COLD WEATHER ISSUE (not sure if it's oil separator)

flyingmachine · #1 01-25-2011, 12:42 PM

It was freezing yesterday and car stopped on highway last evening on my way back home. When it happened, I felt losing power and service engine soon light was flashing. Pulled over and tried restarting it. It didn't want to start and had misfire.

After car was towed back and I pulled the codes, misfire errors as expected(1,2, 3,5) and I also saw ECU and EEPROM checksum errors. I replaced the 2 rubber hoses that go to oil separator about 2 years ago and they still look fine. Could it be oil separator itself that's going bad?

I'm not sure because of the EEPROM checksum error. Could it be something wrong with my ECU and caused the misfire? Or misfire would contribute EEPROM checksum error? If later is possible, then I can make myself believe it's not computer issue.

I visually checked valve cover gasket and I see no sign of oil. I checked oil cap and did see a little tiny bit of white/yellowish stuff(really small like half dime size on cap). Spark plugs were replaced just a couple months back. What would you do to narrow down the issues?

I'm thinking to take plugs off and see the condition and take intake hose(before throttle) off to see if there is any oil in the manifold. And maybe clean MAF at the same time. If I'm seeing oil on both(plugs and inside of manifold), I can assume it's oil separator that needs to be replaced?

Any different opinions about where to look into?

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JCL · #2 01-25-2011, 02:18 PM

It would help if you listed all the actual codes.

Model?

Year?

flyingmachine · #3 01-25-2011, 02:42 PM

Quote:

Originally Posted by JCL

It would help if you listed all the actual codes.

Model?

Year?

I'll check the original codes once I'm back home. I'm using autoenginuity and that's how it interprets the codes pulled.

It's a 01' 4.4

flyingmachine · #4 01-25-2011, 11:29 PM

okay. here are the DTCs

32, 33, 39, 37 for misfire on 1, 5, 2, 3 cylinders
3E for multiple misfires
01 for ECU reset
16 for EEPROM checksum error

Davy_Jones · #5 01-26-2011, 07:08 AM

First check the fuel pump.

flyingmachine · #6 01-26-2011, 11:19 AM

Quote:

Originally Posted by Davy_Jones

First check the fuel pump.

but I don't get the lean error.. if fuel pump is gone, itself would throw error too, right?

Davy_Jones · #7 01-26-2011, 12:38 PM

It was the similar problem with my E39. Misfire errors were among others, but I did not get the lean error also. Just replaced the fuel pump.

flyingmachine · #8 01-27-2011, 03:25 PM

does fuel delivery system on 4.4 X5 have fuel pressure testing port? I don't recall seeing it in the engine bay though.

or anyone knows how to use multimeter to test the fuel pump?

flyingmachine · #9 01-30-2011, 12:54 AM

okay. just got some time to check the issue. I connected my obd tool and test the fuel pump and the fuel pump did run. then I searched again for the fuel pressure testing port and I finally found it. it's pretty obvious though. it's on the fuel rail. I originally thought it would be somewhere before entering into fuel rail. you need to take the top plastic engine cover to see it. it's on the passenger side on the front. so, I hooked up the fuel pressure gauge and use the obd tool to activate fuel pump. guess what... it read only 5-10 psi on the gauge. so, apparently, it's fuel delivery issue now.

it was already late. so, I didn't do any further testing on the fuel pump. first thing I did after back from garage was to order fuel filter online. since the car is already 88K miles. will need to replace fuel filter soon anyways..

plan for tomorrow is to test the fuel pump. since it's still running. I'll try to measure the amp consumption to find out if it's working properly. worst case is... another $300-$400 for the pump.

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