ECU not learning,,,?

[DrRich 1]

Hi,

my ECU doesn't seem to learn any adaptation values. It's an OBD2 from a '96 Golf, in a Mk2 chassis. The previous owner did cut off the Carbon Canister solenoid (N80), so this always shows as a fault on VAGCOM, but I've heard others with the same code but whose ECU does learn.

Basically, in the measuring blocks for idle/mid range adaptation the values are always 0. I'd love to think that my engine has a perfect balance of air and fuel all the time, but that doesn't seem likely...

One other thing is that it may have been remapped in the past (it's been rolling roaded at Stealth but no mention of remap in the pile of receipts) to take advantage of Schrick cams and VGI which it used to have. The ECU is up behind the carpet on the bulkhead so not easy to get at and open up to check for an EPROM. If it has been remapped, does anyone know whether it's normal to 'deactivate' the self learning ability? Is there a way to tell from VAGCOM if it's been remapped?

I read that the ECU doesn't learn if codes are stored, so assumed the N80 code would do that. I've been meaning to hunt down the cut wires and attach a spare plug and valve I have, but the rat's nest of wires puts me off every time!

At some point soon I'll take it for a remap again, but just wonder what's going on?

Thanks for any advice...

Rich

[FishWick 21]

The ECU is expecting N80 to be connected, so I would reconnect it, even if you're not venting the carbon can into the intake.

Remappers often change the Eprom label file to their own name, so look for that in the top right corner of the engine module page.

Have you got an air fuel ratio guage (wideband - narrowband meters are next to useless) to verify that your ECU isn't in perfect tune? Although you are right, it's unusual to see an ECU not making minor adjustments at best.....

[DrRich 1]

Thanks Kev,

I suppose I'll have to brave the wiring... I can find the green/yellow wire as it exits the ECU but not sure where to tap into the blue/red return. Previous owner ran the wires down the chassis legs so can't get at it there...

I don't have an AFR gauge, been thinking about one - Innovate perhaps.

The car is modded - decat, VGI and 268 cams, 4 Bar FPR (because it was spare when the old when broke, not because I thought it would improve performance) amongst others so I can't believe it would run normal AFRs without adjustment. According to the Torque app on my phone, the STFT does vary when driving (usually +/- 5%, rarely up to -9% is the biggest I've seen) but LTFT sits firmly at 0%. I have put VAGCom on it and there is a Lambda reading which is usually around -12 to -15%, but it doesn't say any more than just "Lambda %" - can't remember which block. The idle and part throttle values have always been 0%.

[DrRich 1]

Well, Kev was spot on. After furtling around under the dash I eventually traced one wire from the ECU, and followed another from the fuse box. Spliced wires to a spare connector, plugged in a spare N80, and stuffed it up behind the fusebox. Test drive showed adaptation already!!!!! Result!!!!

Only problem is the valve chatters away while it's working - not normally a problem if it's in the engine bay but loud in the cabin!

Still, I'm more happy that the ECU is adapting so I'll live with the noise until I can be bothered to extend the wires...

So it looks like it's true that the ECU won't learn if faults are stored.

[FishWick 21]

Yeah if I remember correctly, N80 only directs carbon can vapours into the intake at idle, so if the valve isn't connected, that does explain your lack of adaptations.

Glad you solved it! Try wrapping the valve in some foam or something, which should quieten it down a bit!