Heat soaked engine cutting out
Discussion
I have a Tuscan mk1 from 2000 and I'm still finding my way around the car so this is my first real challenge. The car has been recently serviced with new plugs, throttle balance and an oil change. Last 200 miles it has been driving really nicely but I have experienced this issue on the last two run outs. Both were a local school run, drive to work, drive home via country lanes type runs.
So the car is starting OK from cold in our cool autumn mornings now and only just really gets up to temp for the 10 miles for the school run and drive into work. Not a lot of town traffic, the odd lights and slow traffic over speed humps. All OK.
After work, it's more of a spirited drive back through the country lanes once up to a decent temp (oil and water). Probably 10-12 miles before I get back into town. Once in town and slowing down, the car is prone to cutting out. Water and oil temp are around 90 degrees.
Once the car cuts out it needs a ‘cool down’ at the side of the road for 2 – 3 mins before starting again. Generally, when I'm pootling up to lights or idling at lights. Once cooled down, it’ll start and run for a few mins and then cut out again. No info to be gleaned from the diagnostic codes on the dash. Occasional L or E error but they clear when cycling the key. Immobiliser light stays off and all other electrical items seems to work OK. I believe the fuel pump primes ok as when I got back home eventually, I could here it prime fine without all the road noise going on.
The first time this happened on the way home I thought it was just a glitch and that I'd just stalled the engine and somehow flooded it when restarting. The second run, it happened pretty much on the same route when I got back into town but this time I needed 4 cool down hops to make the 2 miles back to home. So definitely getting worse quickly.
It seems to be engine heat related so the extra heat going into the engine or engine bay is causing an issue when I get into town traffic and something pops. That then cools down a bit, makes a connection again and you’re good to go. Definitely a lot, lot worse than my last drive to work.
Checked the ignition related fuses and relays, nothing obvious. Only diagnostic fault that shows up using the MBE software is a low battery voltage every now and again but I keep it charged in the garage in between drives and it shows 13.7V at idle which I think is OK. Everything off, the battery is around 12.6V
I think I’ll go for another very local drive after work tonight to try and troubleshoot further and check the fuel pump is 100% priming ok when the car cuts out. It’ll be quieter on country roads by then. I don’t think idling the car in the garage up to temp will induce the fault yet. Might try that once the fault occurs and I limp it home. Or drive until I get it up to temp, tip toe home and idle until the fault occurs.
My thinking at this stage is that it might be the coil pack as that sits right against the engine block. When my power amplifier started to fail on my Chimaera it felt like the same thing. Engine hot and electrical failure occurs. I'm thinking once heat soaked after the country lanes driving, the extra heat causes the coil pack to pop until it cools down again. My understanding of the coil pack is that it is the power amplifier and high voltage coils combined in one unit.
Could you please let me know if I'm on the right track? Other threads have mentioned 100A strip fuses but I thought if they blow that would take out the rest of the electrics and/or cause intermittent faults with the rest of the electrics at the same time.
Is there a good way to test the coil pack apart from replacement with a good one? Anything else I missed or should check?
Is changing the coil pack simply removing the airbox to get access?
Thanks everyone.
So the car is starting OK from cold in our cool autumn mornings now and only just really gets up to temp for the 10 miles for the school run and drive into work. Not a lot of town traffic, the odd lights and slow traffic over speed humps. All OK.
After work, it's more of a spirited drive back through the country lanes once up to a decent temp (oil and water). Probably 10-12 miles before I get back into town. Once in town and slowing down, the car is prone to cutting out. Water and oil temp are around 90 degrees.
Once the car cuts out it needs a ‘cool down’ at the side of the road for 2 – 3 mins before starting again. Generally, when I'm pootling up to lights or idling at lights. Once cooled down, it’ll start and run for a few mins and then cut out again. No info to be gleaned from the diagnostic codes on the dash. Occasional L or E error but they clear when cycling the key. Immobiliser light stays off and all other electrical items seems to work OK. I believe the fuel pump primes ok as when I got back home eventually, I could here it prime fine without all the road noise going on.
The first time this happened on the way home I thought it was just a glitch and that I'd just stalled the engine and somehow flooded it when restarting. The second run, it happened pretty much on the same route when I got back into town but this time I needed 4 cool down hops to make the 2 miles back to home. So definitely getting worse quickly.
It seems to be engine heat related so the extra heat going into the engine or engine bay is causing an issue when I get into town traffic and something pops. That then cools down a bit, makes a connection again and you’re good to go. Definitely a lot, lot worse than my last drive to work.
