Greentech, Engine control light, firing but not starting

[speckle]

Hi!

Anyone have similar issue to this?

Car driving fine on sat / sun. Went out to use it this morning (weds) and ignition fires but engine doesn't start.
Check engine light on ( officially called Emissions Control Light). 
Pop bonnet. Have a look around. Nothing.... until I spot that the air filter box has come loose from the two pin type fixings and the round rubber ring  that goes over the circular exit at the front right. Everything else is still in place. 
I can't think how it's become loosened and can't see any obvious broken fixings or housing.
I pressed it all back into place and tried starting again, but no difference. 

So my question is... is the fact that the filter box was loose incidental or coincidental.
Is the engine check light on because there was too much air getting in and causing a fuel imbalance? (no I don't fully understand what i'm saying but I've been searching forums like mad and have an inkling that this might be possible?)

Or could it be a complete coincidence and am I potentially looking at a different issue?
The car does sound a bit like it's misfiring but no bangs or putt putt sounds, no plumes of black smoke evident
A couple of random flashes of the battery light but doesn't stay on
I managed to dig out my security bits and get the filter box cover off enough to peek at the filter, which is admittedly dusty (not sooty or black but obvious dust)

Weather had been... frost.... rain... rain and I know that skodas can get a bit damp....

I have breakdown cover but am not sure if they'll do both roadside and recovery as I'm within 1 mile of home and there's a limit of £65 cost apparently.

Does anyone have an idea of what this might be or what steps I can take myself to work it out?
Failing that, if the recovery person manages to start it, is it likely safe to drive to an electrical specialist (about 6 miles) or is there any risk it could cause further damage?


Sorry for the essay but wanted to get down everything I could think of.
Would really appreciate any input, thanks!

 

[KenONeill]

9 hours ago, speckle said:

is the fact that the filter box was loose incidental or coincidental.

Yes. I think it may well be a symptom in that it was knocked loose by the rough running rather than the cause of same.

 

Beyond that, I think you may well need a fault code to diagnose the actual issue. Kudos on including everything else though.

[speckle]

1 hour ago, KenONeill said:

Yes. I think it may well be a symptom in that it was knocked loose by the rough running rather than the cause of same.

 

Beyond that, I think you may well need a fault code to diagnose the actual issue. Kudos on including everything else though.

Thanks Ken. I'm currently debating whether or not to book in with an electrical specialist or the local garage and whether or not to change the filter before I do that.
Don't want to have too much time with car off road but will kick myself if it's something simple I could have picked up on.

[freemansteve]

How did you determine "ignition fires" ?  Does the car partly run, kind of trying to pick up?

It'll usually come down to one of a) lack of fuel being injected, b) lack of spark or c) immobizer

 

Easiest check first - If c), I'd disconnect and reconnect the battery to reset the ECU etc, (like you would re-power a PC), then go through the key-coding procedure (in the manual).

 

Check plug leads end-to-end. A long shot theses days though, as HT is buried in the coil packs....

 

Least likely is fuel filter (pain to get to) or most expensively, HP fuel pump....

 

 

 

 

[speckle]

47 minutes ago, freemansteve said:

How did you determine "ignition fires" ?  Does the car partly run, kind of trying to pick up?

It'll usually come down to one of a) lack of fuel being injected, b) lack of spark or c) immobizer

 

Easiest check first - If c), I'd disconnect and reconnect the battery to reset the ECU etc, (like you would re-power a PC), then go through the key-coding procedure (in the manual).

 

Check plug leads end-to-end. A long shot theses days though, as HT is buried in the coil packs....

 

Least likely is fuel filter (pain to get to) or most expensively, HP fuel pump....

 

 

 

Sorry... probably using the wrong terminology. Car initiates but engine doesn't start. well it did for about 1 second on a couple of occasions.
No indications of any issues at all when last driven 3 days before.
My thoughts are around fuel / spark too, which could make sense with fuel air filter having been loose and the fact that the air filter does need cleaning.

The thing that's making it more of a mystery is that there was nothing running up to this to indicate an issue

 

 

[freemansteve]

Hmmm, as already said, the air filter is probably a consequence not a cause, and even if it's 'dirty' the engine should start (it does not suck much air for idling).

