Another Starting Problem... but possibly a one off?! (1.4 petrol 2003)

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jonbad

jonbad

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Hi all,

Hopefully a simple one for all you A2 gurus out there!

Car started fine several times today, but has been sat for the last 2 weeks with only occasional starting as I'd been doing it up etc.

Drove to a local supermarket and parked up (temp up to 90), did some shopping and then went back to the car and it would not start a few times.

The symptom was it turned over fine (i.e. battery was fine) but it would not catch for 3 to 4 attempts, then it did start. Temp would have probably dropped to 45 or thereabouts after the shopping duration. I might have put a little throttle and pushed the clutch down to ease the rotation of the engine but I don't know if that would affect it. The only other thing was the fuel was pretty low. Mind you, not low enough to give me a fuel warning light. As the car started on the 4th/5th attempt, I drove it to a petrol station and filled it up completely - and in the meanwhile obviously turned the engine off - and the car started absolutely perfectly on the forecourt and engine temperature was at 90.

So, is this a crankshaft sensor problem, a throttle body, something else entirely, or merely a low/dirty fuel issue and a one off?!

Any help/advice would be very much appreciated.

Thanks in advance!
 
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The symptoms are too vague for an accurate diagnosis so it would be useful if you could have a diagnostic scan to see if this highlights any fault codes.

Cheers Spike
 
Thanks Spike - I had hoped it would be something obvious/common, but of course it could be caused by several things as you suggest. Does anybody have a VAGCOM diagnostic machine/computer around Hertfordshire/St.Albans area that I could plug my car into, to find out?
 
Thanks Bret, I had wondered about that upon looking at other's threads/posts but didn't want to suggest in case it was something else entirely.
 
Hi jonbad, please let us know how you get on, I have exactly the same fault on my 1.4 petrol. Starts from cold fine, hot engine,fine. If it has been left for 40 to 50 mins from hot takes ages to start.
 
Just to update on my car's status, since the non-start and reason for posting this thread, in typical car fashion, it has not repeated the symptoms at all and it has started on the button religiously ever since the "hiccup"! So, fingers crossed and touch wood all seems ok and it could have simply been dirt in an injector or similar. Of course I would love to check the earth points as kindly suggested by Bret, but I have had a look (albeit brief) on this forum for instructions as to how to get access to them and so far come up with nothing. If anybody who has fathomed out how to use this forums search facility can help me out, I'd be very grateful!

As a second point, I have gotten myself VagCom and am awaiting the cable to arrive so I will plug it in and run a diagnostic as soon as I can to update on this issue, see if any faults were thrown up at the time. Also I would be willing to plug it into any other A2 owners cars who live local to St.Albans, but please note I have not yet got much of a clue as to how to use it properly, but I am software capable so will pick it up quickly I'm sure.
 
A further update, this morning went to the station (about 3-4 miles) no problems, then stopped at the station for a few minutes and got back into the car, went to start it and it didn't fire up as had happened at the start of this thread. Turned off ignition and tried again, and it started but had low revs so required a little throttle to keep it alive. It's almost as though the idle speed isn't high enough. Anyway, my vagcom cable should arrive today so I will plug that in and see what it says and post a further update. Am thinking that the throttle body would benefit from a clean so will be attempting that either this week or next to see what that does.

Lastly, Could anybody point me in the right direction as to how to get at the A-pillar earth points without breaking bits of trim?!
 
Update to last post: Since receiving my OBD2 cable, I've run a full VAGCOM diagnostic scan.
The only engine fault found was an intermittent coolant temperature sensor reading too high. Nothing aside from that engine wise, so I've cleared that fault and will check again if the issue repeats itself. Not yet got around to checking the earth points in the A-pillars due to the current weather!

Aside from the engine, there is an issue reading VagCom number 08, Auto Hvac but I've seen that other people have also had this issue come up. The unit itself works beautifully and without issue though. Anyway, that's another story for another thread!
Only other faults detected were a radio fault and the alarm has been set off a few times in the long distant past.
 
A faulty coolant temp sensor could affect fuelling which would contribute to poor starting.

There a few tips on A pillar trim removal here - http://www.a2oc.net/forum/showthread.php?t=5562&highlight=glovebox+removal

I'd add that I also partially lift the carpet (peel it away from the door opening trim) and pull off the rubber seal around the bottom of the door opening (make a note of how it fits with the plastic trim first) as this allows better finger acces to lift the trim.

Cheers Spike
 
Going to check the A-pillars this morning, and do another VAGCOM scan as starting issue happened again this morning. Found this diagram on vagcat.com which seems to confirm Bret's input stating the covers are just clipped in - thought it might be useful for the other people with similar starting issues trying to view their A-pillar earth points.
View attachment 9097

Edit: The A-pillars are a "pull off", but you need to be fairly forceful and careful at the same time. There are three clips (not 2 as shown in the diagram). The easiest way to remove the trim is (standing outside the car) reach in and pull up on the inner edge in various places along the lower length of the trim (the edge that adjoins the carpet). Once you've done that a bit, you should have heard the clips come out a bit and the trim may well be bulging in the middle slightly. Next put one hand under the trim where the rubber seal is and the other beneath the trim where it is next to the carpet (so on either side of the trim) and then pull up gently along the length again. This should unclip the three clips. Be aware that at either end of the trim it is clipped into the adjoining trim pieces, one small long thin part that goes higher up the A-pillar and the other is the continuation of the door shut.

All earth points are as good as new, no sign of any corrosion and nothing loose etc. so that is not the problem...

