Rover Gauge and the readings it's given me
Discussion
Hi,
A bit of background - my car has jest been decatted and precats out. It also has a stealth cam. Running a standard 14CUX set-up. It seems to get 18MPG no matter how you drive it, motorway, back roads, fast, normal.
After it was decatted it really smelt of petrol from the exhausts, I thought the car as running rich but it sounds as if it's quite normal for a petrol smell from decat cars.
I was out today with other TVR owners and one of the drivers behind me said my car was exhibiting black smoke on the overrun. It was fine when accelerating and cruising, just smoke on the overrun.
I have just loaded up Rovergauge and to be honest, I don't really know what to look for so hope somebody can advise if my readings are normal.
Front screen says I am running fuel map 5
It does show up a fault code however (21) Tune resistor out of range:
I was a bit of a fool though as I cleared the fault code. It now won't come back so it 'might' have been am old fault code. Either way, I don't know what it means.
I left this as it was:
I also have no idea what this means but it might mean something to somebody kore knowledgable than me:
Any comments by those in the know are most welcome as I would like to eradicate the black smoke (and increase MPG if something is wrong).
Thanks.
A bit of background - my car has jest been decatted and precats out. It also has a stealth cam. Running a standard 14CUX set-up. It seems to get 18MPG no matter how you drive it, motorway, back roads, fast, normal.
After it was decatted it really smelt of petrol from the exhausts, I thought the car as running rich but it sounds as if it's quite normal for a petrol smell from decat cars.
I was out today with other TVR owners and one of the drivers behind me said my car was exhibiting black smoke on the overrun. It was fine when accelerating and cruising, just smoke on the overrun.
I have just loaded up Rovergauge and to be honest, I don't really know what to look for so hope somebody can advise if my readings are normal.
Front screen says I am running fuel map 5
It does show up a fault code however (21) Tune resistor out of range:
I was a bit of a fool though as I cleared the fault code. It now won't come back so it 'might' have been am old fault code. Either way, I don't know what it means.
I left this as it was:
I also have no idea what this means but it might mean something to somebody kore knowledgable than me:
Any comments by those in the know are most welcome as I would like to eradicate the black smoke (and increase MPG if something is wrong).
Thanks.
Mine doesn't do that, and is a fully decatted 5 litre ruining a stealth cam. I am sure someone would have told me on a track day.
I have seen Peter's smoking on the over-run, just as you describe, and he knows he has fuelling issues.
The tune resistor comment requires someone who knows WTF it means, but did you change the resistor when you decatted, or did you leave it alone, or on the white setting on the switch if you bothered to install it. Are your lambdas still in the manifolds?
Basically, the white setting is if you have the lambdas in, the green setting if you have removed them. You should have left them in.
I have seen Peter's smoking on the over-run, just as you describe, and he knows he has fuelling issues.
The tune resistor comment requires someone who knows WTF it means, but did you change the resistor when you decatted, or did you leave it alone, or on the white setting on the switch if you bothered to install it. Are your lambdas still in the manifolds?
Basically, the white setting is if you have the lambdas in, the green setting if you have removed them. You should have left them in.
Ooo errr. Firstly you should have little green bars showing the values in addition to the % readings- so check say the throttle position display moves its green bar as you move the throttle pedal with the ignition on. Assuming its not some strange glich in RoverGauge, the readings are way out- firstly the idle control valve should be around 30-50 % at idle. Also Try the MAF reading as direct. Most importantly the short term trim value should constantly move up and down as the engine runs on a WARM engine, and check the long term trim- you should have values for this but less than 100%. If you have no lambda trim values, are the lambda probes plugged back in? Check both ends of the lambda extension cable--- The car will run rich without them- but it "should" throw a lambda error code after a period. The fuel map is 5, and that's correct for a car with Lambda probes. The tune resistor fault should clear if you unplug the ECU to reset it. It typically occurs if the tune resistor has been unplugged and put back without an ECU reset.
Edited by blitzracing on Sunday 23 February 16:35
Edited by blitzracing on Sunday 23 February 16:37
Thanks
So summary is:
Check Lambdas are actually connected.
Take car for a drive and warm it up.
Check bars move on throttle movement
Change MAF to 'direct'
Check for lambda trim % numbers on long and short term.