Checked the ignition related fuses and relays, nothing obvious. Only diagnostic fault that shows up using the MBE software is a low battery voltage every now and again but I keep it charged in the garage in between drives and it shows 13.7V at idle which I think is OK. Everything off, the battery is around 12.6V
I think I’ll go for another very local drive after work tonight to try and troubleshoot further and check the fuel pump is 100% priming ok when the car cuts out. It’ll be quieter on country roads by then. I don’t think idling the car in the garage up to temp will induce the fault yet. Might try that once the fault occurs and I limp it home. Or drive until I get it up to temp, tip toe home and idle until the fault occurs.
My thinking at this stage is that it might be the coil pack as that sits right against the engine block. When my power amplifier started to fail on my Chimaera it felt like the same thing. Engine hot and electrical failure occurs. I'm thinking once heat soaked after the country lanes driving, the extra heat causes the coil pack to pop until it cools down again. My understanding of the coil pack is that it is the power amplifier and high voltage coils combined in one unit.
Could you please let me know if I'm on the right track? Other threads have mentioned 100A strip fuses but I thought if they blow that would take out the rest of the electrics and/or cause intermittent faults with the rest of the electrics at the same time.
Is there a good way to test the coil pack apart from replacement with a good one? Anything else I missed or should check?
Is changing the coil pack simply removing the airbox to get access?
Thanks everyone.
It's probably worth checking the 100A fuse under the airbox that charges the battery hasn't crumbled and become intermittent in operation, also measure the voltage at the battery when the engine is running or has been run for a while after the charging and drive out.
The first coil pack that started to fail on mine manifested itself as a slight misfire when under load in 4th/5th gear, the second one was related to a faulty engine Ecu and would only fire on 4 cylinders making the car almost impossible to drive. With the air box off visually inspect the coil pack for hairline cracks, good luck!
The first coil pack that started to fail on mine manifested itself as a slight misfire when under load in 4th/5th gear, the second one was related to a faulty engine Ecu and would only fire on 4 cylinders making the car almost impossible to drive. With the air box off visually inspect the coil pack for hairline cracks, good luck!
Access is a pain.
Did the garage mention the condition of the throttle bodies? What is the 'warm' idling speed? Is it solid? If it is idling lumpy and slow then it could be the throttle body bushes have gone. You can get these modified so they are much more robust.
Worth checking the strip fuses and earth points regardlessly. The fuses are rubbish even before you factor in the rubbish install in the TVR. Earth points aren't great either. Check the cables aren't 'stiff' too. A lot of them take a pounding in the hot / cold cycling. TVR also undersized the cables too which doesn't help with longevity.
If not done already, I would fit midi or midival encapuslated fuses. Plus rellocate the holders to somewhere more accessible (I appreciate it is on a S6 Tuscan).
Also swap the bulk head through bolt that TVR used to send power into the cabin in the passenger footwell. Use a section of M8 stainless steel bar, penny washers and nyloc nuts on both sides to fix it in place. Then fit the power cables and more nyloc nuts and washers to secure them. Cap the ends with a plastice end cap. Oh and there is another strip fuse to replace with an encapsulated item there to.
Did the garage mention the condition of the throttle bodies? What is the 'warm' idling speed? Is it solid? If it is idling lumpy and slow then it could be the throttle body bushes have gone. You can get these modified so they are much more robust.
Worth checking the strip fuses and earth points regardlessly. The fuses are rubbish even before you factor in the rubbish install in the TVR. Earth points aren't great either. Check the cables aren't 'stiff' too. A lot of them take a pounding in the hot / cold cycling. TVR also undersized the cables too which doesn't help with longevity.
If not done already, I would fit midi or midival encapuslated fuses. Plus rellocate the holders to somewhere more accessible (I appreciate it is on a S6 Tuscan).
Also swap the bulk head through bolt that TVR used to send power into the cabin in the passenger footwell. Use a section of M8 stainless steel bar, penny washers and nyloc nuts on both sides to fix it in place. Then fit the power cables and more nyloc nuts and washers to secure them. Cap the ends with a plastice end cap. Oh and there is another strip fuse to replace with an encapsulated item there to.
My first thought was the 100amp fuse or holder. For some these are almost a service item of preventative maintenance.
The symptoms don't immediately suggest coil pack in my experience, the only time one played up it was a misfire that you could drive through not a total loss of power.
You may reach a bigger audience on the speed 6 forum but I'd definitely start with the big fuse.
The symptoms don't immediately suggest coil pack in my experience, the only time one played up it was a misfire that you could drive through not a total loss of power.
You may reach a bigger audience on the speed 6 forum but I'd definitely start with the big fuse.
Thanks will check both fuses first before ordering anything.
One thing I can't quite get my head around is how a failing fuses will kill the engine but allow the other electrics to still function ok while the car is cooling? Is it because the electrical draw for the running engine is way higher than running the dash, ECU, lights, windows etc?
So when I crank over the engine, the draw is too much for a poorly connected fuse to the ignition system as a whole and the car doesn't fire.
Will post on the S6 forum too, thanks.
