e53 M57 3.0d 2006 intermittent starting

[AUSBMX]

Hi all,

Hopefully someone can lend some ideas here - I've done a lot of googling/code reading but getting stuck - essentially the car will intermittently crank but not start. It's my mums car, she's already had it at a diesel specialist for 2 months who just charged her $1700 and just changed the glow plugs and starter motor (I said they weren't the problem, but oh well, it does crank a lot faster now @ 250 RPM). Initially I suspected either injector leak rate too high, pressure reg on rail, or the flow control valve on back of HPFP (I'd already checked pre supply pressure looked okay @ 4 BAR +).

After changing the glow plugs and starter the mechanic decided the problem was the pressure regulator on the rail, he also said he couldn't find a new pressure regulator anywhere, and that the rail was damaged somehow where the regulator screws on (no idea how that could happen), so needs a new rail as well. I ended up going to the wreckers and pulling a rail + regulator off a e53 x5 there and sending it up (also took the flow control valve off the wreck as well just in case). Apparently this 'fixed' the problem, and my mum took the car home - it apparently broke down a few times on the way home, apparently losing power on the highway, but she managed to limp it home. It would start fine, but the throttle had zero effect on the engine, and CHECK FUEL INJ SYSTEM would come up on the dash. This problem then randomly disappeared, and she used it for like a week with no problems, then the problems started happening again as before it was sent to the mechanic. She managed to start it the other day, and just immediately drove it to me in Melbourne (3~ hours away), and borrowed my spare car to get home. After she parked it, it wouldn't start, just crank.


Original symptoms: Occasional starting problems, both hot and cold, but more common hot. Usually can just try again in 10 seconds and it will start fine and drive fine with typical power level. Sometimes multiple hours wait before it will start, however always once started there is no problem, even under high load (100% throttle). Occasional problem started ~12 months ago, but was very rare (ie once every few months), however has got increasingly common, now every day.

Battery is near new, fuel filter was replaced ~12 months ago.

I've got ISTA+, so I've looked at all the fault codes and taken a few videos monitoring Rail Pressure for successful starts, and unsuccessful starts.

This is the faults that come up after initially clearing all faults, and starting successfully and taking for ~5 min drive (including some 100% throttle).https://drive.google.com/file/d/1rrI...ew?usp=sharing

1A IHKA: Relay, heated rear window (think this is just a bad relay in cargo area)
BD IKE: Electronic braking-force distribution (No idea what's causing this, but some googling suggests its common and may be a bug)
4212 DDE: Glow plug, cylinder 1 (these were just replaced recently, but I don't believe in these temperatures (Melbourne Australia) we ever really need glow plugs).
54C6 VTG: Oil Wear (Probably legit but unrelated to the actual problem, I've got a bottle here to put in when I get around to it).

A video of the start+short drive of while monitoring fuel rail pressure in ISTA+ shows basically as you would expect: https://drive.google.com/file/d/1VIH...ew?usp=sharing

Can achieve ~1600 BAR rail pressure no worries.

Now after driving, parking, and turning off engine, I crank and fail to start 3 times:
https://drive.google.com/file/d/1z19...ew?usp=sharing

Oddly the rail pressure doesn't budge off of the pre supply of ~4.3 BAR all 3 times even while cranking at ~250 RPM. Another oddity is before cranking the rail pressure seems to digitally jump between 2.1 and 4.3 BAR occasionally. Is this just poor pressure resolution at this low pressure? Maybe dodgy pressure sensor/wiring/DME? Although I believe there is some logic that would flag a faulty pressure sensor and throw an appropriate code.

To rule out any battery issues, I also monitored battery voltage while failing to start: https://drive.google.com/file/d/1Mti...ew?usp=sharing
Initially voltage before crank: 12.7V, and drops to 11.2V while cranking at 250 RPM, which seems pretty good to me, back to 12.4/12.5 after finished cranking. Note I've got a trickle charger on the whole time while I'm messing around with this.

I have noticed in the past a bunch of error codes like "IKE: No CAN identification (DME)", "IKE: EGS signal line disturbed", and "No message, receiver EGS, transmitter DME-DDE" - but I think these are likely just due to messing around trying to start without a battery charger for extended periods of time and probably just due to low battery voltage.

I've checked all the fuses in the glovebox and electrical box under the bonnet, all good there. Perhaps an intermittent relay... I can clearly here the fuel pump relay clicking in the glovebox when I use the Prime function on/off in ISTA+, but I haven't investigated any relays further.

