Thread: Help needed to understand Nanocom EVO Codes from my D2 Td5

OK I had a quick look around to see where the ECU wires run from the TPS.I had a fiddle under the dash at the accelerator pedal just quickly.I hooked up the nanocom and left the ignition on and started pressing the throttle but the engine light started flashing.So I stopped.Now heres the strange bit.

I started the car up to see if all was ok.It started first go as per usual.But now the car revs beautifully with no flat spot or hesitation.I can hold 2000RPM in park and it holds there as smooth as silk. The other strange thing is there use to be a vibration at idle and now that is gone as well.When I mean gone I mean less severe.The motor seems smoother at idle with less shaking.

I don't know what to make of it.

Originally Posted by SPROVER

OK I had a quick look around to see where the ECU wires run from the TPS.I had a fiddle under the dash at the accelerator pedal just quickly.I hooked up the nanocom and left the ignition on and started pressing the throttle but the engine light started flashing.So I stopped.Now heres the strange bit.

I started the car up to see if all was ok.It started first go as per usual.But now the car revs beautifully with no flat spot or hesitation.I can hold 2000RPM in park and it holds there as smooth as silk. The other strange thing is there use to be a vibration at idle and now that is gone as well.When I mean gone I mean less severe.The motor seems smoother at idle with less shaking.

I don't know what to make of it.

Pressing the throttle several times with the ignition on triggers the purge sequence on the fuel system, as indicated by a flashing check engine light.
Can't help with the rest.

Originally Posted by Disco Muppet

Pressing the throttle several times with the ignition on triggers the purge sequence on the fuel system, as indicated by a flashing check engine light.
Can't help with the rest.

Yeah that's why I stopped.I remembered that after reading it on here somewhere.I wanted to get a reading off the nanocom for OffTrack but I better make sure its the correct way to do it first.It still doesn't explain why it runs much better now either. I haven't driven it yet and wont be able to until later in the day.

But now since it has been idling smoother I have also noticed all the vibrations from in the car have stopped.For example the glove box doesn't vibrate and make noise.Either does my boost gauge on the pillar.Strange very strange!

Originally Posted by SPROVER

Yeah that's why I stopped.I remembered that after reading it on here somewhere.I wanted to get a reading off the nanocom for OffTrack but I better make sure its the correct way to do it first.It still doesn't explain why it runs much better now either. I haven't driven it yet and wont be able to until later in the day.

But now since it has been idling smoother I have also noticed all the vibrations from in the car have stopped.For example the glove box doesn't vibrate and make noise.Either does my boost gauge on the pillar.Strange very strange!

There isn't exactly a correct way to do it.

It more a case of thinking through the question "how can we get data that will help identify the issue out of the Nanocom"? The Nanocom only gives you the numbers - it up to the "pilot" to make sense of them.

The Nanocom samples once per second so you'd need to make a single zero to full stroke cover 20-30's. If you do a purge sequence which is 5 rapid strokes you won't see anything worth while.

The fact that fiddling with the wiring under the dash has helped is probably a good indicator that there is an intermittent wiring fault or contact in that area. You might want clean the plug with contact cleaner and make sure none of the contacts have backed out.

cheers
Paul

Well after doing about another 60 km the problem has come back again It's starting to slightly miss at light throttle as per usual. I left it at my brothers place tonight because I didn't want to drive it all the way home So just to confirm with you Paul.I should turn the ignition on and record the throttle inputs for about 2-3 min by pressing it to the floor and releasing it?

Will the engine light stop flashing or doesn't it really matter? Just keep pressing away? I always read about how temperamental these td5s can be. I think I might take you up on that offer Paul to see if it fixes the problem.
Cheers
Chris

Originally Posted by SPROVER

Well after doing about another 60 km the problem has come back again It's starting to slightly miss at light throttle as per usual. I left it at my brothers place tonight because I didn't want to drive it all the way home So just to confirm with you Paul.I should turn the ignition on and record the throttle inputs for about 2-3 min by pressing it to the floor and releasing it?

Will the engine light stop flashing or doesn't it really matter? Just keep pressing away? I always read about how temperamental these td5s can be. I think I might take you up on that offer Paul to see if it fixes the problem.
Cheers
Chris

The purge mode is triggered when you pump the pedal 5 time in a couple of seconds. If you do it slowly you shouldn't set it off.

It may well be a pointless exercise as it seems to be triggering at reasonably long intervals.

I'm suggesting doing the recording as a way of checking the TPS response and to see if there are any anomalies. Because the Nanocom records data at roughly 1 second intervals you'll want to move the pedal evenly and slowly through the range of travel. If you take 30 seconds to go from 0% - 100% throttle you'll have 30 data points from the pedal. Recording two full cycles at that pace will give a pretty decent idea of how the throttle is behaving.

cheers
Paul

Ok I just got the reading off the nanocom.I drove the car from my brothers place earlier on and it was fine again No missing and was still smooth.I did as you said and just left the ignition on and pressed the throttle down slowly till it reached the bottom.Then released and repeated the same.
I hope these readings make sense to you Paul. I have no idea.

Doesn't look like there is too much wrong in the recording, but unless you caught the conditions that are causing the fault it's not too surprising.

You can see track one and track two moving in opposite directions. The supply looks fine.

c4+c5 is track 1 and track 2 added together. They should be close to the supply voltage so there is a bit of discrepancy there. Not 100% sure what is acceptable in that regard.

Anyway it's not obviously bjorked, but that doesn't preclude an intermittent fault.

The fact that wobbling the wiring seems to have made an improvement bothers me. I'd be investigating the connectors and continuity in the harness just to make sure it's not a wiring fault.

Otherwise it's looking like a pedal change might be worth trying.

cheers
Paul