How sooty is your exhaust?

[TVR Beaver]

Mine is quite sooty… If you run your finger around it after a run your finger would be covered in black sot?
Is it running too rich?...

The plugs look fine.. the ceramic electrode bit is a good colour and shows no indication of rich running… but the bottom of the screw thread on the plug may show a bit of black if rubbed?....
Also, the CAT mat be getting hotter (or is that my imagination??)

It was running quite grey at the exhaust last year but was running too lean… but may be now it’s the other way…

What does your look like

[v8 racing]

depends how much throttle you are using!, on a gentle sunday afternoon cruise down to the local pub you want it to be a very light grey colour, after a track day you want it to be black

[MrMCI]

Too rich tends to be good for power, I would think that most Griffs will have a little black smoke under hard acceleration. Mine is certainly a little sooty around the exhaust pipes, as is my Lotus.

[TVR Beaver]

Mmmm. so may be a bit rich...
Rob.. when you did the cam I'm assuming you also move the tune screw (now in the foolwell) to get it running right.. when I measured the voltage is was set very close to the no-cat setting?... but this tended to run lean towards the back end of the year when the air temperature dropped (strange as I thought the cars without cats would run richer??) .. so I re-set it to the cat voltage as given in MA's instructions... and from that point it now appears to run richer?? which to me is the opposite way to what I expected??

Edited by TVR Beaver on Tuesday 24th May 07:32

[MPoxon]

The soot on mine builds up very quickly. I have a pair of slot in silencers which do not slot in until I have removed some of the with a wire brush.

I am planning on getting mine to Mark Adams next year as I think mine would really benefit from a few hours mapping.

[TVR Beaver]

MPoxon said:

The soot on mine builds up very quickly. I have a pair of slot in silencers which do not slot in until I have removed some of the with a wire brush.

I am planning on getting mine to Mark Adams next year as I think mine would really benefit from a few hours mapping.

I'm thinking I may have to go the same way as we've changed the cam, added a thermal gasket to the trumpett base (helped a lot with low down running ) and fitted a new ECU temp sensor... Last year something appeared to be changing and I think the sensor could have been on it's way out... Only issue being MA mapped it with this in place so did it get done right??..
And now its sooty....
How much rich running can cause damage to the cat? (main only)
,
Chris52 has one of thoes things you put in the exhaust... will have to have a go with that again see where we are...

[LordGrover]

Sooty? You want to see my garage doors.

When I first got my Griff, I'd reversed onto the drive. Started it up the first morning and grinned. Went for a spin which probably lasted for an hour or two. When I got back I couldn't believe the two huge, black circles on the door I'd left there.

Parked up nose first from then on.

[Hoover.]

LordGrover said:

Sooty? You want to see my garage doors.

When I first got my Griff, I'd reversed onto the drive. Started it up the first morning and grinned. Went for a spin which probably lasted for an hour or two. When I got back I couldn't believe the two huge, black circles on the door I'd left there.

Parked up nose first from then on.

Done that to a wedding dress

[LordGrover]

What? Nose first?

[TVR Beaver]

last summer.. folk outside the pub... started it up and gave it a blast (as encouraged by the guy's at the side of me).. then looked in the mirror
Group of girls in white skirts / pants etc... Woops... Drove of quick and didn't go back for a long time!!

[JamesK]

Aye mine is quite adept at leaving black marks on the wall of the house! It's definitely rich at the moment - Mr. Adams is (supposed) to be booking me in but my MOT runs out tomorrow so no sunshine fun until I see him

[FlipFlopGriff]

Extremely and lots of carbon chucked out on start up. You can't get it off anything.
Paper behind the car in garage and its covered.
FFG

[TVR Beaver]

JamesK said:

Aye mine is quite adept at leaving black marks on the wall of the house! It's definitely rich at the moment - Mr. Adams is (supposed) to be booking me in but my MOT runs out tomorrow so no sunshine fun until I see him

.
Who says it won't pass?.. It's not the carbon they measure.. Not sure how it relates to what they do measure tho?

