High Hydrocarbon readings
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High Hydrocarbon readings
My mate just had he westfield seight IVA'd today and it failed on hydrocarbons - which were about 4000. Fitted new plugs and it came down to 3000 - but still way over the 1200 limit. CO was down at .3 % (very low). Lambda was 1.6 iirc.
I assume that cam should work in that engine and shouldn't cause such high HC? Going to fit a megaquirt and wideband - but just wanted to make sure there's nothing fundamental i'm missing or overlooked.
Engine is 1990 3.9 v8, fully rebuilt by me, ported heads & manifold, RPI piper 285 cam. Standard Lucas hotwire ECU - which is from a range rover.
I assume that cam should work in that engine and shouldn't cause such high HC? Going to fit a megaquirt and wideband - but just wanted to make sure there's nothing fundamental i'm missing or overlooked.
Engine is 1990 3.9 v8, fully rebuilt by me, ported heads & manifold, RPI piper 285 cam. Standard Lucas hotwire ECU - which is from a range rover.
- Ian Anderson
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Do you want to try another ECU? - You would have to have a tame MOT tester or sniffer yourself
I have a 1990 unit in the GT40 and it gets me through emissions. On regular unleaded it is tight but on high octane stuff it sails through
Ian
I have a 1990 unit in the GT40 and it gets me through emissions. On regular unleaded it is tight but on high octane stuff it sails through
Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
Basically, it's running weak at idle. A lambda of 1.6 translates into an A/F ratio of 23.5:1 - I'm surprised it runs at all. My RV8 factory setting is approx 14.1 :1 which would be 0.95 lambda.
I dunno the hotwire, but on the flapper changing to a non standard cam results in poor running somewhere in the range.
I dunno the hotwire, but on the flapper changing to a non standard cam results in poor running somewhere in the range.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
- Ian Anderson
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Mine also ran very week at idle at SVA
Changed tune resistor and also ECU (Original had been modified by John Eales)
It now works well and meets requirements
Last year it only passed at "fast idle" this year on high octane much better
Ian
Changed tune resistor and also ECU (Original had been modified by John Eales)
It now works well and meets requirements
Last year it only passed at "fast idle" this year on high octane much better
Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
- Ian Anderson
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Hi
I also believe the 285 cam is a lot milder and less duration then the radical JE102 cam that is in my engine
Ian
I also believe the 285 cam is a lot milder and less duration then the radical JE102 cam that is in my engine
Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
I agree that 1.6 is very lean, but the plugs are black and it smells very rich - which is the complete opposite.DaveEFI wrote:Basically, it's running weak at idle. A lambda of 1.6 translates into an A/F ratio of 23.5:1 - I'm surprised it runs at all. My RV8 factory setting is approx 14.1 :1 which would be 0.95 lambda.
I dunno the hotwire, but on the flapper changing to a non standard cam results in poor running somewhere in the range.
I'm going to weld a lambda boss into the collector and take it from there.
Not only does lambda 1.6 say it's lean, but low CO/high hydrocarbons confirms this. The CO should be approx 1-2%.Eliot wrote:I agree that 1.6 is very lean, but the plugs are black and it smells very rich - which is the complete opposite.DaveEFI wrote:Basically, it's running weak at idle. A lambda of 1.6 translates into an A/F ratio of 23.5:1 - I'm surprised it runs at all. My RV8 factory setting is approx 14.1 :1 which would be 0.95 lambda.
I dunno the hotwire, but on the flapper changing to a non standard cam results in poor running somewhere in the range.
I'm going to weld a lambda boss into the collector and take it from there.
The condition of the plugs suggest more than one fault.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
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The high lambda could simply be an air leak in the exhaust. Or perhaps the engine is off a cylinder ? Similar effect.
Air getting pumped through along with unburnt fuel.
High lambda, high hydrocarbons. A wideband only tells part of the story. Pull all the plugs and check they are all getting a good solid spark.
And black plugs can mean a fuelling problem. But also an inadequate spark problem.
A cheapy Gunsons spark jumper style tool will let you check for a good spark.
Air getting pumped through along with unburnt fuel.
High lambda, high hydrocarbons. A wideband only tells part of the story. Pull all the plugs and check they are all getting a good solid spark.
And black plugs can mean a fuelling problem. But also an inadequate spark problem.
A cheapy Gunsons spark jumper style tool will let you check for a good spark.
- Ian Anderson
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Reset the ECU (Power off for 30 seconds)
Restart and immediatly run like you are running in a cam 2000 rpm till it is hot
It worked on mine and seems to clear the readings from the sensors etc
Are you running Lambda sensors? in 1990 there was not a requirement to do so (year of change). likewise there were engines - no sensors, sensors and sensors with cats. it all depends what yoyr ecu is looking at and what the tune resistor colour is
Ian
Restart and immediatly run like you are running in a cam 2000 rpm till it is hot
It worked on mine and seems to clear the readings from the sensors etc
Are you running Lambda sensors? in 1990 there was not a requirement to do so (year of change). likewise there were engines - no sensors, sensors and sensors with cats. it all depends what yoyr ecu is looking at and what the tune resistor colour is
Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
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- Joined: Sat Nov 18, 2006 6:22 pm
- Location: Northern Ireland
Only problem with a wideband. Is it only looks at one thing. And that can either mean lean, missfires, air leak etc etc.
But doesnt actually identify which one. So it could read very lean, yet is actually very rich. Although in this instance obviously CO doesnt indicate rich.
But could indicate missfires or just poor combustion.
And of course if the wideband is up the tailpipe, it's only measuring an average of all 8.
If you could split the exhausts to each bank, it might help pinpoint a problem on one bank at least.
But doesnt actually identify which one. So it could read very lean, yet is actually very rich. Although in this instance obviously CO doesnt indicate rich.
But could indicate missfires or just poor combustion.
And of course if the wideband is up the tailpipe, it's only measuring an average of all 8.
If you could split the exhausts to each bank, it might help pinpoint a problem on one bank at least.
Its got side pipes - so during the IVA we tested both sides and got the same readings.stevieturbo wrote:If you could split the exhausts to each bank, it might help pinpoint a problem on one bank at least.
Will double check the tune resistor, as it was missing and I made a new one up. Original vehicle was never fitted with lambdas.