Petrol 1.4 odd starting issue

S

smilesbernard

Member
Hello there
New to this group and trying to get through some wrinkles with my old A2 that has after 7 yrs of misuse found its way back to my ownership
I had a battery drain issues - sorted (wiring on the central locking showed up as a drain on circuit 36 and 42 I think)
Now I'm having odd staring issues and could really use some help
I don't have a code reader ... yet
Meantime it seems to start fine when cold but struggles after a short run or after cooling down a bit
I have seen I'm notnthe 1st with this issue and likely 1st thing to try is the temp sensor
That looks like a standard VAG G62 sensor. Is that right ?
Stupid question .... my temp gauge is not working atm. That's a completely separate problem right ? Different temp gauge completely for that? If so I'm struggling to know where that one is located :)
Also what best option for a workshop manual for these cars please .... as I'm wondering about trying to clean the throttle body too!

Many thanks for any pointers

Loving having the car back - super to drive. Need to keep the wife on board though so must get the starting issue nailed !

All the best
 
The temperature sensor has two separate elements in the same body. One feeds ECU, the other the gauge, so duff gauge may be (one half) of the sensor, use genuine VAG only.
Starting could also be, (the other half), of the sensor, especially if it was not genuine Audi/VAG.
Other suggestions will be available.

Mac
 
smilesbernard said:
...
Stupid question .... my temp gauge is not working atm. That's a completely separate problem right ? Different temp gauge completely for that? If so I'm struggling to know where that one is located :)
.....
Click to expand...
Good Evening,

Just to add to Mac's reply, Yes and No. The coolant temperature sensor on the A2 is two independent sensors in one (4 wires). One half reports to the ECU and other half reports to the instrument cluster. One half can work fine and the other half fail.

Andy
 
PlasticMac said:
The temperature sensor has two separate elements in the same body. One feeds ECU, the other the gauge, so duff gauge may be (one half) of the sensor, use genuine VAG only.
Starting could also be, (the other half), of the sensor, especially if it was not genuine Audi/VAG.
Other suggestions will be available.

Mac
Click to expand...
thanks for this - i see so the sensor drives ecu and gauge in single component with separate parts - great to know - many thanks
 
thanks for this all
just to check ... i just need an VAG G62 sensor? that is the sensor with 4 wires that does both functions ? Many thanks
 
Andrew said:
Good Evening,

Just to add to Mac's reply, Yes and No. The coolant temperature sensor on the A2 is two independent sensors in one (4 wires). One half reports to the ECU and other half reports to the instrument cluster. One half can work fine and the other half fail.

Andy
Click to expand...
My thoughts were that if both halves failed, you'd get no temperature gauge reading, and the ECU would not know the correct engine temperature. That's quite unlikely with a genuine VAG part but not so with a aftermarket part.
Could be loose connector, perhaps.
Mac.
 
smilesbernard said:
thanks for this all
just to check ... i just need an VAG G62 sensor? that is the sensor with 4 wires that does both functions ? Many thanks
Click to expand...
Slow down.

I note you have no code reader and you are just assuming and about to play part darts, guessing really, you may be right it but it would be good to have more evidence before doing anything.

You need to have the car scanned and monitor both halves of G62 to determine what coolant temperatures the instrument cluster and ECU are seeing. Either buy some diagnostic kit, VCDS is considered best or have the car scanned by a member of the Free Scan Register.

Roughly where abouts are you? The Register is here

Free Scan Register

This is a register of members who generously offer free scans for other members. To arrange a free scan: 1. Click the pdf map in the footer and choose a location. 2. Cross reference the location number in the table below to identify the member. 3. Click on their username on the left, click...
www.a2oc.net www.a2oc.net

VCDS Lite unregistered is free but limited, Mac is knowledgeable about options and what is involved.

Welcome by the way.

Andy
 
Last edited:
PlasticMac said:
My thoughts were that if both halves failed, you'd get no temperature gauge reading, and the ECU would not know the correct engine temperature. That's quite unlikely with a genuine VAG part but not so with a aftermarket part.
Could be loose connector, perhaps.
Mac.
Click to expand...
Good Evening Mac,

My guess is both halves of G62 have failed, we know the instrument cluster feed is suspect and if the ECU feed is bad then the ECU will forced to assume a cold engine with such associated (wrong if actually warm) fuel delivery and ignition timings, accounting for the hot start reluctance. Yes maybe the connector is suspect hence possibly both bad feeds.

Andy
 
Last edited:
Andrew said:
Slow down.

I note you have no code reader and you are just assuming and about to play part darts, guessing really, you may be right it but it would be good to have more evidence before doing anything.

You need to have the car scanned and monitor both halves of G62 to determine what coolant temperatures the instrument cluster and ECU are seeing. Either buy some diagnostic kit, VCDS is considered best or have the car scanned by a member of the Free Scan Register.

