Keeps spluttering and cutting out.... :-(

[MPoxon]

Evening Gents,

I am after some advice. Every 5 miles or so my car kangroos, splutters, missfires and cuts out. Sometimes it will restart straight away and sometimes a considerable snake off traffic forms behind me before it bursts back to life.

The car drives perfectly in between times.

I have done as little research on here which is challenging with the PH search down but have come up with some possible faulty items.

• Ignition Amp
• Fuel Pump Relay
• Dizzy
• Imobiliser
• 100A Fuse connection
• Fuel filter

I would greatly appreciate any suggestions or ways to begin eliminating items to troubleshoot the problem.

[Loubaruch]

To help narrow down the problem it would help to know when the fault occurs if all power is lost i.e. do instruments stop working. If yes it could be the 100 Amp fuse in the passenger well or possibly a loose earth. Some cars apparently only have an 100 amp fuse in the charging circuit others have both.It would not be the charging fuse.

Regarding ignition amps and fuel pump relays it is definitely worth keeping these as spares as neither will probably be available in your local spares shop. Both are easy to substitute. Note: The Bosch relays are not standard although they look similar to ordinary Lucas ones they have a diode in series with the coil to protect the ECU. The ignition amps may have one of two types of connector check you buy the correct type.

It could be the immobiliser but as this is rather more difficult to verify perhaps better to check other areas initially.

when it does cut out and you switch the ignition back on can you hear the fuel pump prime? If not could be the pump the relays or the immobiliser or even possibly the ECU but the latter is unlikely. You can wire the pump directly to bypass all this equipment and if the fault clears you know the pump is OK and the fault lies elsewhere in the pump circuit.
Best of Luck!

If the fuel supply is restricted unless the fuel filter has not been changed for an age or some particularly dirty fuel has been purchased this is unlikely to cause the problem as it would most likely be a permanent feature.

Edited by Loubaruch on Friday 1st October 22:17

[MPoxon]

Thanks for the advice Paul.

All the instruments stay on when the car cuts out including the lighting so I believe that may rule out the 100A fuse.

The car has only been run on Shell V-Power since I have owned it and the fuel filter has been changed recently.

Good call with regards to the fuel pump prime. I'll take it out for a spin tomorrow and see if I can hear the fuel pump priming when it cuts out and fails to start.

I will try replacing the relays and ingition amp as suggested as they should be nice and easy.

[Derek Smith]

See here:

http://www.rv8r.co.uk/misfire.html

and

http://www.rv8r.co.uk/ecu.html

[MPoxon]

Thanks for the links Derek.

Funily enough my two ports of call today were going to be your fantastic resource and Steve Heaths book. The step by step guide to misfire in your resource looks great.

[Derek Smith]

MPoxon said:

Thanks for the links Derek.

Funily enough my two ports of call today were going to be your fantastic resource and Steve Heaths book. The step by step guide to misfire in your resource looks great.

You couldn't tell me what the problem is when you find it, could you?

[jonnyboy]

I had a similar problem once, most inconvienient when it splutters and dies as your crossing a mini roudabout - with traffic everywhere !! If i left it for a couple of minutes it would start again - it turned out to be a hairline crack in the distributor cap, well I presume that was the cause as once replaced, normal service was resumed.

Cheers

Jonny Boy

[MPoxon]

Derek Smith said:

You couldn't tell me what the problem is when you find it, could you?

I am still not sure as yet. I have completed the following:

• Checked the connectors on the stepper motor which look OK
• Rotated the all the HT leads to make sure they are all connected OK
• Checked the connectors to the coil - look OK
• Disconnected the multipin ECU connector and refitted

I went for a 14 mile drive afterwards, everything fine until the last 2 miles when it misfired and kangrooed on 2 occasions but not enough for it to cut out.

This is much better than yesterday when it misfired and cut out 11 times in 16 miles.

I can see this being very difficult to troubleshoot. The only colleralation I have at the moment is that it only happens when it is raining and the engine is hot, which is not particulaly useful. I have also noticed that the indicator warning lights in the warning panel sometimes work and sometimes don't since the misfire problem.

I may try doing the simple things such as change the dizzy cap, rotor arm, HT leads, coil, plug extenders etc. The HT leads, dizzy cap and coil are all original so probably need changing anyway. I don't really use it during winter do I can do this gradualy and test each time I fit something.

I will most certainly let you know if I do find it.

[Mark_S_24]

Not an expert, but with it doing strange things with indicators, I'd have a look at your earths.
Isn't the earth for the dash also for the ECU?

Hope you find the fault soon
Mark

[MPoxon]

Mark_S_24 said:

Not an expert, but with it doing strange things with indicators, I'd have a look at your earths.
Isn't the earth for the dash also for the ECU?

