Hard starts - worse the longer it sits

[upallnight]

Originally Posted by Mike1261

Just wanted to come back here to conclude the thread in case anybody else runs across this same issue.

I replaced the Fuel pump with a $70 Amazon special. Fuel pressure was still dropping when sitting.

I replaced the Fuel filter in case something in there was leaking. Fuel pressure was still dropping when sitting.

I installed an in-line fuel check valve by the fuel pump just in case the check valve in my cheap replacement was faulty. Fuel pressure was still dropping when sitting.

I got a set of reman Siemens injectors off eBay for $90, pulled up the fuel rail, and saw cylinders 1, 3, 4 and 5 were all leaky. Not spraying out under pressure or anything like that, but every time I touched my finger to the nozzles there'd be more fuel on my finger.

Replaced injectors.... everything is hunky dory so far.

The hard starting issue was 75% eliminated with the fuel pump replacement, and now with the new injectors it's 100% there. I can leave it sitting for days and it'll start right up, and no longer sounds like it'll stall when first starting. I can turn the key by leaning over from the passenger side and not need to run over to the gas pedal to get it to stop sounding like it'll stall.

I was praying that it would also fix my Front-Bank O2 sensor problem (reading Out of Range) and get rid of the pesky CEL that's plagued me since buying this thing.... No such luck, it came back on after resetting the computer.

Thanks all for the help and advice!

Poster #14 to this thread nailed the diagnosis. You should buy him a beer.

https://xoutpost.com/1186186-post14.html

[upallnight]

As for the front 02 sensor, get a scanner that allows you to view real time data. Look at the voltage for the front 02 sensors. The voltage should be varying widely, if they are not varying widely you got a worn out sensor.

[Mike1261]

Originally Posted by upallnight

As for the front 02 sensor, get a scanner that allows you to view real time data. Look at the voltage for the front 02 sensors. The voltage should be varying widely, if they are not varying widely you got a worn out sensor.

The sensor has been replaced twice (Bosch), so I don't think it's worn out.

I posted a screenshot of the error from INPA on a different thread a while back and someone commented that it was trying to correct a lean condition but unable to get enough fuel so throwing out-of-range error.

I was hoping that 2 leaky injectors in the front bank might have been clogs sticking the valve open but restricting fuel, and replacing injectors would clear that issue up as well. No such luck.

It was suggested in that same thread that there might be a vacuum leak. I haven't gone down that rabbit hole yet - but there is a vacuum line under my intake manifold that's just sitting there disconnected that nobody seems to know what it's supposed to go to...

It would make my year to get rid of that CEL LOL. I'm sure I'll post a new thread on that subject soon. Keep your eyes peeled ;-)

[upallnight]

Here's a Youtube video on the voltage fluctuation for the front 02 sensor in a X5.

https://www.youtube.com/watch?v=zyh_4SktmFM

[upallnight]

Originally Posted by Mike1261

The sensor has been replaced twice (Bosch), so I don't think it's worn out.

I posted a screenshot of the error from INPA on a different thread a while back and someone commented that it was trying to correct a lean condition but unable to get enough fuel so throwing out-of-range error.

I was hoping that 2 leaky injectors in the front bank might have been clogs sticking the valve open but restricting fuel, and replacing injectors would clear that issue up as well. No such luck.

It was suggested in that same thread that there might be a vacuum leak. I haven't gone down that rabbit hole yet - but there is a vacuum line under my intake manifold that's just sitting there disconnected that nobody seems to know what it's supposed to go to...

It would make my year to get rid of that CEL LOL. I'm sure I'll post a new thread on that subject soon. Keep your eyes peeled ;-)

Get a "Golf Tee" and plug the vacuum hose and see if that will prevent the CEL from coming on after you reset the computer.

[upallnight]

Originally Posted by Mike1261

The sensor has been replaced twice (Bosch), so I don't think it's worn out.

I posted a screenshot of the error from INPA on a different thread a while back and someone commented that it was trying to correct a lean condition but unable to get enough fuel so throwing out-of-range error.

I was hoping that 2 leaky injectors in the front bank might have been clogs sticking the valve open but restricting fuel, and replacing injectors would clear that issue up as well. No such luck.

It was suggested in that same thread that there might be a vacuum leak. I haven't gone down that rabbit hole yet - but there is a vacuum line under my intake manifold that's just sitting there disconnected that nobody seems to know what it's supposed to go to...

It would make my year to get rid of that CEL LOL. I'm sure I'll post a new thread on that subject soon. Keep your eyes peeled ;-)

That could be the vent for the front differential. If there's a hook to it and the end is facing toward the ground it is the vent.

For the vacuum leak check the rubber intake at the throttle body. The elbow that connects it to the IAC valve is the most likely to be torn.

[upallnight]

Picture of the vent tube in questiion.

[Mike1261]

Originally Posted by upallnight

That could be the vent for the front differential. If there's a hook to it and the end is facing toward the ground it is the vent.

For the vacuum leak check the rubber intake at the throttle body. The elbow that connects it to the IAC valve is the most likely to be torn.

The vac tube in question is under the intake manifold just forward of the DISA Valve. It's not the one that's by the dipstick for the transmission.

Attached is a pic. Does it look like it would be a differential vent tube? Does that location make sense?

As for the OAC/TB Bellow. I replaced it when I did the CCV system. Previous owner thought using zip ties to fix a torn rubber boots was a good idea?!?!?

[andrewwynn]

After changing any fuel feedback part (O2, MAF), definitely reset fuel adaptations.

[Mike1261]

Originally Posted by andrewwynn

After changing any fuel feedback part (O2, MAF), definitely reset fuel adaptations.

I reset the EM and IM in INPA. Is that sufficient or is there something else that needs resetting?