 

Could still be an immobilizer issue - I'm not certain if it's the ignition that is blocked, or whether the engine stater motor is also blocked, if the car is in an immobilised state. Try what I said above.

 

Do you have an OBD dongle to check any fault codes ?

 

[KenONeill]

2 hours ago, freemansteve said:

I'm not certain if it's the ignition that is blocked, or whether the engine stater motor is also blocked, if the car is in an immobilised state.

Well, anything I've driven with an immobiliser and fuel injection, the immo blocked the starter motor and/or the injection system.

Edited 3 December, 2021 by KenONeill

[freemansteve]

Indeed - as you say yourself "starter motor and/or the injection system"

Has anyone checked what the Citigo or Up! does (or doesn't do) if immobiliser is activated?

I've no idea myself!

 

 

[speckle]

On 03/12/2021 at 12:41, freemansteve said:

Hmmm, as already said, the air filter is probably a consequence not a cause, and even if it's 'dirty' the engine should start (it does not suck much air for idling).

 

Could still be an immobilizer issue - I'm not certain if it's the ignition that is blocked, or whether the engine stater motor is also blocked, if the car is in an immobilised state. Try what I said above.

 

Do you have an OBD dongle to check any fault codes ?

 

Funnily enough I borrowed one yesterday (not on your advice but because I was thinking along the same lines. Only just saw your comment today as was working til late yesterday and then off out to collect the diagnostic.

So... updates

Since I initially posted. I went out the following day to try again. Checked the wiring. Checked the fuses in the engine box. Unscrewed the front side and top of the filter box (didn't have right tool to take the back 3 off)... filter actually wasn't that bad. So I started to wonder if the box working loose had upset one of the sensors.
Anyway I tried to start the engine and it initiated but didn't start. This time different lights illuminated - the EPC and the battery light (battery red).
Same thing happened 2 or 3 times.

So I went back out this afternoon with the OBD, plugged it in... it read 4 codes and then came up with 'linking error' message, tried a couple more times, same thing. I'm thinking 'oh no'... perhaps I need a different, more up to date code reader. So I did a few more checks... everything in the engine compartment that I could get too, using an inspection light this time. All connections in firmly, all piping secured. Also went under and checked the exhaust. Then tried the fuse box under the dashboard. Pushed all of the fuses firmly in.

Then started it, not thinking it would have changed anything.
Started first time. Bit faltering on the revs, but started.
Switched it off and tried again. Started. Less faltering this time. Purring.
Tried a third time. Same... took it for 3 short drives.

Zero dashboard lights
Everything appearing to work. 

Not convinced that the car sounds right though

So now I'm really uncertain (think my car is gaslighting me)... Did the petrol air box (or whatever version of the name you use) becoming loose affect the air intake filter and did resetting it make the difference... or have I got something on it's way out?

[speckle]

*air intake sensor! 

I meant to say that not filter.
Honestly so tired this week I am really not explaining myself well

[freemansteve]

Aha! We're glad you are sorted, or at least mobile.

 

I think the sensor you're talking about is the MAP sensor (manifold absolute pressure), so if disconnected, the ECU sees zero air pressure, so zero fuel is needed, so it decides it's a fault, not unreasonably

 

 

Edited 6 December, 2021 by freemansteve

[speckle]

2 hours ago, freemansteve said:

Aha! We're glad you are sorted, or at least mobile.

 

I think the sensor you're talking about is the MAP sensor (manifold absolute pressure), so if disconnected, the ECU sees zero air pressure, so zero fuel is needed, so it decides it's a fault, not unreasonably

 

 

Thank you!
That's a big help.

Took test run to Aldi. Car wouldn't start from the carpark (after shopping TG). Got recovered home. Was hoping with roadside assist I'd get an indication from driver but no.
Failing MAP sensor would make sense of the engine fan not turning off in the summer wouldn't it? As it also senses temperature.
I had some incidents where it was running much longer than usual. On one occasion it wouldn't stop running for hours even when disconnecting the battery and reconnecting it. Didn't stop until I'd left it overnight with the battery unplugged. Took it to an electrical specialist for a check afterwards but they couldn't find anything and the fault didn't reoccur while they had it for the day. Haven't had the problem since but then we haven't had the hot weather since. 

I didn't think to check for VW up faults / how to videos. Good call, I'll bear that in mind as there's more info on VW up than the citigo online.