Vito 2006 646.980

[Jmdiag]

I'm hoping someone will be able to help me here, ive been diagnosing a 2006 2.2 cdi vito van. It starts and runs fine, drives fine with plenty of poke. At idle it smokes a reasonable amount but when revving or under load it smokes an awful lot more, leaving massive clouds behind. Its definitely a rich diesel smoke but in an effort to eliminate everything else I've blanked turbo off, removed egr cooler, removed intake piping, the engine has just been rebuilt with new rings and stem seals, ive sent all injectors away for testing and they say they're not leaking at all.

It appears that it is overfueling and burning excessive fuel in the exhaust thus creating the smoke. I tried using my snap on verus pro to scope the injector triggers, they're bosch piezo injectors but snap on guided say they should peak at 50v, I was seeing around 120v.

I assume the ecu is holding injectors open for too long and over fueling engine.

Can anyone advise me the best way to confirm ecu is faulty?

I can't find anyone who will test this specific ecu number, plenty for other variants but not this one unfortunately.

Any advise would be much appreciated.

Many thanks

[Iver]

I

ive sent all injectors away for testing and they say they're not leaking at all.

Injectors cannot be tested properly off the car.

it appears that it is overfueling

You CANNOT over fuel a Diesel engine. The rpm will rise in direct proportion to the fuel injected !!

bosch piezo injectors but snap on guided say they should peak at 50v, I was seeing around 120v.

Snap on is not the "Guide to the Galaxy"

120v is just fine.

I

assume the ecu is holding injectors open for too long and over fueling engine.

Let's not assume. We can test !!!

Can anyone advise me the best way to confirm ecu is faulty?

I can't find anyone who will test this specific ecu number, plenty for other variants but not this one unfortunately.

The best test bench for that ECU is the car or van it lives in.

No mention of actual values !!

Temp Values. ?
MAF?
Smoke test ?
Individual Cylinder Contribution Test
Boost Values.

Ditch the Snap On. Get Star on it.

Injector Seals & Seating !! Have you been cleaning the seats ??

A lot more graft for you to do before you throw the towel in call the ECU.

This is very unlikely to be an ECU fault unless it has a dodgy MAP in it.

[Jmdiag]

Okay let's say its not over fueling rather the engine isn't burning the fuel its being delivered with. When I take the manifold off you can literally see the deisel being blown out the exhaust ports.

Temp values - engine reaches 87°c as expected

Maf - has been disconnected and reconnected, perhaps this isn't the best way to test this but I thought if ecu didn't see maf input it would give it a default value?

Smoke test - do you mean like an mot smoke test or the kind youd use to confirm no boost leaks?

Cylinder contributions - I've given it a compression test, all seem okay. The live data was showing interesting injection quantity values between cylinders.
Cy 1 +0.73 mm3g/Stroke
Cy 2 -1.3
Cy 3 +0.43
Cy 4 +0.20

Boost values - at idle is reading 1009 hpa, at 3k rpm is reading 1531 hpa.

I've recut the injector seats with a seat cutter, fitted new Mercedes copper washers and injector bolts and torqued to the 3 stage spec. Unfortunately someone previously has snapped the bolt on removal and hellicoiled the injector bolt thread so the longer bolts no longer fit.

I agree star would be better and tbh I havnt been that pleased with the snap on on this van, live data is horrendous, autel was much better for it. Unfortunately I cant justify spending £700 on a tool to do 1 job and I cant find anyone locally with star.

Thanks for your reply

[seafordmotors]

Reading your post it seems you perform more " Guesnostics " than Diagnostic.

The compensation Values are OK with the exception of cyl 2 just a bit high compared to the rest.
The ECU seems in control of the injectors. As a rule the sum of all corrections is about O.
You should not disconnect or block off any components for diagnostic purposes.
After repairs you have to reset adaptation parameters eg: MAF, Hi pressure pump,EGR etc.
I would suggest to look more to any mechanical faults. The ECU from Bosch is very reliable.
Injector testing off vehicle is not always reliable.