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Gav.

03' E39 530d auto Failure to start ***RESOLVED***

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The car i bought just one week ago, is dead. It won't start. Here's the story (get a brew).

The day i bought the car, i knew there was something wrong with it. It was down on power, and didn't seem to be boosting properly. I had already guessed it was probably the MAF sensor, so i found a replacement about 100 miles away in Cornwall. The guy also had a few other bits i needed, including a complete leather interior, so i organised with him and took a trip to collect it all. On arrival, we switched out the MAF and took it for a test drive. Problem solved! WOOO!!... and then, not so much. While driving the car along onto a carriage way, it just cut out. Complete engine shut down. We towed it off the crriageway, and back to his house, where we began to look into the problem.

When i say the car doesn't start, it cranks fine, turns over quite quickly but i've put that down to no fuel in the cylinders so nothing to compress. No DDE light either, though it did come on when the engine first shut down so it does work.

I'd been getting bubbling sounds in the fuel tank (was at 3/4 full), so we guessed at a tank pump failure. He had one, so we swapped them. The bubbling stopped, but the car still wouldn't start. I ended up getting recovered by the RAC, who also plugged it in and gave me these fault codes...

DTC: 0100,Air mass meter
DTC: 3505,Glow Plug Module Control Circuit
DTC: 0400,Exhaust Gas Recirculation
DTC: 0110,Air inlet temperature sensor
DTC: 1195,Fuel Rail Pressure Sensor Circuit Malfunction
DTC: 1A22,Swirl flap
DTC: 1E30,Boost pressure regulation
DTC: 3520,Engine lager actuation
DTC: 1E25,Engine speed control
DTC: 09F6,Rail pressure monitoring; rail pressure too low during start


From that, i took a stab at it being the rail presure sensor on the end of the fuel rail. This is something that failed on my brothers 330d (same engine), though his still started and ran, so it seemed like a good place to start on mine. No difference. The next thing to check was the inline pump. i bought a new one and fitted it, and it's loud so i know it's definitely running. No difference. I double checked the intank pump, and replaced the pump itself, just to be sure, still, no difference. I then replaced the fuel filter, again, no difference.

When priming the fuel system (as soon as ignition is turned on), for the first couple of times after i'd changed the filter, inline and intank pumps, there was air visible in the pipes. Now, there isn't. What i do hear though, as soon as the inline pump stops running, is fuel returning to the tank.

From what i can see, the fuel system is laid out like this...



Tank->intank pump*--->inline pump*--->Fuel filter*--->High pressure fuel pump->high pressure regulation valve--->fuel rail->fuel rail pressure sensor*->injectors


Anything with a * i've replaced.

I have ordered a regulator valve, but i'm not convinced it's going to be that.

My thoughts so far are that the fuel is getting to the rail, but it's not under enough pressure (hence the fault code DTC: 09F6,Rail pressure monitoring; rail pressure too low during start). According to INPA, the pressure it's getting to is around 40bar, when it should be around 350bar. My personal thoughts are that it's the high pressure fuel pump itself, which is a pain in the arse of a job. The inline pump only pressurises up to about 5bar maximum, so if it's getting to 40bar, the pump must be doing something, just not enough.



So, onto the questions...


Will the valve be stopping it getting to pressure?
Can the valve get stuck open/closed?
If the valve doesn't solve the problem, is there anything else i can check before changing the main fuel pump?

Is there any way i can test the fuel pump? (without having to buy pressure guages etc)


Thoughts?

Edited by Gav.

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From my limited expirience I would say its either down to the high pressure pump or worn injectors.

 

I looked at a landrover freelander a few months ago with the 4 cylinder diesel BMW engine (varient as ours, just the 4 cylinder version) - this was a non starter, which turned out to be worn injectors - we sent them for refurbishment and the engine ran brilliantly again.

We managed to get the freelander running before we had the injectors refurbished (badly) using easy-start - maybe worth a try on yours for diagnostic purposes?

 

Not sure how you would test the HPFP, however I had to replace this on my car a few weeks ago as mine started leaking - the job itself isnt too bad, I purchased a recon pump for less than £200.

Edited by AlexGSi2000

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I don't suspect the injectors, or a wiring fault. All Diagnostics are saying low fuel pressure. The way it failed is the confusing part. It was low powered, right up until we changed the MAF. for 10 minutes, it drove faultlessly, back to full power as it should be, but then just complete, instant shutdown. Total loss of fuel pressure.

 

If the injectors were failing, there would have been a gradual loss in my opinion. I also don't think it would have just shut down instantly. The way it happened was like it had run out of fuel (there's still 3/4 of a tank), which is why i've replaced both the intank and inline pumps. The fuel is getting to the rail, but it's not at sufficient pressure. Either the Regulator valve has failed and is not allowing the pressure to increase, or the seals on the pistons inside the High pressure pump have failed, so it's just not creating the pressure.

Edited by Gav.

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To go from WOW to sod all, suggests something broke rather than worn out. Can you get a good secondhand regulator valve and try it, before splashing out on a new pump?  And/or, get a specialist opinion.

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I've read about wiring breaks in the wires from the control box to the rail pressure sensor, and the spades in the plug breaking off, so it might be worth checking anyway. The rail pressure circuit malfunction might point in that direction too.

 

 

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I don't think it is a wiring fault, the rail pressure sensor is giving me readings so i'm pretty confident it is working. I've now replaced the HPFP too, which came with a high pressure valve already fitted. It's made no difference. The car still just turns over and will not start. If i spray Easystart into the air filter, it fires while spraying it, but won't stay running.

 

The current line of thought is either a leaking injector, allowing the fuel to flow straight to the return, or cam or crank sensor.

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Update, Cam sensor has now flagged up a fault, got one on order so hopefully the problem will be solved in the next couple of days.

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So, after banging my head against a wall for a couple of hours, we decided to go back to the begining and work our way through everything again. Fuses first, there's a block of 30amp fuses in the ECU housing..


E3B0DF4A-BC78-4BF1-8F2E-0891DB3B9468.jpg

One had popped, so we swapped it out and tried the car....

yup. Fixed it. Fuckingwhorefuckingjesuslovinggoddammedpileofshitthankfuckthatsover.

In total, after a refund of a sensor that i sent back this morning and the Surcharge from the HPFP that i didn't even need, i've spent around £700. And all i needed was a £1.50 fuse.

Good bye 2016, you fucking dirty bitch.

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