Various running problems - what to try next?

[carsy]

Excellent news. For what they cost i`d be putting new ones in. Personally i used BPR6ES. Oh and dont buy them off ebay. There`s plenty of poor fakes out there, go to a proper motor factors.

[Dr Mike Oxgreen]

Any comments on the sootiness of my plugs? Are they "normal for Norfolk" when it comes to a TVR RV8, or normal for a stuck-in-traffic run, or is my engine over-fuelling?

I must admit I've never bothered to remove the plugs before so I don't really know what is normal for this engine. Access is a bit tight, isn't it? I was glad of the universal joint adaptor in my socket set. It also took me a while to realise that life would be easier on the nearside if I removed the intake elbow first.

Actually, I've just realised I did do one other thing as I was putting things back together: I squirted some contact cleaner into the connector of the air mass sensor. That might have made a difference; who knows? And I might splurge a bit of dielectric grease in there as well.

[shake n bake]

Might be a curve ball but have you looked at/changed your stepper motor? Something in the original post made me think it was worth questioning.
Your plugs look rough but as your fighting an issue its hard to properly assess them.

[QBee]

These are mine. From an, if anything, slightly over-fuelling, but otherwise nicely running five litre Chimaera

[QBee]

If I lived within 75 miles of Surrey I would pop round tomorrow with my 8 perfectly working extenders for you to try on your car.
I can post them to you if nobody more local offers to pop round, but I do need them back by Friday.......

[FlipFlopGriff]

My plugs looked liked that. Changed to BPR6ES and they are now brown.
I've ditched the extenders but only a few days ago so still testing.
FFG

[Dr Mike Oxgreen]

So are the standard extenders resistive? If so, I should replace the plugs with resistive ones if I'm going to ditch the extenders, should I?

Thanks for the kind offer, QBee, but I think I've decided to ditch the extenders altogether. I've ordered a set of socks, and will consider changing plugs as well. Yours look very clean compared to mine!

Edited to add: Now ordered a set of BPR6EIX as well. Heck, it's only money!

Edited by Dr Mike Oxgreen on Sunday 13th September 08:18

[QBee]

Personally I thing the BPR6EIX are worth the extra money over the BPR6ES (about an extra £35). The Iridium tips allow a more consistent spark burn and a much longer life, so you will waste less fuel and have to replace them far less often. Iridium plugs lasted 60,000 miles between changes on my Lexus. Just remember to tell your TVR service expert you have put them in, or some muppet apprentice mechanic will take out your nice long-life expensive plugs at the next service without even looking at what's written on them, bin them, and stick a set of standard 7s back in!

FWIW I think your dirty plugs are a sign of the rough running.....

As for resistive, I have to conclude that the extenders are resistive, otherwise why would TVR recommend the non-resistive 7s as standard spec plugs? To back this up, I heard a DTEC race car at Rockingham having all sorts of running problems in the first race of the season, and every time he passed the commentary position during the warm up there was horrendous interference for a few seconds on the PA system. He had to retire from the first race before it had really started, and I popped over to see how he was doing after the race, to find Mat Smith (my TVR guru) talking to him about it. I mentioned the PA system issue and Mat immediately asked him if he was running resistive plugs, and commented that the lack of them could do damage to the ignition system. Resistive plugs were sourced, swapped in, and the car ran fine. Draw your own conclusions. I am sure he wasn't running extenders.

[ukdj]

Original extenders were indeed resistive, replacements currently available would appear to not be resistive or at least I have not found a resistive set of late.

+1 for removing the extenders and fitting heat socks

[blitzracing]

You simply need a resistive element in the HT line- it can be leads, extenders or plugs. Stock carbon cored leads are resistive enough on their own to control the coil discharge and RF interference,so you dont neeed to add any extra resistance with plugs or extenders. Its only a problem if you run silly "race " HT leads that have a lower core resistance. Adding "one" extra bit of resistance wont have much of an effect in the scheme of things- ie adding resistive plugs to resistive leads- but if you added resistive caps as well, then you are pushing things too far, and spark energy will suffer.

[blitzracing]

Your plugs are typical of what happens with a misfire- the lambda probes pick this up a lean mixture and the ECU chucks in extra fuel- so its a vicious circle- it misfires, the plugs soot, so it misfires even more,

[QBee]

So would new plugs be a starting point and see if it still misfires?
Or look for the misfire first?

[blitzracing]

Well all 8 plugs are black- so that means IF its a misfire its something prior to the dizzy so the HT is common to all 8 cylinders. If it was a plug extender on one side, then just that side would be sooty- not both, unless by chance you have an extender on both sides failing. Another option is you have say an AFM output high that is causing the engine to over fuel to the point it fouls the plugs. Lots of chickens and eggs scenarios here. Id think first point would be to pop in 8 new plugs and see if it misfires- it wont straight away if its over fueling as it takes time for enough carbon to build up and short the plug out. As a matter of course it would be good practice to plug in RoverGauge or ECU mate to check the lambda cycling and AFM ouput and any error codes , as the good old TVRs wont tell you the ECU is in a fault condition as the ECU light is not wired in correctly in most cases.