Edit:
Went to sort out my starter motor today and found the cable run from the battery is unfused and 35mm. Must have misread the labelling. I am thinking my cable has become 'brittle' along it's length so will order replacement and some terminals.
Not sure it should be fused.
I'll use the 25mm and 125amp Midival fuse I ordered to upgrade the alternator feed from the battery.
Plus TVR used several feeds from the battery. So a failing fuse on one feed doesn't effect the others.
Went to sort out my starter motor today and found the cable run from the battery is unfused and 35mm. Must have misread the labelling. I am thinking my cable has become 'brittle' along it's length so will order replacement and some terminals.
Not sure it should be fused.
I'll use the 25mm and 125amp Midival fuse I ordered to upgrade the alternator feed from the battery.
Plus TVR used several feeds from the battery. So a failing fuse on one feed doesn't effect the others.
Edited by mk1fan on Friday 28th October 22:28
Fuse in the passenger footwell inspected and while not pretty looked OK. Noticed that the carpet was a bit damp which will need looking into.
No idea yet where that fused 7A line is going yet but I suspect towards the dashboard. Noticed the feed cable was discoloured compared to the output from the fuse holder.
So next I had a look in the battery compartment. The thin cables to go a CTEK battery charger that I installed as soon as I got the car to keep the battery sweet. Voltage of the battery when not charging was around 12.8V using a multimeter.
Again not pretty.
Of note was the feed cable to the passenger footwell was crushed against the sloping brace at the rear of the compartment and the battery itself. I slackened off the battery clamp and tugged it free. I don't have a pic but it was squished to 5-6mm!
To add to the tidy-up list for the winter!
Back to the fuse/relay board and I've also got some flying leads to investigate. The black and red wires in this pic.
I think the red wire disappears under the leg of the (radiator?) fan relay. Will need to investigate. I ran out of time last night to check the other 125A fuse under the airbox. Job for the weekend I think.
Plan to have a drive tomorrow night whilst logging the ECU data and see if/when the electrics cut out. Perhaps log the battery voltage as that was throwing a fault. I do know the dealer let the battery go completely flat at some point so hopefully that hasn't damaged it.
No idea yet where that fused 7A line is going yet but I suspect towards the dashboard. Noticed the feed cable was discoloured compared to the output from the fuse holder.
So next I had a look in the battery compartment. The thin cables to go a CTEK battery charger that I installed as soon as I got the car to keep the battery sweet. Voltage of the battery when not charging was around 12.8V using a multimeter.
Again not pretty.
Of note was the feed cable to the passenger footwell was crushed against the sloping brace at the rear of the compartment and the battery itself. I slackened off the battery clamp and tugged it free. I don't have a pic but it was squished to 5-6mm!
To add to the tidy-up list for the winter!
Back to the fuse/relay board and I've also got some flying leads to investigate. The black and red wires in this pic.
I think the red wire disappears under the leg of the (radiator?) fan relay. Will need to investigate. I ran out of time last night to check the other 125A fuse under the airbox. Job for the weekend I think.
Plan to have a drive tomorrow night whilst logging the ECU data and see if/when the electrics cut out. Perhaps log the battery voltage as that was throwing a fault. I do know the dealer let the battery go completely flat at some point so hopefully that hasn't damaged it.
Edited:
I wouldn't fit a 125amp fuse to the holder under the airbox. Although a very short run between the alternator and the starter the cable was only 16mm from the factory which has a 110amp rating.
Upgrade the cable to 25mm and a 125amp fuse will be fine.
The fuse and holder in the wheel well doesn't serve the starter.
Looking at your photo, on the phone, the crimping of the ring terminal on the battery feeds look frayed.
I wouldn't fit a 125amp fuse to the holder under the airbox. Although a very short run between the alternator and the starter the cable was only 16mm from the factory which has a 110amp rating.
Upgrade the cable to 25mm and a 125amp fuse will be fine.
The fuse and holder in the wheel well doesn't serve the starter.
Looking at your photo, on the phone, the crimping of the ring terminal on the battery feeds look frayed.
Edited by mk1fan on Friday 28th October 22:33
When you say that the car cuts out and won't restart, 1) Does the starter motor actually turn the engine 2) Does it turn it fast enough?
If the answer to these questions is 'yes', then personally, I'd be looking at checking the condition of the throttle bodies and that they're set up properly (ie balanced). Once the idle is correctly set, use the diagnostic software to reset the throttle and adaptives. Also check for air induction leaks - as standard there are no gaskets between the throttle bodies and the head.
Another issue could (could) be the Dallas chip in the ECU. It has it's own lithium battery which dies over time - apparently this means the chip loses it's settings each time the ignition is turned off and has to 're-learn' them - this can cause starting and idling issues.
Good luck - hope you get it fettled.
