minute).
Right after the engines stoppes, one can hear the fuel pump buzzing (like just before starting the engine).
If I try to restart the engine more than two times, it just refuses to start and I need to wait until the engine bay is cold until it fires again.
Does that type of fault ring a bell to some of you?
Thanks for your help.
Of-course the battery went down and has been recharged since.
But now, the car has developped a strange fault.
It starts ok, runs fine for a minute until water temp. reaches 70°C, then the engine stalls.
The car hasn't moved from the garage yet. I am just trying to operate the engine through a couple of heat cycles.
When I attempt to restart the engine, it fires ok but stalls shortly afterwards (half a minute).
Right after the engines stoppes, one can hear the fuel pump buzzing (like just before starting the engine).
If I try to restart the engine more than two times, it just refuses to start and I need to wait until the engine bay is cold until it fires again.
Does that type of fault ring a bell to some of you?
Thanks for your help.
The pump should stop a second or two after the engine stops. If it keeps going its possibly a stuck relay (unlikely) or the microprocessor in the ECU has stopped running for some reason, although it would seem strange if its tied in with engine temp. Worth checking the fuel chip has not come loose in its socket in the ECU, as a faulty or missing chip makes the fuel pump keep running.
I came-up wrong....
The pump stops after one or seconds when the engine stalls. No issue there!
But this is not the normal way the pump should operate, right?
Normally, when turning the ignition off, all what is heard is the by-pass valve setting-up for the next cycle. The fuel pump shouldn't normally be energised when shutting down.
I have pluged the ECU fault code reader and it shows nothing.
When holding the revs up above idle speed, I can keep the engine running without stalling. As soon as I release the accelerator with the engine sufficiently hot, it stalls. It really looks like it's the idle control which is screwed-up.
Since this morning, I can't restart the bloody engine at all. The coil is energised (+13V measured at both connectors) therefore it is not the immobiliser.
How can I test the ignition module and hale effect sensor in the distributor?
Thanks
Philippe
The pump stops after one or seconds when the engine stalls. No issue there!
But this is not the normal way the pump should operate, right?
Normally, when turning the ignition off, all what is heard is the by-pass valve setting-up for the next cycle. The fuel pump shouldn't normally be energised when shutting down.
I have pluged the ECU fault code reader and it shows nothing.
When holding the revs up above idle speed, I can keep the engine running without stalling. As soon as I release the accelerator with the engine sufficiently hot, it stalls. It really looks like it's the idle control which is screwed-up.
Since this morning, I can't restart the bloody engine at all. The coil is energised (+13V measured at both connectors) therefore it is not the immobiliser.
How can I test the ignition module and hale effect sensor in the distributor?
Thanks
Philippe
im going to be mr obvious and say "have you cleaned the idle stepper"?
something elst to check - there are 2 identical temp sensors one on the intake manifold (coolant temp) and one on the fuel rail. when everything is cool, they should have the same resistance - check. as ive had ALL sorts of weird problems on various cars caused by bad temperature sensors.
something elst to check - there are 2 identical temp sensors one on the intake manifold (coolant temp) and one on the fuel rail. when everything is cool, they should have the same resistance - check. as ive had ALL sorts of weird problems on various cars caused by bad temperature sensors.
Philippe,
It sounds to me like you may have flooded the engine by now. They do have a tendency to do this if the engine isn't allowed to get up to temperature before it's shut down.
The fuel pump will stop as soon as you turn off the ignition as the ignition breaks the circuit to the ECU and pump, but if the engine stalls the pump will run for a second or two as the ECU allows this to happen as the ignition is still on.
I would check the stepper motor is clean and working and also check the air flow meter connector is sound and free from corrosion. (on top of the nearside inner wing) My Chim sometimes wants to stall and begins to smell of fuel, but a quick unplug and plug back in of the AFM connector half a dozen times and normal service is resumed.
If you think it might be running rich when hot, it may be worth changing the ECU coolant temperature sensor, only about 7 quid from a Landy specialist and are also known to cause grief.
Good luck.
Paul.
It sounds to me like you may have flooded the engine by now. They do have a tendency to do this if the engine isn't allowed to get up to temperature before it's shut down.
