4.6 dieing on the road

pb2624 · #1 06-12-2017, 11:09 AM

Hello all,

Long time lurker and just recently joined to participate. Have a 02 4.6 with 145K that died last week showing a P0172/0175 on the odb2 scanner and the Multiplicat errors in the PASOFT scan. I cleared the codes and replaced my MAF and all was fine until this morning when after about a mile it died at a stop light and would not restart. Get the thing home and it will start as nothing is wrong and it doesn't have a SES light. I will run PASOFT again this eve and I have a smoke machine that shows delivery this afternoon, just thought I would get any of the boards inputs before I get home and have to starting figuring out why she is unhappy at the moment. Thanks in advance for any troubleshooting inputs.

CleanIsFast · #2 06-12-2017, 12:28 PM

Need more information about the vehicle. Last time you replaced the spark plugs, fuel filter, fuel pump. Do you have an aftermarket or oiled intake filter? Report back any findings on the smoke test.

Check the connection to the battery, alternator voltage, etc

upallnight · #3 06-12-2017, 03:02 PM

Most likely you have a fuel pump that is failing. Happened to me on my E34 Touring.

pb2624 · #4 06-12-2017, 05:28 PM

My response below in red.

Quote:

Originally Posted by CleanIsFast

Need more information about the vehicle. Last time you replaced the spark plugs (7 or 8k ago when the valley pan was replaced), fuel filter (no record from PO), fuel pump (no record from PO). Do you have an aftermarket or oiled intake filter? (No, all stock) Report back any findings on the smoke test.

Check the connection to the battery, alternator voltage, etc

williamx5 · #5 06-12-2017, 03:21 PM

Good day!

I agree with the above suggestions! It sounds like a classic fuel pump failing... more so if it dies a lot with half a tank or less... pumps usually are better off if submerged in fuel... once that level drops, the pumps trends to heat up enough to stop spinning... once they cool, they work great again...

Good luck and let us know what you discover please!

Cheers!

bcredliner · #6 06-12-2017, 04:53 PM

I would read the codes again as you mentioned doing and do other troubleshooting to confirm the codes aren't misleading. I don't think you know enough to buy any parts yet.

X53Jay4.8is · #7 06-12-2017, 06:53 PM

Quote:

Originally Posted by pb2624

Hello all,

Long time lurker and just recently joined to participate. Have a 02 4.6 with 145K that died last week showing a P0172/0175 on the odb2 scanner and the Multiplicat errors in the PASOFT scan. I cleared the codes and replaced my MAF and all was fine until this morning when after about a mile it died at a stop light and would not restart. Get the thing home and it will start as nothing is wrong and it doesn't have a SES light. I will run PASOFT again this eve and I have a smoke machine that shows delivery this afternoon, just thought I would get any of the boards inputs before I get home and have to starting figuring out why she is unhappy at the moment. Thanks in advance for any troubleshooting inputs.

Yes voltage check first and then look at the possible fuel symptoms. Fuel pumps seem to be a pretty common failure item on these X's past to 100K mark. The throttle actuator/motor is a another one but usually you get some type of code on this one that lets you know its coming.

pb2624 · #8 06-12-2017, 08:10 PM

No DME codes present so I proceeded with a fuel pressure test. The POS HF fuel pressure test showed 110lbs at the rail at idle and dropping slightly when lightly revved. Let the car idle and in 15 -20 minutes and it started to stumble and the fuel pressure dropped to 20lbs then died losing all pressure. Went ahead and had FCP send over a fuel pump and filter so I can change it before the weekend. Now I need to go see why the AC in the 540 is dead. Will update later in the week after parts are installed.

Overboost · #9 06-12-2017, 08:26 PM

Quote:

Originally Posted by pb2624

No DME codes present so I proceeded with a fuel pressure test. The POS HF fuel pressure test showed 110lbs at the rail at idle and dropping slightly when lightly revved. Let the car idle and in 15 -20 minutes and it started to stumble and the fuel pressure dropped to 20lbs then died losing all pressure. Went ahead and had FCP send over a fuel pump and filter so I can change it before the weekend. Now I need to go see why the AC in the 540 is dead. Will update later in the week after parts are installed.

$419 for the pump assembly for the X5 from FCP Euro. I just replaced the Siemens/VDO pump assembly in my E46 for $140 from FCP. It was a "no brainer" PM on the 3 series but at over $400 I might just wait until it quits on the X5. I'm sure I'll catch hell when it leaves the wifey stranded.

upallnight · #10 06-12-2017, 10:11 PM

Quote:

Originally Posted by pb2624

No DME codes present so I proceeded with a fuel pressure test. The POS HF fuel pressure test showed 110lbs at the rail at idle and dropping slightly when lightly revved. Let the car idle and in 15 -20 minutes and it started to stumble and the fuel pressure dropped to 20lbs then died losing all pressure. Went ahead and had FCP send over a fuel pump and filter so I can change it before the weekend. Now I need to go see why the AC in the 540 is dead. Will update later in the week after parts are installed.

Only, time a fuel pump will throw a code is if there is an insufficient pressure which will result in a lean condition will result in lean codes.

A failing or dead fuel pump will not present a DME code.