Hi all.
My Vitesse is EATING plugs for fun.
I had fitted a set of Bosch plugs (can't recall which type) just before Xmas. All was well until a month ago, when it started missing. Found one plug was dead, so I bought a set off Rimmers. They arrived, and were DENSO plugs (!), so I fitted them about 3 weeks ago. I've done about 600/700 miles since, and yesterday I got the missfire again. Located yet another dead plug, so put one of the old Bosch plugs back in (one that looked like it HAD been firing OK), and all is well.
Question 1 : Why is my car eating plugs
Question 2 : What is the preferred plugs for TP Vitesse?

The car has had since December:
Coil, cap, rotor arm, leads, plugs.
All cylinder compressions are around 120 PSI.

The dead plugs are NOT coming out of the same cylinder, not even the same bank...
Cheers,
Tommo

Is your timing set correctly?

6° BTDC I think.

Hello Tommo,

tommosredone wrote:

Question 1 : Why is my car eating plugs DENSO or BOSCH mean nothing without quoting the Type No. Lets assume that you are not running with the correct type of spark plug and they are specified for an engine that does not burn as hot as the Rover Efi. According to my experience the Rover Efi does run on the lean side with the result that the plugs are usually a light shade of straw tending towards very light grey. Thats what mine look like and the plugs used to last 10 to 12000 miles before they looked in need of a change. As it happens, more recently, I change them every 4 to 6000 but that's just me being fussy. Now, if your car is set up to run VERY lean then the resulting plug temperature would be very high - much higher than your (possibly) incorrect plus can stand so they will all quickly burn out. OK, but you may rightly say that the plugs are of the correct type, then, what can make the spark plugs fail early? Still too much heat caused by too far advanced ignition PLUS system running too lean. Recommended ignition timing with low RON unleaded should be 4 to 6 degrees retarded from the workshop manual value to prevent pre-ignition, so for an SD1 Efi, something like 2 to 4 degree BTDC. How can it be too lean? It is possible that the AFM is maladjusted to produce that effect over the whole throttle range. If you have the mixture checked professionally they may be able to advise and/or adjust. Alternatively read all about the AFM on my website How else might the engine run too hot? Well with low RON unleaded fuel, current wisdom is NOT to thrash the engine, keep the rpm sensible and don't overstress it on hills or with heavy loads (trailer) etc. Let the engine rev freely in a lower gear rather than run a heavy load in a higher gear. Perhaps the thermostat or the whole cooling system is not working properly and the coolant temperature is all over the place. It should be a tad under 90 deg C. rock steady. If not - why not? Air Locks, Blocked Rad, blah blah blah. Question 2 : What is the preferred plugs for TP Vitesse? I use Champion RN9YC or better still RNYCC the NGK equivalents are BPR6E and BPR6ES. (I think thats the right way round) anyway they are all suitable for the 3.5 Efi.

Hope that helps?

As always, Ramon, a classic reply!
My car runs WAY to rich ALWAYS! It STINKS. It is the smelliest car I've ever had!
The Denso plugs were Rimmers, listed for SD1 EFI.
Did you notice in the big manual that TP EFI has a different plug?
I have a high cap rad, and have just fitted a new viscous and fan. Temp NEVER goes over 80!
It's definately not lean!

Not meant to question your mechanical skills, but are you tightening the
plugs correctly? Wind in by hand, then nip with a plug spanner or
torque wrench?

I've no idea why the workshop manual lists different Unipart numbers
for the TP spark plugs. I would hazard a guess one may be the
supression type plug, possibly specified when the aerial was deleted
and incorporated into the rear window de-mister element (which most
TPs have, and most SPs don't).

I use an additive in my Vitesse, should I still retard the timing?

Hi Ramon!
Fuel consumption is about 22/23 av on my stop-start commute, I got ave of 33 on a (very) steady run back from Brum at the weekend, at an ave of 45 mph, so I don't think fuel use is that excessive (My Mrs. does though...).
Plugs don't look too black when they come out, more of a peaty brown to beige. The dead ones just look oily.
I'm happy the EFI components are in good order, and I have a spare set of everything that I can subsitute, nothing seems to affect it's running.
Motor was fresh when I bought the car last Feb, including new bearings, rings, cam, permatorque HG's etc.
Apart from an appetite for plugs, the only other foibles are:
Very rough running from cold; it will not idle until warm,
Lot of oil burnt on start-up, hot or cold,
Always a slight "miss", detecable on tick-over, by "feeling" the gearknob. I assume that to be present all through the rev range too.
High oil pressure when cold (over 45psi), accompanied by a single "knock" under load.
Car runs at steady 70/80°, never overheats. Heater works pretty well too.
Bit of a contradiction, but it does smell rich, eye wateringly rich!