Roughly where abouts are you? The Register is here

Free Scan Register

This is a register of members who generously offer free scans for other members. To arrange a free scan: 1. Click the pdf map in the footer and choose a location. 2. Cross reference the location number in the table below to identify the member. 3. Click on their username on the left, click...
www.a2oc.net www.a2oc.net

VCDS Lite unregistered is free but limited, Mac is knowledgeable about options and what is involved.

Welcome by the way.

Andy
Click to expand...
Thanks Andy
Great advice and I'll work out what I need for a scan tool - I don't know much about this at all yet but have a computer background so will probably enjoy it
I assume that is free software
Wondering what the best cheapest compatible scanner is? Any recommendations most welcome
I'm based in thw SW between Exeter and Plymouth- I'll have a look at that free register - great idea
Thanks again
 
Andrew said:
Good Evening Mac,

My guess is both halves of G62 have failed, we know the instrument cluster feed is suspect and if the ECU feed is bad then the ECU will forced to assume a cold engine with such associated (wrong if actually warm) fuel delivery and ignition timings, accounting for the hot start reluctance. Yes maybe the connector is suspect hence possibly both bad feeds.

Andy

Andy
Click to expand...
Thanks Andy
Feels like a cheap option to replace this and based on your logic and the symptoms - it could well fix things
I'll give it a go!
I've read I need to also get a spare oring and clip so is it best to call my local VAG garage for these parts do you think ?
Many thanks for your help 👍
 
smilesbernard said:
Thanks Andy
Great advice and I'll work out what I need for a scan tool - I don't know much about this at all yet but have a computer background so will probably enjoy it
I assume that is free software
Wondering what the best cheapest compatible scanner is? Any recommendations most welcome
I'm based in thw SW between Exeter and Plymouth- I'll have a look at that free register - great idea
Thanks again
Click to expand...
There are many options for a scan tool. I don't think there is any free, (other than counterfeit/hacked), tool that will read measuring blocks.
VCDS Lite is free, and a KKL USB to Serial lead is under £10, but will only do a basic error scan. A payment of $99 will upgrade it to do everything you're likely to need, but only on pre 2005/06 VAG vehicles. So think about your applications then do your research. OBD Eleven is good, no cable it's Bluetooth, and available for Android and iPhone, good kit, useless support.
If you go the VCDS Lite route, and pay the $99, Ross-Tech will credit your purchase against a full version, which supports current production VAG vehicles, and is regularly updated.
Mac
 
I have both VCDS Lite and OBD Eleven. OBD Eleven is more convenient being Bluetooth.
VCDS wins for me though, as there is a huge amount of information out there, and Ross-Tech support is excellent. OBD Eleven support is poor, and biased to current and recent vehicles.
If you have a Windows laptop, for $99 it's a bargain. As Andy says, couple of minutes, and you'd know it the ECU engine temperature sensor was good or bad.
Mac.
 
Afternoon Again ?,

(Bernard I assume).

If you choose the VCDS Lite route you need a Windows machine (which can be very old) and a USB cable to connect the car to your computer. As Mac says cables available on ebay for a few pounds, most work but some don't. Personally, to avoid the adage 'buy cheap buy twice',

I would buy from a reputable supplier and it will probably be more robust but more expensive, I am thinking of this

www.gendan.co.uk

VW Audi Seat Skoda USB Interface for VCDS Lite - for most VAG cars 1996-2003

VW Audi Seat Skoda USB Interface for VCDS Lite - for most VAG cars 1996-2003 - only £19.94 including VAT & UK delivery!
www.gendan.co.uk

(You get an amazing email with the product!).

Andy
 
I have a Gendan cable, and two ebay cables, one two meters long. They all work perfectly, and the quality seems much the same. I've had the first, ebay, cable for about six years, since buying the Mk1 TT, in 2017.
Mac.
 
Andrew said:
Afternoon Again ?,

(Bernard I assume).

If you choose the VCDS Lite route you need a Windows machine (which can be very old) and a USB cable to connect the car to your computer. As Mac says cables available on ebay for a few pounds, most work but some don't. Personally, to avoid the adage 'buy cheap buy twice',

I would buy from a reputable supplier and it will probably be more robust but more expensive, I am thinking of this

www.gendan.co.uk

VW Audi Seat Skoda USB Interface for VCDS Lite - for most VAG cars 1996-2003

VW Audi Seat Skoda USB Interface for VCDS Lite - for most VAG cars 1996-2003 - only £19.94 including VAT & UK delivery!
www.gendan.co.uk

(You get an amazing email with the product!).

Andy
Click to expand...
Thanks for this Andrew that's very helpful
Just starting a new job but I'll look into this soon and make a call
 
You must log in or register to reply here.
Back
Top