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.
Get yourself a 'Rovergauge' setup.
I suspect one of your Lambda sensors has gone down.
Next you will tell me it has no Lambda sensors.
If it is a TVR then they often mounted the coil on the side of the plenum. The bracket pressed on the lead to the first injector and in time rubbed through. If it then shorted the earth wire all the injectors on that side stay on as it is wired as bank fire.
Steve
I suspect one of your Lambda sensors has gone down.
Next you will tell me it has no Lambda sensors.
If it is a TVR then they often mounted the coil on the side of the plenum. The bracket pressed on the lead to the first injector and in time rubbed through. If it then shorted the earth wire all the injectors on that side stay on as it is wired as bank fire.
Steve
Without the Lambdas I doubt RG will be able to tell you anything. Lambdas are the only thing (I can think of) that specifically looks at one bank or the other.
If it is just one bank flooding then my earlier comment about a short, possibly intermittent, on the earth return to the ECU is still valid.
Steve
If it is just one bank flooding then my earlier comment about a short, possibly intermittent, on the earth return to the ECU is still valid.
Steve
Check your throttle pot voltage for closed throttle!
The ecu uses an open loop fuel mass for the cranking and runup injection events, and these are based on coolant temp at start and throttle angle. A dodgy TPS can result in the system chucking in too much cranking fuel before it transfers to the MAF for the main running fuel mass determination!
The ecu uses an open loop fuel mass for the cranking and runup injection events, and these are based on coolant temp at start and throttle angle. A dodgy TPS can result in the system chucking in too much cranking fuel before it transfers to the MAF for the main running fuel mass determination!
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.
100SRV said:
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.
As it transitions on to the MAF meter for load determination once above the minimum "running speed" (typically around 500rpm) a misadjusted or flaky TPS doesn't tend to make it run rich.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.
For ignition timing, i just used to take a lever bar out on a road test, advance the dissy till you could hear it pink a little at around 2000rpm WOT, then back the disy back till it stops pinking. (using the lever bar mean't you don't have to wrestle with that stupid 9/16" bolt that holds the dissy clamp plate
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.
100SRV said:
When I removed the spark plugs all were wet and sooty.
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)
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)
paintman said:
Might be of interest:
http://www.carelect.demon.co.uk/rrp2.html
Used these guys some years ago. Great service ECU back and working in one day and not expensive either.http://www.carelect.demon.co.uk/rrp2.html
Steve
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!
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
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
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?
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.
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.
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.
Of interest the RV8 is a direct result of our work. When the factory decided to do the RV8 they borrowed a TVR and they also borrowed an MGB V8 conversion belonging to Rog Parker, this was a 3.5 efi that Rog worked hard fitting and tuning. It helped as his mate designed the Rover injection setup, still has a sort of plasticene biscuit tin sort of plenum chamber knocking around! Rover were so impressed with Rogs car they went down his route....including the forward facing K&N factory fit air filter. The factory considered our tweaked V8 heads as OE but were concerned the chassis wasn't good for 20 bhp or so more...shame as the heads add such sparkle.
Rog also tells us of the 'sexy' quad cam V8 heads he saw laying around in the factory....forerunner of the V6 Metro 6R4?
Peter
Rog also tells us of the 'sexy' quad cam V8 heads he saw laying around in the factory....forerunner of the V6 Metro 6R4?
Peter
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