1.0 won't start when hot weather/engine hot.

[Dannijaime]

So some may remember I had the issue with the car not starting atall and vagcom have me loads of codes and none helped point me in the direction that wires had become loose lol but one of the codes was about the O2 sensor.

Now the wirings all fixed and car starts... Usually! If I leave her in the sun and the car heats up the engine won't fire in just turns over, and like last night I can literally be stuck for 3 hours waiting for it to cool down. Also happens of I get fuel for example and when I got to start it back up because its warm it won't start and have to wait for it to cool down again! I had a problem with the oil breather as it was overly clogged and smoking like a trooper, however that's been cleaned out and still having the issue, also the temp gauge is iffy but being a normal lupo fault I've over looked this, if I stop at lights or something ill notice the temp has dropped right to the bottom then ill start driving again and it'll come back up to the middle. I'm waiting to get it plugged in again but may be a few weeks, any ideas? I've been thinking 02 sensor but starting to doubt myself!

[matt123roll]

Have a look into replacing the coolant temp sensor

There's a thread on here about a guy having similar issues when he pops to the shop, he'd go in for something come out and the car wouldn't start until it cooled down. He resolved it by replacing the coolant temp sensor so it's worth a shot.

Sounds like a mighty annoying problem!

[Skezza]

This might sound stupid, but along with the coolant temperature sensor perhaps theres a heat soak issue. I assume your Lupo is standard? You've not fitted any aftermarket air filters etc?

[Dannijaime]

Annoying doesn't cover it! Had to wait 3 hours after work yesterday and nearly 2 hours tonight just for it to cool down to start! Yeah that would explain the temp fluctuating too! Any idea where on the car this is or how much they are? I'm gonna mosey on ebay but if cheap enough can crab one from vw Monday morning!

Edited July 5, 2013 by Dannijaime

[danoid]

Drop by your local vw tomoz, should have one, if not a quality one from gsf should do! Make sure you buy the o-ring and have enough coolant to top it up as it'll piss out when you remove it

If you take the top part of your engine off (plastic bit) it'll be to the right at the front.

When you sayit doesnt start what does it do? I say this because my old A6 when it was hot, wouldn't turn on first time because the starter solenoid wouldn't eject to start the engine. Think I hit the starter motor and was alright in the end.

[Dannijaime]

It just turns over until it's cool enough, I've found a few on ebay but I'm gonna ring vw tomorrow and fingers crossed if they have one ill do it on Monday, is it hard to do? I'm gonna look for some guides online of you can recommend any. The reason temp sensor makes sense is because the temp gauge plays up whilst I'm driving, it'll completely drop down to 0 on idle then usually comes back up after a few feet lol

[danoid]

I was thinking of making a guide when I replaced ours, but was so simple it wasn't really worth it, but I did make a mistake.

Is your engine an AUC?

If so follow below

+ Take off top engine plastic, 2 x 10mm bolts, few pipes to remove (left+right of engine cover)

+ Locate coolant temperature sender

+ Remove cable that goes to it

+ Remove plastic clip

+ Pull out sensor

+ Quickly remove o-ring if it doesn't come out with sensor, will have to use your finger to pull it out - Whilst this is going on, all your coolant will leaking out very quickly.

+ Insert new coolant temperature sensor (with o-ring already onit)

+ Push in black clip

+ Plug wire back in

+ Top off coolant

Jobs a goodun, two thumbs fresh

[danoid]

http://oi42.tinypic.com/n207wj.jpg

thats roughly where it is on an UAC

[Dannijaime]

I know bits about a car but not too much technical stuff, it's a 2000 1.0, but yeah that looks like my engine without the cover/air box on. I'm gonna talk to euro parts tomorrow and get it dropped off, with the weather this hot I'm having to park my car in the corner of the car park under the trees and the amount of bird poop is impressive! Apart from it eating through my paint which means I'm gonna have to machine it all over again lol!

[danoid]

I'd personally buy a genuine one or from gsf. ecp seem crap these days to me

[Dannijaime]

Well just replaced it and... Car won't start still lol! It's the right one and everything but still just turning over

[James827]

02 sensor is plausible. i've seen them make a car run like a bag or spanners when warm but they run fine cold.

could try unplugging it, and seeing if it starts and runs unplugged? (the car this problem was on did this)

no idea where it plugs in and it could be a bit of a shot in the dark, but for unplugging a connector there's nothing really to loose

[danoid]

Hmm, sorry I forgot to add you didn't need to take off the top plastic bit, was in our lupo spraying the contacts for the oil pressure switch and noticed, so sorry if you went through all that for nothing.

So let me get this straight. You start your car in the morning la la la, stall for example, then if the engine is hot it won't start? And there are no noises when you turn the key just silent? Like I said my old Audi done this, but I could hear the starter motor trying to spin the engine, but it wasn't poking the solenoid out correctly so not start when warm.

Disconnect the battery for an hour, cures everything

[Dannijaime]

If I stall/park in the sun all day it will just turn over forever on end. Getting to the end of my tether and might just bin the engine lol!

[danoid]

Record a video of someone starting the engine, whilst your around there filming.

I'm sure it's your starter motor solenoid

[Skezza]

Did you disconnect the battery as suggested?

I wonder if scanning the codes might help. Probably not as the car starts in the cold hmmm.

[Dannijaime]

Yeah it just set my radio back to the display setting and I can't remember how to turn it off I'm thinking it could be the fuel pump really and it's flooding it? But apparently a 2001 1.0 relay you can only get from the dealer, I've found ones that go upto 2000 online for cheap but not for 2001

[Skezza]

Have you had it scanned? Might not show anything, but can't hurt...?

[lupoluke]

Get your codes read, a stab in the dark would be the crank sensor breaking down.

[Dannijaime]

Yeah had it read just get O2 sensor but that wouldn't stop it from starting, it now won't start atall, when turning the key off and back on it's not priming, but take it out for a bit then it does, is that normal? Just turning over and occasionally might sound like it's about to kick in but doesn't

[Skezza]

Hmm, no, I would still expect a car to start with a bad O2 sensor. It would run like a bag of nails but it should still start.

[Dannijaime]

any idea on the difference between a 2001 fuel relay and a 2000? found loads of cheap ones for engines upto 200 but nothing from mine, lookslike it may be a dealer only thing? :S

[Skezza]

You mean the Fuel Pump Relay?

http://www.ebay.co.uk/itm/Fuel-Pump-Relay-VW-Lupo-98-05-/300778394438

Not convinced that it will fix it though. If the fuel pump relay was ****ered I'd have thought it wouldn't start at all? (anyone?)

But keep trying, I'm sure it can be fixed.

Have you taken it to a garage and just asked for some advice? Flutter your eyelids a bit and I'm sure they'll help haha :) Sorry, shouldn't suggest that lol

[Dannijaime]

Haha someone's sorting it, it's at a garage and an auto electrician is coming out tomorrow, it won't start atall now just turns over and tries to start but doesn't

[VW-LUPO-S]

i know your going to think im stupid but, my van today wouldnt start after being sat in the heat and i just hit the starter motor with my pry bar numerous times then it started and i havent had a problem since really...worth ago maybe?