Rovergauge and lambda readings
Discussion
Hi chaps,
After a bit of advice. I bought my car as a project so haven't drive it on the road yet. When I got it the lambda sensors weren't connected, the extension loom was missing on the o/s and the plug was missing from the sensor on the n/s. I got a new cable and sensor, when I ran the car and let it get up to temperature. Short term were both showing -100% and when the long term appeared it was -15% on the even bank and -100% on the odd bank, it also threw a code for injector bank even.
I checked the wiring to the injector for continuity through the ecu plug and used noid lights to check the pulses which was all fine. The car was in with Mat Smith last week and whilst he had it I asked him to test and clean the injectors. He said the spray pattern from a couple on the even bank wasn't great before cleaning but none were awful. When I got it back I thought I'd swap the lambdas over, I hadn't previously as both looked like the were switching when revved. It ran better when I switched them, short term still -100% but long term settled at -15% on one bank and -14% on the other. It did eventually throw two codes one for low fuel pressure and one for the odd lambda.
I ordered a new sensor as I figured as I'd had faults on both the banks it had been in that could be lambda related it was probably faulty. I put the new one in today reset the ecu and ran it up to temperature. I'm still getting -100% on short term and long term settled at -15% on both. I did get the low fuel pressure fault again but nothing else.
Any ideas about the short term readings? I can't find any air leaks when spraying with brake cleaner. Mat used a heat gun on the headers when I ran it quickly there and they were all pretty equally warm. I have a log file from when I ran it today.
After a bit of advice. I bought my car as a project so haven't drive it on the road yet. When I got it the lambda sensors weren't connected, the extension loom was missing on the o/s and the plug was missing from the sensor on the n/s. I got a new cable and sensor, when I ran the car and let it get up to temperature. Short term were both showing -100% and when the long term appeared it was -15% on the even bank and -100% on the odd bank, it also threw a code for injector bank even.
I checked the wiring to the injector for continuity through the ecu plug and used noid lights to check the pulses which was all fine. The car was in with Mat Smith last week and whilst he had it I asked him to test and clean the injectors. He said the spray pattern from a couple on the even bank wasn't great before cleaning but none were awful. When I got it back I thought I'd swap the lambdas over, I hadn't previously as both looked like the were switching when revved. It ran better when I switched them, short term still -100% but long term settled at -15% on one bank and -14% on the other. It did eventually throw two codes one for low fuel pressure and one for the odd lambda.
I ordered a new sensor as I figured as I'd had faults on both the banks it had been in that could be lambda related it was probably faulty. I put the new one in today reset the ecu and ran it up to temperature. I'm still getting -100% on short term and long term settled at -15% on both. I did get the low fuel pressure fault again but nothing else.
Any ideas about the short term readings? I can't find any air leaks when spraying with brake cleaner. Mat used a heat gun on the headers when I ran it quickly there and they were all pretty equally warm. I have a log file from when I ran it today.
Also not sure if it's relevant. The car was missing the ECU when the person I bought the car from got it. He sourced one and it does say 4.0 on the label but I think the car is an HC. The engine number on the ID plate ends HC and it has pocketed pistons when I scoped it. I'm not sure if they should have a different map to the standard 400?
Are you happy the lambdas are connected to the right side as it does matter.
I can't answer the mapping question tbh but I would guess the HC does use a different map.
Some great info here regarding testing etc, pay particular attention to the lambda section and make sure they have voltage on them or they won’t switch correctly.
http://g33.co.uk/pages/technical-fuel-injection.ht...
I can't answer the mapping question tbh but I would guess the HC does use a different map.
Some great info here regarding testing etc, pay particular attention to the lambda section and make sure they have voltage on them or they won’t switch correctly.
http://g33.co.uk/pages/technical-fuel-injection.ht...
Edited by Belle427 on Wednesday 12th July 20:49
Edited by Belle427 on Thursday 13th July 06:36
Yeah, I've double checked and they are in the correct sides.
I pulled the plug extenders this afternoon and plugged the leads straight on to the plugs. I found one cylinder, number 7 was cooler than the others put a new plug in and that side then got hot and the odd lambda then started fluctuating rather than being at completely - 100% I think the spark must be stronger on the plugs without the extenders as the fan belt started squealing I'm guessing due to more draw on the alternator.
