Lean on both banks......I am about to give up
#1
Lean on both banks......I am about to give up
Sorry, I posted this in my intro, and it should have gone here instead...my bad.
At any rate, I have codes po174, po171...lean on both banks. I have all but given up. I have replaced the IMT (sp?) o-rings, the intake gaskets, the plenum gaskets, have had the intake smoked (not at the dealer), replaced the fuel filter and stared at the engine for hours with and without carb cleaner in my hand. (Although I have now found out that with an electronic throttle, carb cleaner will not change the idle.) Oh, and changed the mass air flow sensor.
I even bought the lower breather hose, from the dealer, only to find the 06 does not have one. So I am really pleased with my dealer selling me this part and allowing me to spend 3 hours R&Ring the intake, again.
Any thoughts?
Minutes ago I checked the gas cap....it appears fine.
Again, thanks for all that have helped me over the years, even though you didn't know it.
Khris
At any rate, I have codes po174, po171...lean on both banks. I have all but given up. I have replaced the IMT (sp?) o-rings, the intake gaskets, the plenum gaskets, have had the intake smoked (not at the dealer), replaced the fuel filter and stared at the engine for hours with and without carb cleaner in my hand. (Although I have now found out that with an electronic throttle, carb cleaner will not change the idle.) Oh, and changed the mass air flow sensor.
I even bought the lower breather hose, from the dealer, only to find the 06 does not have one. So I am really pleased with my dealer selling me this part and allowing me to spend 3 hours R&Ring the intake, again.
Any thoughts?
Minutes ago I checked the gas cap....it appears fine.
Again, thanks for all that have helped me over the years, even though you didn't know it.
Khris
#3
As you have already diagnosed, P0174 is Bank 2 combustion too lean.
The possible causes are:
1. Engine misfire
2. Air intake leak between MAF Sensor and cylinder head
3. Fuel filter / system restriction
4. Fuel injector restriction
5. IP Sensor fault (low fuel pressure)
6. Low fuel pump output
7. HO2 Sensor(s) (2/1, 2/2) harness wiring condition fault
8. EFT Sensor fault (low fuel temperature)
9. MAF Sensor fault (low intake air flow)
10. Exhaust leak (before catalyst)
11. ECM receiving incorrect signal from one or more of the following components:
a) ECT Sensor
b) MAF Sensor
c) IAT Sensor
d) IP Sensor
e) EFT Sensor
f) TP Sensor
The same goes for P0171.
Graham
The possible causes are:
1. Engine misfire
2. Air intake leak between MAF Sensor and cylinder head
3. Fuel filter / system restriction
4. Fuel injector restriction
5. IP Sensor fault (low fuel pressure)
6. Low fuel pump output
7. HO2 Sensor(s) (2/1, 2/2) harness wiring condition fault
8. EFT Sensor fault (low fuel temperature)
9. MAF Sensor fault (low intake air flow)
10. Exhaust leak (before catalyst)
11. ECM receiving incorrect signal from one or more of the following components:
a) ECT Sensor
b) MAF Sensor
c) IAT Sensor
d) IP Sensor
e) EFT Sensor
f) TP Sensor
The same goes for P0171.
Graham
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khriss (03-09-2013)
#4
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khriss (03-09-2013)
#5
Khris welcome to the forum.
Check this link out:
https://www.jaguarforums.com/forum/s...ics-faq-52720/
Check this link out:
https://www.jaguarforums.com/forum/s...ics-faq-52720/
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khriss (03-09-2013)
#7
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#8
I'd get an OBD tool with live data.
Look at the freeze frame data in case it helps.
Also, check all the main sensors for plausibility at idle (easy) and if you can at the conditions in the freeze frames but at least look hard at that data. Be vigilent.
Watch the upstream O2s as you blip the throttle and again if you squirt a bit of propane into the air intake.
Make sure the downstream O2s are very different as they're not the same technology.
I think your car (being 06) has SAIR (which means extra air added after the engine into the exhaust) so you just about could have a problem there but as you have both banks lean it's far more likely to be earlier.
Always remember the car can only measure O2. It can't measure unburnt fuel, for example.
So it has to adjust fuel based on the O2 and what it sees the O2 sensors saying. It trusts the injectors etc to be nearly right and the O2 lets it see how to trim the fuelling. And so on.
Over here we measure tailpipe gases every year and that means it would be easy to pay for an extra test because that way you get far more than just O2 readings. May or may not be helpful
Here's the kind of thing modern cars do (as per CARB / EPA) OnBoardDiagnostics.com - Engine Basics
Look at the freeze frame data in case it helps.
Also, check all the main sensors for plausibility at idle (easy) and if you can at the conditions in the freeze frames but at least look hard at that data. Be vigilent.
Watch the upstream O2s as you blip the throttle and again if you squirt a bit of propane into the air intake.
Make sure the downstream O2s are very different as they're not the same technology.
I think your car (being 06) has SAIR (which means extra air added after the engine into the exhaust) so you just about could have a problem there but as you have both banks lean it's far more likely to be earlier.
Always remember the car can only measure O2. It can't measure unburnt fuel, for example.
So it has to adjust fuel based on the O2 and what it sees the O2 sensors saying. It trusts the injectors etc to be nearly right and the O2 lets it see how to trim the fuelling. And so on.
Over here we measure tailpipe gases every year and that means it would be easy to pay for an extra test because that way you get far more than just O2 readings. May or may not be helpful
Here's the kind of thing modern cars do (as per CARB / EPA) OnBoardDiagnostics.com - Engine Basics
Last edited by JagV8; 03-10-2013 at 09:28 AM.
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khriss (03-10-2013)
#9
Check the EGR and it's tube communicating with the passenger side exhaust manifold. Though unlikely for an 06, the tube and vaccume lines rot out. Also check the brake booster hose where it attaches to the intake manifold. The smoke test should have uncovered the preceeding but are we sure the tech was efficient with this test?
Last edited by bfsgross; 03-10-2013 at 11:40 AM.
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khriss (03-11-2013)
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khriss (03-11-2013)
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Panthro (03-03-2020)
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Khriss, if you've changed all that already, and still got 'em....I'd take it to Bob(Motorcarman); well worth your drive.
FWIW, Swapping MAF's between my 03 and 05 cured the same problem on the 05.....for a year, then the 03 (with original 05 MAF aboard) started popping 171/1474. Swapped 'em back and ordered a new MAF. In the 3 weeks or so between when I put the 05's original MAF back on and when I got 'round to installing the replacement, no codes.
FWIW, Swapping MAF's between my 03 and 05 cured the same problem on the 05.....for a year, then the 03 (with original 05 MAF aboard) started popping 171/1474. Swapped 'em back and ordered a new MAF. In the 3 weeks or so between when I put the 05's original MAF back on and when I got 'round to installing the replacement, no codes.
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khriss (03-11-2013)
#20