Surging idle please help
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10-28-2019, 07:51 PM
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Surging idle please help
Has anyone had the problem of a surging idle ? The idle on my 2010 XF 5.0 N/A is surging up and down for the last few months.I have taken it to several different mechanics with no luck and now it’s at the Jaguar dealership for about a week and so far no answers. I’m not sure if the dealership has some sort of database that their mechanics can access to see if there has been any other 5.0 engines with the same issues brought into other Jaguar repair facilities or not I just find it hard to believe that with all the problems these cars are prone to that I am the only person that has had a surging idle.If any of you fellow Jag owners have any ideas I would love to hear them thank you
Mike
Mike
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10-28-2019, 09:29 PM
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Thank you mghirsh I will test for that. What mine is doing is when sitting in park and even while driving is the idle is Rev’ing up and down constantly
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10-28-2019, 09:35 PM
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Hi Mike,
In general, malfunctions that lead to surging idle will also trigger diagnostic trouble codes (DTCs). Have the previous mechanics or dealer scanned the codes, and if so, what codes are stored? The Powertrain codes (P-prefix) are probably most relevant, but it's also possible that one or more Network (U-prefix) codes could be involved.
As mghirsch has already noted, the most common cause of surging idle is an air or vacuum leak that allows unmetered air to enter the engine intake somewhere between the Mass Air Flow Sensor (MAFS) and the intake manifold gaskets. The air intake system includes a lot of plumbing, so finding a leak can take some detective work. Tools used by mechanics include a smoke machine, flowmeter and manometer. Have any of those tools been used on your engine?
Problems with the Evaporative Emissions system (EVAP), such as an air leak or stuck-open valve can contribute to idle problems.
Viewing Live Data with a scan tool, a technician can monitor the Short Term Fuel Trims (STFT) and Long Term Fuel Trims (LTFT) at idle and other engine speeds (e.g. 1,500 rpm and 2,500 rpm) to see if the engine is running lean (too much air vs. fuel) or rich (too much fuel vs. air). Lean running is a common result of an air leak.
If, on the other hand, your engine is running rich, contributors can include an obstructed air filter, an Engine Coolant Temperature Sensor (ECTS) that is stuck at a "cold" setting or coolant thermostat that is stuck open, prompting the Engine Control Module (ECM) to continue to apply cold-start fuel enrichment even after the engine has reached full operating temp.
The scan tool can also view the signals from all the other relevant engine management sensors to see if any signals appear out of range or implausible.
Plenty of other issues can contribute to surging idle. A clogged fuel filter/fuel pump sock, a dirty throttle body, a failing fuel pump, problems with fuel pressure management, a cracked exhaust manifold, dirty throttle body, etc.
Hopefully the dealership will be able to figure out what's going on, and we'll be anxious to know. But if the previous mechanics found any DTCs, please post them here and we'll try to help you make sense of them.
Cheers,
Don
In general, malfunctions that lead to surging idle will also trigger diagnostic trouble codes (DTCs). Have the previous mechanics or dealer scanned the codes, and if so, what codes are stored? The Powertrain codes (P-prefix) are probably most relevant, but it's also possible that one or more Network (U-prefix) codes could be involved.
As mghirsch has already noted, the most common cause of surging idle is an air or vacuum leak that allows unmetered air to enter the engine intake somewhere between the Mass Air Flow Sensor (MAFS) and the intake manifold gaskets. The air intake system includes a lot of plumbing, so finding a leak can take some detective work. Tools used by mechanics include a smoke machine, flowmeter and manometer. Have any of those tools been used on your engine?
Problems with the Evaporative Emissions system (EVAP), such as an air leak or stuck-open valve can contribute to idle problems.
Viewing Live Data with a scan tool, a technician can monitor the Short Term Fuel Trims (STFT) and Long Term Fuel Trims (LTFT) at idle and other engine speeds (e.g. 1,500 rpm and 2,500 rpm) to see if the engine is running lean (too much air vs. fuel) or rich (too much fuel vs. air). Lean running is a common result of an air leak.
If, on the other hand, your engine is running rich, contributors can include an obstructed air filter, an Engine Coolant Temperature Sensor (ECTS) that is stuck at a "cold" setting or coolant thermostat that is stuck open, prompting the Engine Control Module (ECM) to continue to apply cold-start fuel enrichment even after the engine has reached full operating temp.
The scan tool can also view the signals from all the other relevant engine management sensors to see if any signals appear out of range or implausible.
Plenty of other issues can contribute to surging idle. A clogged fuel filter/fuel pump sock, a dirty throttle body, a failing fuel pump, problems with fuel pressure management, a cracked exhaust manifold, dirty throttle body, etc.
Hopefully the dealership will be able to figure out what's going on, and we'll be anxious to know. But if the previous mechanics found any DTCs, please post them here and we'll try to help you make sense of them.
Cheers,
Don
Last edited by Don B; 10-30-2019 at 11:46 PM.
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10-30-2019, 11:12 AM
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10-30-2019, 05:15 PM
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Hi Mike,
In general, malfunctions that lead to surging idle will also trigger diagnostic trouble codes (DTCs). Have the previous mechanics or dealer scanned the codes, and if so, what codes are stored? The Powertrain codes (P-prefix) are probably most relevant, but it's also possible that one or more Network (U-prefix) codes could be involved.
As mghirsch has already noted, the most common cause of surging idle is an air or vacuum leak that allows unmetered air to enter the engine intake somewhere between the Mass Air Flow Sensor (MAFS) and the intake manifold gaskets. The air intake system includes a lot of plumbing, so finding a leak can take some detective work. Tools used by mechanics include a smoke machine, flowmeter and manometer. Have any of those tools been used on your engine?