The fuel pump will stop as soon as you turn off the ignition as the ignition breaks the circuit to the ECU and pump, but if the engine stalls the pump will run for a second or two as the ECU allows this to happen as the ignition is still on.
I would check the stepper motor is clean and working and also check the air flow meter connector is sound and free from corrosion. (on top of the nearside inner wing) My Chim sometimes wants to stall and begins to smell of fuel, but a quick unplug and plug back in of the AFM connector half a dozen times and normal service is resumed.
If you think it might be running rich when hot, it may be worth changing the ECU coolant temperature sensor, only about 7 quid from a Landy specialist and are also known to cause grief.
Good luck.
Paul.
Edited by paulathome on Sunday 20th March 16:47
e635815 said:
When holding the revs up above idle speed, I can keep the engine running without stalling. As soon as I release the accelerator with the engine sufficiently hot, it stalls. It really looks like it's the idle control which is screwed-up.
Philippe
Even if the stepper motor is not working as it should, the engine should not die, as there is a basic tick over setting of about 600-700 rpm set by a screw on the plenum chamber near the throttle plate. All the stepper motor does is "top up" the idle to around 800 rpm.Philippe
Ive covered setting the base idle here:
http://www.g33.co.uk/fuel_injection.htm
blitzracing said:
Even if the stepper motor is not working as it should, the engine should not die, as there is a basic tick over setting of about 600-700 rpm set by a screw on the plenum chamber near the throttle plate. All the stepper motor does is "top up" the idle to around 800 rpm.
Ive covered setting the base idle here:
http://www.g33.co.uk/fuel_injection.htm
Mark.Ive covered setting the base idle here:
http://www.g33.co.uk/fuel_injection.htm
Excellent web page!
I need to set up my idle properly.
Which order should it be done in?
Stepper clean,
Base idle,
Throttle position sensor, (I was told to set at .32v?).
paulathome said:
Philippe,
It sounds to me like you may have flooded the engine by now. They do have a tendency to do this if the engine isn't allowed to get up to temperature before it's shut down.
The fuel pump will stop as soon as you turn off the ignition as the ignition breaks the circuit to the ECU and pump, but if the engine stalls the pump will run for a second or two as the ECU allows this to happen as the ignition is still on.
I would check the stepper motor is clean and working and also check the air flow meter connector is sound and free from corrosion. (on top of the nearside inner wing) My Chim sometimes wants to stall and begins to smell of fuel, but a quick unplug and plug back in of the AFM connector half a dozen times and normal service is resumed.
If you think it might be running rich when hot, it may be worth changing the ECU coolant temperature sensor, only about 7 quid from a Landy specialist and are also known to cause grief.
Good luck.
Paul.
The engine is certainly not flooded since it was allowed to operate until water temp. reaching 90°C just before it stalled for the last time.It sounds to me like you may have flooded the engine by now. They do have a tendency to do this if the engine isn't allowed to get up to temperature before it's shut down.
The fuel pump will stop as soon as you turn off the ignition as the ignition breaks the circuit to the ECU and pump, but if the engine stalls the pump will run for a second or two as the ECU allows this to happen as the ignition is still on.
I would check the stepper motor is clean and working and also check the air flow meter connector is sound and free from corrosion. (on top of the nearside inner wing) My Chim sometimes wants to stall and begins to smell of fuel, but a quick unplug and plug back in of the AFM connector half a dozen times and normal service is resumed.
If you think it might be running rich when hot, it may be worth changing the ECU coolant temperature sensor, only about 7 quid from a Landy specialist and are also known to cause grief.
Good luck.
Paul.
Edited by paulathome on Sunday 20th March 16:47
The injectors are only triggered if the coil receives pulses from the ignition module. I haven't been able to generate any spark since, therefore no more fuel has reached the cylinders.
I will check the stepper motor but that will not solve my second problem which is: the engine doesn't restart...
How can I diagnose the Hall effect sensor and the ignition module?