[ChimpOnGas]

Staying away from the undisputed benefits of a fully 3D mapable engine management system with a wasted spark DIS ignition system and keeping my comments focussed on a standard 14CUX & distributor equipped Chimaera, pretty early on in my Chimaera ownership it became blindingly obvious to me the ignition side was where I would find the biggest improvements in the way the car ran.

The 14CUX system actually does a respectable job of the fueling, even though the TVR fuel map is a rather crude enriched development of the Range Rover one. The system's sensors, processor and fuel delivery systems all work together to deliver a perfectly acceptable result.

The very antiquated distributor and canister type coil system on the other hand can at best be described as marginal, it'll do the job just fine but only if everything else in the system is in 100% first rate condition. Introduce a bad HT lead, a failing plug extender or the wrong temperature/type spark plug and misfires are an inevitability.

But dont worry you'll probably never know it's misfiring because 7 cylinders can sound very much like 8 to the initiated even at idle, raise the RPM above idle and detecting occasional ignition faults by ear on a V8 becomes almost impossible.

Some years ago I came in for quite some stick on these pages for condemning the dreadful original shrouded electrode (non projected) type NGK B7ECS chosen by TVR, but I ignored the doubters and continued with my claims these plugs are completely unsuitable for a road driven Chimaera.

As an absolute minimum every one of us should at least be using NGK BPR6ES plugs, fact!

As a long time burner of LPG which quickly and cruelly seeks out and exposes any little weakness in a vehicles ignition system I can tell you a projected electrode plug is essential in this engine.

Better still I recommend the use of the projected electrode type NGK BPR6EIX iridium plugs which no matter what anyone tries to tell you will deliver improved combustion and far greater longevity. There's a reason why most modern car manufacturers use this type of plug in their higher end and performance models.

NGK are the undisputed world leaders in spark plug technology and have been for many years, when they came into the market they absolutely revolutionised the industry. The quality of their plugs, their service life and the accuracy of their pre-gapped plugs made offerings from the likes of Champion and many others look like stone age technology over night.

NGK do not sell gimmicks or snake oil products, they only offer extremely well developed and proven spark plugs that do exactly what they claim they do. Nothing more and nothing less, just exactly what their marketing literature claims, simple.

Being a committed gas sniffer I have followed the NGK developments in spark plug technology closely and have moved from their BPR6EIX iridium plugs which showed immediate and very noticeable improvements over the comically cool and over protected electrode B7ECS and finally settled on the latest NGK Laserlines that are specifically designed for demanding ignition conditions found when burning LPG.

LPG LaserLine spark plugs have an iridium tipped centre electrode just like the BPR6EIX but add a ground electrode that contains a chip of pure platinum. The advantage being that these precious metals are extremely resistant to the unfavorable conditions in gas powered engines, the spark gap remains virtually unchanged throughout it's entire service life which is massively extended over even the BPR6EIX iridium plugs.

These LPG LaserLine spark plugs may be a step too far if you're just burning petrol but my tests on the notoriously hard to strike LPG show they are the very best you can buy.

For all you original equipment TVR Chim & Griff petrol drinkers out there I recommend the following full ignition service:

• New good quality distributor cap - new Lucas brand seem fine
• New (new old stock) genuine Lucas rotor arm or the red one from the Distributor Doctor - avoid new Lucas brand!
• New genuine Bosch branded coil - avoid Intermotor and other cheap rubbish brands
• New ignition amp - new Lucas brand seem fine
• Replace your leads with the best you can buy - in this case my testing has lead me to MSD Super Conductors
• Ditch the God awful plug extenders and double wrap starting with MSD Pro-Heat Guard and followed by DEI Titanium Protect-A-Boots over the top
• Use an advance adjusting strobe to accurately set your dynamic (not static) timing
• Set your throttle pot and base idle as per the Land Rover workshop manual
• Fit a set of the best extended electrode NGK plugs you can afford

Option 1: NGK BPR6ES (Already a vast improvement over the highly inappropriate B7ECS chosen by TVR)

Option 2: NGK BPR6EIX iridium plugs (Better combustion and longer lasting than the BPR6ES)

Option 3: NGK LaserLine (Largely unnecessary unless you're burning propane but will last for ever in a petrol only Chimaera)

You can do all of the above for half the cost of a Tornado ECU chip, and I've seen loads of Chim & Griff owners spend a fortune on MA magic chips and iffy rolling road sessions when they would have been infinitely better off turning their attention away from the fuel side and putting their money into upgrading the ignition components.

The 14CUX is largely a reliable & robust fuel system that makes it's own corrections and compensations as best it can without the need of external owner interference.

The ignition system on the other hand needs all the help it can get.


Some additional reading for you here:

http://www.pistonheads.com/gassing/topic.asp?h=1&a...


And here too:

http://www.pistonheads.com/gassing/topic.asp?t=125...


