Rough idle, stall, misfire problems.

[upallnight]

Originally Posted by ahair121

So I just bought a 2003 X5 4.4i for super cheap (206,000 miles on it). Daughter inherited it from her father who passed away. She drove it to her house and it sat for close to a year. When she went to start it for the first time it ran rough and died. So I thought I'd give it a shot. From what I've been able to see he took care of it and had it serviced regularly. Before he passed he had all the cooling lines and the engine gaskets replaced.

First thing I did was pump all the old gas out of the tank and I put in 5 gallons from Chevron with two bottles of sea foam. I also replaced the fuel pump. I took out all the old spark plugs (which were wet with fuel) and put in new NKG plugs. I've tested both crankshaft position sensors with my multi meter. When I touched them to my wrench they didn't go all the way to 0, but I think it was .04 so probably fine right? I cleaned the throttle body (which already looked pretty clean) and the MAF. I also charged the battery.

When I start the car sometimes it'll start strong then quickly idle rough below 1,000 rpm, sometimes it'll backfire once from the intake while starting. If I pump the gas it won't really make it much higher than 2. If I unplug the MAF I can get the RPM's high and hold, but once I let off it dies right away. I replaced the MAF with a reconstructed Bosch from O'Reilly but the same thing happens. The OBD reading shows on both MAF's 10 g/s and it'll quickly dip to 6 for a second then back to 10. So I might have been lucky and gotten a bad MAF, but I'm hoping I can get some more direction from you guys on what other things I should try next.

I'm not a mechanic, but I'm mechanically inclined and I've done head gaskets, I brought a 2001 330i back to life by reading forums and watching YouTube. So I can follow instructions real well, but not experienced enough to diagnose. If you guys can just give me more ideas of whats wrong that will help me out a lot. In the mean time I'll keep searching through forums.

Codes I'm getting
P0343 Camshaft Position Sensor "A" Circuit High
P0363 Misfire Detected - Fueling Disabled.

There's your problem, you went to O'Reilley and bought a reman BOSCH and not a genuine Siemens.

[Overboost]

Originally Posted by upallnight

There's your problem, you went to O'Reilley and bought a reman BOSCH and not a genuine Siemens.

^ This. Get a Siemens/VDO MAF from FCP Euro. Too many stories about the cheap MAF sensors causing all kinds of issues.

https://www.fcpeuro.com/products/bmw...em-13627567451

[ahair121]

Originally Posted by Overboost

10 g/s is way too much at idle. It should be around 3-4. Turn off all electric devices (AC, radio, lights) and check it again. You could try unplugging the MAF and it will default to a throttle position map. This will light up your dash like a Christmas tree but if it runs, it will let you know if your MAF is at fault.

If I unplug the MAF I can hold it at 3/4+ RPM smoothly, but as soon as I let off the gas RPM's drop and it immediately dies.

Originally Posted by upallnight

Since the misfire code is still in the same cylinder after the swap, the next thing to do will be to look at the plug and do a compression test. What type of scanner are you using? Are you sure the unit for the MAF is set for G/S and not lb/M?

Yes I'm going to do a compression test this week, hopefully tonight. I'm using OBD Fusion and it says g/s. When I use it on my 330i I'm getting 3 or 4 on idle, but on the X5 its 10. Sounds like I need to get the Siemens.

Originally Posted by Overboost

^ This. Get a Siemens/VDO MAF from FCP Euro. Too many stories about the cheap MAF sensors causing all kinds of issues.

https://www.fcpeuro.com/products/bmw...em-13627567451

Yeah this makes sense, I was just excited that I found the cause and didn't want to wait for FCP to ship me a new one. I will get one on order, but I have a feeling it's not the only thing wrong. I should still be able to idle with it unplugged right? I can get rev my engine high with it unplugged, but as soon as I let off the gas it dies. I also need to figure out why it's flooding. Could bad gas still be in the system (assuming 1 year old gas is bad)? I pumped the old gas out from the two holes under the back seats where the fuel pump is, but I don't know how long the car would need to idle to burn out any fuel already in the engine and fuel lines.

[ahair121]

Originally Posted by Overboost

^ This. Get a Siemens/VDO MAF from FCP Euro. Too many stories about the cheap MAF sensors causing all kinds of issues.

https://www.fcpeuro.com/products/bmw...em-13627567451

Actually for my car these are my options: https://www.fcpeuro.com/BMW-parts/X5...03&m=227&e=188

BOSCH or BREMI

BOSCH is good through right?

[Overboost]

Originally Posted by ahair121

Actually for my car these are my options: https://www.fcpeuro.com/BMW-parts/X5...03&m=227&e=188

BOSCH or BREMI

BOSCH is good through right?

Sorry, I have a LCI facelift 2004 3L. Of those choices you listed, I would go with the Bosch not the Bremi especially for only a $15 difference.

Yes, I believe it should idle with MAF unplugged, I have seen guys running their E46's unplugged for weeks but again, I do not know the 2003 4.4 system to give you a solid answer. I would look towards an intake leak somewhere in the system causing the stalling but get the new MAF installed and go from there.

[upallnight]

Originally Posted by Overboost

Sorry, I have a LCI facelift 2004 3L. Of those choices you listed, I would go with the Bosch not the Bremi especially for only a $15 difference.

Yes, I believe it should idle with MAF unplugged, I have seen guys running their E46's unplugged for weeks but again, I do not know the 2003 4.4 system to give you a solid answer. I would look towards an intake leak somewhere in the system causing the stalling but get the new MAF installed and go from there.

E46 and an X5 with a 4.4 are two different animals. One is a V8, the other is an inline 6. A common intake leak on 4.4 engine is the CCV at the rear of the intake manifold.

[ahair121]

Originally Posted by upallnight

E46 and an X5 with a 4.4 are two different animals. One is a V8, the other is an inline 6. A common intake leak on 4.4 engine is the CCV at the rear of the intake manifold.

Yes I've seen that in other posts. I'm going to look into that too after work today. I can see that going out after sitting for a long time. It was probably already on its way out before she parked it. I kind of wish it was a 3.0 because I know a lot more about that engine, but I'm excited for the new challenge.