RV8 start-up behaviour
Discussion
Hi,
after being parked in a garage for a while (about three weeks) I started the RV8 in my car (14CUX) and it fouled one bank of spark plugs. I cleaned them, next start slightly better and it cleared up after a spirited run.
I'm due to make an hour's journey this morning and thought it a good opportunity to give it a long run (being a week since I last used it)...same problem.
Any ideas where to start looking?
No time to pull the 'plugs now, I'll have to use TDi power.
after being parked in a garage for a while (about three weeks) I started the RV8 in my car (14CUX) and it fouled one bank of spark plugs. I cleaned them, next start slightly better and it cleared up after a spirited run.
I'm due to make an hour's journey this morning and thought it a good opportunity to give it a long run (being a week since I last used it)...same problem.
Any ideas where to start looking?
No time to pull the 'plugs now, I'll have to use TDi power.
Hi Max Torque, good tip!
Job for tomorrow morning.
Could that explain why it feels as though it is running too rich - throttle pot problem - or could be me getting used to the engine behaviour after retarding the ignition a bit (it was around 6° too far advanced due to misleading crank pulley markings). It did pull really well and rev nicely too, now it feels a bit limp.
Job for tomorrow morning.
Could that explain why it feels as though it is running too rich - throttle pot problem - or could be me getting used to the engine behaviour after retarding the ignition a bit (it was around 6° too far advanced due to misleading crank pulley markings). It did pull really well and rev nicely too, now it feels a bit limp.
Steve_D said:
I don't see how either the TPS or MAF would cause it to foul all the plugs on one bank only which was the original symptom.
Steve
When I started the engine it sounded like it used to when one of the carburettor floats had stuck; awful (like an air cooled VW) hence me assuming that it had fouled one bank.Steve
When I removed the spark plugs all were wet and sooty.
I will have a good poke around the engine this afternoon.
Hello,
Thank you for suggestion Paintman!
MaxTorque:
all eight were pretty sooty and wet which is what confused me.
14CUX is bank fire: Odd or Even banks.
It has been parked outside for almost 48 hours since it's last trip, fingers crossed else it is spanner time.
Thank you for suggestion Paintman!
MaxTorque:
all eight were pretty sooty and wet which is what confused me.
14CUX is bank fire: Odd or Even banks.
It has been parked outside for almost 48 hours since it's last trip, fingers crossed else it is spanner time.
Max_Torque said:
all 8 or all 4 on one bank only?
Pretty sure 14CUX is a "dual" bank fired non sequential injection system, but both banks will be fed the same injection duration. It's possible for an injector driver to fail (either open or closed) but the engine won't run on that bank at all if that's happened. (and it's quite unusual)
Pretty sure 14CUX is a "dual" bank fired non sequential injection system, but both banks will be fed the same injection duration. It's possible for an injector driver to fail (either open or closed) but the engine won't run on that bank at all if that's happened. (and it's quite unusual)
Hello,
thank you for all the suggestions of things to check and places who can help repair.
I put a few miles on the car (Bowler 100") with the problem engine this weekend and it is once again purring like a kitty.
I asked Paul at Tomcat Motorsport whether he'd encountered plug wetting, here is his reply:
"Wetting plugs is not uncommon for 14 CUX, basically as you say use it more. The TVR is even worse than a std engine - in house rule is warm engines up to full temp everytime if possible and ALWAYS fully warm up after every third start up - if not a TVR will not start the 5th time.
They really do not like short runs or shunting, a grade hotter plug can help if doing this, trials cars can benefit from this sometimes.
I wouldn't get too stressed looking for a fault unless it becomes a regular thing that you cannot control with regular full warm ups. It is unlikely you would find a fault code anyway."
Fingers crossed that it is lack of use.
Thank you again!
thank you for all the suggestions of things to check and places who can help repair.
I put a few miles on the car (Bowler 100") with the problem engine this weekend and it is once again purring like a kitty.
I asked Paul at Tomcat Motorsport whether he'd encountered plug wetting, here is his reply:
"Wetting plugs is not uncommon for 14 CUX, basically as you say use it more. The TVR is even worse than a std engine - in house rule is warm engines up to full temp everytime if possible and ALWAYS fully warm up after every third start up - if not a TVR will not start the 5th time.
They really do not like short runs or shunting, a grade hotter plug can help if doing this, trials cars can benefit from this sometimes.
I wouldn't get too stressed looking for a fault unless it becomes a regular thing that you cannot control with regular full warm ups. It is unlikely you would find a fault code anyway."
Fingers crossed that it is lack of use.
Thank you again!
PeterBurgess said:
You just stirred some dim memory in my head. In the early 90s I can remember folk having 'plug wetting' (yes we kept thinking they meant bed wetting) when the small 'lump' in the chamber adjacent to the spark plug was removed, we have always left this in place. Maybe this has an effect on mixture and turbulence? I had a problem with my old hot wire Vitesse with fouling plugs, it turned out the ecu was on its way out 
As a get by I removed the 9th injector from the plenum which gave me a fighting chance to fire it up. I also ran BP5ES plugs which ran a little hotter quicker.
Peter
Glad it got the grey cells working Peter. As a get by I removed the 9th injector from the plenum which gave me a fighting chance to fire it up. I also ran BP5ES plugs which ran a little hotter quicker.Peter
Do you have any photos of the lump or where it should be? I'm pretty sure my cylinder heads are standard for 3.9, I bought them from ACR a long time ago.