I think my next port of call is going to be putting in the new set of plugs I've got, I'd been holding off putting them in until it was MOT ready so I didn't get them all sooted up. I'm going to do a compression test at the same time.
I pulled the plug extenders this afternoon and plugged the leads straight on to the plugs. I found one cylinder, number 7 was cooler than the others put a new plug in and that side then got hot and the odd lambda then started fluctuating rather than being at completely - 100% I think the spark must be stronger on the plugs without the extenders as the fan belt started squealing I'm guessing due to more draw on the alternator.
I think my next port of call is going to be putting in the new set of plugs I've got, I'd been holding off putting them in until it was MOT ready so I didn't get them all sooted up. I'm going to do a compression test at the same time.
Check Steve Sprints 14CUX maps page looks like the 4 and 4.3 have different maps.
http://www.remap-14cux.uk/bins/
Trim is set at idle RPM only so changes in an engines breathing will have a big affect on the trim. So you really need the correct map.
In terms of if its lean or not try unplugging the vacuum pipe to the fuel regulator and block it off so no air gets into the plenum. This will boost the fiel pressure so see it the trims move in this new condition . Misfires also show as a lean mixture so will produce a removing trim or adding fuel status in RoverGauge.
http://www.remap-14cux.uk/bins/
Trim is set at idle RPM only so changes in an engines breathing will have a big affect on the trim. So you really need the correct map.
In terms of if its lean or not try unplugging the vacuum pipe to the fuel regulator and block it off so no air gets into the plenum. This will boost the fiel pressure so see it the trims move in this new condition . Misfires also show as a lean mixture so will produce a removing trim or adding fuel status in RoverGauge.
On the face of it what you are seeing makes little sense.
If the short term trim is heavily negative that would suggest (as a fuel pressure fault) too much pressure rather than too little, so the reported fault is incorrect for the visible evidence.
If the short term trim goes rich or weak for any length of time then the long term trim moves to bring the short term trimming around the zero point .. having -100 short term but the long term only moving to -15 or so makes no sense. How long did you leave it? and also you sometimes need to blip the throttle to wake the lambda trimming up, it can freeze after a while.
Did Mat stick a wideband up the exhaust to see what the mixture actually *is* rather than relying on what rovergauge trimming is reporting ? That's the first thing I'd do .. prove that it's achieving lambda=1 or at least initially richer than that to justify the heavily negative trim values.
Also use blitzracing's guides as to how to check the lambda voltage output. An output skewed towards 1volt will mean the ecu tries to trim back what it thinks is a rich mixture.
We don't know anything about the base idle setup, but 2 pieces of evidence (the stepper open a long way, and reading line 3 of the fuel map rather than straddling lines 2 and 3) suggests ..
(1) actually that the mixture is already too weak, the resulting drop in power means the stepper has to open more to achieve the target idle, meaning the afm output is higher because of the increased airflow.
(2) Caveat to that is that retarded ignition timing will also cause those same two readouts. have you checked it? and the accuracy of the TDC mark?
It's always difficult to diagnose based on a couple of screenshots though ..
If the short term trim is heavily negative that would suggest (as a fuel pressure fault) too much pressure rather than too little, so the reported fault is incorrect for the visible evidence.
If the short term trim goes rich or weak for any length of time then the long term trim moves to bring the short term trimming around the zero point .. having -100 short term but the long term only moving to -15 or so makes no sense. How long did you leave it? and also you sometimes need to blip the throttle to wake the lambda trimming up, it can freeze after a while.
Did Mat stick a wideband up the exhaust to see what the mixture actually *is* rather than relying on what rovergauge trimming is reporting ? That's the first thing I'd do .. prove that it's achieving lambda=1 or at least initially richer than that to justify the heavily negative trim values.
Also use blitzracing's guides as to how to check the lambda voltage output. An output skewed towards 1volt will mean the ecu tries to trim back what it thinks is a rich mixture.
We don't know anything about the base idle setup, but 2 pieces of evidence (the stepper open a long way, and reading line 3 of the fuel map rather than straddling lines 2 and 3) suggests ..
