Car won't start when HOT.

[Russell2686]

Ok so normally it seems that peoples cars won't start when its cold but my car does not like to start when it gets HOT.

If i go for a long drive and the car gets up to temp (middle of the gauge) and then i stop to go in a store and come back within 5 minutes it will not start back up. Ill have to crank it for a while.

If its too hot I have to open the hood then crank it for a little and it will fire up.

Now if i let it sit for a little and cool down it will start right up no problems.

Is there anything simple i should be looking for? There isn't a CEL.

[andyrew]

Starter turns over just fine?

[Poopie]

coolant temp sensor

[Russell2686]

coolant temp sensor

I replaced that less then 10k miles ago, think it would be that? Car started fine before the BT.

Starter turns over just fine?

Yeah it turns perfect.

[Poopie]

well you may not have a CEL but you could have some stored codes that may point you in the right direction. I'm still leaning towards the coolant temp sensor.

[GetAwayFromMe]

How does it act when you turn the key? Go out and check if there is any spark if it does than next step would be to look if it's getting fuel. How old is the fuel pressure regulator? Like poopie said temp sensor would do that, check the wires that go to it maybe it looses ground when it get's hot.

[Russell2686]

Does it turn over, clicks? How does it act when you turn the key? Go out and check if there is any spark if it does than next step would be to look if it's getting fuel.

It starts up everytime everyday. When its cold its normal turn key start up. When its hot its hold key and crrank for 30-40 seconds.
Ill try and check it out today, the FPR is the stock origonal one.

Poopie ill try and get a VAG to check for some codes.

I actually did get a CEL yesterday after boosting real hard but i didn't think that had anything to do with this problem being that ive drove for 3.5k miles now with it starting like this.

[Ayefore]

start off by checking your plugs, make sure they are the right ones for your setup and ensure that the fuel is being delivered.

[Russell2686]

The plugs are what autospeed used so they should be ok i forget what ones they are ill have to look.

[Nebone]

Hmm. I learned my lesson to diagnose an issue right as it starts happening and not 3.5k miles in. 30-40seconds on the starter heats it up

I'm also thinking it's the coolant temp sensor. It is probably faulty and tells the ECU that the temp is higher than normal. The vag can tell you the temperature of the sensor but there is also a way to check what the sensor reads by using the climate control hidden function but I forgot how to access that exactly.

[AudiRacerS4]

i have the same problem with my car as well...changed the plugs, coil packs, and CTS and it still sucks starting it when its hot. I have to crank it for 45sec and give it gas. if its cold it starts right up

[Russell2686]

Hmm. I learned my lesson to diagnose an issue right as it starts happening and not 3.5k miles in. 30-40seconds on the starter heats it up

I'm also thinking it's the coolant temp sensor. It is probably faulty and tells the ECU that the temp is higher than normal. The vag can tell you the temperature of the sensor but there is also a way to check what the sensor reads by using the climate control hidden function but I forgot how to access that exactly.

Well it runs fine once started so im not to worried about it. Just an inconvenience. Im gonna try and get a vag com tonight and see if i can find anything out.

[Russell2686]

i have the same problem with my car as well...changed the plugs, coil packs, and CTS and it still sucks starting it when its hot. I have to crank it for 45sec and give it gas. if its cold it starts right up

Oh yeah i remember PMing you a little while back, i guess you still havn't figured it out either and you replaced all that stuff hmmm

I also have to give it gas when cranking it.

[solowb5]

110% the crank sensor located behind the oil filter. Replace that and bam you guys are back in service.

[Russell2686]

110% the crank sensor located behind the oil filter. Replace that and bam you guys are back in service.

Thanks man you sound pretty confident and I do need an oil change so probably would be a good time to give it a try. Does anyone know the P/N or somewhere i could get one the dealer wants 130 for it.

edit found the DIY i think the crank sensor and engine speed sensor are the same thing just two different names?: Im not sure if the p/n is the same for a B5
http://www.audizine.com/forum/showthread.php?t=104097

[solowb5]

I believe there are vendors on ebay that have them for around 50ish.

[Russell2686]

I believe there are vendors on ebay that have them for around 50ish.

Ive noticed people with this sensor problem also get an EPC light and the car stalls often, my car never stalls and i havn't got the EPC light either, think it would still be the be the problem?

[Nebone]

I did a generic search on google for various engines for this issue and its either coolant temp sensor or crank position sensor.

[Matt@JHM]

I had the same exact symptoms/problem and it was the coolant temp sensor. I couldn't even stop for gas without having to wait 20 minutes to start the car again! Very inconvenient.

I picked one up at a VW dealership for 30 bucks. They had it in stock. Tada Problem Fixed.

[solowb5]

I had mine go out and didn't get a epc. I am an 01 by the way.

