Hi all,

 

I believe I posted about this issue before as the car was running rich to offset this lean running issue. It still isn't running quite right, despite a replacement front section/downpipe, pair of new lambda sensors, and a new manifold pressure sensor. All the sensors fitted are Bosch/NTK/VW OEM spec sensors. I've been dealing with this for some time, with my wallet taking the brunt of it.

 

Note - The engine cutting out issue I had previously was resolved by replacing the pre-cat lambda sensor.

 

Although the worst of the running issues was resolved, I still see inconsistent fuel economy (measured with Fuelly) with it varying wildly between 28mpg and 56mpg (on one occasion). Instead of furthering my parts darts crap (although a few things were actually FUBAR, like the downpipe which was amusing until I was nearly gassed), I decided to finally get VCDS-Lite running to find some fault codes. This is what I've found:

 

Control Module Part Number: 03E 906 023 D

Component and/or Version: SIMOS91 1.2l 4V 9510

Software Coding: 0000071

Work Shop Code: WSC 13765

 

1 Fault Found:

16555 - Fuel Trim; Bank 1: System Too Lean

P0171 - 006 - Short to Plus - Intermittent

Readiness: N/A

___________________________________________________________

 

As far as I'd read on here and elsewhere, many of these issues are caused by dicky pipework and suchlike, particularly the PCV valve and brake servo hose. The former looks fine, and felt alright too. The latter had split previously and was replaced for a brand new TPS part. As discussed with Breezy_Pete previously, he suggested 'short to plus' would indicate an electric issue, but I'm wondering if there's anything specific I should be concerned about. Both of the earth leads (I had one, and then fitted another) are perfectly grounding the car when it's checked with a multimeter.

 

I have, of course, tried the old 'IT Crowd' method of "Have you tried turning it off and on again?" - this has caused no change, besides me having to set the clock and my stereo again.

 

As a potentially related note - I seem to have an electrical gremlin that crops up periodically, where if I have the headlights and wipers on, the car sometimes switches both off and on again at random, causing the likes of the wiper relay to reset. May be related as I think this is a grounding issue, but not sure where to start.

 

If it isn't clear, I'm not sure where to start at all in sorting this out, I've tried ruling out usual suspects but could do with more advice before I go completely insane and set this bloody thing alight or something.

 

Cheers.

Edited 28 December, 20223 yr by AnnoyingPentium

What's the mileage?

Plugs OK? Gapped correctly and a good spark? 

Maybe consider a compression test. 

 

Just a couple of almost 2am thoughts.

Edited 29 December, 20223 yr by @Lee

http://wiki.ross-tech.com/wiki/index.php/Fuel_Trim_Info

19 hours ago, @Lee said:

What's the mileage?

Plugs OK? Gapped correctly and a good spark? 

Maybe consider a compression test. 

 

Just a couple of almost 2am thoughts.

 

Mileage - 72,000 (nearly)

Plugs are gapped correctly, good spark. Changed at 62k.

 

11 hours ago, sepulchrave said:

http://wiki.ross-tech.com/wiki/index.php/Fuel_Trim_Info

 

Had a look at this, and the attached video. I can retrieve the VCDS figures tomorrow if/when it's a bit less rainy.

It is worth replacing the vacuum hoses and pcv valve if you haven't done all of them. Sometimes the splits can be very hard to spot unless you take them off and give them a good flex (had it on my PD octy once). and I assume you've used a decent fuel cleaner like Archoil to make sure its not gummed injectors?

49 minutes ago, robt100 said:

It is worth replacing the vacuum hoses and pcv valve if you haven't done all of them. Sometimes the splits can be very hard to spot unless you take them off and give them a good flex (had it on my PD octy once). and I assume you've used a decent fuel cleaner like Archoil to make sure its not gummed injectors?

 

I've done the brake servo one as it had split. Yet to check the rest, but the PCV valve seemed alright last time I checked.

