Running super-rich all of a sudden. Help!
Discussion
Just had the AA out again...
Car originally died on start-up last week with no warning, having driven home the previous night seemingly with no problems... Spluttered on start-up, gave a few seconds of that "bubbly/woofly" noise characteristic of ignition-problems, then died and would not restart.
My next door neighbour (hotrod rebuilder
) tested and worked over it for a couple of days, and finally (having gone all through the ignition components) founds the spark plugs to be totally carbonised on both banks at 3000miles old - and the car fired up as soon as he changed them.
So we figured that the build-up and carbonisation was the cause of the failure.
Took it out for the first time tonight, and after about 4kms the car started losing power, firing with the same "bubbly" sort of feel, and then lost cylinders until it seemed to be firing on only about 3 - really jerky and almost impossible to drive.
So pulled over, got out the AA - and yup, you guessed it - spark plugs black on both banks, seemingly carbonised and looking the same as the last lot... in about 4kms
So looks like its overfuelling - and the sparkplugs were a symptom of the over-fuelling, rather than the only cause themselves? (if that makes sense?)
Would I be right in thinking that the options would be:
1. Both lambdas died and need replacing
2. ECU knackered
Anything else?
Which is more likely - are there any tests I can run myself, or should I just chuck it in the garage and be done with the bl**dy thing..?
Any advice etc gratefully appreciated.
Dom
Car originally died on start-up last week with no warning, having driven home the previous night seemingly with no problems... Spluttered on start-up, gave a few seconds of that "bubbly/woofly" noise characteristic of ignition-problems, then died and would not restart.
My next door neighbour (hotrod rebuilder
) tested and worked over it for a couple of days, and finally (having gone all through the ignition components) founds the spark plugs to be totally carbonised on both banks at 3000miles old - and the car fired up as soon as he changed them.So we figured that the build-up and carbonisation was the cause of the failure.
Took it out for the first time tonight, and after about 4kms the car started losing power, firing with the same "bubbly" sort of feel, and then lost cylinders until it seemed to be firing on only about 3 - really jerky and almost impossible to drive.
So pulled over, got out the AA - and yup, you guessed it - spark plugs black on both banks, seemingly carbonised and looking the same as the last lot... in about 4kms
So looks like its overfuelling - and the sparkplugs were a symptom of the over-fuelling, rather than the only cause themselves? (if that makes sense?)
Would I be right in thinking that the options would be:
1. Both lambdas died and need replacing
2. ECU knackered
Anything else?
Which is more likely - are there any tests I can run myself, or should I just chuck it in the garage and be done with the bl**dy thing..?
Any advice etc gratefully appreciated.
Dom
Thanks guys, thought about the AFM last night...
Dom
DarkMatter said:
If you have a good multimeter, and a copy of the Steve Heath 'Griffith & Chimaera' manual, then you can perform a number of checks on the sensors which send signals to the ECU.
Unfortunately I don't have either, Darkmatter Dom
Id go for the AFM. Both AFM testsing and the original Range Rover test manual here:
http://www.g33.co.uk/fuel_injection.htm
It wont be lambdas- even when they dont work it does not run that rich, but a bad misfire can cause the plugs to soot as the ECU mistakes unburnt mixture for a lean mixture, so pumps in more fuel to compensate.
http://www.g33.co.uk/fuel_injection.htm
It wont be lambdas- even when they dont work it does not run that rich, but a bad misfire can cause the plugs to soot as the ECU mistakes unburnt mixture for a lean mixture, so pumps in more fuel to compensate.
domV8 said:
DarkMatter said:
If you have a good multimeter, and a copy of the Steve Heath 'Griffith & Chimaera' manual, then you can perform a number of checks on the sensors which send signals to the ECU.
Unfortunately I don't have either, Darkmatter Dom
I didn't know that it was possible to run a TVR without those items.The garage has said they unplugged the AFM, and the engine (spluttering away on what sounds like about 3 cylinders) dies altogether...
Is there anything else aside from either:
1. both lambda's dying
2. AFM problems
that would cause this problem - or is it best to go back to AFM and check loom connection etc for dodgy connection (if AFM is only cause possible).
Garage are looking at Lambdas - but I think v. unlikely both would go at once..?
Dom
Is there anything else aside from either:
1. both lambda's dying
2. AFM problems
that would cause this problem - or is it best to go back to AFM and check loom connection etc for dodgy connection (if AFM is only cause possible).
Garage are looking at Lambdas - but I think v. unlikely both would go at once..?
Dom
blitzracing said:
Id go for the AFM. Both AFM testsing and the original Range Rover test manual here:
http://www.g33.co.uk/fuel_injection.htm
It wont be lambdas- even when they dont work it does not run that rich, but a bad misfire can cause the plugs to soot as the ECU mistakes unburnt mixture for a lean mixture, so pumps in more fuel to compensate.
Have to disagree there with when the lambda’s don’t work it does that run rich, When I first got my chim it was running very rich and heavy over fuelling , any way cut a long story short turned out the wrong fuel pump relay was fitted it only had 4 pins instead of 5 as the 5th pin is the 12v feed for the lambda’s so in effect they were not working. http://www.g33.co.uk/fuel_injection.htm
It wont be lambdas- even when they dont work it does not run that rich, but a bad misfire can cause the plugs to soot as the ECU mistakes unburnt mixture for a lean mixture, so pumps in more fuel to compensate.
Symptoms of this 15mpg at best driving very frugal and looking at the back of my nice yellow paint work above the exhaust was black after only a few miles and the plugs heavily carbonised , also very easy to stall when pulling away and would cut out and die if at idle too long, was put on a RR and this was confirmed once the relay was changed over the car ran great and up to 30mpg now no more black back ends any more.
So the lack of working Lamddas certainly affected my chim to run pretty rich and also make it down on power as well.
Cheers Scotty
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