Idle checklist
#41
Turn on the AM stereo and run the engine noticing a background hum varies with engine RPM
Compare to AM background noise with the engine not running and stereo being powered by pure battery DC electricity
Your data on the STFT swings back and forth like sharks teeth
The off scale of 24.2 has been observed by others
MAF X 100 ?
Are the readings at constant throttle ( idle or other ) ?
Compare to AM background noise with the engine not running and stereo being powered by pure battery DC electricity
Your data on the STFT swings back and forth like sharks teeth
The off scale of 24.2 has been observed by others
MAF X 100 ?
Are the readings at constant throttle ( idle or other ) ?
Last edited by Parker 2; 07-29-2020 at 09:10 PM.
#42
Turn on the AM stereo and run the engine noticing a background hum varies with engine RPM
Compare to AM background noise with the engine not running and stereo being powered by pure battery DC electricity
Your data on the STFT swings back and forth like sharks teeth
The off scale of 24.2 has been observed by others
MAF X 100 ?
Compare to AM background noise with the engine not running and stereo being powered by pure battery DC electricity
Your data on the STFT swings back and forth like sharks teeth
The off scale of 24.2 has been observed by others
MAF X 100 ?
Idle is pretty smooth for first 30ish minutes of operation and progressively gets slightly rougher, but again no dips.
MAF x 100 sounds about right. the Range Rover P38 guide says 20-25 kg/h is normal range at idle.
The following users liked this post:
Parker 2 (07-29-2020)
#44
By unplugging the ECTS the resistance value is infinitely high or out of expected range so the ECU probably rejects the data / variable and reverts to a different , less then optimal set of data maps minus a ECTS data / variable
This would be different then a " excepted " value in which case would mimic a cold coolant temp tp go to open loop mode
In my opinion you would be better to resolve your idle in the closed loop mode using the O2 sensors and full engine regulation
Without knowing that you were reading a properly operating O2 sensor system in your example you can swap the front 2 O2 sensors to the rear
All 4 are the same length and connector no key
Eesier said then done
On the X300 4 o2 sensor setup the rear sensors regulate the engine and the front determains catalytic converter efficiency error CEL code
swap one pair at a time while the ECU learns of it's new perimeters and then swap the second pair less the chance the ECU would get lost by the change
Rear firewall small ground post clean , 2 , these are the shield wires to the sensitive O2 sensor return wires to the ECU
Rear O2 sensor connectors clean ?
crush washers on the O2 sensor mounting boss , 12 or 14 mm different then the spark plugs . The position of the sensor in the gas stream seams to make a difference
You can source some from a cheap copper 12 mm spark plug
Cap the vacuum hose fitting under the intake manifold around cylinder 2
cap the banjo fitting to the brake boost cylinder
This would be different then a " excepted " value in which case would mimic a cold coolant temp tp go to open loop mode
In my opinion you would be better to resolve your idle in the closed loop mode using the O2 sensors and full engine regulation
Without knowing that you were reading a properly operating O2 sensor system in your example you can swap the front 2 O2 sensors to the rear
All 4 are the same length and connector no key
Eesier said then done
On the X300 4 o2 sensor setup the rear sensors regulate the engine and the front determains catalytic converter efficiency error CEL code
swap one pair at a time while the ECU learns of it's new perimeters and then swap the second pair less the chance the ECU would get lost by the change
Rear firewall small ground post clean , 2 , these are the shield wires to the sensitive O2 sensor return wires to the ECU
Rear O2 sensor connectors clean ?
crush washers on the O2 sensor mounting boss , 12 or 14 mm different then the spark plugs . The position of the sensor in the gas stream seams to make a difference
You can source some from a cheap copper 12 mm spark plug
Cap the vacuum hose fitting under the intake manifold around cylinder 2
cap the banjo fitting to the brake boost cylinder
Last edited by Parker 2; 07-30-2020 at 12:50 AM.
#48
It would be more of a pulsing or swirling noise that varies with RPM
The source of the pulse if present would be from the alternator diode package or the separate noise suppressor that further smooths out the AC waves to be more flat pure DC electricity
Coils can induce a AC component into the electrical system including the power to the ELM reader
The engine block large ground helps this in theory
The CEL codes are not perfect but odd they would show up now which should relate to the confidence the codes are valid information
Also your data is not stable or on one side of expected or the other
The codes can be found on page X of the Jaguar 801s document
The source of the pulse if present would be from the alternator diode package or the separate noise suppressor that further smooths out the AC waves to be more flat pure DC electricity
Coils can induce a AC component into the electrical system including the power to the ELM reader
The engine block large ground helps this in theory
The CEL codes are not perfect but odd they would show up now which should relate to the confidence the codes are valid information
Also your data is not stable or on one side of expected or the other
The codes can be found on page X of the Jaguar 801s document
Last edited by Parker 2; 07-31-2020 at 01:08 AM.
#49
This looks very reminiscent of a problem I had, with excessive fuel trim at low RPM. The problem turned out to be a leak at the exhaust manifolds to downpipe connection. Counterintuitively, this was allowing oxygen to be sucked IN between exhaust gas pulses, confusing the O2 sensors into thinking the engine was running lean, and causing the ECU to enrich the mixture. Remaking the joint solved the problem.
#50
I have the part # for the donut gasket ( 2 ) downstairs in the garage someone helped me out with
Easy to obtain from the local auto parts store
60 mm in size
Look for a clean unbent not damaged flair on the downpipe
The studs get in the way
Easy to obtain from the local auto parts store
60 mm in size
Look for a clean unbent not damaged flair on the downpipe
The studs get in the way
Last edited by Parker 2; 07-31-2020 at 04:17 AM.
#51
#53
#54
One thing to consider with your ELM - 327 reader and what information it gives you is the difference in a bluetooth data link and the wired USB port version reception
The data it receives refresh rate is slower with the bluetooth as the databus communication ( from what I have discerned from reading ) and this is critical with reading what your O2 sensor system is doing as it oscillates by design to force the ECU to recalculate the injector pulsewidths ( fuel trim ) as the ECU does not have a heartbeat monitor
This does not instill confidence in what the ELM - 327 does or does not tell you but is a variable of consideration in troubleshooting
The data it receives refresh rate is slower with the bluetooth as the databus communication ( from what I have discerned from reading ) and this is critical with reading what your O2 sensor system is doing as it oscillates by design to force the ECU to recalculate the injector pulsewidths ( fuel trim ) as the ECU does not have a heartbeat monitor
This does not instill confidence in what the ELM - 327 does or does not tell you but is a variable of consideration in troubleshooting
Last edited by Parker 2; 08-02-2020 at 03:15 PM.
#57
#58
Alright a little update. Spoke a little too soon when I changed coils with a hot engine, after the next cold start it started running smoother than ever and has been like that since.
Marriage falling apart? Replace all 6 coils
Dog won’t behave? Replace all 6 coils
Bleeding out from a gunshot wound? Replace all 6 coils
IRS going after you for tax evasion? Replace all 6 coils
Marriage falling apart? Replace all 6 coils
Dog won’t behave? Replace all 6 coils
Bleeding out from a gunshot wound? Replace all 6 coils
IRS going after you for tax evasion? Replace all 6 coils
The following 2 users liked this post by xalty:
Cafcpete (08-20-2020),
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#60