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Misfire Code P0301 on 2000 Discovery II
3 years 5 months ago #44767
by madprof
Misfire Code P0301 on 2000 Discovery II was created by madprof
Land Rover Discovery II 4.0L V8 gas
TC0301 (only)
I have a 2000 Discovery 2 with 115k miles. It is a recent purchase and I have worked through a pile of trouble codes. It still has a persistent PO301 cylinder 1 misfire.
It runs normal at speed. Slightly rough at idle. Not a hard misfire. The CES light is on but not flashing. If I disconnect spark 1, it runs rougher and CES starts flashing.
I ran a compression test with these results (which seems pretty good):
#1: 175 #2: 190
#3: 185 #4: 180
#5: 175 #6: 190
#7: 180 #8: 190
Leakdown test also good. Leakdown test - Cyl 1: 8% Cyl 2: 6% etc
I checked the injectors with an injector pulse tester and compared pressure drop with a fuel pressure gauge.
Fuel Trims seem good. Long range bank 1: -3.1, bank 2: 1.6.
I just realized it has exhaust leaks at both manifold flanges. I have tried addressing this, but will have to redo that.
I am an amatuer mechanic, and ScannerDanner fan. I am using a Fluke 190, 4-channel scope with a ES 695 low current probe on A channel, Hantek spark probe on B Channel, and 200PSI PX3AN1BH200PSAAX on C Channel to generate the 2 traces attached. I've been having difficulty getting a clean current reading so I have Channel A (Current) on AC coupling. The #1 cylinder always has lower current, but the pressure sensor reads about the same for #1 and #3 during cranking. Seems like the misfire is due to mechanical issues
to me. Any input on my setup, or results interpretation would be most appreciated.
TC0301 (only)
I have a 2000 Discovery 2 with 115k miles. It is a recent purchase and I have worked through a pile of trouble codes. It still has a persistent PO301 cylinder 1 misfire.
It runs normal at speed. Slightly rough at idle. Not a hard misfire. The CES light is on but not flashing. If I disconnect spark 1, it runs rougher and CES starts flashing.
I ran a compression test with these results (which seems pretty good):
#1: 175 #2: 190
#3: 185 #4: 180
#5: 175 #6: 190
#7: 180 #8: 190
Leakdown test also good. Leakdown test - Cyl 1: 8% Cyl 2: 6% etc
I checked the injectors with an injector pulse tester and compared pressure drop with a fuel pressure gauge.
Fuel Trims seem good. Long range bank 1: -3.1, bank 2: 1.6.
I just realized it has exhaust leaks at both manifold flanges. I have tried addressing this, but will have to redo that.
I am an amatuer mechanic, and ScannerDanner fan. I am using a Fluke 190, 4-channel scope with a ES 695 low current probe on A channel, Hantek spark probe on B Channel, and 200PSI PX3AN1BH200PSAAX on C Channel to generate the 2 traces attached. I've been having difficulty getting a clean current reading so I have Channel A (Current) on AC coupling. The #1 cylinder always has lower current, but the pressure sensor reads about the same for #1 and #3 during cranking. Seems like the misfire is due to mechanical issues
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