So after failing to start a number of times, these are the error codes I get:
https://drive.google.com/file/d/1yyI...ew?usp=sharing
S0017 No communication possible with: Multifunction steering wheel (However the volume controls still work and cruise control controls?)
1A IHKA: Relay, heated rear window (Same as before)
BD IKE: Electronic braking-force distribution (Same as before)
S0046 No communication possible with: Telephone
4212 DDE: Flow plug, cylinder 1 (same as before)
4B90 DDE: Rail-pressure monitoring on engine start (makes sense...)
54C6 VTG: Oil wear (same as before)

It should be noted this failing to move from 4.3 BAR while cranking seems to be new, when I've looked at this in the past it would rise up to ~70 BAR and then fall again while still cranking, but I didn't manage to record the screen. Here is an older recording before the replaced starter motor: https://drive.google.com/file/d/1Bb3...ew?usp=sharing


I just went out to try to reproduce the problem but it started fine like 20 times in a row, at one point the car stoped cranking entirely though, ie when you turn the key to make it crank, nothing happens - no relay click or anything. Repeated turning fully off, and trying again didn't do anything, even removing key entirely and reinserting, finally I removed key, locked and unlocked doors and then it worked and started as normal. Also no extra error codes appeared after this - might just be some internal protection due to trying repeated start/stop events while I was trying to get it to fail to start.

Other things I've checked are a smooth running test, and all injector values are easily in the acceptable range, so don't think it could be crazy injector leak off.

Any ideas where to look? Sorry for the wall of text, hopefully it makes sense!

Edit: Forgot to mention, currently ~ 3/4 full of diesel at the moment.

[wpoll]

#1 - the glow plug controller is probaly causing the glow plug issue - should have been replace along with the glow plugs. and BTW, the glow plugs are part of the correct running and emissions system and used for more than just cold starts. But that's not your problem.. so...

Intermittent ignition switch contacts? The instance where there wasn't even a crank seems very odd...

[Clavurion]

You said that you had checked the supply pressure being 4+ bar. So did you measure this or rely only on the diagnostic rail pressure value? Like you suggested the rail pressure sensor and circuit is very inaccurate on low pressures like under 10 bar. These have the old style inline fuel pump on the supply side but no monitoring for supply pressure like on the older M57 (DDE4). On those situations the vehicle doesn't start can you hear the inline fuel pump activating when you turn ignition to pos.2?

[AUSBMX]

Originally Posted by Clavurion

You said that you had checked the supply pressure being 4+ bar. So did you measure this or rely only on the diagnostic rail pressure value? Like you suggested the rail pressure sensor and circuit is very inaccurate on low pressures like under 10 bar. These have the old style inline fuel pump on the supply side but no monitoring for supply pressure like on the older M57 (DDE4). On those situations the vehicle doesn't start can you hear the inline fuel pump activating when you turn ignition to pos.2?

Only using the diagnostic rail pressure, and I guess by pulling the feed line (clear tube) to the HPFP and it squirted out at a... reasonable pace. I actually just ordered an analogue pressure gauge to check this.

I'm struggling to remember if I can hear the inline pump when it fails now, I just tried recently to get it to fail to start, but it started every time. This was just after I pulled all the relays from the electrical box under the bonnet and the ones in the cargo area and bench tested them (all good) - maybe one is occasionally failing/bad contact. I'll try to make a note of the noises next time. Is the in tank pump used when the tank is almost full? Just so I can rule that out and focus on the inline one.

[Clavurion]

Both fuel pumps get supply via the same K96 relay. So both pumps are active when ignition is on pos.2 but if there is over half tank of fuel the in tank pump is not actually needed. But if inline fuel pump fails there is not enough supply to HP pump and it will reflect on rail pressure.

https://www.pss-autosoft.net/diagram.../E53_EK96A.htm

[AUSBMX]

Originally Posted by Clavurion

Both fuel pumps get supply via the same K96 relay. So both pumps are active when ignition is on pos.2 but if there is over half tank of fuel the in tank pump is not actually needed. But if inline fuel pump fails there is not enough supply to HP pump and it will reflect on rail pressure.

https://www.pss-autosoft.net/diagram.../E53_EK96A.htm

That's the one above the fuse box right? Need to remove glovebox for access. I haven't checked that yet - but I could definitely hear it clicking when I was using the prime fuel pump function in ISTA. However it might not be clicking when it fails to start, I'll remove the glovebox and check tomorrow.

I was just having a look at the old pressure regulator (rail+reg from the wreckers on the car now), I can't seem to get it to energise when supplying 12v to it, resistance across it is ~4.3 Ohm. I hooked a small tube up to the end of it, and my compressed air, seems like it's sealed when non-energised - is this correct? I seem to recall reading in in some literature (here: http://www.londonroadgarage.com/imag...kg&LMCL=UUXura) that it is the other way around.

The pressure-regulating valve is pulse width modulated by the DDE, the
more that it is activated the higher the increase in the rail pressure.
If this component is disconnected, no rail pressure is built up and the engine
will stall and not start.