(1) actually that the mixture is already too weak, the resulting drop in power means the stepper has to open more to achieve the target idle, meaning the afm output is higher because of the increased airflow.
(2) Caveat to that is that retarded ignition timing will also cause those same two readouts. have you checked it? and the accuracy of the TDC mark?
It's always difficult to diagnose based on a couple of screenshots though ..
In terms of physical voltages 0 volts at the probe is a lean mixture, so should give adding fuel up to 100% to get the probe to switch. Anything over 1 volt is rich so should remove fuel until the probe voltage drops below 1 volt Most common failures are 0 volts from the probe so it can be interpreted as an over lean mixture / injector fault / misfire / faulty probe or missing heater voltage. A stuck high voltage is far less common but I've seen it with a short on the probe output to its heater supply.
There is a point of great confusion however......
Fuel trim is removing fuel so making the mixture leaner- so you ADD fuel trim to remove fuel and remove it to add fuel. Its why Rover Gauge is marked adding or removing fuel to try and make things clear. Its why I tend to try and work with voltages more than displayed trim as its easy to get very mixed up.
Mind you you do need the correct map in the ECU to start with.
There is a point of great confusion however......
Fuel trim is removing fuel so making the mixture leaner- so you ADD fuel trim to remove fuel and remove it to add fuel. Its why Rover Gauge is marked adding or removing fuel to try and make things clear. Its why I tend to try and work with voltages more than displayed trim as its easy to get very mixed up.
Mind you you do need the correct map in the ECU to start with.
blitzracing said:
Check Steve Sprints 14CUX maps page looks like the 4 and 4.3 have different maps.
http://www.remap-14cux.uk/bins/
Trim is set at idle RPM only so changes in an engines breathing will have a big affect on the trim. So you really need the correct map.
In terms of if its lean or not try unplugging the vacuum pipe to the fuel regulator and block it off so no air gets into the plenum. This will boost the fiel pressure so see it the trims move in this new condition . Misfires also show as a lean mixture so will produce a removing trim or adding fuel status in RoverGauge.
The car is a 4.0 HC do you think it's running a 4.3 map then? I looked at the site and the tune number matches the Chimaera 400 CAThttp://www.remap-14cux.uk/bins/
Trim is set at idle RPM only so changes in an engines breathing will have a big affect on the trim. So you really need the correct map.
In terms of if its lean or not try unplugging the vacuum pipe to the fuel regulator and block it off so no air gets into the plenum. This will boost the fiel pressure so see it the trims move in this new condition . Misfires also show as a lean mixture so will produce a removing trim or adding fuel status in RoverGauge.
Edited by pmc_3 on Friday 14th July 12:16
spitfire4v8 said:
On the face of it what you are seeing makes little sense.
If the short term trim is heavily negative that would suggest (as a fuel pressure fault) too much pressure rather than too little, so the reported fault is incorrect for the visible evidence.
If the short term trim goes rich or weak for any length of time then the long term trim moves to bring the short term trimming around the zero point .. having -100 short term but the long term only moving to -15 or so makes no sense. How long did you leave it? and also you sometimes need to blip the throttle to wake the lambda trimming up, it can freeze after a while.
Did Mat stick a wideband up the exhaust to see what the mixture actually *is* rather than relying on what rovergauge trimming is reporting ? That's the first thing I'd do .. prove that it's achieving lambda=1 or at least initially richer than that to justify the heavily negative trim values.
Also use blitzracing's guides as to how to check the lambda voltage output. An output skewed towards 1volt will mean the ecu tries to trim back what it thinks is a rich mixture.
We don't know anything about the base idle setup, but 2 pieces of evidence (the stepper open a long way, and reading line 3 of the fuel map rather than straddling lines 2 and 3) suggests ..
(1) actually that the mixture is already too weak, the resulting drop in power means the stepper has to open more to achieve the target idle, meaning the afm output is higher because of the increased airflow.
(2) Caveat to that is that retarded ignition timing will also cause those same two readouts. have you checked it? and the accuracy of the TDC mark?