I'll then report back if that's OK.
Ps it's done about 400 miles since the decat and rich smell
So summary is:
Check Lambdas are actually connected.
Take car for a drive and warm it up.
Check bars move on throttle movement
Change MAF to 'direct'
Check for lambda trim % numbers on long and short term.
I'll then report back if that's OK.
Ps it's done about 400 miles since the decat and rich smell
Edited by A900ss on Sunday 23 February 16:59
I fitted Clive's Y piece yesterday and these are the figures I'm getting from Rovergauge. Mine is a standard 400 with pre-cats in.
This image was taken only abut 2 mins after start-up so its not up to temperature yet, but hopefully it will give you an idea of what you should see if all is ok.
This image was taken only abut 2 mins after start-up so its not up to temperature yet, but hopefully it will give you an idea of what you should see if all is ok.
Your car is almost certainly missing, even when idling on 7 cylinders it's often hard to tell by ear.
Fuel entering a combustion chamber that remains unburnt due to an ignition fault will be burnt in the exhaust manifold which is heated by the other working cylinders.
It was almost certainly doing this when the catalytic converters were still in place but their presence masked the condition.
Remove the cats & the condition becomes more obvious presenting itself as strong smell of fuel & black smoke.
Unburnt fuel is pooling in the inlet manifold, as you snap the throttle butterfly shut on over run you create a big depression in the inlet manifold, the engine is still pumping strongly and the door to atmosphere is firmly shut.
Any pooled fuel sitting in the inlet manifold will be sucked into the non-firing combustion chamber by the falling cylinder and forced right out again on the exhaust stroke, as it enters the hot exhaust manifold it burns in a very inefficient way producing your black smoke & smell of raw fuel.
The other working cylinders will get some too so their mixture will temporarily be super rich, more black smoke.
Put the Rover Gauge software away for a minute, stop fixating on fuelling faults and concentrate on the ignition side.
Check the rotor arm, remove the distributor cap & check the posts also look for signs of tracking in the cap itself (hairline cracks filled with carbon), inspect all HT leads in turn very carefully they have a hard life on a TVR, check your plug extenders the can crack & separate, check all 8 spark plugs.
Better still substitute the word "check" with "replace", a full ignition service should be your starting point.
If the problem persists, then & only then should you return to the fuelling, for example you may have an injector that's sticking open.
But its far more likely your issue is ignition related rather than fuelling.
Good luck with it & let us know how you get on
Fuel entering a combustion chamber that remains unburnt due to an ignition fault will be burnt in the exhaust manifold which is heated by the other working cylinders.
It was almost certainly doing this when the catalytic converters were still in place but their presence masked the condition.
Remove the cats & the condition becomes more obvious presenting itself as strong smell of fuel & black smoke.
Unburnt fuel is pooling in the inlet manifold, as you snap the throttle butterfly shut on over run you create a big depression in the inlet manifold, the engine is still pumping strongly and the door to atmosphere is firmly shut.
Any pooled fuel sitting in the inlet manifold will be sucked into the non-firing combustion chamber by the falling cylinder and forced right out again on the exhaust stroke, as it enters the hot exhaust manifold it burns in a very inefficient way producing your black smoke & smell of raw fuel.
The other working cylinders will get some too so their mixture will temporarily be super rich, more black smoke.
Put the Rover Gauge software away for a minute, stop fixating on fuelling faults and concentrate on the ignition side.
Check the rotor arm, remove the distributor cap & check the posts also look for signs of tracking in the cap itself (hairline cracks filled with carbon), inspect all HT leads in turn very carefully they have a hard life on a TVR, check your plug extenders the can crack & separate, check all 8 spark plugs.
Better still substitute the word "check" with "replace", a full ignition service should be your starting point.
If the problem persists, then & only then should you return to the fuelling, for example you may have an injector that's sticking open.
But its far more likely your issue is ignition related rather than fuelling.
Good luck with it & let us know how you get on
Thanks Dave.
The car was serviced at the time of the cats coming out so if it is dodgy ignition parts, I'll be a bit pissed off honestly.
