2006 E90 320d Won't Start

[thomp1983]

Hi all, 

 

A friend has a 2006 320d that won't start, he was driving it last week and it cut out on him and hasn't started since. 

 

I scanned the car with ista and got the following, 

 

 

The only one on there I think is of relevance is the 004351 as it relates to fueling. 

I tested the pump output vs specified in the dde and got 4.9 bar actual vs 500 bar specified so its not building fuel pressure. 

 

Today I removed the fuse pack by the dde unit under the bonnet and the first 20a fuse was blown (the left most one that's missing in the picture) 

 

 

I substituted this with a spare from the fuse box in the glove box, we then tried to start it with no success and I found the same 20a fuse blown again. 

 

Anyone any ideas? My next steps when the owner gets some more fuses is to first check the fuse after just turning the ignition on to see if it's blowing as soon as 12v is applied which I would suspect a wiring issue as the cause. 

 

If it doesn't blow with just the ignition on then ill remove the pumps under the rear seat and check them for debris build up/being blocked and then work forward through the fuel system my thoughts being maybe a blockage is causing the pump to draw too much current blowing the fuse.

 

Thanks

Chris

Edited February 10, 2023 by thomp1983

[Sir Anthony Regents Park]

Sounds like the ECU box might be full of water. The scuttle drains block with leaves and crap, the water can't drain out so it fills the E box on the passenger side rear corner.

 

If it's water damaged it's scrap so you'll needs an ECU, CAS module and key. Shouldn't be hard to find for an old M47 320d. 

[thomp1983]

Afraid not, it's all nice and dry in there. 

Been doing some more research and fuse f01 leads back to a wiring joint that connects 4 or 5 circuits, I'll spilt this joint and measure for a short to ground on each wire on the joint and then see whats on the circuit that shows a short

[thomp1983]

Had a chance to have another brief look at this, this morning. 

Measured continuity to earth at fuse f01 and proved there was a short, followed the red/white cable from fuse holder to where the multiple wires join as mentioned in previous post. 

Split these wires out and found the thin solid red wire was shorted to earth, with this wire left out and all the others reconnected to each other the car now starts. 

Next step is to find a wiring diagram showing the relevant wiring and/or run a scan in ista and see if any other faults have appeared that may indicate which circuit is now not receiving power 

[thomp1983]

Finally got enough time to get this fixed. 

Couldn't find a wiring diagram that matched with what I was seeing in the car so in the end had to use the mk1 eyeball to follow the wiring all the way from the dde box, eventually found it goes all the way around the engine to the electronic turbo actuator, where the wiring plug does a tight turn behind a metal coolant pipe onto the actuator the cable had been rubbing causing the live to short out. 

Reinsulated the cable and I've removed the harness from the clips holding it against the block so it's free to move which should stop it rubbing through again. 

[BobA]

On 17/02/2023 at 13:13, thomp1983 said:

Finally got enough time to get this fixed. 

Couldn't find a wiring diagram that matched with what I was seeing in the car so in the end had to use the mk1 eyeball to follow the wiring all the way from the dde box, eventually found it goes all the way around the engine to the electronic turbo actuator, where the wiring plug does a tight turn behind a metal coolant pipe onto the actuator the cable had been rubbing causing the live to short out. 

Reinsulated the cable and I've removed the harness from the clips holding it against the block so it's free to move which should stop it rubbing through again. 

An excellent piece of ground-up diagnostics. Well done.