Hi

2002 35c11 ECU MS6.3 Pump CP1

This one has a reoccurring problem with the fuel pressure regulator failing over a period of about 3 years.

The Symptoms are when driving down hill on overrun Injector (EDC) lamp starts to flash but then throttle response is lost when you then want to accelerate, let vehicle idle for a few seconds and power restored. vehicle will pull otherwise drive well. Fault code is general >> fuel pressure check <<<.

The problem was traced to fault with fuel pressure regulator, new valve fitted, filters changed vehicle was then fine for 14 months / 15000 miles approx then same fault re occurred.

This time we removed and cleaned tank (no significant dirt found) flushed pipe, new reg & filters, again ran fine for about 1 year then same problem.

Again ran Ok for for 9 month / 10000 miles new reg fitted.

Now thing seam to have deteriorated as this one has failed after just 6 weeks

There are slight differences this time, driver says it started with same symptom on overrun, but now wont run correctly even at idle EDC light on, fuel pressure check code > shown as current < rail pressure 700 bar requested pressure 260 bar. reg duty cycle was showing at 20% but think this was a default value displayed.

I have had a bit moor of an in depth look today, but found no real cause. A new reg has again sorted the problem, but I need to find an underlying problem. Readings at idle with the new reg showed duty cycle of valve 15 % both requested & actual rail pressure 260 bar.

Contamination is my biggest suspect, Main filter & pre filter opened up, no real trace of muck or swarf found. return pipe pressure checked (4 psi) looks like this is a controlled pressure, pipe after valve to tank clear.

The pressure reg is the type with a very fine metal cone filter fitted, I have inspected with a magnifying glass and cant really say it is contaminated, so no clue there.

I wonder if Third piston cut off is not working correctly and reg valve is struggling on edge of limit to cope ? I can clearly hear it click when i actuate via Scanner, so there is some action. However when I work it with a power prob at idle reg valve duty cycle only changes from 15 to 16 %, I would have expected a bigger change but have no good data to compare any thoughts on that ?

Injector leak of checked, only on combined 4 at return so far, but 30 cc in 30 second and is what I would normally consider acceptable.Not really thinking leak of issue as problem appears over pressure rather than under.

Any suggestion &Thought welcome

Cheers Aidan
phone 01664 822450
If you want to make a lot of money out of some one, do it a bit at a time !!

aidan

Posts: 2039
Joined: Wed Nov 01, 2006 7:22 pm
Location: Long Clawson, Leics 01664 822450

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