[Clavurion]

Originally Posted by AUSBMX

That's the one above the fuse box right? Need to remove glovebox for access. I haven't checked that yet - but I could definitely hear it clicking when I was using the prime fuel pump function in ISTA. However it might not be clicking when it fails to start, I'll remove the glovebox and check tomorrow.

I was just having a look at the old pressure regulator (rail+reg from the wreckers on the car now), I can't seem to get it to energise when supplying 12v to it, resistance across it is ~4.3 Ohm. I hooked a small tube up to the end of it, and my compressed air, seems like it's sealed when non-energised - is this correct? I seem to recall reading in in some literature (here: http://www.londonroadgarage.com/imag...kg&LMCL=UUXura) that it is the other way around.

Yes, that relay is above front fuse panel.

My understading is also that rail pressure control valve is open on rest state and closed with PWM. Though I have not personally tested this.

[AUSBMX]

Good news! I managed to get it to fail again. Quite interesting series of events.

Tried a number of times sitting in the driveway and it always started. Took it for a 10 minute drive, and no problems. Back in the driveway, and before even attempting to start again, I checked for any new error codes - I get the following new ones: https://drive.google.com/file/d/1gHr...ew?usp=sharing

F6 IKE: No CAN identification (DME)
F5 IKE: No CAN identification (ASC)
F7 IKE: No CAN identification (DME)
5140 No message, receiver EGS, transmitter DME-DDE

So these messages aren't just due to 'low voltage' cases from cranking too much. At this point, I'm like - I bet it won't start now.

But what do you know it starts... I turn it off, and try to start again (can clearly here fuel pump running in both cases), and while still monitoring rail pressure in ISTA (in the same recording), it fails to start: https://drive.google.com/file/d/1LmI...ew?usp=sharing

(Fail start attempt begins ~38 seconds in, successful start at beginning, some more fail attemps afterwards with longer cranking)

I see the same behaviour I mentioned previously, RPM goes up with cranking, rail pressure gets to about 70 BAR, then decreases while still cranking. At some point I loose connection to the DDE with ISTA when I try to start again. To reiterate, I can definitely hear the inline fuel pump running even when it fails to start.

After these start fails, I have some extra new error codes to (as well as the previous ones): https://drive.google.com/file/d/1chZ...ew?usp=sharing

D35C DSC: No message (transfer case 192)
5141 No Message, receiver EGS, transmitter DSC
4B90 DDE: Rail-pressure monitoring on engine start
53FF VTG: Supply, control unit: terminal 15

So definitely some electric shenannigans going on. I'll go pull and replace the relays in the ebox under the bonnet again and see if that fixes things. The other possibility is the ignition switch as suggested earlier, but I don't have any other the other symptoms (dash lights doing weird stuff).

Edit: So I didn't need to pull any relays to fix it, simply clearing all the codes and it started with no issues a number of times. So it seems possibly while driving with higher vibration level or something some communication issues start happening.

[AUSBMX]

Might be a bit premature, but I changed over the ignition switch today (as that kept coming up when searching about weird electrical issues, however the common visor test type stuff I didn't have), and it seems to have solved the problem. I'm not getting any of the weird communications faults I was before after driving.

For reference, I could see nothing on the ignition switch to suggest it was faulty, all the pins looked fine. I did give the connector a blast with contact cleaner but nothing obvious visible.

I'll post back if symptoms reappear but I'm feeling hopeful.

[AUSBMX]

Okay I'm back, turns out the ignition switch didn't solve all the problems - although there isn't any weird communication errrors anymore in the fault codes, so thats a bonus.

I'm certain the intermittent no start is a low pressure problem. When I can get the car to fail to start, if I unhook the low pressure pipe quick connector under the bonnet nothing comes out (obviously squirts out when it does work). The relay for the fuel pump is fine, bench tested it, and also monitored all the pins live, and they function correctly even when the car fails to start - this seems like the DDE and computer side of it is totally fine to me?

The inline pump however runs fine when I hook it up to a 12v battery, I measured the voltage at the pump connector and it gets ~11v (bit low, and down to ~10v while cranking) - this is with the actual pump disconnected.

Resistance across the pump terminals is 1.1 Ohms, but 0.5 ohms of that was wires+multimeter leads, so only ~0.6 Ohms which seems a little low? Only thing I can think of is sometimes the inline pump just fails to generate pressure/partially shorted motor. Obviously realised I can't use the rail pressure to check the pump functionality, as even with the pump disconnected it still reads 2.1 or 4.3 BAR, so just doesnt have the resolution at low pressure.

Any ideas besides just buy a new inline pump? A little confused as I would have thought you would notice an issue while actually driving the car if it was faulty.