AquallamaXJ
NAXJA Forum User
- Location
- Pottstown, PA
Hello, my 2000 XJ (4.0L, AW4, NP231, 230,000+ miles) is running poorly with codes P0108 (Map Sensor High Voltage)and P0132 (Left-Upstream O2 Sensor Shorted to Voltage).
I first noticed the jeep running poorly when driving in a hilly area in the rain. The next day on a 30 minute drive I couldn't keep up speed over 45, and acceleration was sluggish. At some point in this drive, the CEL lit up.
It stalls from either a warm or cold start, unless I give it gas for 10-20 seconds, then it idles. The idle is rough and surges slightly. If I give it gas slowly (in Park), it will rev up to 2500+ but then it surges violently with an occasional backfire. The high rpm surge sounds really sad.
When driving, light acceleration up to 2500rpm is fine, including normal shift points. Hard acceleration bogs the engine until you back off, but it has not stalled. It makes for slow and frustrating driving.
What I've done/history:
-The idle doesn't change if the MAP is disconnected. Possible wiring issue?
-I checked the MAP sensor voltage (brake bleeder pressure test), and it appeared fine.
-Swapping a cheap parts store MAP did not change anything, the original is back on.
-Swapping a cheapo TPS just gave me a TPS low voltage code, so the original is back on there.
-The spark plugs are black and sooty, and the fuel pump sounds fine.
-A pressure test on the intake indicates I may have clogged catalytic converters (2 pre cats + 1 regular cat).
-Engine/chassis grounds appear fine, recently upgraded 6mo prior.
-Engine has a history of P0303 (Cyl 3 misfire) associated with heat soak. One day it was flashing with this code (hot start up. 2 hours down the road after wheeling), but ran normally after cooling down for 10 minutes.
-Mileage has been getting worse this year, down from 19hwy/15city to 17/12, with 14-15mpg average.
I have not yet checked the upstream 02 sensor.
The jeep is parked for now, and plan to test the wiring on the weekend.
My plan of action includes:
Test continuity of wiring harness between sensors & pcm, confirm voltage from harness to sensors, check all grounds.
Test 02 sensor if possible, maybe replace 02 anyway (Bosch?).
Replace MAP and/or TPS with MOPAR parts
Remove/replace main cat and check for restrictions, then maybe remove exhaust manifold to replace pre-cats.
Does anyone have new ideas or suggestions? If its not a failed sensor or broken wire, what else? Could a clogged cat cause the codes and surging?
Thanks!
I first noticed the jeep running poorly when driving in a hilly area in the rain. The next day on a 30 minute drive I couldn't keep up speed over 45, and acceleration was sluggish. At some point in this drive, the CEL lit up.
It stalls from either a warm or cold start, unless I give it gas for 10-20 seconds, then it idles. The idle is rough and surges slightly. If I give it gas slowly (in Park), it will rev up to 2500+ but then it surges violently with an occasional backfire. The high rpm surge sounds really sad.
When driving, light acceleration up to 2500rpm is fine, including normal shift points. Hard acceleration bogs the engine until you back off, but it has not stalled. It makes for slow and frustrating driving.
What I've done/history:
-The idle doesn't change if the MAP is disconnected. Possible wiring issue?
-I checked the MAP sensor voltage (brake bleeder pressure test), and it appeared fine.
-Swapping a cheap parts store MAP did not change anything, the original is back on.
-Swapping a cheapo TPS just gave me a TPS low voltage code, so the original is back on there.
-The spark plugs are black and sooty, and the fuel pump sounds fine.
-A pressure test on the intake indicates I may have clogged catalytic converters (2 pre cats + 1 regular cat).
-Engine/chassis grounds appear fine, recently upgraded 6mo prior.
-Engine has a history of P0303 (Cyl 3 misfire) associated with heat soak. One day it was flashing with this code (hot start up. 2 hours down the road after wheeling), but ran normally after cooling down for 10 minutes.
-Mileage has been getting worse this year, down from 19hwy/15city to 17/12, with 14-15mpg average.
I have not yet checked the upstream 02 sensor.
The jeep is parked for now, and plan to test the wiring on the weekend.
My plan of action includes:
Test continuity of wiring harness between sensors & pcm, confirm voltage from harness to sensors, check all grounds.
Test 02 sensor if possible, maybe replace 02 anyway (Bosch?).
Replace MAP and/or TPS with MOPAR parts
Remove/replace main cat and check for restrictions, then maybe remove exhaust manifold to replace pre-cats.
Does anyone have new ideas or suggestions? If its not a failed sensor or broken wire, what else? Could a clogged cat cause the codes and surging?
Thanks!