Power/Oil Pressure Drop Off!

[jzak]

Hey Guys,

(Note: It’s worth letting you guys know that I recently bought this CJ5 , and I’m still trying to get the temperature and fuel gauges fixed. One’s not accurate, and the other doesn’t work at all.)


So we had are first truly warm day today, and I took my CJ5 out. The day before I changed out the ignition coil. It seemed to fix my rough idle, and my acceleration issue. I drove it for several miles without incident.

This morning, I got to my regular coffee shop without any problems. After being there for about an hour, I started driving back home. About half way down the road, I started loosing power. I would press on the gas nothing would happen, then after a couple seconds it would start to rev-up again. I was able to get to 55mph, and make it home.

I initially thought I was just running out of fuel, so I drove down to the gas station. I filled it up, and started heading back. It was then I noticed my oil pressure gauge was at 20 psi. I immediately pulled over to check under the hood. The oil level was good, and it didn’t feel like it was overheating.

I was able to putter back home, trying to go as slow as possible 35-40mph. The gas station was less than a mile from my house. The oil psi stayed around 25-30 psi throughout the entire drive. Before today, it was almost always around 45-50 psi. The lack of power was even worse then before, and it started idling rough.

I got home, checked the ignition coil, spark plugs, and wires. Everything seems securely fastened. After letting the engine cool, I checked the radiator, and the coolant level was good. I looked underneath the engine, and I couldn’t find any leaking coolant from the water pump.

Any ideas?? Thanks!!

Josh

 

[Rube83]

I wouldn't correlate the change in psi with running poorly. Someone may argue but I see nothing wrong with 20psi. My AMC 258 i6 / 4.2l is only above 40 when its cold and hovers around 15 when warm. I would also throw a gauge on it to confirm yours is correct. I would say you are having a fuel flow issue.

How close are your fuel lines and filter to a heat source? I have seen many of these items get hot and turn to vapor.

 

[Torxhead]

Since you did get an improvement by installing an ignition coil, I think you should start from there. If you are using the oem style plug on cap, there could be an issue with making contact. Installing a new coil is always a good time to get away from from that style of plug on cap and switch to a coil with screw down connectors, but those plug on caps can be replaced also. This would eliminate a possible problem with connections there. The coil should be getting around 1.35 ohms between the plus and minus terminals also. A bad ignition control module can be another way to make your engine crappy also, it is always good to have an extra one around. Another thing that can make an engine run poorly is a bad pick-up coil in the distributor. Those can be checked with an ohmmeter between the orange and violet wires at the distributor plug. You should be getting 400 to 800 ohms there. Usually a bad icm will be warm to the touch during engine operation if it is bad. I think your low oil pressure is due to the engine running poorly.

 

[jzak]

So after the engine got a chance to cool down, the oil psi went up to normal levels. I guess it's just a oil viscosity thing. Maybe I should change the oil to a heavier weight.

I havent gotten a chance to drive it around, so I don't know if it also accelerates normally.

I really have got to get them damn temp gauge working!

 

[Lumpy Grits]

NEVER trust the OEM Jeep oil pressure gauge.
What weight oil do you run?
WHY did you change the coil?
Make sure all manifold bolts are tight and you have no vacuum leaks.
LG

 

[jzak]

Just switched out my NEW MSD coil, with a NEW Accel coil. Looks like that did the job. The power has improved substantially. I guess i just got a bad ignition coil. Go Figure!

 

[Lumpy Grits]

Just switched out my NEW MSD coil, with a NEW Accel coil. Looks like that did the job. The power has improved substantially. I guess i just got a bad ignition coil. Go Figure!

Hope you got away from that horseshoe clip on the coil.
When you had the MSD in-Did you remove the resistance wire in the firewall loom.
The MSD requires a full 12vdc power.

LG

 

[Hedgehog]

I still believe you are having fuel flow problems. It could be gunk moving around, could be a tired old fuel filter or junk in the tank.

Good point about the coil needing nice clean voltage with the resister eliminated from the system.

Your oil pressure problem is no problem at all. Also remember, if your engine is stumbling around, your oil pressure is stumbling around too.