Thanks
Philippe
Remove the distributor cap, and also remove the king lead from the top of the cap, and secure its exposed connector near the chassis, but with an air gap of say 10mm. Then rotate the engine by hand until one of the trigger lobes lines up with the sensor (you now have a very small air gap between the lobe and sensor). Then turn on the ignition and use a screwdriver tip to bridge the air gap and complete the magnetic circuit. The coil should fire each time you tap the screw driver across the gap, and it should be possible to get the spark to jump the 10mm gap quite easily. Its not a hall effect sensor, simply a coil of wire that gets a small pulse induced as the rotor lobe goes by. This is then "amplified" by the ignition amp, to ground the coil as the rotor rotates. You should also hear the fuel pump prime every time the coil fires. More generally the connections to the ignition amp are rubbish and fail in the heat of a TVR engine bay, so check all the connections carefully.
blitzracing said:
Remove the distributor cap, and also remove the king lead from the top of the cap, and secure its exposed connector near the chassis, but with an air gap of say 10mm. Then rotate the engine by hand until one of the trigger lobes lines up with the sensor (you now have a very small air gap between the lobe and sensor). Then turn on the ignition and use a screwdriver tip to bridge the air gap and complete the magnetic circuit. The coil should fire each time you tap the screw driver across the gap, and it should be possible to get the spark to jump the 10mm gap quite easily. Its not a hall effect sensor, simply a coil of wire that gets a small pulse induced as the rotor lobe goes by. This is then "amplified" by the ignition amp, to ground the coil as the rotor rotates. You should also hear the fuel pump prime every time the coil fires. More generally the connections to the ignition amp are rubbish and fail in the heat of a TVR engine bay, so check all the connections carefully.
Great...Sounds feasible!!! But we all know that an easy operation can turn into a disaster on a TVR.Again, the car was working perfectly fine back in October when it was grounded for winter repair.
I will buy leads indicators in order not to mess-up the firing setup when disassembling the distributor.
Hope, this will cure the first problem...
Another quick question.
On the SD1 wiring diagram, the ignition amplifier module is connected, on one side to the reluctor pickup (two wires), on the other side to the coil (White and White & Black wires), but also to the common ground.
I don't have such a ground connection on my amplifier...Am I missing something?
On the SD1 wiring diagram, the ignition amplifier module is connected, on one side to the reluctor pickup (two wires), on the other side to the coil (White and White & Black wires), but also to the common ground.
I don't have such a ground connection on my amplifier...Am I missing something?
The throttle position sensor wont affect the idle as longs as its within the limits .085 - .545 volts when its closed, so around .3 volts or so is fine. I think the reason for the small voltage is so the ECU can detect the TP is within range and connected at power on. If you have it above .545 volts it could cause the idle to raise, but I dont know the exact switch point. The stepper wont affect the base idle as you block off the air feed to it anyway to set it, so the order is not really important.
I have found these valuable information regarding how to diagnose ignition troubles and thought PH community might be highly interested:
TESTNG IGNITION COMPONENTS - BACK TO BASICS
The circuit represents BOTH the system where the amplifier is mounted in an aluminium housing behind the coil AND where it is mounted on the side of the distributor. The effective electrics are the same, just the physical locations of components differ.
Be sure the earths and the wiring from the ignition switch through to the coil, distibutor and amplifier module are pretty much the same as shown.
Getting Started
o Reasons for testing the ignition system are a proven loss of sparks at the spark plugs, or weak/intermittent sparks causing misfiring.
o To proceed, separate the Low and High Tension circuits to find out immediately which circuit is faulty, then persue the fault condition in either circuit according to the results of some logical tests.
o Remove the king lead from the distributor, connect it to a good spark plug and lay the plug on the engine somewhere.
o Switch on the ignition and crank the engine.
o Is there a fat spark at the spark plug.
o If Yes - then the problems are downstream and away from the king lead at the dizzy cap, rotor arm, plug leads, plugs, or ignition timing so that is where to look - see " Other Components" (later) for checking the usual suspects, inspect, clean, substitute and only replace if faulty.
o If No - change the king lead.
o If still No - then the problems are upstream from the king lead and towards the coil, amplifier, distributor innards or their local connections all the way back to the ignition switch.