 

Haven't used an fuel cleaners or stuff like that really. I've driven it like I've nicked it quite a few times to try and gut things out, Italian tune-up, in other words, but no joy.

Have you replaced the CTS during your 'parts darts' campaign?

Just now, sepulchrave said:

Have you replaced the CTS during your 'parts darts' campaign?

 

Have not touched the coolant temperature sensor on this. Although, I would not be surprised if it was actually the problem the whole time, knowing my luck/sod's law etc.

8 hours ago, AnnoyingPentium said:

 

Have not touched the coolant temperature sensor on this. Although, I would not be surprised if it was actually the problem the whole time, knowing my luck/sod's law etc.

 

It's cheap, replace it, there's no possibility it'll be giving an accurate reading after all this time.

Get a genuine one too. Some of the cheaper ones are poor.

 

Part number 06A 919 501 A

Edited 5 January, 20233 yr by TMB

Look what it's reading in engine ECU measuring blocks when engine is at ambient and operating temperature. 

10 hours ago, sepulchrave said:

 

It's cheap, replace it, there's no possibility it'll be giving an accurate reading after all this time.

 

8 hours ago, TMB said:

Get a genuine one too. Some of the cheaper ones are poor.

 

Part number 06A 919 501 A

 

Cheers guys. I'll get a hold of one.

 

8 hours ago, Breezy_Pete said:

Look what it's reading in engine ECU measuring blocks when engine is at ambient and operating temperature. 

 

I take it you mean with VCDS? 

Yep. No sense in replacing it if the readings are good.

Replaced the coolant temperature sensor today, preliminary testing indicates the code has gone, but will do some more runs with the car to see if that is still the case. Photo below is to help anyone who may be looking for the same sensor on their car.

 

Just now, AnnoyingPentium said:

preliminary testing indicates the code has gone

Nah, you jinxed it now 😄

Hopefully it's all good now. 🤝

9 minutes ago, varooom said:

Nah, you jinxed it now 😄

 

It's a Mk1 Fabia, now that I've sorted this, something else will go!

Did you manage to get a genuine sensor, Ryan?

13 minutes ago, TMB said:

Did you manage to get a genuine sensor, Ryan?

 

I bought a Febi Bilstein one. I've had their stuff before and it's been pretty decent, so hoping this is the same. Was about the guts of a tenner and was here in a day or two.

I've always found Febi Bilstein to be decent too

1 minute ago, TMB said:

I've always found Febi Bilstein to be decent too

 

The dog-bone mount I've got here is the same brand (I'll get around to that eventually, it's not any worse at the moment), seems like a good bit of kit, and I'm sure I've fitted more of their stuff before.

 

Very disappointed for you Ryan, but you should've listened to uncle Pete and looked to see if the old one was giving odd readings before that throw of parts darts.

There was a thread very recently where a blocked precat was giving weird symptoms on a 1.4/16V. Might be worth a torch-facilitated look through the hole that the precat lambda sensor goes in?

 

What is the MAP sensor pressure reading at idle with cold and fully warm engine?

(Happy to compare with ours)

19 minutes ago, Breezy_Pete said:

Very disappointed for you Ryan, but you should've listened to uncle Pete and looked to see if the old one was giving odd readings before that throw of parts darts.

 

Aye you're right. It didn't cost me too much so I'm not really too bothered, thankfully.

 

15 minutes ago, Breezy_Pete said:

There was a thread very recently where a blocked precat was giving weird symptoms on a 1.4/16V. Might be worth a torch-facilitated look through the hole that the precat lambda sensor goes in?

 

Good shout. I'll have a shot at the weekend I think.

 

16 minutes ago, Breezy_Pete said:

What is the MAP sensor pressure reading at idle with cold and fully warm engine?

(Happy to compare with ours)

 

I haven't got any recent readings, but can do that tonight, once I remember how to work VCDS-Lite!

The car has presented the delightful little amber light of doom. Will run a code reader over and see what the story is. I'm hoping it'll bring another code with it.