N47D20 120d no start. Where to?

[KwS 2425]

Cold kills batteries; its the most profitable time of the year for battery suppliers for a reason.

[Cammsport 390]

I think a new battery is in order either way. Its almost 10 years old, undersized and negative temperatures. I'll get a new Varta F18 from Battery Town tomorrow. Not a bad innings considering the average lifespan is 5 years according to forums. Doesn't seem to have IBS either. 

If this honestly fixes it, you'll hear the sigh of relief from your place. 

[Palazzo 477]

At 10 years old and negative temps, I believe you’ve found your problem. Hope so.

[Cammsport 390]

New Exide Extreme. 750 CCA, 80ah. 14 degrees outside. Ive checked the injectors are getting a signal. Back to the drawing board 😓

I got the fault codes below after connecting the battery and firing up ISTA. Weirdly, the 4 bottom codes look to have come up 2kms before it's final rest. The car is currently at 169,178kms and hasn't driven since the start of this saga. 

I cleared them, disconnected ISTA, ignition off, attempted start of the car, connected ISTA, no fault codes showing now. But still, no start. 

I'm getting the exclamation mark and CEL when I press the ignition, but no fault codes on ISTA or the OBC (after I cleared them the first time).

That throttle body fault is bugging me. I ran through the ISTA diagnostics for it though and it all checked out OK. So maybe it's a battery disconnect/connect thing that upsets it? 

Unsure where to go from here. Compression check and timing? Biggish jobs with having to remove the injectors and the valve cover (after removing all the stuff on top).

[Cammsport 390]

Service plan for the throttle actuator fault code, assuming it wasn't battery disconnect related. 

[Allanw 1071]

Assuming you didn't buy from a dealer?

That last vid: It still winds with no real compression spikes intially (like the plugs are out, or the valves aren't closing, soz!), then sounds not regular enough for a 4 cylinder cranking at that speed. 250 rpm should kind kind of enthusiastic.

can you check the timing via the hole from the cam sensor and the crank mark?

I still reckon a compression issue: head gasket massively blown, bent valves or a valve train issue like a slipped chain or cam pulley. Timing off may explain the camshaft code too, because the DME may not be seeing the signal within the required window of crank sensor signals, so treats it as implausible.

Pretty sure you'll be taking the rocker cover off at least ☹️

I'd be a little concerned about additional damage if it did start...

[Cammsport 390]

Yea private sale. And I don't *think* she put me wrong. My friend collected it and had no issue for the couple of days he had it. No chain noise. Quiet as a diesel can be. 

I'd be interested to hear what a N47 sounds like with the injectors unplugged. I feel like it's cranking fine considering there's nil help from combustion. 

I'll prep for valve cover off 🤦 Like I said earlier, I don't feel like it's anything catastrophic because it drove 450kms with stops in between, no worries. No laziness to it at all and ran fine. I'm sure it's a sensor/DDE/electrical fault. Whether that's induced by the negative temperatures or pure bad luck, who knows. 

[Lubed 55]

Are your injectors activating while cranking? The DDE will not pulse injectors until a specific fuel rail pressure is reached and you  mentioned  a fuel leak in an earlier post. Is it possible you have a air in the fuel system preventing the target pressure being achieved? 

[Cammsport 390]

3 hours ago, Lubed said:

Are your injectors activating while cranking? The DDE will not pulse injectors until a specific fuel rail pressure is reached and you  mentioned  a fuel leak in an earlier post. Is it possible you have a air in the fuel system preventing the target pressure being achieved? 

Target pressure is being struck. Voltage spiking at injectors when turning over. 

[NZE90 9]

Did you ever get this problem sorted out Cam?

[Cammsport 390]

48 minutes ago, F30N20 said:

Did you ever get this problem sorted out Cam?

Unfortunately not. The plan is to replace the leaky injector and the throttle body that keeps throwing codes (I don't think this will fix it) and if it still won't start, it's getting trailered to an independent euro place in Queenstown. I don't have the space/time/patience to continue fault finding to the point of pulling cam covers to check timing etc. 

I'll have to suck it up and accept the bill! Support local right... 😅

[Bronsk 3]

Hey dude. Did you happen to find out what the cause was? Mine desided to do some very similar, and im basically at rocker cover off and checking the chain and timing also, just intrested in what you found beacsue my sounds the exact same 😳 ran sweet, till it didnt sigh

[Cammsport 390]

No solution yet @Bronsk. I dropped the car off to a place in Queenstown on 27/08 that specializes in BMW/Jag etc. They called called a couple of days later, and they couldn't figure out why it wouldn't start (partial relief that I didn't miss anything obvious/worry that they won't find the fault). Their next step was to order a special compression tester from BMW in AKL as their one kept getting blown off apparently. His suspicion is that its compression (or lack of) related as it sounds like it is turning over too quickly. Bloody diesels.  