[FlipFlopGriff]

I had a report when I gave it to someone to service and MoT and it can back with a hydrocarbon report which from memory was a pass at 2,500 pass and it was 2,497 or something like that. Don't get this from where I take the cars normally, in fact can't recall them sticking a probe up the exhaust this year.
FFG

[v8 racing]

TVR Beaver said:

Mmmm. so may be a bit rich...
Rob.. when you did the cam I'm assuming you also move the tune screw (now in the foolwell) to get it running right.. when I measured the voltage is was set very close to the no-cat setting?... but this tended to run lean towards the back end of the year when the air temperature dropped (strange as I thought the cars without cats would run richer??) .. so I re-set it to the cat voltage as given in MA's instructions... and from that point it now appears to run richer?? which to me is the opposite way to what I expected??

Edited by TVR Beaver on Tuesday 24th May 07:32

Nope definetly didn't move the co trim, mark have done this on the rollers as he prefers it in the car, probably so it doesn't get so hot, to be honest and i am happy to be proved wrong i was under the impresion that on cars with lambda's it doesnt really give a monkey where the co trim is set as the lambda's will correct it anyway, certainly all the cars i have ever done if you adjust the airflow meter, or co trim the lambda's just change it back, as for outside temperature affecting the richness of the engine, this must be the airflow meter i would of thought, as if the stat is working as it should the engine temp should be the same on a cold day or hot day.

[TVR Beaver]

Interesting.. Must have been Mr Adams then?.. I returned your tune resistor if you remember so assumed youd been setting things
Wonder why he'd done it.. would have thought he could have sorted that out in the chip?..
.
Agree with your other comments about adjusting it.. Mark (Blitzcar) also say he's never known it change things as the sensors change it back (within limits)... but it defo did ?
Will have a play and turn it back a bit.. may be half way between see what I get??
.
It wasn't the engine running cold.. more the intake air temp.. the engine holds up at 80 deg plus all weathers...
The tables / scales the ECU uses appeared non-linear and again I assumed this was because of the adjustable tune resistor being out of position... below 9 deg there is a step change in the control of the system according to MA as sensed by the MAF meter and it appeared to lean off as the air temp dropped in November...
.
So, will get the CO measuring kit from Chris52 and see what we get... 12.5 2/3rds and full load.. and 14.6 cruising as I recall?
.
What ECU's are you guy's fitting these days... The plug and play one you sold that fit the existing plug.. can you home tune it??
(don't answer that.. just been on the V8D site and looked at all the info.. does look very interesting and easy to mess about with .. could be a plan?? )
.

Edited by TVR Beaver on Tuesday 24th May 22:27

[JamesK]

TVR Beaver said:

JamesK said:

Aye mine is quite adept at leaving black marks on the wall of the house! It's definitely rich at the moment - Mr. Adams is (supposed) to be booking me in but my MOT runs out tomorrow so no sunshine fun until I see him

.
Who says it won't pass?.. It's not the carbon they measure.. Not sure how it relates to what they do measure tho?

Ahhh apologies - that's not a related event I am trying to coincide a service/MOT and mapping session at Austec but it's taking so long my MOT has expired.

[blitzracing]

v8 racing said:

Nope definetly didn't move the co trim, mark have done this on the rollers as he prefers it in the car, probably so it doesn't get so hot, to be honest and i am happy to be proved wrong i was under the impresion that on cars with lambda's it doesnt really give a monkey where the co trim is set as the lambda's will correct it anyway, certainly all the cars i have ever done if you adjust the airflow meter, or co trim the lambda's just change it back, as for outside temperature affecting the richness of the engine, this must be the airflow meter i would of thought, as if the stat is working as it should the engine temp should be the same on a cold day or hot day.

The CO trim is definately turned off on the catalyst map, and has no effect what so ever, I know MA states it should be a certain voltage on the cat map, but I have never mangaged to get it to alter the mixture at all, not even for a moment before the lamdas could correct it. Why bother with a pot when the lambdas do all the trimming needed? The AFM output is critical to get the mixture correct, it only needs it to be out by about 150-200 mv at idle to throw the mixture out beyond the range the ECU can trim it back (its about +/-20% trim available). This is quite obvious by the loss of switching of the lambda probes, as the output voltage will stick at 1 to 1.2 volts. Mind you its perfecly possible to get the exhausts to run sooty black or clean with the lamdas cycling correctly, as you have both the open loop part of the map, and the exhaust gas temperature that will also affect the deposits. Other sensor inputs such as temp are far less critical to error as the majority of the fuel control is metered by the AFM, the other inputs really only trim the mixture.