Testing the Low Tension Side Voltage Feed
o Switch on the ignition and use a multimeter to verify there are 12 volts at coil positive.
o If No - find out why, by checking the circuit between coil positive and the ignition switch and beyond, all the way back to the battery if necessary, for corroded or loose/broken connections.
o If Yes - dont take it for granted, waggle local wiring and toggle the ignition switch a few time to ensure the voltage is reliable, even using a bright lamp to check the wiring can supply a load.
Test the coil independently
o Disconnect the wire from coil negative to the amplifier.
o Turn ignition on, and strike coil negative to earth with a flying lead to see how good is the king lead spark.
o If sparks are absent/poor/weak and +12 volts is still present at coil positive then the coil is prime suspect for inspection/replacement.
o If sparks are fat/healthy then coil must be OK, so look for amplifier/pickup coil problemss.
Test the Amplifier and Distributor Pickup Coil Together.
o Remove Distributor Cap.
o Disconnect ECU trigger wire from the 6.8k ohm resistor to prevent spurious signals getting to the ECU.
o Disconnect amplifier wire from coil negative.
o Connect a 12v 21W bulb from the same amplifier wire to coil positive (12 volt supply).
o The 21W bulb acts as a substitute coil load.
o Turn ignition on and rotate distributor rotor arm back and forward against the vacuum/mechanical advance springs.
o As the toothed reluctor wheel triggers the pickup coil, the amplifier should flash the bulb.
o If bulb flashing is positive and consistent the amplifier and pickup coil are working correctly together.
o If lamp does not flash or is inconsistent/weak either the amplifier or pickup coil is faulty.
Check the pickup coil independently
o Remove the amplifier connections to the pick-up coil and measure the resistance of the distributor pickup coil for a steady value between 500 ohms to 1500 ohms on the ohm-meter. Flex the wires at the same time to test their integrity.
o Outside the above range, short or open circuit indicates a croaky pickup coil.
o By process of elimination, if the pickup coil is OK, one might conclude the amplifier is faulty but nothing is ever that simple with electronic components, so to be sure:
Test the Amplifier independently
o What follows is an elegant but slightly complex test process.
o Use a 1.5 volt pen-cell battery connected in series with a (say} 2,700 ohm resistor and two flying leads to simulate the pickup coil.
o With the coil and amplifier connected normally and the distributor pickup coil disconnected from the amplifier, connect one flying lead to one of the amplifier input connectors and touch the other flying lead intermittantly across the second amplifier input connector.
o This emulates a pulsed input thereby activating the amplifier in sympathy to generate sparks from the coil?
o Polarity of this simulation is non-critical as neither flying lead is connected to earth, only to the amplifier input connectors, and the pulsing voltage from the pen-cell via the 2700 ohm resistor acts similar to the pickup coil input without causing stress or damage to the amplifier.
o The above test can be performed with the 21 watt bulb as the coil substitute as previously described, except in that circumstance, the pick-up coil simulation will flash the bulb.
Alternatively (for even more elegance), going one step further:
o Construct a small test box complete with switch, 21 watt bulb/holder, pen-cell battery, 2700 ohm resistor, 12 volt pos/neg power connections (from a car battery), spade connectors to the amplifier, etc.
o Connect up the 12 volts power and the amplifier to the test box and flick the switch repeatedly to emulate the pulsed input from a pickup coil and see the 21 watt bulb flash in sympathy to show the amplifier is working correctly.
Other Components
o Another possible component failure will be the suppressing condenser breaking down under the back-EMF from the coil.
o Remove condenser from circuit to see if the problem disappears.
o If yes, replace the condenser.
o Almost finally! For all the previous components check the LT wiring is not corroded, broken, dodgy or otherwise failing.
o Because all the components upstream of the king lead now check out OK, if fat sparks emerge from the king lead but not at the spark plugs its time to review the downstream components to see if they are dragging down, or failing to conduct, the Hi-Tension energy.
o Rotor arm - inspect for carbon tracking, clean with WD40, smear with a trace of silicon grease to prevent moisture ingress.
o Distibutor cap - inside and outside - inspect for carbon tracking, clean with WD40, smear with a trace of silicon grease to prevent moisture ingress. Wipe completely clean and shiny, especially between the turrets.
o Plug Leads and Hi-tension connectors - inspect for breaks and contact damage, clean with WD40, smear with a trace of silicon grease to prevent moisture ingress. Wipe completely clean and shiny.
o Spark Plugs - Check for recommended type, clean and gap to correct spec, inspect for insulator damage externally and whiskering/crud between central contact and body. Clean externally to a shine.
o The above four items are "zero cost" actions. Many owners replace them all never knowing which of the components may have been faulty.
o Check by swapping is an easy process before buying replacements.
o Looking for spark tracking on a dark night generally reveals faulty hi-tension parts
http://www.v8forum.co.uk/forum/viewtopic.php?t=780...
