reset fuel trims; lasted about 60 miles or about an hour

[andrewwynn]

When I rebuilt my DISAs I always wrapped some premium Teflon tape around the seal to make it snug. I used a brand called fastape or fasttape; it's three times as thick as typical Teflon but more importantly it's color changing: turns dark under pressure so you can do a test fit and confirm complete seal.

[andrewwynn]

I had slightly rough idle on both my e53 until I added about 50 rpm to the idle speed then they smoothed right out.

[workingonit]

After reading the above replies, here are my responses, in part:

• 1) a cheap fuel pressure test kit, with multiple metric adapters, is on the way, since local HF doesn't have any, and a thicker Teflon tape is coming, too,
• 3) I still have six cans of carb spray left to further test for leaks,
• 4) I need a better heat source than a cheap soldering iron to rebuild my smoke tester,
• 5) I found a VDO MAF on RockAuto, for $160, a lot less than FCPEuro (if I need to get another), and
• 6) I adjusted my idle speed DOWN about 10 rpm, to 700 in gear, with A/C on, just to try it...my M54 idles smooth anyway, at any rpm

I need to solve this problem soon, since the '04 Chevy 2500HD truck I use has a slight slip in first gear now (but not when tow/haul mode is engaged), so I need to get the X5 reliable if the Lucas Transmission fix doesn't work (again)...it worked for the same issue 25k miles ago. And...

I'm also about to put my wife's Cobalt in a shop, since it's been sitting a year while I replaced pads, shoes, rotors, adjusted the rear drums, bled all the lines, then replaced the master cylinder, and bled the ABS with my Foxwell, and still have spongy brake feel. I need a pro to look at it, I guess. My wife is rapidly tearing up my HHR Panel, so I need to take it back before she destroys it. And...

It's time again, to refresh the A/C on her '98 GMC pickup that she uses to haul her massive purchases of gardening supplies she consumes each spring & summer. She never drives it until then, and there's always something wrong in the A/C system (refrigerant leak, fan resistor, control panel, fan itself, leak again, rinse & repeat....), so I will be expected to fix it immediately. And...

Did I mention that the brakes on the HHR are now showing more wear from her driving it this past year just around here, than would occur when I was commuting to work daily, thru the worst traffic in Texas, in 35000+ miles per year? She stomps pedals. And...

No. For the reasons shown above, she will not get to drive the X5 until I've gotten senile or incapacitated.

[RocketyMan]

Originally Posted by workingonit

After reading the above replies, here are my responses, in part:

• 1) a cheap fuel pressure test kit, with multiple metric adapters, is on the way, since local HF doesn't have any, and a thicker Teflon tape is coming, too,
• 3) I still have six cans of carb spray left to further test for leaks,
• 4) I need a better heat source than a cheap soldering iron to rebuild my smoke tester,
• 5) I found a VDO MAF on RockAuto, for $160, a lot less than FCPEuro (if I need to get another), and
• 6) I adjusted my idle speed DOWN about 10 rpm, to 700 in gear, with A/C on, just to try it...my M54 idles smooth anyway, at any rpm

I need to solve this problem soon, since the '04 Chevy 2500HD truck I use has a slight slip in first gear now (but not when tow/haul mode is engaged), so I need to get the X5 reliable if the Lucas Transmission fix doesn't work (again)...it worked for the same issue 25k miles ago. And...

I'm also about to put my wife's Cobalt in a shop, since it's been sitting a year while I replaced pads, shoes, rotors, adjusted the rear drums, bled all the lines, then replaced the master cylinder, and bled the ABS with my Foxwell, and still have spongy brake feel. I need a pro to look at it, I guess. My wife is rapidly tearing up my HHR Panel, so I need to take it back before she destroys it. And...

It's time again, to refresh the A/C on her '98 GMC pickup that she uses to haul her massive purchases of gardening supplies she consumes each spring & summer. She never drives it until then, and there's always something wrong in the A/C system (refrigerant leak, fan resistor, control panel, fan itself, leak again, rinse & repeat....), so I will be expected to fix it immediately. And...

Did I mention that the brakes on the HHR are now showing more wear from her driving it this past year just around here, than would occur when I was commuting to work daily, thru the worst traffic in Texas, in 35000+ miles per year? She stomps pedals. And...

No. For the reasons shown above, she will not get to drive the X5 until I've gotten senile or incapacitated.

Well if you are for SURE you checked all vacuum leaks, then yeah, I would suspect the MAF next. If you had an issue with the fuel pressure regulator, then it would more likely code fault. Otherwise, I'd be curious what the fuel pressure is at idle. Maybe checking fuel pressure is the cheaper option to check first.

[andrewwynn]

Three e53 brain has no way to know what is the fuel pressure so no way to report an error based on it. You will get random errors that hint at a possibility of a fuel pressure problem.

The fuel delivery is calculated based on assumption that fuel pressure is 50.00 psi. If it's anything else even briefly, the wrong amount of fuel is delivered.

When wife's FPR was defective she would have random difficult starts but other than than rarely ever any problem.

When I finally got the pressure gauge, what I discovered was the pressure at idle would vary with every pulse of injectors (think: water hammer). It only changed about 1/2 psi but so fast it basically made the needle transparent.

The defect was determined to be a 50¢ o-ring (4¢ in quantity). I replaced the whole FPR+fuel filter since they were about 20 years old and 170,000 miles and it would have taken days to source the exact o-ring.

Take a slow motion video of the pressure at idle to see if the needle is dead solid or wiggles. Then the acid test of FPR is to leave the gauge on overnight and determine if it holds pressure.

