X5 35 diesel Hard Start

[bluefish7]

Looking for advice on next steps for 2010 X5 35 diesel, intermittent hard start. Diagnostics have been run by two dealerships in Atlanta, checked out low pressure fuel pump and rail pressure control valve and they are ok. Next they suggested checking volume control valve but intake manifold would have to come off. One of the dealerships just wanted to throw a new high pressure fuel pump at it, but figured that since I have it at home, could possibly check out volume control valve if I have reasonable success as a DIYer? Thanks

[Greydog]

Hi Josh

Welcome to the Forum

Dealers can be great at throwing OUR money at problems they should be able to fix!!!

Do you have access to a diagnostic program? If not a copy of INPA/INSTA on a lap top or BMW 1.4.0 are a great help and not horrendously expensive Foxwell also have some excellent readers but a little more expensive. If you use a code reader with www.newtis.info a BMW Technical information site (Dealers use this same information) for repair and replacement of stuff and have reasonable DIY skills you should be OK. Use www.realoem.com to make sure you have correct part numbers when replaceing stuff just put the last 7 digits of your Vin into the search box it will bring up your model.

When you say hard start does it crank but no start or is it lazy cranking? if it's cranking well it could be an intermittent fault with the crank sensor as the dealer has indicated fuel pressure is OK.

I hope the information helps

Dave

 

[bluefish7]

Thanks for the tips, I have been to Newtis but only have a OBDLink MX+ for reading codes, I guess I should look into a better program for my X5, 2000 328i, and 2017 Wrangler if I'm going to keep weekend warrioring.

Condition is a real lazy start, like 3 or 4 seconds of cranking and a few times it has just failed to start. Repeatedly in the last few days, I've been able to start it but when I get about 2 blocks away from my house, the car acts like it is being thrown from 3rd gear to 1st gear, or starved for fuel. It recovers quickly and then I have a chassis/stability control malfunction light after that for the duration of the drive, this resets itself every day so it is brought on by that event.

I have seen a lot of folks post about the fuel relay issue but that is for gas engines and so I have been ignoring it.

No other CEL or codes that I can tell, dealerships did not see fuel rail codes, at least were not present at the time.

Thanks

[Greydog]

Hi Josh

A general code reader certainly wont read all the control units, your diesel has a a fuel relay as well worth checking, as are the glow plugs controller and relay. A BMW specific code reader will be a help with the 328i as well. I use BMW 1.4.0 and it finds everything and in English to

Two things come to mind from your description (1) starter motor, if the starter is on it's way you could be getting massive current draw at start killing the battery then once started you get malfunctions due to low battery voltage. So check the current draw at start use a clamp Ammeter there are cases of 900+ amps being drawn by failing starters. My thinking is dealers tend to hook up to power boosters as they do a lot of diagnostics engine off.  (2) What is the battery condition/age as a dying battery can give similar symptoms.

Dave

 

 

 

[bluefish7]

The battery was actually just replaced, unfortunately it was not reprogrammed until a few days afterwards, the foot control module reared its head and was replaced and the new battery was programmed I think all in July. From what I'm hearing about the car, it has been a long time with these hard starts though before the battery was replaced, it was my parents car until last week.

I guess one way to check your theory would be to start the car and let the battery fully recharge before driving out (maybe 25 min?) and then see if the engine rears back like it has been doing.

For the BMW 1.4.0, where do I get that? Also would need to pick out an OBD cable for this laptop, assuming it would be OBD2 to USB?

Also, do you have a preferred Fluke Ammeter for this type of job? Thanks

[Greydog]

If the battery wasn't registered to the car it quite possibly hasn't been receiving a correct charge. I would start by hooking up a good charger/battery re conditioner for as long as possible. I use a Ctek MXS 5 I still hook up my X5 once a month over night. If you don't have a charger then start the car and let it run to charge as you already worked out.

A healthy battery should test as 12.8v ignition off around 14v engine running/charging.

The slow/hard start could have been the original battery dying then continued as the new battery wasn't registered to the car. The original battery should have been 70ah AGM 800cca or something close. 

The diagnostic program I use is BMW 1.4.0 it comes with all the leads to connect to the car BMW INSTA/INPA like wise both programs are easy to find online INSTA is the most comprehensive being Garage quality in all the functions available but 1.4.0 has served me well.

Hope this helps

Dave

[bluefish7]

Have you ever replaced a high pressure fuel pump? Service tech manual says to put this blocking in the transmission but there is also a special tool that goes in the crankcase so I'm wondering if both are necessary.

[Greydog]

Hi Josh

Sorry my diesel experience is limited my X5 is a much simpler V8 petrol 

On newtis they often give a part number for the special tools if you click on the part number a picture or description comes up which may give more clues.

Dave