 

[Bronsk 3]

Damit, So they didnt think it has jumped a couple of teeth? Im about to pull my motor out this w.e and have a good look at the chain timming as i disconnected the downpipe off the turbo and when i turned it over, it sounded like the exhaust side valves are slightly out of time. But im grasping at straws till i see the timing, has me stumped currently. Il keep ya posted, fingers crossed 

Edited September 12, 2022 by Bronsk

[Cammsport 390]

Not the best news from the mechanic. Compression test shows low numbers on #2 cylinder and a leak down check shows its not from the top end. He thinks because the engine was so sooty, that it could be coked up piston rings that aren't spreading freely. He said if it was his, he'd be replacing the motor. 

Couple of options. 1)have them investigate further, head off etc and see what the issue is. This will take me further down the rabbit hole with no garunteed fix. 2)have them source a 2nd hand engine and replace it. This'll be very costly I'd imagine but the quickest. 3)i source and swap the engine myself. The cheapest but most time spent. And I worry that its something electrical and the car still doesn't start 😅

Anyone have a N47D20 lying about? 

[Gaz 1060]

Got a borescope handy? Might not be able to see anything but easier than tearing the engine down

[jon dee 500]

How many cylinders does that engine have ?? I have had 4-cylinder (N.A. petrol engines) that ran, not well, but ran with only two cylinders firing. Don't see why one cylinder with low compression should stop the engine starting unless there was some other factor at play.  

Cheers...

[Lubed 55]

Has the camshaft timing been checked?

[Bronsk 3]

@cammsport , dunno dude. Weather hasn't been the best here so far hopefully tomorrow is abit better to start the mission for me  . Sounds weird that only one piston would have " soot buildup " if u ask me. My first thought with mine was that is had got a bad case of bore wash causing the same problem with the rings not completely sealing . But yeah  i've been searching for a block or buying a wrecked 320,520,120 with the same block and swopping  out , end up costing the same as just buying the block  cheapest ive found was around the 3ish mark and that way u can sell parts to get cost back but depends on ur space i guess . Ive Turned to (gumtree and ebay now) alot better prices and better condition blocks , and chain replacement kits , huge difference in price ,just the shiping costest is the biggest issue ,as a backup ,if it turns out ive jumped teeth and bent a valve or 3 

[F10er 65]

Low compression on one cylinder won't cause a no start situation. I think they're barking up the wrong tree there.

Next logical step would be to check the valve timing.

[Cammsport 390]

7 hours ago, F10er said:

Low compression on one cylinder won't cause a no start situation. I think they're barking up the wrong tree there.

Next logical step would be to check the valve timing.

Could've been "bad compression, especially on #2", but I'll ring them on Tuesday and go over a few things. Like checking the timing 

[jon dee 500]

2 hours ago, Cammsport said:

Could've been "bad compression, especially on #2", but I'll ring them on Tuesday and go over a few things. Like checking the timing 

... and what was the compression like on the other cylinders ? Manufacturers usually stipulate a minimum compression psi below which the engine is considered worn out. And on a compression ignition engine low compression on all cylinders would be a major contributor to a crank - no start condition. 

Cheers...

[polley 916]

[Spinner99 55]

On 9/24/2022 at 10:12 AM, Cammsport said:

Anyone have a N47D20 lying about? 

might be one in here @Cammsport  ?
https://www.trademe.co.nz/a/motors/car-parts-accessories/bmw/other/listing/3791791717 

[Cammsport 390]

Have had another chat with the workshop. Getting pretty frustrated to put it lightly. 

I asked what was the compression on the other cylinders. "have only checked #1 and #2, #1 is 250psi and #2 is 150". Compression significantly picked up with abit of oil in the cylinders and then faded again. No air can be heard/felt from tge intake/exhaust manifolds. Apparently to check cylinders 3 & 4 "would be around 3 to 4 hours labour due to access". I asked if they had a boroscope to check inside the bore, "oh yea we might do, I'd have to ask around". I asked if the timing had been checked, "yea that could be another step". He said if the timing was off, he'd expect error codes. They can't see any codes, like i couldn't with ISTA. He's going to get back to me with a full job card of what they've done. I don't know how I'm already $1k+ in the hole for a code readout and  for compression testing two cylinders. 

I've been watching alot of m539 lately and old Streten has definitely given me some motivation. The madman puts himself through alot of pain. I'm considering collecting the vehicle and doing my own analysis. I'd find a leakdown kit and really make sure what was happening on all 4 cylinders. I'd buy a boroscope and check to see what the bores/pistons look like. Then most likely pull the engine, split the block and go from there. Options would be rebuild (if the cylinder walls aren't too damaged) or find an engine to swap out. The N47 is looking hard to find. Either of these options gives me tge chance to replace tge timing gear too. 

First lemon I've bought. Frustrating, but worse things have happened. Let me know if you have the scoop on an engine!