To describe the problem a little further, the non-start is almost like either the immobiliser has not deactivated (i.e. no fuel is sent to the injectors) and when it does start, it's as though the revs are too low, i.e. the autochoke is not open enough.

So... I'm thinking that it is possibly the throttle body as (being critical) the idle and throttle response is a little on the rough side and I have been able to start the car by giving it a little throttle. I know that back in the day, it used to be standard procedure to put your foot on the throttle completely then take it off, then attempt to turn the engine over so I will try this if/when the non-start occurs again to see if it is throttle related. I had planned to clean out the throttle body anyway, but the car is in use everyday so this is tricky to time when to set about doing it!


PS. Under the passenger (near) side trim, I found these two clips:
CIMG4405.JPG
They look to me like they're some kind of wire clip, but there weren't attached to anything and they certainly didn't have any wires in them. I couldn't see where they'd come from, and actually they were kind of wedged under the carpet rather but that would be inacessible to anybody but Audi/garage/previous owner who took the A-pillar trims off before me. Any ideas what they are?!!?

spike said:
A faulty coolant temp sensor could affect fuelling which would contribute to poor starting.
...
Cheers Spike
Click to expand...

Thanks for the info Spike. Yes, it might be worth me investigating and replcing this part considering what you say. The only thing that I wonder is that the results from this mornings VAGCOM scan came up negative with regard to any fault with the coolant temp sensor, so presumably there wasn't a fault with it this morning when the car didn't start immediately. Can't hurt changing it though eh! Where is it located?
 
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Changed the temperature sender today, it was a bit of a hassle with largish hands but would be ok for anybody with tiny hands. The clip was a bit of a nuisance as it wouldn't go onto the new sensor easily as it was an extremely tight fit to get the tongue to go over the hook. Anyway, managed in the end. As others have stated, you lose about a pint or so of coolant in the process but not the end of the world. I would recommend when filling the coolant reservoir (so with the cap off) that you squeeze the upper radiator hose which pumps the system and gets any trapped air out - old mechanics trick.
Next up will be the throttle body, just gotta go and collect the gasket from Audi today.

jonbad said:
PS. Under the passenger (near) side trim, I found these two clips:
View attachment 9098
They look to me like they're some kind of wire clip, but there weren't attached to anything and they certainly didn't have any wires in them. I couldn't see where they'd come from, and actually they were kind of wedged under the carpet rather but that would be inacessible to anybody but Audi/garage/previous owner who took the A-pillar trims off before me. Any ideas what they are?!!?
Click to expand...

*Bump* anybody any ideas?
 
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Throtte body now cleaned so have now completed the following fault finding issues:

1. Checked A-pillar (and other) earth points. - All fine.
2. Replaced temperature sender unit - £2.40 from ebay, plus 30 mins to fit.
3. Cleaned throttle body - £2.30 gasket from Audi, carb cleaner (I already had some) plus 1hr remove, clean & refit.

The car does seem to already be running much smoother now and the temperature sensor actually seems to be saying it is getting up to temperature more slowly than the previous sensor that it replaces. I could assume from this that when I was having the non-starting problem, that it was because the temperature sensor was saying "hot" when actually the engine was cold, and so an incorrect choke was being applied as a result. Also the throttle body having been FILTHY wouldn't have helped any compensation in the butterly movements, whereas now it is much more free to move as needed and the air flow is more consistent and 'easy'.

*TOUCH WOOD* so far I've not had a repeat of the non-start.
 
Hi jonbad. I am going to have a go at changing the temp sender when it stops raining. Had a quick look yesterday, do you have to remove anything to get to the sender? If I have identified the position of it correctly, it seems impossible to get to it. Also,did you have to re-calibrate the throttle with VAG COM after you cleaned it?

Thanks for up-dating this thread,
 
Hank said:
Hi jonbad. I am going to have a go at changing the temp sender when it stops raining. Had a quick look yesterday, do you have to remove anything to get to the sender? If I have identified the position of it correctly, it seems impossible to get to it. Also,did you have to re-calibrate the throttle with VAG COM after you cleaned it?

Thanks for up-dating this thread,
Click to expand...

No need to remove anything, though the job did make me wish I had much smaller hands for this kind of thing! I replaced the temperature sensor rather than cleaning it. it is a push fit against a rubber o-ring and is then held in place with a black plastic 'horseshoe' as you can see in this photo:
Audi A2 Temperature Sensor.jpg

The location of it is as shown in this photo:
Audi A2 BBY Temp Sensor Location.jpg

And the parts diagram:
Audi A2 Temp Sender Location.jpg
As seen here: http://www.vagcat.com/epc/cat/au/A2/2003/248/49/3096788/

Notice on the parts diagram that there is (what looks like from the outside) a blank (item number 10 on the image) to the left of the temperature sender. On that diagram, where number 7 is would be where the side of the engine is.

Mine was a 4 pin green type temperature sender, cost £2.40 inc. delivery from ebay with an alleged 2 year warranty. So far, it works perfectly but I've only had it installed a few days.

Hope that helps.
 
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Just as a final closing comment to this thread. All has been well for over a month now since replacing the coolant temperature sensor. No more non-starting issues at all; so seems to have been the culprit.
 
jonbad said:
Just as a final closing comment to this thread. All has been well for over a month now since replacing the coolant temperature sensor. No more non-starting issues at all; so seems to have been the culprit.
Click to expand...

Thanks for the update. Its always useful to know when things work out (or don't for that matter)

Cheers Spike
 
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