[Russell2686]

I had the same exact symptoms/problem and it was the coolant temp sensor. I couldn't even stop for gas without having to wait 20 minutes to start the car again! Very inconvenient.

I picked one up at a VW dealership for 30 bucks. They had it in stock. Tada Problem Fixed.

damn i really cant imagine it being the coolant sensor after i just replaced it but for 30 bucks its worth trying both to see if it gets fixed.

thanks everyone for the help

[Nebone]

I seen a bad Coolant Temp sensor right out of the box. Gauge would never go above cold.

[mike-2ptzero]

Are you running a new tune?

[firstars]

Are you running a new tune?

this is a yes

[mike-2ptzero]

this is a yes

If so then it could just be his "hot start" fueling, the tuner can fix that.

[Russell2686]

If so then it could just be his "hot start" fueling, the tuner can fix that.

yeah this is most likley it because it did not happen until they started to tune my car and after it was tuned.

To bad i just bought the engine speed sensor for 95$ and it will be installed tommorrow

[1fstavant]

either what hood said or coolant temp....my ko4 setup had that happen first it was crank for a like 30secs when it was hot then it just wouldnt start....

[Flying]

Hi guys.
Did you fix your problem and what part did you change???
I have an A6 1,9tdi with engine code AVF and it´s the same problem i have when the engine is hot,have changed the coolant temp sensor with out succes. what to do now ??????

Flying ...

[pac1085]

I'd check your manifold air temperature sensor too.

[Militant-Grunt]

I'd check your manifold air temperature sensor too.

That wouldn't cause the car not to start when the car it hot. Would just make for thrown off fueling. I was driving around with one disconnected for an hour before I realized I forgot to reconnect it after working on the car.

[Flying]

I forgot to tell the begin of the story: I filled the tank with diesel and the car stopped suddenly after 1 km.Cheched it out with the vagcom no faults.
Changed the diesel filter thought it might be full of shit didn´t help.tryed to start the engine no succes.Tow the car to a freinds workshop emptyed the tank and the diesel was dirty and with some water in it.New filter and filled diesel and the engin started.
It worked fine for a couple of days,spoke with an audi mechanic and he suggested that i should put some carburater alcohole in the tank to get all
water out of it.I than hade the vagcom on againe and it said something with "engine speed sensor" deleted and went for a drive no fault.
The next day it worked fine in the morning, but in the evning was for a drive
and stopped by a gasstation stopped the car and came out after 15 min and it wouldn´t start it only cranked and cranked.But if I spary some diesel start help in the air intake it starts fine.

So I don´t now what´s wrong

[Don Supreme]

Diesel huh? Not sure we can help.

[AudiA4_20T]

Hey Russel, Dougyfresh was havign the same problem, I dont think Mark@ASP has figured it out yet

[Russell2686]

I never actually installed my sensor, at 95$ i wasn't going to chance that it "might" help. I'm leaning towards mine being tuning and i should be getting it fixed in Oct. Ill let you know if it was just my tune if not ill replace some sensors. I might also try to find a cheap sensor (didn't feel like looking before and just got it at the VW dealer) and try it out anyway.

[Russell2686]

Hey Russel, Dougyfresh was havign the same problem, I dont think Mark@ASP has figured it out yet

Yeah, i was talking to Dougyfresh in some PMs and he said he had the same problem. I know he has his car down there now so hopefully Mark can figure it out and fix mine also!

[Matt@JHM]

I never actually installed my sensor, at 95$ i wasn't going to chance that it "might" help. I'm leaning towards mine being tuning and i should be getting it fixed in Oct. Ill let you know if it was just my tune if not ill replace some sensors. I might also try to find a cheap sensor (didn't feel like looking before and just got it at the VW dealer) and try it out anyway.

So did you install the new coolant temp sensor yet?

[Russell2686]

So did you install the new coolant temp sensor yet?

nah i didnt install any sensors or anything. i think its my tune because someone with the same tune as me is having the same problem and also it never happened until after i got my kit installed

[ForceFed]

hey just wondering if you fixed it yet. iam having the same exact problem. i cant seem to find out whats causing it. iam getting fuel i know that. i have unitronics tune for the gtrs eilm turbo. my problem also started the day after i installed the turbo/tune/injectors. so iam hoping that its not the tune but might be.....any help or info would be great if you figured anything out yet

[Russell2686]

hey just wondering if you fixed it yet. iam having the same exact problem. i cant seem to find out whats causing it. iam getting fuel i know that. i have unitronics tune for the gtrs eilm turbo. my problem also started the day after i installed the turbo/tune/injectors. so iam hoping that its not the tune but might be.....any help or info would be great if you figured anything out yet

Yeah I had it fixed. It was the tune. It was giving to much fuel when hot. They tweaked the file and it was all good.

[ForceFed]

what tune do/did you have?