Oil Pressure, Guage Problem?
05-23-2017, 01:40 PM
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Oil Pressure, Guage Problem?
2000 Jeep XJ. Original engine had a broken piston skirt so I replaced it with an engine from a '92 XJ. I used the '00 head/intake/exhaust in this swap after making sure the head was fine.
After 50k miles, oil pressure started to drop. It had always held very steady at 40 pounds or so, but then over a few months it was 30, then 25, and at hot idle 7-8. When I parked it, after driving it for 5 minutes and stopped at a stop sign, "check gauges" would light up and no oil pressure.
Funny thing is, the engine made no noise like a lack of oil pressure would do. And yes, I put in a new pressure sensor and I did check the pressure with a cheap mechanical gauge which did show low oil pressure.
A friend of mine had a '94 Grand with an electrical issue that he didn't want to mess with so I bought it from him and installed that engine. I used the entire engine, head included in this swap. Used his exhaust, my '00 intake, and coil packs. He told me, and I believe him, that the engine was fine with good oil pressure. He was driving the GC quite often, is a Jeep junky and I trust him in its condition.
I finished this swap quite a while ago, but never did any driving...just start it up, let it warm up, check temps, etc., make sure no leaks, etc.
Today I finally took it on it's maiden voyage, about a 10 minute drive. After about 7 minutes, I see the pressure going from 40+, to 35, to 30 and when I get home and stop, pressure does the same as with the old engine...check gauges comes on, oil pressure drops to 0, but rises when I rev the engine. And again, no engine noises which I should hear with no pressure.
I will check again with a mechanical gauge. Fresh oil and good filter.
It just seems like too much of a coincidence to have the same exact situation happen again. I mean it's the same as it was when I parked it the last time.
Could it be a gauge problem or wiring problem instead of an engine problem? What should I check?
After 50k miles, oil pressure started to drop. It had always held very steady at 40 pounds or so, but then over a few months it was 30, then 25, and at hot idle 7-8. When I parked it, after driving it for 5 minutes and stopped at a stop sign, "check gauges" would light up and no oil pressure.
Funny thing is, the engine made no noise like a lack of oil pressure would do. And yes, I put in a new pressure sensor and I did check the pressure with a cheap mechanical gauge which did show low oil pressure.
A friend of mine had a '94 Grand with an electrical issue that he didn't want to mess with so I bought it from him and installed that engine. I used the entire engine, head included in this swap. Used his exhaust, my '00 intake, and coil packs. He told me, and I believe him, that the engine was fine with good oil pressure. He was driving the GC quite often, is a Jeep junky and I trust him in its condition.
I finished this swap quite a while ago, but never did any driving...just start it up, let it warm up, check temps, etc., make sure no leaks, etc.
Today I finally took it on it's maiden voyage, about a 10 minute drive. After about 7 minutes, I see the pressure going from 40+, to 35, to 30 and when I get home and stop, pressure does the same as with the old engine...check gauges comes on, oil pressure drops to 0, but rises when I rev the engine. And again, no engine noises which I should hear with no pressure.
I will check again with a mechanical gauge. Fresh oil and good filter.
It just seems like too much of a coincidence to have the same exact situation happen again. I mean it's the same as it was when I parked it the last time.
Could it be a gauge problem or wiring problem instead of an engine problem? What should I check?
05-23-2017, 04:03 PM
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Year: 2000 and 1998
Model: Cherokee
Engine: 4.0
2000 Jeep XJ. Original engine had a broken piston skirt so I replaced it with an engine from a '92 XJ. I used the '00 head/intake/exhaust in this swap after making sure the head was fine.
After 50k miles, oil pressure started to drop. It had always held very steady at 40 pounds or so, but then over a few months it was 30, then 25, and at hot idle 7-8. When I parked it, after driving it for 5 minutes and stopped at a stop sign, "check gauges" would light up and no oil pressure.
Funny thing is, the engine made no noise like a lack of oil pressure would do. And yes, I put in a new pressure sensor and I did check the pressure with a cheap mechanical gauge which did show low oil pressure.
A friend of mine had a '94 Grand with an electrical issue that he didn't want to mess with so I bought it from him and installed that engine. I used the entire engine, head included in this swap. Used his exhaust, my '00 intake, and coil packs. He told me, and I believe him, that the engine was fine with good oil pressure. He was driving the GC quite often, is a Jeep junky and I trust him in its condition.
I finished this swap quite a while ago, but never did any driving...just start it up, let it warm up, check temps, etc., make sure no leaks, etc.
Today I finally took it on it's maiden voyage, about a 10 minute drive. After about 7 minutes, I see the pressure going from 40+, to 35, to 30 and when I get home and stop, pressure does the same as with the old engine...check gauges comes on, oil pressure drops to 0, but rises when I rev the engine. And again, no engine noises which I should hear with no pressure.
I will check again with a mechanical gauge. Fresh oil and good filter.
It just seems like too much of a coincidence to have the same exact situation happen again. I mean it's the same as it was when I parked it the last time.
Could it be a gauge problem or wiring problem instead of an engine problem? What should I check?
After 50k miles, oil pressure started to drop. It had always held very steady at 40 pounds or so, but then over a few months it was 30, then 25, and at hot idle 7-8. When I parked it, after driving it for 5 minutes and stopped at a stop sign, "check gauges" would light up and no oil pressure.
Funny thing is, the engine made no noise like a lack of oil pressure would do. And yes, I put in a new pressure sensor and I did check the pressure with a cheap mechanical gauge which did show low oil pressure.
A friend of mine had a '94 Grand with an electrical issue that he didn't want to mess with so I bought it from him and installed that engine. I used the entire engine, head included in this swap. Used his exhaust, my '00 intake, and coil packs. He told me, and I believe him, that the engine was fine with good oil pressure. He was driving the GC quite often, is a Jeep junky and I trust him in its condition.
I finished this swap quite a while ago, but never did any driving...just start it up, let it warm up, check temps, etc., make sure no leaks, etc.
Today I finally took it on it's maiden voyage, about a 10 minute drive. After about 7 minutes, I see the pressure going from 40+, to 35, to 30 and when I get home and stop, pressure does the same as with the old engine...check gauges comes on, oil pressure drops to 0, but rises when I rev the engine. And again, no engine noises which I should hear with no pressure.
I will check again with a mechanical gauge. Fresh oil and good filter.
It just seems like too much of a coincidence to have the same exact situation happen again. I mean it's the same as it was when I parked it the last time.
Could it be a gauge problem or wiring problem instead of an engine problem? What should I check?
might start with a mechanical gage huh.
05-24-2017, 01:50 PM
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Nope. First swap used head from original, everything else was from donor. Second swap used original intake, everything else is donor.
I didn't drop the pan on this one, previous owner is a friend, I knew the car, knew he drove it almost daily, and he told me there was no issue with anything, including oil pressure. Guess I was wrong.
I didn't drop the pan on this one, previous owner is a friend, I knew the car, knew he drove it almost daily, and he told me there was no issue with anything, including oil pressure. Guess I was wrong.