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Discussion Starter #21
🤙🏼🤙🏼🤙🏼 IT STARTED 👍🏻👍🏻👍🏻

Today I fitted a new fuel stop solenoid, sprayed some quick start into the intake and the van started! I left it running for about ten minutes while plumes of unburnt diesel finally escaped.

While it was running I began putting the front end back together and moved the ECU - the engine died immediately. I could not get it restarted even with easy start and with the battery dying decided to put it on charge for another go tomorrow.

Plugged it into VCDS lite and no new fault codes. Immobiliser is good.

Any ideas why it won’t restart, not even with quick start. Turn over is strong just like before...

😩
 

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I think you answered your own question “moved the ECU - the engine died immediately” connector or wiring fault or unlikely something loose in the ECU
 

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Discussion Starter #24
Pulled more conduit off the loom running from the ECU to the engine and found a bunch of broken or crimped wires thanks to a securing clamp...

177817


Obviously some of these have been in a bad way for a while but it doesn’t really explain how the van ran so well for most of the two years we’ve had it. It’s been to Spain & Portugal more than one in that time...unless these were finally broken when the VW Indy dug in here to lube the gear mechanism.

Anyway, the broken & damaged wires have been repaired but as it’s miserable outside now all checking on the engine loom has stopped. I’m guessing the weather will be glorious again during the week..

177818


Fitted a new temp sensor with correct size o-ring as well Which will cure that leak. Why are people so blooming lazy?

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177819


I’m still trying to trace the reason why the N75 valve is getting a open circuit or short to ground fault. The resistance checks out at 26.6 ohms but the N18 valve with the same fault only reads 16.6ohms, so that one may be goosed, I’m going to have to check.
 

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Having a similar fault code on my van and whilst checking the wires discovered that one of the blue/brown wires (there are 2) going to the ECU comes from the N75 so hopefully now that you have reconnected them it should go away.
 

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Discussion Starter #26
Sadly I’m still getting open circuit short to ground on N75 & N18 - no broken wires. Doing my head in actually.

After repairing the wires and cleaning all the connectors, on starting I now have a buzzing quantity adjuster!

I fires up but idles like a lumpy tractor. Dreadful!

I first suspected the solenoid but that checked out. I have a new quantity adjuster max limit fault code so decided to remove the cover - no gunk but the little lever moves rapidly on ignition on...that’s causing the buzzing from the pump.

178388


see my other thread Quantity Adjuster gone mental

Now I need to figure out why it’s started doing this?

Any ideas?
 

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Discussion Starter #27
It was all the ECU - despite the obvious things that needed fixing during this frustrating troubleshooting process, the underlaying problem with open circuits and short to grounds, and the erratic behaviour of fuel stop solenoid & the quantity adjuster - was the ECU.

i did all the checks on the fuse box, relays and wiring, at least twice to make absolutely sure.

Yesterday I managed to swap out the original ECU and fit a replacement - the van started up and idled smoothly like it always has. None of the previous fault codes appeared and there was no erratic behaviour or lumpy idle. I let it run up to temp took a few pics of the readings in VCDS lite so I can now look into the fuel pump timing as it was smoking quite a bit.

Let’s see if it starts tomorrow...
 

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Discussion Starter #29
Thank @BitterandTwisted

Ive got one fault code now - Glow plug relay short or open to ground that must be stopping it from starting now. but I’ve tried three different 103 relays and still have the same issue. Any ideas?

The van starts with a short shot of quick start and then idles perfectly.
 

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A 2.5tdi is direct injection so shouldnt really need or use the glow plugs at this time of year. I'd double check the pump timing at a start

Sent from my SM-A505FN using Tapatalk
 

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I don't have any experience with these i'm afraid mate but have my fingers are crossed you'll get to the bottom of this very soon .🤞
 
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