Everything points to this being the MAF, but I have changed that with a genuine from Volkswagen dealer, no better. Another feature is that it revs up when you start it as if I've blipped the throttle. Any ideas?
Well check the Pedal position sensor then, or subsitute a new / known good one.
Tim..
Good chance. Get it on a code reader as well: the sensor has two tracks and the ECU compares them so it might store a code.
OK thanks, I'm seeing a guy about oneish to plug in, last guy reckoned it was deffo the AMM but it's not, tested both old and new now myself and output of both go to 4.3V at flat out.
Noticed that the vacuum? pipework that operates the wastegate? is a bit crumbly but it seems to be more the braiding, was going to replace that this morning. Also the length that goes from the inlet manifold to pressure sensor looks a bit chafed just behind the fuel filter...
Is this the 110 or 130 engine?
If it has the VG turbo, i've seen the actuator seized / pipework split etc, but this ALWAYS causes the MIL to illuminate.
You would normally have good response at low revs, but it suddenly goes flat as you pass circa 2500rpm...
I would definately go with the MAF if the PPS looks fine. The easiest thing is to go for a test drive watching the live data via a VAGCOM or similar- as the turbo spools up you should see the MAF figure rise quickly, and then continue to do so as revs build. If its getting stuck at a certain figure, dispite engine rpm increasing, its definately knackered.
After that- check for detatched turbo hoses, splits, burst intercooler etc, (though you;d normally hear the leak) and after that, check turbo boost pressure. (roughly 1bar, depending on engine varient.)
Tim..
Could be a 115 as well IIRC. That's the first PD engine, with VG/VNT turbo.
100PD, 110, 115PD, 130PD or 150PD engines have the VG turbo, if that helps. I don't know which got fitted to the Ford though.I've seen it not trip the MIL- but in that case the symptoms are lots of power, then it all dissapears. The seized mechanism can cause an overboost, then the ECU shuts down the turbo. In that case you get an overboost recorded. It seems that the MIL illumination is almost random on VAG TDis.
Interestingly Car mechanics mag has a Sharan with symtptoms like that this month. It was jammed VNT as you suggest, plus other turbo damage. It looks like it dropped a valve, and when the new head was fitted, bits got left behind and hit the turbo vanes. It was a real mess.
Even better: log requested/actual MAF in VAG-COM & plot in excel, and you get a pretty graph that shows it's duffness. Worked for me with my A3. MAF sounds favourite to me too, but he has changed it.
Unless there's an intake restriction, but not that likely.
You can log that too with VAG-COM.
Actually, given it's 97, I'd say it's a TDi90, so a normal wastegate turbo, not a VG. Don't they fail safe (ie: wastegate open)=no boost?
I'd check the N75 valve on the bulkhead, and the tubing between that and the turbo.
Hi all. Yes it is the 90 bhp. I assume the waste gate thing is either open or shut? If it's open then no power? N75 is either ported to vacuum or pressure?
wastegate
boost?
either
Excuse the bad form of replying to ones own post. So overnight we experienced this loss of power. Bloke down the road reckoned he's plugged in and diagnosed MAF. Changed the MAF, no better. Tested both MAFs on the car, 4.3 V output at flat out which is correct according to Pierburgs bumff. Put the old MAf back on. Replaced all the vacuum tubing associated with the waste gate actuator, no better. Tried different combinations of valve bypassed, disconnected etc, no better. Took off the inlet to the turbo and could spin the fan by hand, so happy it was not siezed. As a last resort was going to remove the stop solenoid to see if it was restricing the fuel. Couldn't shift the damn thing, access a bit poor. Gave up and came home for lunch and f**k me the bloody car went like a rocket... So either we sorted something while wrestling with the wiring round the injector pump as we tried to get the stop solenoid out or the vacuum pipe thing worked and it takes a few runs to get back into the swing of things. Either way, it's working but am a bit concerned that I don't know what the problem was. Thanks all of you that responded to my pleas for help.
The N75 could be sticky perhaps?
This N75, is it either one way or the other or is it modulating?
Its either open or shut- the ECU supplies a square wave signal, but several times per second (at times) so its continually opening and closing.
Tim..
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