augielocost
01-20-2007, 04:26 PM
Hi,
I have a 1994 2.5l manual YJ with about 95,000 miles. I've changed all of the fluids since I bought it a few months ago, I run 10W-30 oil. I checked compression and all cylinders are in spec and within 20 psi of one another. My running oil pressure is about 10-40 psi from idle to 3500 RPM. But when I first bought it the oil guage read 0 until I jiggled wires on the block and now it seems to work...not sure how well though.
There are several noises from the engine. It seems to be worse after the first 30 seconds of running, but it is not very consistent. There is a constant noise which I think is the 2.5l engine operating normally and then there is a noise only between 2000 and 3000 RPM. The noise immediately goes away if I accelerate in that RPM range. The noise is there while standing if I rev it up to between 2k and 3k. The noise will suddenly come back if I down shift into the 2k-3k RPM range even if I am not accelerating. I was hoping it was the crappy exhaust.....
I replaced some exhaust components today since they were rusted and some of the noise went away at higher RPMs, but not all. :(
I removed the serpentine belt and the noise is still there. The pulleys on the PS pump and the idler seemed fine after inspection. Not sure on the water pump.
I tried the hose in the ear thing and it's just generally loud (the wind didn't help either). No, I wasn't driving, it was windy outside. I think the noise is more pronounced in the lower part of the engine, or at least I hear more under the Jeep, but the ground also reflects the noise, so who knows.
My questions are:
Could it be the lifters or valves/cam ? How do I tell?
Could it be the oil pump ? How do I tell?
Please tell me it isn't the main bearings. How do you tell if they are bad?
The Jeep had a bad MAP sensor when I bought it and I think the MAP sensor was bad for awhile, but the previous owner only drove it about 2k miles per year for the two years he had it. There was carbon buildup in the cylinders when I tuned it up. I did the SEAFOAM and water thing a few times and changed the oil only after the first 400 miles I drove it. The oil was very black after only 400 miles, it looked more like what comes out of my other car with 180k on it and 5000 miles between changes. I passed emissions after I changed the MAP sensor. Other than the noise it seems to run fine.
Any ideas what to check next?
Does anyone think the Jeep should not be driven until I find out what the problem is?
Thanks in advance for the help.
I have a 1994 2.5l manual YJ with about 95,000 miles. I've changed all of the fluids since I bought it a few months ago, I run 10W-30 oil. I checked compression and all cylinders are in spec and within 20 psi of one another. My running oil pressure is about 10-40 psi from idle to 3500 RPM. But when I first bought it the oil guage read 0 until I jiggled wires on the block and now it seems to work...not sure how well though.
There are several noises from the engine. It seems to be worse after the first 30 seconds of running, but it is not very consistent. There is a constant noise which I think is the 2.5l engine operating normally and then there is a noise only between 2000 and 3000 RPM. The noise immediately goes away if I accelerate in that RPM range. The noise is there while standing if I rev it up to between 2k and 3k. The noise will suddenly come back if I down shift into the 2k-3k RPM range even if I am not accelerating. I was hoping it was the crappy exhaust.....
I replaced some exhaust components today since they were rusted and some of the noise went away at higher RPMs, but not all. :(
I removed the serpentine belt and the noise is still there. The pulleys on the PS pump and the idler seemed fine after inspection. Not sure on the water pump.
I tried the hose in the ear thing and it's just generally loud (the wind didn't help either). No, I wasn't driving, it was windy outside. I think the noise is more pronounced in the lower part of the engine, or at least I hear more under the Jeep, but the ground also reflects the noise, so who knows.
My questions are:
Could it be the lifters or valves/cam ? How do I tell?
Could it be the oil pump ? How do I tell?
Please tell me it isn't the main bearings. How do you tell if they are bad?
The Jeep had a bad MAP sensor when I bought it and I think the MAP sensor was bad for awhile, but the previous owner only drove it about 2k miles per year for the two years he had it. There was carbon buildup in the cylinders when I tuned it up. I did the SEAFOAM and water thing a few times and changed the oil only after the first 400 miles I drove it. The oil was very black after only 400 miles, it looked more like what comes out of my other car with 180k on it and 5000 miles between changes. I passed emissions after I changed the MAP sensor. Other than the noise it seems to run fine.
Any ideas what to check next?
Does anyone think the Jeep should not be driven until I find out what the problem is?
Thanks in advance for the help.