It's always difficult to diagnose based on a couple of screenshots though ..
I had the car running for a good 20 minutes, blipped the throttle a few times once up to temperature and the short terms moved but went back to -100%. I have since found cylinder 7 was cold and with a new plug, removing the extenders and fiddling with the leads that one got warm as well and the short term on that bank is no longer -100%, it's still high but is constantly cycling. The even bank is still -100% and all headers were hot that side.If the short term trim is heavily negative that would suggest (as a fuel pressure fault) too much pressure rather than too little, so the reported fault is incorrect for the visible evidence.
If the short term trim goes rich or weak for any length of time then the long term trim moves to bring the short term trimming around the zero point .. having -100 short term but the long term only moving to -15 or so makes no sense. How long did you leave it? and also you sometimes need to blip the throttle to wake the lambda trimming up, it can freeze after a while.
Did Mat stick a wideband up the exhaust to see what the mixture actually *is* rather than relying on what rovergauge trimming is reporting ? That's the first thing I'd do .. prove that it's achieving lambda=1 or at least initially richer than that to justify the heavily negative trim values.
Also use blitzracing's guides as to how to check the lambda voltage output. An output skewed towards 1volt will mean the ecu tries to trim back what it thinks is a rich mixture.
We don't know anything about the base idle setup, but 2 pieces of evidence (the stepper open a long way, and reading line 3 of the fuel map rather than straddling lines 2 and 3) suggests ..
(1) actually that the mixture is already too weak, the resulting drop in power means the stepper has to open more to achieve the target idle, meaning the afm output is higher because of the increased airflow.
(2) Caveat to that is that retarded ignition timing will also cause those same two readouts. have you checked it? and the accuracy of the TDC mark?
It's always difficult to diagnose based on a couple of screenshots though ..
Mat didn't actually look at the issue he was just doing outriggers and fuel lines and I asked him to check the injectors whilst the plenum was off.
I did a compression test last night and they were all pretty even and not low. I've put in a new set of plugs and am going to get some new leads.
Edited by pmc_3 on Friday 14th July 12:53
blitzracing said:
Belle427 said:
I think there is some confusion here, yours is a 4.0 HC not a 4.3 as Mark (blitzracing) may be thinking.
Quite possibly. I blame old age :-(I'm pretty sure the short term readings are correct and it's not a lambda wiring issue. Now I've found the issue on the odd bank with cylinder 7 not firing and it's back to how it was with that one adjusting on the short term. I'm not sure about the even bank though as it's not injectors and all of the exhaust headers get hot but it smells of over fueling. This is the sensor that came out of that side when I put the new one in.
I've put the new spark plugs in and will try a new set of leads as I managed to pull the end off one trying to get it off the plug. I'm wondering if it's got an intermittent misfire on that bank.
Edited by pmc_3 on Friday 14th July 16:56
If you can run a logfile of data I will check all the Inputs/outputs and make an assessment of each of them for you.
Logfile has to be fone as followd.
From cold
Run RoverGauge (RG)
Turn on ignition position 1.
Connect RG
Set RG to record all data values but not road speed and not gear selection.
Set MAF DIRECT, THROTTLE ABSOLUTE, TRIM SHORT.
Start the logfile
Start the engine.
Allow the car to run like that at idle for about 20 minutes.
Stop the log file and send it to me.
PS have done this now for 20+ cars and have data that I can compare to to establish condition of the inputs and outputs.
Logfile has to be fone as followd.
From cold
Run RoverGauge (RG)
Turn on ignition position 1.
Connect RG
Set RG to record all data values but not road speed and not gear selection.
Set MAF DIRECT, THROTTLE ABSOLUTE, TRIM SHORT.
Start the logfile
Start the engine.
Allow the car to run like that at idle for about 20 minutes.
Stop the log file and send it to me.
PS have done this now for 20+ cars and have data that I can compare to to establish condition of the inputs and outputs.
blaze_away said:
If you can run a logfile of data I will check all the Inputs/outputs and make an assessment of each of them for you.
Logfile has to be fone as followd.
From cold
Run RoverGauge (RG)
Turn on ignition position 1.
Connect RG
Set RG to record all data values but not road speed and not gear selection.
