[Tambohamilton]

I'm wondering if I have an injector that's leaking a tiny bit, but not really sure how to test.

Symptoms are slow starts (maybe 2-3s; not crazy, but worse than it ever has been), and sometimes it stutters once before starting. No fault codes.

Checked selective mass adjustment in INPA, which reported:
1. +0.52
2. -0.2
3. -0.05
4. -0.3
5. +0.12
6. -0.04
So all well within spec, but not very even.

Not really sure what else to check...? Maybe read rail pressure when the engine is shut down, immediately after turning off. Then read again 1h (or whatever works best) later to see how much it's dropped and compare that with a known good reading?

I know pulling them all and having them all tested would be ideal, but I don't have time for that really, and would rather not disturb them unless I have to.

Thanks for any suggestions!

[mifesto]

I personally wouldnt blame injector based on your symptoms. Maybe get your batt load tested

[Tambohamilton]

It cranks quite happily - it's not slow to turn over. I'll check out the battery, but the reason why I don't believe it's to blame is the fact that the engine stutters occasionally - that doesn't make sense on a DI engine, where the DDE should have complete control over fuel.

[lnxguy]

How's your glowplug/module/battery?

Diesels have been DI since basically forever. This makes no difference.

[Tambohamilton]

I replaced the lot about 30k miles ago. No errors.

Battery is only a few years old, Varta. Alternator replaced recently due to noisy bearing.

Given there are no fault codes on the DDE at all (only one in the whole car is for the windscreen misting sensor), what could cause a stutter at startup and/or long crank other than an injector not doing what it's supposed to?

[maryjane]

Those values are VERY close to even. Do you have protool or testo? It could be a failing rear PCV. Monitor rail pressure when cranking and the stuttering.

[Tambohamilton]

I have protool...I imagine I could sort Testo, but I never have.

Will see if I can log them in protool - thanks!

PCV = positive crankcase ventilation?

[barf]

With increased backflows the problems would be more apparent/worse on warm engine usually but not always with piezo injectors, which you have (more commonly on solenoid its the case).
You can check with INPA if your rail pressure is slow to climb until it reaches over ~200-300bar where it would start.
Backflows you can measure when you take the injectors to a specialist who measures everything in a testing bench or you can buy/make yourself a kit with identical 6 bottles which you connect to backflow and then measure the quantites after cranking/starting. By this method you compare which is the worst one and replace that one. They also sell special backflow measuring kits which are quite cheap.
Other issues might be valves in fuel tank that are bad but I doubt it.
I would start with measuring backflow, there is no point in speculating anything else before that.

Selective mass adjustment tells you almost nothing regards to backflow and long crank issues.

[maryjane]

Originally Posted by Tambohamilton

I have protool...I imagine I could sort Testo, but I never have.

Will see if I can log them in protool - thanks!

PCV = positive crankcase ventilation?

NO....pressure control valve. The 1 on the rear of the fuel line.

[Tambohamilton]

Because these are piezo injectors they need 10bar backpressure on the leak off, so leak off measuring kits are super expensive. :|

[Tambohamilton]

Originally Posted by maryjane

NO....pressure control valve. The 1 on the rear of the fuel line.

Right! Couldn't see the link to the crankcase vent, to be fair

[maryjane]

So have you logged while trying to crank it? Or while its sputtering?

[Tambohamilton]

Not yet - maybe tonight. Got heaps on at the moment - house renovation, work, kids, life....and this car just adding a bit to my stress levels!

[Tambohamilton]

Took a log tonight. Link: Log

Car started ok, but definitely a tiny bit rough as it came to life.

My observations are:

Battery voltage seen by the DDE did drop to 8.6v immediately after pressing the button, but climbed steadily while cranking. That's 22h since last run, and it was -5C overnight. About 0C while cranking. I think that's not amazing, so I'll check connections and ground straps sometime...and maybe charge the thing. Voltage was 11.3 before pressing the button, which I guess isn't super impressive. As soon as it started voltage came up to 14.8.

Rail pressure was ~0 before cranking - I'm going to guess that's pretty normal after standing for 22h. It started climbing immediately when the button was pressed, and reached 500bar within a second... When it hit 500bar, setpoint pressure was only 435bar, which is pretty far out compared with the rest of the readings (though I guess unlikely an issue). After that initial bounce up to 500bar, it settled to the idling pressure of 345bar within another second. Total cranking time about 1.8s.

I should have logged rpm, but didn't think of that until writing this out...


I should say, I understand I'm being picky here, and I'm not concerned that it's about to take a dump...it's just that it's noticeably worse than it used to be, so something isn't 100%.

[maryjane]

Cant see log. What did you log with? Testo or protool? Sounds even more like the rear control valve after reading this. or the 1 on the rear of the HPFP.

[Tambohamilton]

Logged with protool. Should be a link to a Google sheet in my last post? Does it not work?

[lnxguy]

So you've verified battery, glow plugs and glowplug module? If these issues pop up once it gets a bit cooler out, these are what you need to look at.

[Tambohamilton]

Battery may not be 100%, but no errors for glowplugs or module and they were all replaced under 40k mi ago.

Will do further battery checks soon, if I can get a chance

[Tambohamilton]

Took a couple more logs tonight, and added engine speed, fuel temp and charge temp. Results for rail pressure and batt voltage basically the same as before. Fuel temp looks reasonable (1C on a cold start, where outside was reporting -2C)..but intake temp said 21C. It definitely looks to be reading about 20C hotter than the actual temp.

Not sure that's a smoking gun, but I don't suppose it's helping at all! I'll have a quick check of the wiring tomorrow, and maybe check it with INPA before ordering a replacement.

[lnxguy]

If you aren't getting IAT codes, your MAF is most likely just fine. 20 degrees isn't a big deal. If it read -40, then you'd have a problem.

[Tambohamilton]

Originally Posted by lnxguy

If you aren't getting IAT codes, your MAF is most likely just fine. 20 degrees isn't a big deal. If it read -40, then you'd have a problem.

I think it's the sensor between the intercooler and the egr? Anyhow, it seemed not so far out today, so who knows. I'll keep an eye on it.

Noticed it missed a couple of beats immediately after starting today. Checked the codes and got 4262, #6 glow plug. Cleared it and it came back on the next engine start. So now I've got 1 smoking gun! I'll change all 6 of them, when I get time. Don't think I'll change the controller, because Beru ones are hard to come by/£$€.

[lnxguy]

Originally Posted by Tambohamilton

I think it's the sensor between the intercooler and the egr? Anyhow, it seemed not so far out today, so who knows. I'll keep an eye on it.

Noticed it missed a couple of beats immediately after starting today. Checked the codes and got 4262, #6 glow plug. Cleared it and it came back on the next engine start. So now I've got 1 smoking gun! I'll change all 6 of them, when I get time. Don't think I'll change the controller, because Beru ones are hard to come by/£$€.

It's most likely the controller and not the glowplugs. If you're going through the hassle of pulling the intake you'd be crazy not to swap everything (module and glowplugs)