308 hdi 90 occasional stall - Injector ?

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tmead
Donor 2023
Posts: 195
Joined: 06 Jul 2010, 23:30
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308 hdi 90 occasional stall - Injector ?

Unread post by tmead »

Our 308 has stalled unexpectedly a couple of times recently. It happens at low revs and is normally preceded by some slightly odd feeling surging. That was pretty gentle though. It started up again after stalling, but required a bit more cranking than normal. Subsequent starts are as normal. No other running issues, and MPG is still solidly at 61.3 average, as it has been for 100K miles.
No warnings, no EML, nothing recorded in the ECU. Diagnosis is a little tricky based on that !

On a bit of a hunch, and after some googling, I've taken a look at injector corrections in Diagbox, and I think there's something wierd there. It looks like the ECU is struggling a bit with injector 2 ?
1 and 2.png
3 and 4.png
All others are stable lines, even if injector 4 is lower than 1 and 3 with a value of -2.

I'm tempted to grab a couple of used injectors and replace number 2 as it doesnt look right to me. Might leave number 4 for a while, as it seems pretty stable.
tmead
Donor 2023
Posts: 195
Joined: 06 Jul 2010, 23:30
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Re: 308 hdi 90 occasional stall - Injector ?

Unread post by tmead »

OK so now that I've changed injector 2 nd coded it in the ecu, I've got another issue.
It started up immediately, and ran for a few seconds, then stalled. Since then it hasn't even coughed. I've got the battery on charge now, but it was spinning over reasonably well.
Live data shows a measured fuel pressure of zero - that can't be right? Doesn't budge at all.
Perhaps that reflects the air bubble that inevitably is in the pipe ? Do I need to bleed the pipes to the injectors?

Tim
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Muir
Donor 2024
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Joined: 16 Nov 2024, 18:33
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Re: 308 hdi 90 occasional stall - Injector ?

Unread post by Muir »

Hi Tim

Like you are I'd suspect air in the injector fuel lines, best way to purge that is disconnect all injectors electronically and crank the engine for 10s+ seconds.
Reconnect injectors after and try if it'll fire up.
It does sound odd the ecu detects zero fuel line pressure - is the fuel pressure sensor properly connected and are all high pressure fuel lines fitted snugly and leak-free?
Until the ECU detects the minimum required fuel rail pressure it will not fire, even if the fuel lines are purged.
tmead
Donor 2023
Posts: 195
Joined: 06 Jul 2010, 23:30
x 11

Re: 308 hdi 90 occasional stall - Injector ?

Unread post by tmead »

Thanks Muir, looks like it may have been air in the low pressure side too. I hadn't really thought of that until a colleague mentioned it today. I'd expected the high pressure pump to prevent fuel flowing back, but there was quite a bit of air to let out.
I'm never convinced that the one way valve on the low pressure circuit works, so I popped the return fuel pipe off and pumped fuel out into a tin, putting my finger over the end to prevent drawing air back. There were quite a few pumps with air in before it flowed properly.

Its running now, with a pretty stable correction value. Shame its between -2 and -3, but that may correct as the ecu learns it.
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Muir
Donor 2024
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Re: 308 hdi 90 occasional stall - Injector ?

Unread post by Muir »

Glad you got it sorted without having to replace anything.
If the engine runs good and is stable I wouldn't worry too much about correction values.
Depending on the age of the car they're probably where you'd expect with wear & tear considered.
tmead
Donor 2023
Posts: 195
Joined: 06 Jul 2010, 23:30
x 11

Re: 308 hdi 90 occasional stall - Injector ?

Unread post by tmead »

With a run from Cambridge to Lancaster and back giving an average indicated consumption of around 68mpg, up from the previous rock solid 61.3, I'll take it!

Just to note - anyone coding in injectors - grab a ascreenshot of the injector codes beforehand, as when you try to edit one of them, its likely that they will all disapear and need typing in again !