T4 Boost cut off!

[Alex121]

Hmm interesting. I don't think there's a solenoid on the fuel pump but surely if something were sticking there would be a misfire sort of feel rather than a perfectly fine car that gets put in limp mode?

Does anyone have any info from diagnostics in VIDA/DICE that determines what triggers limp mode?

I've ruled out MAF for now in the theory that when MAFs go they tend to either work or don't, they aren't intermittent in the way that this problem is.

Gonna give the pressure sensor on the intake a good clean tomorrow before work, see how it behaves.

[DXMachina]

I honestly dont know how it'd manifest - I've never even driven a T4 let alone owned one.

All I can say is that on my cars, the manifestation of a stuck fuel pump valve was a smooth and steady total lack of performance. It really does sound like the symptom of some sort of failing mechanical device.

[malteser]

Have you ever changed the Fpr?

Like Dx said, sounds like fuel related or air leak

[Alex121]

Originally Posted by malteser

Have you ever changed the Fpr?

Like Dx said, sounds like fuel related or air leak

Would I not have cold start issues if it were the FPR? Not changed that yet though no...

The systems tight, no leaks anywhere, most of the hoses got pulled off and inspected when my turbo was replaced and I've checked most of them myself, plus surely an air leak would just give me less boost all the time?

Boost always peaks at 1.35/1.4 bar WOT until the 'problem' trips limp mode. I assume a leak would give less boost/intermittent readings?

[malteser]

Fpr doesn't mean cold start issues only.
Mine used to start fine hot and cold but changed anyhow.
After that it felt so more responsive.

The only way to check for an air leak would be with a smoke test to be a 100%

I've had air leaks and still running on 18 psi boost, come to think of it I got an air leak on the way home from Gatos once and the car went into limp mode.

The ecu might notice after a good drive then goes to base 0,6 bar if I remember rightly.

Have a word with Ashok about Fpr and air leaks even the slightest air leak could cause a nightmare lol

[Alex121]

Originally Posted by malteser

Fpr doesn't mean cold start issues only.
Mine used to start fine hot and cold but changed anyhow.
After that it felt so more responsive.

The only way to check for an air leak would be with a smoke test to be a 100%

I've had air leaks and still running on 18 psi boost, come to think of it I got an air leak on the way home from Gatos once and the car went into limp mode.

The ecu might notice after a good drive then goes to base 0,6 bar if I remember rightly.

Have a word with Ashok about Fpr and air leaks even the slightest air leak could cause a nightmare lol

We've exchanged 18 emails over the last 24 hours trying to work this one out lol. Gonna get some Wurth MAF cleaner on order, give that a go and pop it in for a smoke test on the weekend, along with the pressure sensor clean tomorrow as a first point of call

[Matt86]

Don't know if it's any help Alex, but I know that sometimes if the problem clears by the time you go to get codes read it doesn't always keep it stored. (I've had this on mine)

Does the problem remain the same until you turn the engine off and back on? If that's the case if you can get it to happen again while your this way pop by and leave the engine running and we'll see what DICE shows?

Just a thought.

[Alex121]

Happened again this morning - 10 minutes into journey this time, only happened the once though.

Would have popped by Matt but had a company meeting this morning so had to be in on time. Plus, another 40 odd minutes of driving with 0.5 bar would have been horrible lol

[Matt86]

Originally Posted by Alex121

Happened again this morning - 10 minutes into journey this time, only happened the once though.

Would have popped by Matt but had a company meeting this morning so had to be in on time. Plus, another 40 odd minutes of driving with 0.5 bar would have been horrible lol

lol - put up with the drive or put up with the problem

[Alex121]

Originally Posted by Matt86

lol - put up with the drive or put up with the problem

Lol, had I been able to stop at yours I would have put up with it.

Strangely, it never does it on my way home. I'm logging the short term and long term fuel trims on torque pro at the moment so will be interesting to see if that shows anything.