If the answer to these questions is 'yes', then personally, I'd be looking at checking the condition of the throttle bodies and that they're set up properly (ie balanced). Once the idle is correctly set, use the diagnostic software to reset the throttle and adaptives. Also check for air induction leaks - as standard there are no gaskets between the throttle bodies and the head.
Another issue could (could) be the Dallas chip in the ECU. It has it's own lithium battery which dies over time - apparently this means the chip loses it's settings each time the ignition is turned off and has to 're-learn' them - this can cause starting and idling issues.
Good luck - hope you get it fettled.
wily_coyote said:
When you say that the car cuts out and won't restart, 1) Does the starter motor actually turn the engine 2) Does it turn it fast enough?
If the answer to these questions is 'yes', then personally, I'd be looking at checking the condition of the throttle bodies and that they're set up properly (ie balanced). Once the idle is correctly set, use the diagnostic software to reset the throttle and adaptives. Also check for air induction leaks - as standard there are no gaskets between the throttle bodies and the head.
Another issue could (could) be the Dallas chip in the ECU. It has it's own lithium battery which dies over time - apparently this means the chip loses it's settings each time the ignition is turned off and has to 're-learn' them - this can cause starting and idling issues.
Good luck - hope you get it fettled.
Sorry, I should have been clearer. When the car had stopped then I could turn over the starter, it just wouldn't fire up. The starter turned over as usual.If the answer to these questions is 'yes', then personally, I'd be looking at checking the condition of the throttle bodies and that they're set up properly (ie balanced). Once the idle is correctly set, use the diagnostic software to reset the throttle and adaptives. Also check for air induction leaks - as standard there are no gaskets between the throttle bodies and the head.
Another issue could (could) be the Dallas chip in the ECU. It has it's own lithium battery which dies over time - apparently this means the chip loses it's settings each time the ignition is turned off and has to 're-learn' them - this can cause starting and idling issues.
Good luck - hope you get it fettled.
The immobiliser is new and bought/fitted by the dealer so the Dallas should have a new battery. The Dallas key works fine and turns out the red immobiliser light and you can hear the fuel pump fire up OK. I do know the dealer didn't since up the immobiliser to the alarm so I will need to send these off to be synced together over winter. Not a big issue.
I took the car for a run Thu night, driving around the country lanes close by home. Got the car up to temp and everything was fine. Drove 20 miles all OK. Only errors that popped up on the MBE software was the AFRs after I gave it a bit of blast. These cleared on engine restart. Popped back home and then to get petrol. All OK with stopping and starting. Around 25 miles all up OK.
Pic of final MBE data. Does all look OK?
I have a new fuel pump relay just in case and will drive the car more this week to build up my confidence in it again. Fingers crossed and I'll keep this thread updated.
I don't know if the Tuscan set up is the same as the Tamora / T350 but this might be worth a read if you're thinking fueling is an issue - https://www.pistonheads.com/gassing/topic.asp?h=0&...
What I found in the tank was terrible. I am very grateful there wasn't a fire - thanks in no great part to fuses.
What I found in the tank was terrible. I am very grateful there wasn't a fire - thanks in no great part to fuses.
wily_coyote said:
Hi @Dalamar - the Dallas chip I was referring to is inside of the ECU - not related to the immobiliser. It powers the NVRAM (? I think) memory which holds the fuel maps.
Hello Wily_coyote. I don’t think that’s my issue as the MIL light doesn’t come on and no EFI error beep. Hope to get out for another drive this week. Latest update today:
Drove 30 miles OK, got home and idled on the driveway for 2 mins and then it cut out.
Cycled the key and noticed fuel pump wasn't priming.
Fuel pump relay warm. Pulled, waved around (to cool), re-installed but no pump priming. Key to off position.
Noticed main ignition relay was warm too. Pulled, waved around and re-installed. By this time the immobiliser had kicked in. Used the immobiliser contact key and the fuel pump primed. Started OK.
All this took about 2 mins tops.
When started again, it idled fine for 10 mins, fans tripping on and off ok before I pulled the car back into the garage.
Drove 30 miles OK, got home and idled on the driveway for 2 mins and then it cut out.
Cycled the key and noticed fuel pump wasn't priming.
Fuel pump relay warm. Pulled, waved around (to cool), re-installed but no pump priming. Key to off position.
Noticed main ignition relay was warm too. Pulled, waved around and re-installed. By this time the immobiliser had kicked in. Used the immobiliser contact key and the fuel pump primed. Started OK.
All this took about 2 mins tops.
When started again, it idled fine for 10 mins, fans tripping on and off ok before I pulled the car back into the garage.
Hello. I’m calling this fixed now. Another 120 miles and no further issues after a new fuel pump relay fitted.
Info on what I found is at:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Going to move on to other winter jobs now.
Thanks for everyone’s help on this.
Info on what I found is at:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Going to move on to other winter jobs now.
Thanks for everyone’s help on this.
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