Howdo all.

66 plate Custom, 2.2, 127K mileage.

Had her in for MOT a few weeks ago and had the egr valve replaced at the same time. The old valve was clogged solid and the check engine light had been lit since last year but due to a protracted illness I couldn't do anything about it. No problem with the MOT but since then the engine is "off" - under light acceleration there's a surging, for want of a better description, that I can feel and hear, but when I accelerate hard the van is off like a whippet. Took the van back to the garage and went for a ride out with the tester who had his diagnostic machine plugged in. He heard and felt the problem but didn't get any fault codes so wasn't much help. I've since downloaded Forscan to my laptop but to be honest I'm  not sure what to check for, tried checking fuel trims this morning but I can't find them anywhere??

For further info, I've had the van for 2 years and before this she's run like a dream and has seen numerous 1000 mile scuba diving round trips to the top of Scotland without missing a beat. Oil and oil and air filters were changed at 125k and fuel filter changed at 126K. If anyone can point me in the right direction to sort this I'd be very appreciative, I live near Bishop Auckland but I'm happy to travel if anyone can help.

Much thanks,

Martyn.

Hi,

Fuel trims are for petrol engines.  They don't apply to diesels.

Unfortunately faults like this are very difficult to diagnose.  Cheapest option is just to wait until it gets bad enough to trigger a fault code.

Forscan and an approved lead?
One "equivalent" to fuel trims may be rail pressure and on ours, there is a Demanded and Actual value in Forscan?
I set up a page in the spreadsheet view and add things like engine speed, air temperature etc etc which I believe can be recorded or looked at by a passenger.
If you can find some parameter that "surges" in tie with your noted symptoms then that may point you in the right direction?

2 hours ago, Benthos Boy said:

I live near Bishop Auckland but I'm happy to travel if anyone can help.

Give ARC Binchester a call 01388-665114

Thanks all for the replies.

Just been playing with Forscan, and I'm a long way from being competent with it, and got the following readings parked on my drive:

At idle (804 rpm) EGRP 20%, MAF 6.6g/s

1600 rpm, EGRP 30+%, MAF 32g/s

2400 rpm, EGRP 49%, MAF 58g/s

Am I safe in assuming there's a fault with the "new" egr valve and either the maf sensor is shot or there's a leak in the vacuum system?

58g/s does seem very high for 2500rpm.

If the EGR is meant to be 50% open then the engine would have to be taking a huge amount of exhaust gas & fresh air.

Something does seem wrong here, but I'm not sure what from those figures alone.