TESTNG IGNITION COMPONENTS - BACK TO BASICS
The circuit represents BOTH the system where the amplifier is mounted in an aluminium housing behind the coil AND where it is mounted on the side of the distributor. The effective electrics are the same, just the physical locations of components differ.
Be sure the earths and the wiring from the ignition switch through to the coil, distibutor and amplifier module are pretty much the same as shown.
Getting Started
o Reasons for testing the ignition system are a proven loss of sparks at the spark plugs, or weak/intermittent sparks causing misfiring.
o To proceed, separate the Low and High Tension circuits to find out immediately which circuit is faulty, then persue the fault condition in either circuit according to the results of some logical tests.
o Remove the king lead from the distributor, connect it to a good spark plug and lay the plug on the engine somewhere.
o Switch on the ignition and crank the engine.
o Is there a fat spark at the spark plug.
o If Yes - then the problems are downstream and away from the king lead at the dizzy cap, rotor arm, plug leads, plugs, or ignition timing so that is where to look - see " Other Components" (later) for checking the usual suspects, inspect, clean, substitute and only replace if faulty.
o If No - change the king lead.
o If still No - then the problems are upstream from the king lead and towards the coil, amplifier, distributor innards or their local connections all the way back to the ignition switch.
Testing the Low Tension Side Voltage Feed
o Switch on the ignition and use a multimeter to verify there are 12 volts at coil positive.
o If No - find out why, by checking the circuit between coil positive and the ignition switch and beyond, all the way back to the battery if necessary, for corroded or loose/broken connections.
o If Yes - dont take it for granted, waggle local wiring and toggle the ignition switch a few time to ensure the voltage is reliable, even using a bright lamp to check the wiring can supply a load.
Test the coil independently
o Disconnect the wire from coil negative to the amplifier.
o Turn ignition on, and strike coil negative to earth with a flying lead to see how good is the king lead spark.
o If sparks are absent/poor/weak and +12 volts is still present at coil positive then the coil is prime suspect for inspection/replacement.
o If sparks are fat/healthy then coil must be OK, so look for amplifier/pickup coil problemss.
Test the Amplifier and Distributor Pickup Coil Together.
o Remove Distributor Cap.
o Disconnect ECU trigger wire from the 6.8k ohm resistor to prevent spurious signals getting to the ECU.
o Disconnect amplifier wire from coil negative.
o Connect a 12v 21W bulb from the same amplifier wire to coil positive (12 volt supply).
o The 21W bulb acts as a substitute coil load.
o Turn ignition on and rotate distributor rotor arm back and forward against the vacuum/mechanical advance springs.
o As the toothed reluctor wheel triggers the pickup coil, the amplifier should flash the bulb.
o If bulb flashing is positive and consistent the amplifier and pickup coil are working correctly together.
o If lamp does not flash or is inconsistent/weak either the amplifier or pickup coil is faulty.
Check the pickup coil independently
o Remove the amplifier connections to the pick-up coil and measure the resistance of the distributor pickup coil for a steady value between 500 ohms to 1500 ohms on the ohm-meter. Flex the wires at the same time to test their integrity.
o Outside the above range, short or open circuit indicates a croaky pickup coil.
o By process of elimination, if the pickup coil is OK, one might conclude the amplifier is faulty but nothing is ever that simple with electronic components, so to be sure:
Test the Amplifier independently
o What follows is an elegant but slightly complex test process.
o Use a 1.5 volt pen-cell battery connected in series with a (say} 2,700 ohm resistor and two flying leads to simulate the pickup coil.
o With the coil and amplifier connected normally and the distributor pickup coil disconnected from the amplifier, connect one flying lead to one of the amplifier input connectors and touch the other flying lead intermittantly across the second amplifier input connector.
o This emulates a pulsed input thereby activating the amplifier in sympathy to generate sparks from the coil?
o Polarity of this simulation is non-critical as neither flying lead is connected to earth, only to the amplifier input connectors, and the pulsing voltage from the pen-cell via the 2700 ohm resistor acts similar to the pickup coil input without causing stress or damage to the amplifier.
o The above test can be performed with the 21 watt bulb as the coil substitute as previously described, except in that circumstance, the pick-up coil simulation will flash the bulb.
