75ZT Community

My IPK (Instrument pack (IPK from the German)) engine light has periodically been illuminating (solid not flashing), over the past few weeks. On 2 occasions the local dealer’s scanner showed firstly a front fuel pump fault and then yesterday a Maf / mass air error?

I’d always considered (wrongly), they had a T4 (Testbook version 4.Computer Diagnostic System), but not so, only a sort of grand daddy version of my own U480 OBD2.

I have a Pierburgh (new at 23k) with a Synergy 2, EGR (Exhaust Gas Recirculation Valve) bypass, and filterless PCV (Positive Crankcase Ventilation Valve). The car runs faultlessly. Presuming therefore that the physical set up is correct, one contention seemingly is to replace the MAF (Mass Air Flow Sensor) sensor, viz,

http://www.ebay.co.uk/itm/NEW-air-flow- ... 4cf096a3b2

I don’t think my workshop’s knowledge of diesels is that deep, despite their overall competence elsewhere. The car has now covered 63k, last service was at 60k (big one).

Formatively the obvious answer is to find a diesel specialist, with a T4 to gain a more detailed analysis, if such a thing exists? However are there any formative steps, worth trying first?

I’ve attempted wriggling the wires under the bonnet etc, but without effect. Literally one day the tell tales on, the next off.

Any thoughts/experiences please …

Hi Martin,

It was my belief that if the MAF was dead, then it would just result in poor performance. However, I am not sure if the Pierburghs work differently.

That said, I personally would stick with the OEM MAF - I got a steal off of ebay the other week, but prior to that, I didn't think these were a bad price:

http://www.ebay.co.uk/itm/250941696852? ... 1423.l2649

Thanks Jake,

I've noticed my mpg has dropped from an overall of 39 last year, to 33 currently, (filled up today), but I think thats more down to the recent temperature changes. Also I only fill up once every 36 days or so, as I now use the Smart more, especially for say 10 mile overall journeys, taking my wife to the local shopping centre etc!

I'm unsure if the Pierburgh is defunct? If the ebay item you linked includes the sensor, it's not expensive, as the former costs forty quid alone?

The performance seems unchanged ...

I know you've "wiggled the wires" Martin but it is still worth pulling the connector out on the fuel filter head and re-seating it.

Thanks Paul,

I'll give it a try - when the temperature improves here, although from what I read it's worse up your way?

John says that the ipk light can often be caused by the unit on top of fuel filter, and Paul may remember that fault? Wiggling the wires doesn't often cure it. The MAF sensor doesn't read as faulty on T4 as a rule. If replacing with oem maf don't forget to turn off correction switch on synergy?
Message ends.

Eventually after 5 months of attrition uncertainty and probably £400 in T4 testa and re-tests etc. etc. it's been solved.

A contact on the 'Dark Side' recommended seeing Terry Shaw (TS Auto's of Stourbridge), and being in the area on another matter I visited him, albeit with an expectancy of yet more failure. He replaced my Pierburgh Maf with an original Bosch, reinstated the EGR valve (By-passed), then discovered (as the process of elimination expanded) the fault - Synergy 2 connecting block had virtually disintegrated, and the wiring leading to it had chafed as well. As it hadn't worked properly since January I wasn't missing it, and it's removal saves £162 on insurance as well as a 10% plus improvement in mpg.

Also being a coward and hating all the trauma this wretched light has caused me, I'm sticking to the original spec as set up by BMW, with the possible exception of restoring the EGR by pass?

The Synergy is now back in it's box. So if anyone wants to buy it / and or a new and unused Pierburgh Maf please contact me.

I cannot recommend Terry highly enough, and he's undertaking other jobs on the car for me, an ex Rover technician, with a T4 and the knowledge to understand it, he's an excellent find, with very reasonable rates in parallel.

It's worth the trip to find someone who not only cares for our marque, but is able to practically diagnose problems, beyond the interest of the 'ex-branded' pirates that proliferate down here.

Excellent news. As you say having a T4 is only half the story. It only ever gives you clues, never the answer!

That's great news, it must be nice to have the car running nice again.

If you don't mind drop me a PM with his details and I'll add them to the list.

Cheers

Great result Martin

Hi Martin, I am out at the moment, but will drop you a PM about the synergy and other things when i am next at a computer.

Glad you got sorted!

Thanks everyone,

In the end it became a real puzzle that just had to get sorted? Shame on me though or checking the synergy connection, but only at the battery box end - idiot!

Hi Martin.
Stay with the EGR as it is i asked you to do this on the other thread if you was able to get to the nano but very glad you have it sorted. hope to se you at the next one in july Arctic.
it-s-over-and-nearly-out-t5425-20.html?hilit=engine light

Yes, and thanks, I did remember your advice and a few others agree wholeheartedly with it too. I thought I'd keep it this way (back to OEM), until July (nano), and then have a chat with a few people at Four Ashes? When the EGR valve was in place originally though, I do seem to remember a lot of goo and muck had to be removed every so often?

However currently the mpg is very good, and there's no black soot yet on the rear bumper, which I suffered from prior to the Synergy and Pierburgh change. The EGR blank supposedly runs the engine more efficiently and burns up the non combustibles plus, in parallel, boosts MPG!. However, I'm not convinced, and not wishing to tempt the 'one-eyed yellow monster' I'll keep it in the boot and keep an open mind?