I replaced the coil in November but I also purchased new Bosch HT leads, a new rotar arm and a new dizzy cap at the same time. Just never fitted them. The spark plugs are new at the time of the service. I haven't got any spark plug extenders but they are oldish so I might do them as well.
I don't think I'll put RG away just at the moment as that doesn't explain the lack of lambda trim readings of the low MAF reading.
Best to renew the ignition parts as you say and investigate the strange RG readings.
Thanks again.
The car was serviced at the time of the cats coming out so if it is dodgy ignition parts, I'll be a bit pissed off honestly.
I replaced the coil in November but I also purchased new Bosch HT leads, a new rotar arm and a new dizzy cap at the same time. Just never fitted them. The spark plugs are new at the time of the service. I haven't got any spark plug extenders but they are oldish so I might do them as well.
I don't think I'll put RG away just at the moment as that doesn't explain the lack of lambda trim readings of the low MAF reading.
Best to renew the ignition parts as you say and investigate the strange RG readings.
Thanks again.
The issue with ignition would get picked up by RoverGauge, as unburnt mixture looks like a lean mixture to the probes, so the ECU adds huge amounts of additional fuel trim to try and correct it, so you see +100 trim. Also if it was ignition on one side of the V8, you will still get one set of sensible readings for the working side only. The fact that he has NO trim values is more than suspect.
A900ss said:
Hi,
A bit of background - my car has jest been decatted and precats out. It also has a stealth cam. Running a standard 14CUX set-up. It seems to get 18MPG no matter how you drive it, motorway, back roads, fast, normal.
After it was decatted it really smelt of petrol from the exhausts, I thought the car as running rich but it sounds as if it's quite normal for a petrol smell from decat cars.
I was out today with other TVR owners and one of the drivers behind me said my car was exhibiting black smoke on the overrun. It was fine when accelerating and cruising, just smoke on the overrun.
I have just loaded up Rovergauge and to be honest, I don't really know what to look for so hope somebody can advise if my readings are normal.
Front screen says I am running fuel map 5
It does show up a fault code however (21) Tune resistor out of range:
I was a bit of a fool though as I cleared the fault code. It now won't come back so it 'might' have been am old fault code. Either way, I don't know what it means.
I left this as it was:
I also have no idea what this means but it might mean something to somebody kore knowledgable than me:
Any comments by those in the know are most welcome as I would like to eradicate the black smoke (and increase MPG if something is wrong).
Thanks.
The Fuel Map and Fuel Map Multiplier shown in your screen capture is for a Chimaera 500 and from your profile it looks like you've a 450. There's no Tune version shown either in addition to the missing trim and MAF values, so I'd check to see if there is any id on the EPROM installed on the ECU or on the case label.A bit of background - my car has jest been decatted and precats out. It also has a stealth cam. Running a standard 14CUX set-up. It seems to get 18MPG no matter how you drive it, motorway, back roads, fast, normal.
After it was decatted it really smelt of petrol from the exhausts, I thought the car as running rich but it sounds as if it's quite normal for a petrol smell from decat cars.
I was out today with other TVR owners and one of the drivers behind me said my car was exhibiting black smoke on the overrun. It was fine when accelerating and cruising, just smoke on the overrun.
I have just loaded up Rovergauge and to be honest, I don't really know what to look for so hope somebody can advise if my readings are normal.
Front screen says I am running fuel map 5
It does show up a fault code however (21) Tune resistor out of range:
I was a bit of a fool though as I cleared the fault code. It now won't come back so it 'might' have been am old fault code. Either way, I don't know what it means.
I left this as it was:
I also have no idea what this means but it might mean something to somebody kore knowledgable than me:
Any comments by those in the know are most welcome as I would like to eradicate the black smoke (and increase MPG if something is wrong).
Thanks.
A900ss said:
PS - if it is running on 7, it's going to be a beast running on 8. I was out today with the Bristol TVR CC and didn't seem to be lacking power. 
If it's running on 7 I'll eat the spoiler off my SEAC ! When you 'flew' past me it looked AND sounded like all 8 were there.... if not then I think you've got a 5.4 not a 4.5 (you're welcome to join the club!).
Karl is too modest to say he's got the best sounding Chimaera (alongside Adam Palmers ('misteradz') that I have ever heard .....
Paul.
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