Set MAF DIRECT, THROTTLE ABSOLUTE, TRIM SHORT.
Start the logfile
Start the engine.
Allow the car to run like that at idle for about 20 minutes.
Stop the log file and send it to me.
PS have done this now for 20+ cars and have data that I can compare to to establish condition of the inputs and outputs.
Thanks, will do. Just waiting for the new plug leads to arrive. I’ll fit those then do the log.Logfile has to be fone as followd.
From cold
Run RoverGauge (RG)
Turn on ignition position 1.
Connect RG
Set RG to record all data values but not road speed and not gear selection.
Set MAF DIRECT, THROTTLE ABSOLUTE, TRIM SHORT.
Start the logfile
Start the engine.
Allow the car to run like that at idle for about 20 minutes.
Stop the log file and send it to me.
PS have done this now for 20+ cars and have data that I can compare to to establish condition of the inputs and outputs.
blaze_away said:
If you can run a logfile of data I will check all the Inputs/outputs and make an assessment of each of them for you.
Logfile has to be fone as followd.
From cold
Run RoverGauge (RG)
Turn on ignition position 1.
Connect RG
Set RG to record all data values but not road speed and not gear selection.
Set MAF DIRECT, THROTTLE ABSOLUTE, TRIM SHORT.
Start the logfile
Start the engine.
Allow the car to run like that at idle for about 20 minutes.
Stop the log file and send it to me.
PS have done this now for 20+ cars and have data that I can compare to to establish condition of the inputs and outputs.
I've got the new plugs and leads in and have done a log file, let me know where I need to send it for you to take a look. I'm back to where I was a little while back, short term lambda odd is cycling but even is -100% long term is -100% on odd and - 15% even, fault code of injector bank even.Logfile has to be fone as followd.
From cold
Run RoverGauge (RG)
Turn on ignition position 1.
Connect RG
Set RG to record all data values but not road speed and not gear selection.
Set MAF DIRECT, THROTTLE ABSOLUTE, TRIM SHORT.
Start the logfile
Start the engine.
Allow the car to run like that at idle for about 20 minutes.
Stop the log file and send it to me.
PS have done this now for 20+ cars and have data that I can compare to to establish condition of the inputs and outputs.
Quick update.
Logfile shows all sensors are working and specifically the MAF is good with std dev of 0.003 ie good ones ate <0.005.
Looks like issue is ignition related.
Even bank short term trim is 100%
OP checked sparks and cyl 8 appears weak compared to others ergo unburnt fuel on O2 sensor.
Op has changed plugs and leads. Have suggested checking timing coil amp cap rotor arm next.
Logfile shows all sensors are working and specifically the MAF is good with std dev of 0.003 ie good ones ate <0.005.
Looks like issue is ignition related.
Even bank short term trim is 100%
OP checked sparks and cyl 8 appears weak compared to others ergo unburnt fuel on O2 sensor.
Op has changed plugs and leads. Have suggested checking timing coil amp cap rotor arm next.
Edited by blaze_away on Monday 24th July 14:11
CHART 01 - All log file data from cold. (to see how the engine warms up and how the sensors detect that warm up phase)
CHART 02 - Last section from 11 minutes after engine is fully warmed up and stable at idle (to analyse the stability of exch of the sensors and especially the MAF which is particularly sensitive to heat soak causing it to become erratic and often is the cause of over fueling)
CHART 03 - The vari distribution analysis of the MAF from data in Chart 02 Shows the variation in the MAF at idle, looking specifically at the Standard Deviation as an indicator of the MAF's stability. <0.005 is good MAF, >0.007 is a bad MAF. between these it is borderline
CHART 02 - Last section from 11 minutes after engine is fully warmed up and stable at idle (to analyse the stability of exch of the sensors and especially the MAF which is particularly sensitive to heat soak causing it to become erratic and often is the cause of over fueling)
CHART 03 - The vari distribution analysis of the MAF from data in Chart 02 Shows the variation in the MAF at idle, looking specifically at the Standard Deviation as an indicator of the MAF's stability. <0.005 is good MAF, >0.007 is a bad MAF. between these it is borderline
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