Have you confused hot wire (14CU and CUX) with the earlier flapper type which had a ninth "cold start" injector in the plenum?
Pumaracing said:
Ok sorry to piss on anybody's chips but from an engineering POV this is all nonsense. Correctly fueled and ignited engines don't foul their plugs or need warming up fully every time they're started, or need regular use or need little bumps in combustion chambers to stop plug wetting. If compression, oil usage and other wear indicators are all normal then any engine should just need a good spark and the right amount of fuel when both cold and hot and it'll run normally, whenever and regardless of how frequently or infrequently it's used. End of.
The very fact that this engine is showing a problem on only one bank eliminates by definition all the BS and old wife's tales about witchcraft or homeopathy being needed to make an engine run properly. There's an issue on one bank and not the other. Simples.
All the plugs were damp and dirty.The very fact that this engine is showing a problem on only one bank eliminates by definition all the BS and old wife's tales about witchcraft or homeopathy being needed to make an engine run properly. There's an issue on one bank and not the other. Simples.
No witchcraft or homeopathy required, just some scientific checks of the control system components and wiring.
I'll check the earth resistances first, could be that the coolant temperature value is misleading the ECU into cold-start fuelling when not needed.
Interesting that the Tomcat chap has had similar problems on various vehicles.
Pumaracing said:
The ability of the average homo semisapiens to make correct inferences and deductions from available data is woefully lacking. There may well be some common link between the ignition or fuel systems on these vehicles which causes issues but starting the engine on a regular basis or having to get it to a certain temperature every time is a band aid not the cure for the cause of the problem.
I agree.I need to do more investigating.
Hi Pete Burgess,
thank you for the reply!
HT leads were new in 2013 and the engine had little use in 2014 as the car was under major refit, is that new enough?
The HT leads look in good condition with no cracks, are routed correctly avoiding contact with metal bits and secured using the plastic combs.
The sparking plugs are NGK BPR6ES, perhaps it is time to try Champions and a new set of leads?
What make / supplier of HT leads would you recommend?
Ignition is by Lumenition with a standard ballasted coil and distributor. I did consider moving to EDIS but am not sure it would be cost effective (open to persuasion).
thank you for the reply!
HT leads were new in 2013 and the engine had little use in 2014 as the car was under major refit, is that new enough?
The HT leads look in good condition with no cracks, are routed correctly avoiding contact with metal bits and secured using the plastic combs.
The sparking plugs are NGK BPR6ES, perhaps it is time to try Champions and a new set of leads?
What make / supplier of HT leads would you recommend?
Ignition is by Lumenition with a standard ballasted coil and distributor. I did consider moving to EDIS but am not sure it would be cost effective (open to persuasion).
Good stuff Dr Blitz!
It appears you were correct about the AFM. I made the mistake of dicking about with it and a multimeter before going for MoT.
The AFM fitted was showing a high voltage at key-on and at start-up way beyond what you prescribed. I started and let it idle to check the voltages when running and the sodding thing fouled all eight plugs (photos to follow) 30 minutes before MoT. Out with the old plugs and in with a new set (NGK again) as there was no time to clean the dirty ones, I also swapped the AFM with my spare.
Time to lock up and set off...luckily nice clean start and no plug fouling.
I got to the test station with a minute to spare (pass).
I'll do some more testing over the weekend.
It appears you were correct about the AFM. I made the mistake of dicking about with it and a multimeter before going for MoT.
The AFM fitted was showing a high voltage at key-on and at start-up way beyond what you prescribed. I started and let it idle to check the voltages when running and the sodding thing fouled all eight plugs (photos to follow) 30 minutes before MoT. Out with the old plugs and in with a new set (NGK again) as there was no time to clean the dirty ones, I also swapped the AFM with my spare.
Time to lock up and set off...luckily nice clean start and no plug fouling.
I got to the test station with a minute to spare (pass).
I'll do some more testing over the weekend.
Hi,
do you clever folks have any recommendations for a compentent company to refurbish my airflow meter?
I've seen a page on the internet showing how to diagnose and repair but would rather pay a professional to do it; I rely on the car to work where it is a long walk for help and would rather not have to carry a spare airflow meter with me.
ETA,
when looking for failure/repair details of the AFM I found the Tornado systems chip page, interesting list of changes and improvements - would it be worth me investing in one?
thank you for your advice and assistance!
do you clever folks have any recommendations for a compentent company to refurbish my airflow meter?
I've seen a page on the internet showing how to diagnose and repair but would rather pay a professional to do it; I rely on the car to work where it is a long walk for help and would rather not have to carry a spare airflow meter with me.
ETA,
when looking for failure/repair details of the AFM I found the Tornado systems chip page, interesting list of changes and improvements - would it be worth me investing in one?
thank you for your advice and assistance!
Edited by 100SRV on Monday 7th December 08:56
Hi,
shipped the faulty airflow meter off to a reputable automotive electronics repair. They inspected it and claim that the fault with the airflow meter would cause it to run lean, they asked for details of the ECU to verify compatibility and to see whether they could repair it. I supplied details and was told that they could check the ECU and repair if required. No mention of whether the airflow meter could be repaired...fishy.
100SRV
shipped the faulty airflow meter off to a reputable automotive electronics repair. They inspected it and claim that the fault with the airflow meter would cause it to run lean, they asked for details of the ECU to verify compatibility and to see whether they could repair it. I supplied details and was told that they could check the ECU and repair if required. No mention of whether the airflow meter could be repaired...fishy.
100SRV
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