Problems with the Evaporative Emissions system (EVAP), such as an air leak or stuck-open valve can contribute to idle problems.
A scan tool can also be very helpful. Viewing Live Data, a technician can monitor the Short Term Fuel Trims (STFT) and Long Term Fuel Trims (LTFT) at idle and other engine speeds (e.g. 1,500 rpm and 2,500 rpm) to see if the engine is running lean (too much air vs. fuel) or rich (too much fuel vs. air). Lean running is a common result of an air leak.
If, on the other hand, your engine is running rich, contributors can include an obstructed air filter, an Engine Coolant Temperature Sensor (ECTS) that is stuck at a "cold" setting or coolant thermostat that is stuck open, prompting the Engine Control Module (ECM) to continue to apply cold-start fuel enrichment even after the engine has reached full operating temp.
The scan tool can also view the signals from all the other relevant engine management sensors to see if any signals appear out of range or implausible.
Plenty of other issues can contribute to surging idle. A clogged fuel filter/fuel pump sock, a dirty throttle body, a failing fuel pump, problems with fuel pressure management, a cracked exhaust manifold, dirty throttle body, etc.
Hopefully the dealership will be able to figure out what's going on, and we'll be anxious to know. But if the previous mechanics found any DTCs, please post them here and we'll try to help you make sense of them.
Cheers,
Don
In general, malfunctions that lead to surging idle will also trigger diagnostic trouble codes (DTCs). Have the previous mechanics or dealer scanned the codes, and if so, what codes are stored? The Powertrain codes (P-prefix) are probably most relevant, but it's also possible that one or more Network (U-prefix) codes could be involved.
As mghirsch has already noted, the most common cause of surging idle is an air or vacuum leak that allows unmetered air to enter the engine intake somewhere between the Mass Air Flow Sensor (MAFS) and the intake manifold gaskets. The air intake system includes a lot of plumbing, so finding a leak can take some detective work. Tools used by mechanics include a smoke machine, flowmeter and manometer. Have any of those tools been used on your engine?
Problems with the Evaporative Emissions system (EVAP), such as an air leak or stuck-open valve can contribute to idle problems.
A scan tool can also be very helpful. Viewing Live Data, a technician can monitor the Short Term Fuel Trims (STFT) and Long Term Fuel Trims (LTFT) at idle and other engine speeds (e.g. 1,500 rpm and 2,500 rpm) to see if the engine is running lean (too much air vs. fuel) or rich (too much fuel vs. air). Lean running is a common result of an air leak.
If, on the other hand, your engine is running rich, contributors can include an obstructed air filter, an Engine Coolant Temperature Sensor (ECTS) that is stuck at a "cold" setting or coolant thermostat that is stuck open, prompting the Engine Control Module (ECM) to continue to apply cold-start fuel enrichment even after the engine has reached full operating temp.
The scan tool can also view the signals from all the other relevant engine management sensors to see if any signals appear out of range or implausible.
Plenty of other issues can contribute to surging idle. A clogged fuel filter/fuel pump sock, a dirty throttle body, a failing fuel pump, problems with fuel pressure management, a cracked exhaust manifold, dirty throttle body, etc.
Hopefully the dealership will be able to figure out what's going on, and we'll be anxious to know. But if the previous mechanics found any DTCs, please post them here and we'll try to help you make sense of them.
Cheers,
Don
#7
10-30-2019, 05:20 PM
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Jssaab thank you for the tip I will pass on your information to the boys at Jaguar as of right now my XF has been there for over a week and still no closer to solving the surging issue
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#8
10-31-2019, 05:35 PM
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Ok so I finally received I call back from the Jaguar dealership and they believe it has a timing issue and wanted $2000. just to find out what the timing issue was that didn’t include them actually fixing any of the problems they might find so I just told them to get it ready for me to pick up. When I got it home I started investigating on my own and found that if I unplugged the passenger side MAF sensor that the engine surging would stop and the car ran great (other than the engine light would come on letting me know that the MAF sensor was not connected) I swapped the other MAF sensor from the drivers side and same thing whatever sensor is plugged into the passenger side it would start surging again. If I unplug the drivers side MAF sensor nothing happens this tells me the sensor itself is fine but maybe there’s an issue with the wiring on the passenger side any ideas ???
the only thing they did when they had the car was a smoke test and found no leaks and checked if any codes were on and found nothing
the only thing they did when they had the car was a smoke test and found no leaks and checked if any codes were on and found nothing
#9
09-06-2023, 07:43 PM
Ok so I finally received I call back from the Jaguar dealership and they believe it has a timing issue and wanted $2000. just to find out what the timing issue was that didn’t include them actually fixing any of the problems they might find so I just told them to get it ready for me to pick up. When I got it home I started investigating on my own and found that if I unplugged the passenger side MAF sensor that the engine surging would stop and the car ran great (other than the engine light would come on letting me know that the MAF sensor was not connected) I swapped the other MAF sensor from the drivers side and same thing whatever sensor is plugged into the passenger side it would start surging again. If I unplug the drivers side MAF sensor nothing happens this tells me the sensor itself is fine but maybe there’s an issue with the wiring on the passenger side any ideas ???
the only thing they did when they had the car was a smoke test and found no leaks and checked if any codes were on and found nothing
the only thing they did when they had the car was a smoke test and found no leaks and checked if any codes were on and found nothing
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Don B (09-06-2023)
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