2000 4.4 Problems Starting

[noncom23]

Great analysis! Can't wait for the verdict.

[supersteve]

OK... So far so good after switching the DME relay with the Headlight washer relay (Blue relays in the Engine Electronics Box). Starting every time and no "auto shut offs."

I have also done some more reading.

The connection between the DME and Starter is to hold the starter in Auto Start. It's not a signal to the DME.

Also, the Engine Electronics Box has a cooling fan. It draws cabin air into the box for cooling. Like most electronics I suspect if the cooling fan is not working properly, neither will the electronics.

The fan has a niffty feature which makes it easy to test. On start up the fan comes on for a moment to prevent the bearings from seizing over long term. Pull the cover, have someone else start her up and the fan should come on then shut off.

If that doesn't work, the fan is supposed to have 12v to it at all times. The DME has a temp switch which gives the fan a ground to turn in on. Check for 12v on the plug to the fan. You can also put 12v to the fan to see if it spins.

The only way I can think of to test the temp switch is to heat up the DME in some way. I just can't think of a safe way to do that. Any ideas?

If the fan tests good and the problems come back, I can say it is an absolute, defininte, maybe that it's the Ignition switch.

[sf_mike]

So, this morning was the worst time I've had yet. Was a half hour late to work because my car wouldn't start. In any case, I tried for about 10-15 minutes, then got the toolkit and tried switching the DME relay with the headlight washer relay. The problem is still happening after switching the relays, but at least it started on the 4th or 5th try (vs. not even coming close to starting). I'm going to take a look at the fan when I get some more time this weekend.

I also took it to my indy shop last week, they ran a number of tests and didn't come up with anything. They did however, come up with a few different service bulletins. The first was 13 50 02 which is "Intake Air Boot Loose" which applies to 4.4. and 4.6 up to 7/25/02. This is located between the mass air flow sensor and throttle body. On mine there was no evidence of leakage, but they refit it because it looked "loose". The other was 12 04 01, which applies to production dates before 11/99 (not me). This bulletin applies if you have FC 164 in your DME. They went ahead and updated the DME in any case, but this didn't do anything either.

Anyone think it could be something related to MAF sensor? That seems to be another thing that has come up in a few of the other threads on other boards.

On another side note, before they reprogrammed the DME, I had Fault Code#40/Bank 1, which is cat converter insufficient conversion error. From what I understood, this error is thrown when the oxygen sensors on either side of the cat don't record a large enough change in emissions. They said my cat might be going bad, but that would be a big surprise to me because I only have 75K miles and passed emissions with flying colors less than 2 months ago. This also went away when the DME updated which was strange (indy shop had no explanation... I'm wondering if it's a software glitch, or glitch with O2 sensor) I only bring this up because I've seen similar issues posted by a few people that had the starting problem. Could just be another common problem.

[supersteve]

Disclaimer: I only know what I'm about to say from experience and recent reading up on this FI and Ign system. I haven't been formally trained on Bosch products. The information your about to read may only be worth what you paid for it. But it makes sense to me.

The MAF sensor doesn't do anything during starting. The DME uses the Ambeint Air Temp (the one displayed on you inst cluster) for starting. The inst cluster forwards the value to the DME for starting only. I proved it to myself the other day. I pulled the entire tube out, MAF included. It started and died right away.

After not starting for 10-15 mins of cranking you may have been a little flooded. It leads me to believe, since it did actually start, swapping relays at the very least helped.

Has the problem come back since switching them?

Additionally, I have found several Vacuum leaks since I started trouble shooting the problem. Specifically, the Blue hose running from the vacuum switch to the secondary air pump, the white hose running from the vacuum res to the vacuum switch, and the oil drain line from the air/oil separator. I suspect you may also have some vacuum leaks.