The other main test is for the pump itself: does the pressure stay constant at WOT. At end of life, the pump won't be able to produce the excess pressure needed to input into the FPR and you'll get a pressure drop at WOT but it holds fine at lower demand.

[workingonit]

Originally Posted by RocketyMan

Well if you are for SURE you checked all vacuum leaks, then yeah, I would suspect the MAF next. If you had an issue with the fuel pressure regulator, then it would more likely code fault. Otherwise, I'd be curious what the fuel pressure is at idle. Maybe checking fuel pressure is the cheaper option to check first.

I can not say for SURE that there isn't a vacuum leak anywhere, but I spent hours looking for it. If the fuel pressure check yields no pertinent info that leads to a solution, then I'll starting checking for leaks, again. Isn't P0313 pointing in the direction of low fuel pressure at times? I'm thinking that somethings not quite right with the MAF, but can't throw $160-$$$ at it, getting a new MAF to test, just to find that the MAF wasn't the problem.

Originally Posted by andrewwynn

• 1) The fuel delivery is calculated based on assumption that fuel pressure is 50.00 psi. If it's anything else even briefly, the wrong amount of fuel is delivered. When wife's FPR was defective she would have random difficult starts but other than than rarely ever any problem...
• 2) I replaced the whole FPR+fuel filter...
• 3) see if the needle is dead solid or wiggles (at idle)...
• 4) leave the gauge on overnight and determine if it holds pressure...
• 5) the pump itself: does the pressure stay constant at WOT?

My responses:

• 1) I've never had a difficult start, random or otherwise, and it idles very smoothly
• 2) the previous owner says he replaced the fuel filter assembly (which I assume means the FPR+fuel filter) less than a year before I got it from him, so odds are it shouldn't have gone bad that fast
• 3) there'll probably be needle wiggling no matter what, from a cheap Chinese gauge; I'd have to step up to a dampened liquid-filled gauge to get a truer picture, wouldn't I?
• 4) that's a good suggestion, I'd not thought about; it should test the O-rings at the FPR and at the injectors, too
• 5) frankly, I'm hesitant to rev the M54 to WOT; it might open a Pandora's box of other problems I don't have (yet)...this X5 is OLD, and retired like myself, not a racecar as in my past

[Effduration]

Originally Posted by workingonit

2) the previous owner says he replaced the fuel filter assembly (which I assume means the FPR+fuel filter) less than a year before I got it from him, so odds are it shouldn't have gone bad that fast[*]]

Last year, I replaced my E39 (M54) fuel filter with a new Hengst brand from FCPEuro.

Hengst is a reputable German brand. And my filter was not made in Asia.

However, I got a defective one, and I ended up with 60psi at the fuel rail and very rich fuel trims...Took a while to figure it out...I posted it on the E39 group and at least one other member had a problem with a Hengst brand. I returned it and replaced with a Meyle (I think).

[RocketyMan]

Originally Posted by workingonit

I can not say for SURE that there isn't a vacuum leak anywhere, but I spent hours looking for it. If the fuel pressure check yields no pertinent info that leads to a solution, then I'll starting checking for leaks, again. Isn't P0313 pointing in the direction of low fuel pressure at times? I'm thinking that somethings not quite right with the MAF, but can't throw $160-$$$ at it, getting a new MAF to test, just to find that the MAF wasn't the problem.



My responses:

• 1) I've never had a difficult start, random or otherwise, and it idles very smoothly
• 2) the previous owner says he replaced the fuel filter assembly (which I assume means the FPR+fuel filter) less than a year before I got it from him, so odds are it shouldn't have gone bad that fast
• 3) there'll probably be needle wiggling no matter what, from a cheap Chinese gauge; I'd have to step up to a dampened liquid-filled gauge to get a truer picture, wouldn't I?
• 4) that's a good suggestion, I'd not thought about; it should test the O-rings at the FPR and at the injectors, too
• 5) frankly, I'm hesitant to rev the M54 to WOT; it might open a Pandora's box of other problems I don't have (yet)...this X5 is OLD, and retired like myself, not a racecar as in my past

Yes, I agree with not throwing money at a new MAF until you absolutely confirmed that it is condemned.

If you don't have a cold-start struggle, that would suggest your FPR is not leaking, I would say--which is good as it appears it's keeping prime. Perhaps it might be worth taking another look at the fuel filter--since you said it was replaced by the PO? Usually when you replace them you can strike the fuel filter a little bit and see "brownish" goo come out with residual fuel emptying out. Now that I think about it, they did have a changeover part on the fuel filter from the earlier 2000's X5 M54s to the later ones.

[EODguy]

There are many MAFS that are sold for our e53's that are actually for the Land Rover. They fit, the connector is the same, but frame holding the sensor is completely different and even though it will work they die usually around a year. Make sure your MAF is for the e53. Also tap on the connector with a screwdriver handle and if the engine stumbles the film is toast.

Over here in Camel land it's a common switch and cheaper to boot, but if it's the Lamb Roller one you would get those readings from a fairly new one that's dying. (approximately 1yr)

Sent from my SM-A730F using Tapatalk

[workingonit]

Originally Posted by EODguy

There are many MAFS that are sold for our e53's that are actually for the Land Rover. They fit, the connector is the same, but frame holding the sensor is completely different and even though it will work they die usually around a year. Make sure your MAF is for the e53. Also tap on the connector with a screwdriver handle and if the engine stumbles the film is toast.

Over here in Camel land it's a common switch and cheaper to boot, but if it's the Lamb Roller one you would get those readings from a fairly new one that's dying. (approximately 1yr)

Sent from my SM-A730F using Tapatalk

This is the best photo I have, and if I read it correctly, it's the proper part.