Hope you find the fault soon
Mark

Cheers Mark, that is also a good call.

I shall do some research on the earths

[Hoover.]

Bit the bullit...... new coil, dizzy cap n rotor arm (make sure it's Lucas).

should sort it... (they need doing anyway if they original)

[richieboy3008]

MPoxon said:

Evening Gents,

I am after some advice. Every 5 miles or so my car kangroos, splutters, missfires and cuts out. Sometimes it will restart straight away and sometimes a considerable snake off traffic forms behind me before it bursts back to life.

The car drives perfectly in between times.

I have done as little research on here which is challenging with the PH search down but have come up with some possible faulty items.

• Ignition Amp
• Fuel Pump Relay
• Dizzy
• Imobiliser
• 100A Fuse connection
• Fuel filter

I would greatly appreciate any suggestions or ways to begin eliminating items to troubleshoot the problem.

Poor Matthew.

[SonicHedgeHog]

Two thoughts.

1. The obvious stepper motor.
2. The speedo transducer. After a few miles mine wouldn't idle properly. The speedo was a bit tempramental so I had the transducer changed and now it runs like a dream.

Unfortunately both suggestions require trial and error with circa £100 parts.

[The Red Baron]

Another thing to check is the chip in the ECU. I once had a similar problem and it turned out to be that the ECU chip wasn't seated in its socket quite correctly. It looked ok, but given a press it clicked in and the problem was solved.

Hope you find the answer.

[CHGRIFF]

Ensure your HT plug leads are not touching the main engine harness. If this happens you can get cross contamination upsetting the signal to the ECU, this being worse if the plug extenders fitted are not the screened type.

[ESDavey]

I had a similar problem & was a duff AFM. I'm told you can run with the AFM disconnected so worth unplugging & see if it helps.

2nd punt would be the coil & check all the HT leads are well fitted. Also worth disconnecting the ECU which will reset. Good Luck.

[rigga]

Cap rotor and leads cured mine when i had this issue,all from famous four landy parts people.

[MPoxon]

Problem Solved

Everytime I post a plea for assistance on here I am always overwhelmed by the number of helpful responses so thanks once again for all your help and suggestion gents, much appreciated as always.

Given the number of suggestions and my lack of expertise I decdied that I would be best to let an expert have a look at the misfire problem. I managed to get hold of Simon from Leven Technology as he has got to know the car quite well over the last few years. I jokingly explained to him I have no idea what the problem may be and that the only correliation I have it that is only happens when it is raining and the car is wet at which point he went on to explain that the problem was exactly that.

The answer is that on friday when I used the car and experienced the problems that car had been left outside in the terrential rain and was soaked through, the air was also very humid. The first 5 or so miles no worries (aside from not having dual speed windscreen wipers)but when the car warmed up and the raditor fan came on condensation built up in the distributor cap. causing the car to repeatidly misfire and stall. When the car has cooled down a bit it would restart and fail once the fans kicked back in. You can feel the heat from the fans when sitiing the car so is must very quickly alter the temperature of the ignition components.

I have completed another 30 miles today and not one misfire.

Fixed for £0.00 - happy days

Thank you very much Simon for your time today expalaining that particular TVR foible, I know you are very busy tieing up loose ends closing the down company etc. Another TVR legend sadly departed.

[richieboy3008]

What happens if you wash your car?

[Derek Smith]

MPoxon said:

Problem Solved

Everytime I post a plea for assistance on here I am always overwhelmed by the number of helpful responses so thanks once again for all your help and suggestion gents, much appreciated as always.

Given the number of suggestions and my lack of expertise I decdied that I would be best to let an expert have a look at the misfire problem. I managed to get hold of Simon from Leven Technology as he has got to know the car quite well over the last few years. I jokingly explained to him I have no idea what the problem may be and that the only correliation I have it that is only happens when it is raining and the car is wet at which point he went on to explain that the problem was exactly that.

The answer is that on friday when I used the car and experienced the problems that car had been left outside in the terrential rain and was soaked through, the air was also very humid. The first 5 or so miles no worries (aside from not having dual speed windscreen wipers)but when the car warmed up and the raditor fan came on condensation built up in the distributor cap. causing the car to repeatidly misfire and stall. When the car has cooled down a bit it would restart and fail once the fans kicked back in. You can feel the heat from the fans when sitiing the car so is must very quickly alter the temperature of the ignition components.

I have completed another 30 miles today and not one misfire.

Fixed for £0.00 - happy days

Thank you very much Simon for your time today expalaining that particular TVR foible, I know you are very busy tieing up loose ends closing the down company etc. Another TVR legend sadly departed.

I'll put that in the next issue of RV8R

Would you like a hotlink?