Burning petrol in a combustion chamber is a cinch compared to LPG, so learn from my LPG experiments to give your standard petrol Chimaera the very best ignition you possibly can

I promise you it'll make the world of difference, and unlike a ludicrously expensive £400 ECU chip it'll be a difference you will really feel too

Edited by ChimpOnGas on Monday 14th September 16:00

[Dr Mike Oxgreen]

ChimpOnGas said:

• New good quality distributor cap - new Lucas brand seem fine
• New (new old stock) genuine Lucas rotor arm or the red one from the Distributor Doctor - avoid new Lucas brand!
• New genuine Bosch branded coil - avoid Intermotor and other cheap rubbish brands
• New ignition amp - new Lucas brand seem fine

Tick, tick, tick, tick. Well, not sure whether the rotor arm I've got on order is new or old stock - it's whatever TVR Parts are selling. That and the cap haven't arrived yet but will be going on.

ChimpOnGas said:

• Replace your leads with the best you can buy

I've gone with OE Lucas leads, because the consensus on most threads I've read is that fancy leads are no better, and may even be worse. Certainly the new leads cured "dead throttle syndrome" for at least a month before something else caused it to return.

ChimpOnGas said:

• Ditch the God awful plug extenders and double wrap starting with MSD Pro-Heat Guard and followed by DEI Titanium Protect-A-Boots over the top

Agreed. I've just done another test drive to confirm that it wasn't a fluke - the engine really is running better without them. I'll wrap the ends of the leads with some woven heat shield material, then with some heat-reflective material, and finally with a set of boot protectors. Should be arriving shortly.

ChimpOnGas said:

• Use an advance adjusting strobe to accurately set your dynamic (not static) timing
• Set your throttle pot and base idle as per the Land Rover workshop manual

I'll let Str8Six take care of that sort of stuff. I know they did calibrate the throttle pot a few years back.

ChimpOnGas said:

• Fit a set of the best extended electrode NGK plugs you can afford

Set of NGK BPR6EIX on order. Should arrive in next couple of days. I'm planning to attach a label to one of the HT leads saying "Iridium plugs - do not replace".

Edited by Dr Mike Oxgreen on Monday 14th September 16:51

[Dr Mike Oxgreen]

Just pulled the number 4 plug again, after two short test drives with the engine no longer missing. It's still not exactly clean, but both the electrodes and the porcelain are definitely cleaner, perhaps even with a hint of brown on the porcelain:

[ChimpOnGas]

Dr Mike Oxgreen said:

Just pulled the number 4 plug again, after two short test drives with the engine no longer missing. It's still not exactly clean, but both the electrodes and the porcelain are definitely cleaner, perhaps even with a hint of brown on the porcelain:

Why are you even still wasting your time with those dreadful and clearly shot B7ECS?

Apart from being wholly unsuitable in the first place if these are your old set of B7ECS you showed us on Saturday you need to be aware they're almost certainly irreversibly chemically poisoned from that shocking period that got them looking so black in the first place.

Chuck the old boogered B7ECS plugs in the bin immediately, putting them back in the engine tells you nothing, they are feked and need changing with new.

Wait for your new fresh set of BPR6EIX iridium plugs and put them in, then if you're still inquisitive buy yourself a proper wide band lambda gauge and sensor as it's the only real way to truly understand your AFRs and whats going on inside your combustion chamber. Obviously your current pugs show severe issues and after you've fitted the BPR6EIX plugs you'll undoubtedly notice an improvement.

But that's the point where you give yourself the perfect opportunity to move on from the ancient practice of looking at plug colour and start understanding what the true AFRs are under all conditions.

Remember, plug colour only really tells you whats happening when you get the opportunity to remove the plugs, and unless you're very clever indeed that will always be after a period at idle.

Get the right right plugs in there, spend £150 on an AEM AFR kit and either sleep easy or track down why you're still running a bit rich or lean under certain driving conditions.

[Dr Mike Oxgreen]

ChimpOnGas said:

Why are you even still wasting your time with those dreadful and clearly shot B7ECS?

Because the new plugs haven't arrived yet!

I was interested to know whether Blitz was right when he said that the fouling is due to the misfire, so I thought I'd take a look, and the fact that they've cleaned up a bit lends weight to what he said. I'd like to fix the problem, but I'd also like to learn by studying the symptoms.

Rest assured, there's a set of BPR6EIX on its way to me, and they will be fitted as soon as free-time allows.

Edited by Dr Mike Oxgreen on Monday 14th September 19:12

[Dr Mike Oxgreen]

By the way, it has occurred to me that motoring is probably the only area of life in which it's a good thing for your porcelain to be coated in brown deposits.

[blitzracing]

Misfires are nasty when it comes to reading AFR ratios either by the cars own lambda probes or an after market AFR meter with a wide band probe- I spent many hours trying to get my Amethyst mapped ignition to work, but it introduced subtle misfires. Although you could hardly feel it, the AFR shifted by 2 points ie- what about 14:1 AFR reading became 16:1 with the misfire, and if you are using Lambda feedback this will cause a major shift in the fuelling. Luckily in my case I run the non cat map so the ECU did not try and compensate, so I knew the lambda readings where wrong.

Edited by blitzracing on Monday 14th September 19:46