The Lucas 5AM does not have a temp sensor as such, but its hot wire design compensates for the air density and temp by directly affecting the one voltage output the ECU reads. The later Bosch units do have a separate temp sensor in them for ignition control on the Sagem ECU.

[TVR Beaver]

blitzracing said:

The CO trim is definately turned off on the catalyst map, and has no effect what so ever, I know MA states it should be a certain voltage on the cat map, but I have never mangaged to get it to alter the mixture at all, not even for a moment before the lamdas could correct it. Why bother with a pot when the lambdas do all the trimming needed? The AFM output is critical to get the mixture correct, it only needs it to be out by about 150-200 mv at idle to throw the mixture out beyond the range the ECU can trim it back (its about +/-20% trim available). This is quite obvious by the loss of switching of the lambda probes, as the output voltage will stick at 1 to 1.2 volts. Mind you its perfecly possible to get the exhausts to run sooty black or clean with the lamdas cycling correctly, as you have both the open loop part of the map, and the exhaust gas temperature that will also affect the deposits. Other sensor inputs such as temp are far less critical to error as the majority of the fuel control is metered by the AFM, the other inputs really only trim the mixture.

The Lucas 5AM does not have a temp sensor as such, but its hot wire design compensates for the air density and temp by directly affecting the one voltage output the ECU reads. The later Bosch units do have a separate temp sensor in them for ignition control on the Sagem ECU.

Even if the trim took it outside the 20%??... I don't know the answer then.. as it certainly changed things...
I will get hold of the gas annoliser and have a play... see what it does?
.
BTW,.. this is a post you put up quoting MA's comments.. these appear to say it changes the idle Co?... :-
.
''''''Thanks to Mark Adams for this- its pretty spot on

Here's a quick fault finding guide.

Note that you can drive without an airflow meter in case of emergency (i.e. airflow meter disconnected), because the system will drop into a default (limp-home) mode based on throttle opening.

Most airflow meter faults will cause the engine to run excessively rich. However if the airflow meter remains connected whilst defective then the vehicle will probably not run. In most cases the output from a defective airflow meter will be in the range 2.0-2.5 Volts, which is a viable value. This represents a moderate load and will cause heavy over-fuelling without setting a fault code.

Testing is performed in the following manner. Peel back the rubber boot on the airflow meter connector and leave it plugged in to the airflow meter. Set up the digital multimeter to read voltage. Insert the negative probe into the Red/Black wire (sensor ground), and the positive into the Blue/Green wire (Airflow signal).

Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts. Most defective airflow meters will overshoot to 0.8 Volts or higher, and take at least 2 seconds to come down to the correct voltage.

Now start the engine, and the reading should rise to 1.6 Volts (3.5 Litre engine) to 1.75 Volts (5.0 Litre engine).

The next test is full load, and as with the fuel pressure test it will require use of a rolling road or a steep hill in the same manner. Under full load the voltage should rise to 4.45 Volts (3.5 Litre engine) to 4.95 Volts (5.0 Litre engine).

On this injection system, the idle CO mixture adjuster is provided on the airflow meter. It is located in a boss on the top of the airflow meter, pointing towards the engine. Leaving the multimeter negative probe in the Red/Black wire, move the positive probe to the Blue/Red wire.

Now turn on the ignition but do not start the engine. Observe the voltage. The normal adjustment range is between 0.0 and 3.6 Volts, with the higher Voltages producing higher idle CO values. There are approximately 20 turns of the adjuster screw to cover the entire range.

Annoyingly, the adjustment may be clockwise or anticlockwise to increase the value, and this varies from meter to meter! For this reason it is always preferable to have the multimeter connected in this manner when adjusting idle CO, so that you see can something is actually happening.

Typical Voltages that would be found at this point are between 0.9 to 1.4 Volts for non-catalyst cars. This Voltage is always factory pre-set to 1.8 Volts for catalyst vehicles. A value near to 3.5 Volts will generally produce an idle CO value of 9-10%. These Voltages may be used as safe initial values particularly if no CO measuring equipment is available.''''''

Edited by TVR Beaver on Wednesday 25th May 15:52

[blitzracing]

I cant read the fuel offset values applied either by lambda or CO trim from within the memory of the ECU itself, so I can see what goes on for sure, only go on what the lambda voltages do (nothing). I asked Mark why the cat map had a CO trim value, and he simply said it was the factory value.