Hello Tommo

tommosredone wrote:

Fuel consumption is about 22/23 av on my stop-start commute, I got ave of 33 on a (very) steady run back from Brum at the weekend, at an ave of 45 mph, so I don't think fuel use is that excessive. Absolutely Right - better than most. Plugs don't look too black when they come out, more of a peaty brown to beige. The dead ones just look oily. Dead because of plug failure I assume? The unburned fuel from a dead pot would go through the engine and if it does not combust in the exhaust it will exit as eye wateringly smelly fumes, I reckon. Yuk. I'm happy the EFI components are in good order, and I have a spare set of everything that I can subsitute, nothing seems to affect it's running. Motor was fresh when I bought the car last Feb, including new bearings, rings, cam, permatorque HG's etc. OK - so all the above 100% because its been checked - but something (or something else) is causing the following faults? other foibles are: Very rough running from cold; it will not idle until warm, A rough running problem at startup when cold means the mixture is wrong. But because you have checked all the Efi components and they are OK now check for connection problems, (particularly around the components that modify the mixture with temperature changes - EAV, TS, AFM Air TS, ECU.) and air leaks. Lot of oil burnt on start-up, hot or cold, Oil in the combustion chamber at start-up, comes from mainly one source. * Valve stems. * But oil in a non functioning pot will be expelled into the exhaust and get heated there before exiting as fumes. Oil in the combustion chambers when hot comes from two sources. * Passing the rings from below or * Down the valve stems from above. But it cant be the rings because they are new, so check to see if there are any valve stem oil seals fitted. Other clues * Oil burning when accelerating = rings - ouch! * Oil burning on overrun = valve stem oil seals - not so ouch! Always a slight "miss", detecable on tick-over, by "feeling" the gearknob. I assume that to be present all through the rev range too. See all of the above High oil pressure when cold (over 45psi), accompanied by a single "knock" under load. Not pinking - something else? Car runs at steady 70/80°, never overheats. Heater works pretty well too. But its NOT hot enough in my opinion. and because the temperature sensor is expecting to be at approx 150 to 200 ohms for 100 degrees C and only gets to 300 to 400 ohm for 80 degrees then the ECU will be over fuelling continuously when you are supposed to be running hot. Only registered users can see links on this forum! Register or Login on forum! Furthermore Rover wisdom for a "Get U Home" trick to emulate a faulty temp sensor is to add a 170 ohm resistor in place of the sensor (source - Rover Tecnician Training Manual). That tells me that Rover were expecting the engine to run near 90 to 100 deg, not near 80 deg. Sure - there are differing schools of thought on what is the correct running temperature. Personally I think they should run at just a tad under 90 degrees C. as demonstrated by the coolant temp sensor RESISTANCE logic above. Others think "cooler is better". Like I said - rock steady at 90 degrees is best for optimum fuel consumption, efficient lubrication and best heater performance. Bit of a contradiction, but it does smell rich, eye wateringly rich! And now you can see some possible reasons.

Exciting isn't it - getting nearer to the fault all the time?

Very exciting Ramon!
Even when causing grief, they still give pleasure!
I'm right with you on the engine temp, the heater is "Passable", but it's not going to keep my takeaway curry hot on the way home!

I was always made up that it didn't run hot, but now I'm not so sure!
I changed my fan a couple of weeks ago, because I had a blade snap off. I put a new Vitesse one on, and the viscous seized (possibly as a result of running with a missing blade for a few days).
I now have a Range Rover assy on, and it works fine.
Temp is always around the line above the 60° mark, I assume that is 80°, but it isn't labelled. There is a better temp gauge wired up, it now rests in the drivers glovebox, so I'll drag that out and see what she really runs at on the way home tonight.
Will the resistor trick "con" the ECU into thinking we are at 90­°?

If I "thrash" it, there is what looks like clouds of unburnt fuel coming out the back, not oil. Also in the morning the cloud on start up is more like fuel than oil. When warm, it's definately oil!
Temp sensor is new.
Cheers
Tommo

Tommo Said

Will the resistor trick "con" the ECU into thinking we are at 90­°?

Yes, have a look at the chart.

Temp sensor is new.

I wonder what it measures compared to the chart?

Ramon

Ok, I think this is important.
Got in it to start it tonight for the journey home, started as quickly as ever, but still very rough and rich. Misfire occurred instantly. Now on the way in to work there was no sign of a misfire. This only started on start-up tonight. About 10 miles into journey, the misfire went away, and has been fine for the last 6 miles.
The misfire is EXACTLY the same as one of the plugs dropping out.
Could my over-rich start up be "ruining" the plugs?
Could this be the route cause?
Temp on way home (including the section of journey on less than 8 cyls) was between 60 and 83°, mainly dead on 70°. It sometimes goes up to 80/83° then drops back to 70°. Sometimes as low as 60°.
So maybe two issues:
a) Overfuelling when cold
b) engine running cool, giving duff info to ECU.

One note, tonight, in car park at work, I took the wires off the CSI while it was running VERY roughly seconds after start-up, and it made NO difference, I.e. the CSI is not stuck on at any point.
A very puzzled Roverist.

If your coolant temp is dropping on cruise then it sounds like the thermostate is stuck open?

Could be! I don't even know if there is one fitted, I certainly haven't checked!

I've just been outside and changed the ECU back over to the original one, and blimey what a difference! Cold starts are MILES better; no rough running, not overfuelling etc.
It wasn't totally cold, as I got in from work at about 5.45 (I changed the ECU at about 8.10), so I'll see what difference it makes in the morning.
I think I'll order a thermostat tomorrow!

Could the horriffic overfuelling from cold ruin plugs?