Vacuum leaks cause the DME to think the engine is pumping more air than the MAF is sensing. It is being told by the O2 sensors it has a lean mixture. This causes the DME to operate out of the "closed loop" giudelines programmed into the DME. This causes the DME to enrichen the mixture; But, only after the 2-3 second start up.

Closed loop means the values being sent to the DME are within the parameters the DME is expecting to see. It can go to sleep because everything else is doing it's job. If the values are out of the parameters (open loop) the DME has to work very hard adjusting spark timing and fuel mixture

I don't think your starting problem is a result of the fan. For the first start of the day your Electronics Box should be stone cold. I would only suspect the fan if your problem consisted of running on a long trip, shutting it off, and then it not restarting or for the "Auto Shut Off" feature.

If the relays haven't fixed it I would start looking at the ignition switch.

My two cents.

[Haroon97]

Hello everyone. New memeber here. I made my purchase of X5 2002 back in Jan of 2006. Great car, very nice ride. However, lately having problem starting the car. I have read a few of the comments, and even managed to open the battery and have it recharged. It seems to be another problem. Any ideas? Plus, is there a repair manual for X5?

[mrbmwx5]

On My X5 Had This Problem Too. First I Thought It Was The Alternater , But I Foul Out It Was The Neautral Safety Swich Gone Bad, It Located On The Right Side Of Transmission(@ Dealer It About $75.00 For The Swich) It Bolted On By Two 8mm Screw.

[supersteve]

Haroon97,

What flavor is your X5. 3.0 or 4.4?

Does it crank and not start or does it not crank at all?

[mrbmwx5]

Originally Posted by supersteve

Haroon97,

What flavor is your X5. 3.0 or 4.4?

Does it crank and not start or does it not crank at all?

2001 3.oi it crank but don't start,and sometime it crank crank crank and sometime it start.

[supersteve]

I don't think it's your neutral saftey switch. The NSS will not let it crank unless it's happy. Another way to test it is the next time it happens take the trans from Park to Neutral. If it starts it could be the NSS. It could also be a sticking relay.

We all have been chasing this problem. Mostly 4.4's though.

First thing you need to do is see if you have any codes. Go to Auto Zone they will read you OBDII codes for free. Any of the sensors or rheostats in the system will throw a code. None of the relays and most of the switches won't. A wiring problem is anybody's guess. Then go back to page one of this thread and start reading.

I'm working on a post that will recap everything we have all done. I won't be able to post it until later this week.

[supersteve]

Ok, I'm going to try to put the last seven pages into one post. I'm going to list all the items related to the fuel and ignition systems I and others have posted on this and other forums.

First it's the things that have been checked that will throw a code. Then it's things that won't. Last it's things in the system that haven't been touched on yet. If I leave anything out, I'm sorry. Please add it on. Here goes it.

Code items:
-Crank position sensor = wouldn't start or run at all. Code.
-Cam position sensor = throws a code.
-Throttle position sensor = code and failsafe mode (limits the engine to about 1300 rpm)
-Mass airflow sensor. Starts then dies. Code.

Non code items:
-Battery voltage and capacity. 13.5v 750cca
-Fuel filter and pressure regulator. (50 psi @ fuel rail)
-Vacuum leaks. Blue hose and white hose on top of engine to/from vacuum switch. Oil/air separator drain line.
-Corrosion on electrical connections. Power supply lug on driver side fire wall. Main engine ground. All starter connections. Ground behind engine electronics box.
-Found outside air temp probe stuffed up in the headlights.
-Switched green relays.
-Switched blue relays.
-Ran over 100 gallons of gas with fuel system cleaner.
-Switched keys
-Changed spark plugs
-Checked electronic's cooling fan
-Cleaned fuzz off crank sensor.
-Cleaned fuzz off cam sensors.
-DME reprogram.
-Changed brand and station of gas

Things that could cause problems and haven't been changed or swapped
-Ignition switch
-Dual water temp sensor
-Wiring

I think this is everything. If it's not please let us all know.
Happy Motoring.
Steve