Alternatively (for even more elegance), going one step further:
o Construct a small test box complete with switch, 21 watt bulb/holder, pen-cell battery, 2700 ohm resistor, 12 volt pos/neg power connections (from a car battery), spade connectors to the amplifier, etc.
o Connect up the 12 volts power and the amplifier to the test box and flick the switch repeatedly to emulate the pulsed input from a pickup coil and see the 21 watt bulb flash in sympathy to show the amplifier is working correctly.
Other Components
o Another possible component failure will be the suppressing condenser breaking down under the back-EMF from the coil.
o Remove condenser from circuit to see if the problem disappears.
o If yes, replace the condenser.
o Almost finally! For all the previous components check the LT wiring is not corroded, broken, dodgy or otherwise failing.
o Because all the components upstream of the king lead now check out OK, if fat sparks emerge from the king lead but not at the spark plugs its time to review the downstream components to see if they are dragging down, or failing to conduct, the Hi-Tension energy.
o Rotor arm - inspect for carbon tracking, clean with WD40, smear with a trace of silicon grease to prevent moisture ingress.
o Distibutor cap - inside and outside - inspect for carbon tracking, clean with WD40, smear with a trace of silicon grease to prevent moisture ingress. Wipe completely clean and shiny, especially between the turrets.
o Plug Leads and Hi-tension connectors - inspect for breaks and contact damage, clean with WD40, smear with a trace of silicon grease to prevent moisture ingress. Wipe completely clean and shiny.
o Spark Plugs - Check for recommended type, clean and gap to correct spec, inspect for insulator damage externally and whiskering/crud between central contact and body. Clean externally to a shine.
o The above four items are "zero cost" actions. Many owners replace them all never knowing which of the components may have been faulty.
o Check by swapping is an easy process before buying replacements.
o Looking for spark tracking on a dark night generally reveals faulty hi-tension parts
http://www.v8forum.co.uk/forum/viewtopic.php?t=780...
I've taken the whole ignition system out of the car today. Checked all of the components. None faulty!!!
Then everything back on the car and whooops, it starts right away!
Great I thought, but not for too long. The car stalled when the water reached 70°C and something.
The battery has been changed and is now brand new but the problems still exist.
Anybody has an idea?
Then everything back on the car and whooops, it starts right away!
Great I thought, but not for too long. The car stalled when the water reached 70°C and something.
The battery has been changed and is now brand new but the problems still exist.
Anybody has an idea?
It wont be the ECU or any of the associated sensors, they have no control over the spark at all. If the ECU does not see the coil being triggered, the fuel pump stops, so its worth listening for the pump as you crank the engine- it should be running. It will also run for a second or two when you turn the ignition on, and then stop. It will restart when you start cranking. If its not running, (together with no spark) then you are back to the distributor trigger head, amp, coil or resistive feed wire to the coil. That fault finding list you put on is pretty good for isolating the fault.
I really start wondering if it is the spark or the fuelling which gets cut.
The car starts and runs ok when overfuelling at cold. As soon as the rpm drops to norrmal idle, it shunts.
With the outside temperature increasing, the engine spends less and less time in overfueling conditions and stalls very rapidely.
Any ideas or suggestions?
I'll give a look at the throttle pot sensor tonight.
The stepper is clean, before you ask.
Thanks
The car starts and runs ok when overfuelling at cold. As soon as the rpm drops to norrmal idle, it shunts.
With the outside temperature increasing, the engine spends less and less time in overfueling conditions and stalls very rapidely.
Any ideas or suggestions?
I'll give a look at the throttle pot sensor tonight.
The stepper is clean, before you ask.
Thanks
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