976 ECUs, maf, limp mode

[Poodle]

As the title suggests really, just looking for other experiences and input from someone who's seen a few maps. Myself and Arron reckon there could be something different in the mapping on the 976 ECUs, with regards to the maf. Our cars go into limp mode when you unplug the maf, both are 976 ecus, the cars are a late T and early V, so both early HDis. Anyone else found this on a 976 ecu, or any other for that matter? What's the difference that causes this reaction, any ideas?

[Just Sean]

Just FYI. Mines a 249 and in plugging the mad hasn't made a difference. Also a v reg hdi... 1999

[HDIkyle]

Mines a 249 also W reg and unplugging it makes no differance. It might be a ecu related thing as they like to mix it about

[Just Sean]

Poodle, do you get any eml lights with it unplugged?

Would it be possible to map the maf out of the ECU to stop it going into limp mode?

[Poodle]

I do, yeah.

It's possible to map almost anything, the problem is usually how.

This thread was just posted out of interest really, nosiness lol.

[Just Sean]

I want Mr whippy to map mine to blip the throttle on downshifts Lol! Think I'm asking for too much tho! Haha

[Toms306]

Mines a 249 also W reg and unplugging it makes no differance. It might be a ecu related thing as they like to mix it about

Mines also 249 on a W plate......no difference....

[Poodle]

Why does everyone commenting have a 249?? Random...

[vlj]

Why does everyone commenting have a 249?? Random...

It's spotted thread syndrome, fairly common around these parts.

[Mr Whippy]

Not sure I've noticed this but I can probably have a check why tomorrow night (yay, I have some remapping to do hehe)

I have a feeling I know why after something I was looking at just the other week.

But I have to ask why unplug the MAF and worry about limp? Surely you want MAF plugged in? The cars 'work' on unplugged MAF only because of a very 'safe' assumed MAF look up table allows you to run without, but it's less responsive and less powerful with it unplugged at a good stage 1 tune or higher.

If you know it's broken, replace it.

I had a customer the other week with a buggered MAF, he got one from a scrapper that afternoon off a 206 HDi for £15, plugged in, sorted. I very rarely see them not working so I can only assume your average 'fresh ish' scrapper will be fine for MAF salvage operations

Dave

[Poodle]

Was hoping you'd have some ideas on this Dave, look forward to seeing what you find.

We only unplug the maf as a diagnosis method, if running remains the same or gets better with it unplugged, then it's a fairly good bet the maf is f*cked lol. For some reason there's the odd person that thinks that means it's better to run with the maf permanently unplugged, regardless of our attempts to educate them otherwise, but you can't win them all i guess. As you say, if you know it's broken, replace it!

[Arron]

Suppose its nice to be able to unplug the maf to rule out performance issues, most recently my car had a slight bumpy idle, slight lag, and at higher revs seemed to hesitate slightly. I knew it was the maf, but unplugging it would of confirmed it.

I think its defiantly down to the ecu code... maybe someone has a spare ecu who's running a 976 and can swap it out to confirm or vise versa...

[Mr Whippy]

Suppose its nice to be able to unplug the maf to rule out performance issues, most recently my car had a slight bumpy idle, slight lag, and at higher revs seemed to hesitate slightly. I knew it was the maf, but unplugging it would of confirmed it.

I think its defiantly down to the ecu code... maybe someone has a spare ecu who's running a 976 and can swap it out to confirm or vise versa...

Thing is, unplugging MAF on a good stage 2 wouldn't have confirmed it, because the built-in MAF values are waaayyyy off those needed to run a good stage 2 fuelling.

You'd be down at just under stage 1 fuellings.


Changing something so fundamentally wouldn't allow you to confirm it in this case imo as the difference would be so huge!


ELM 327's can be had for about £15 these days off eBay, nice all in one cables too, and any half decent OBD scanning software can look at the basic sensors and you'll be able to confirm a lot more about the operation of your car/fault finding with them

Dave

[Arron]

Ah I get it now.

I have a galletto. Not sure what diagnostic programs I can use with that but its probably worth finding out

[Mr Whippy]

The £15 for an ELM is well worth the money imo.

I think there is some free software to watch different PID's over generic OBD protocols so can watch most sensors.

Lets put it this way, it's cheaper than guessing or swapping MAF's to find it's not fixed your problem

Dave

[Jonny81191]

Thing is, unplugging MAF on a good stage 2 wouldn't have confirmed it, because the built-in MAF values are waaayyyy off those needed to run a good stage 2 fuelling.

You'd be down at just under stage 1 fuellings.

This is true I forgot to plug mine back in earlier after fitting a filter, and it was godawful slow