# car wont start when warm/after driven



## Mindfault (Feb 2, 2010)

Ok heres the deal. My car starts fine in the mornings, and after i let it sit for like 3 hours. But if i go to the store or something like that, and get back into it it wont start, it cranks, and wants to start but it just wont. This is ONLY after it is driven. The battery cables and everything are fine. Its really weird. I was thinking maybe crank position sensor is going bad, im not throwing any codes for anything so has anyone had this problem? I dont want to buy parts that i dont need. Also, to check the crank position sensor it would be a resistance test correct? What is the specifica:banghead:tion? Thanks guys!:thumbup:


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## Charlie_M (Mar 23, 2011)

Mindfault said:


> Also, to check the crank position sensor it would be a resistance test correct? What is the specifica:banghead:tion? Thanks guys!:thumbup:


 I just put that in another thread, see here: http://forums.vwvortex.com/showthre...nition-Distributor-Engine-Speed-Input-Circuit 

PS - I did hear about a CPS that crapped out when it was hot, but was fine when it was cold.


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## Mindfault (Feb 2, 2010)

Thanks for the link. It just seems to me like it should throw a code for ckp. But. Ill test that tonight i suppose


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## Mindfault (Feb 2, 2010)

So i just tested my ckp. And 1-2=o.l. 1-3=o.l. and pins. 2-3 = .841k ohms. I think that is out of specification


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## Mindfault (Feb 2, 2010)

This test was after cooling down, so i will be checking after i drive it home tonight


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## Charlie_M (Mar 23, 2011)

Mindfault said:


> So i just tested my ckp. And 1-2=o.l. 1-3=o.l. and pins. 2-3 = .841k ohms. I think that is out of specification


 No, .841k == 841, so it's right in the middle of 730 and 1000 ohms. In spec, at least when it's cold.


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## AmIdYfReAk (Nov 8, 2006)

Mindfault said:


> Ok heres the deal.


 There is no deal here, at all.... 

:sly: 

Moving on, when the car isn't starting, is the tach moving? It'll take 2-3 second of cranking before it should move...


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## Mindfault (Feb 2, 2010)

Yeah i meant to say in spec. Even when warm its at 900 ohms. So the ckp is good. I dont know what else could cause it. Its only doing it when its warm. Its weird


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## Mindfault (Feb 2, 2010)

Kinda sucks haha


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## Mindfault (Feb 2, 2010)

So ruling out the ckp, i believe it could be cts, and other research has led me to the deletes with the uni file. All the deletes are resistored and ill be checking that all soon. Hopefully its one of these things mentioned


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## AmIdYfReAk (Nov 8, 2006)

Sure, Move on.... No problem... 

Crank posistion sensors usually fail when they're cold anyway... kinda like your no start issue.... Ohhh wait...


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## Mindfault (Feb 2, 2010)

?


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## AmIdYfReAk (Nov 8, 2006)

Do i reeeaaallly need to spell it out for you? 

Do the simple test that i mentioned, if it PASSES, THEN Scratch it off the list.


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## Mindfault (Feb 2, 2010)

Oh haha yeah the tach moves, haha. I knew that already. Haha. It JUST started doing this after the cylinder head being put on. Never had this issue before


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## AmIdYfReAk (Nov 8, 2006)

The the tach moves, but the car will still not start? 

The only other thing that i know looks for the engine movement is the Cam posistion sensor, Ohm that and etc.


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## burkechrs1 (Dec 1, 2008)

Mine does the same thing. I never had the issue til I switched to uni stg 2 with all the deletes. My CTS is good and crank position sensor is good too. Maybe it is the tune?

Sent from my DROID2 using Tapatalk


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## Mindfault (Feb 2, 2010)

But all of these things would throw codes. This is nuts


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## Mindfault (Feb 2, 2010)

Im going to do a starter voltage drop and see what is going on. Maybe my starter cant handle it anymore when ots warm


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## IAmTheNacho (Oct 26, 2003)

Mine has done the same thing since the head/cams. I put a newer cps that I had in my pile of parts and it seems to be better but still does stumble if I try and start the car say 3-5 minutes after shutdown from a normal 30 minute drive. I think it has to do with cams. It will start every time if you pull the coolant temp sensor. Replaced that it still does the same thing.


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## Mindfault (Feb 2, 2010)

So nacho, if i unhook my cts it will start if i try when its warm? Yeah i thought it was the cams too, or the stiffer springs. Like my starter doesnt wanna turn that much. High torque starter maybe? Are u still with just the intake cam nacho?


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## IAmTheNacho (Oct 26, 2003)

Yeah still the autotech intake cam. Its not as aggressive as most but I dont pull the vacuum I did before the cam Now its about 16 In.Hg. instead of 22ish. at idle. It will pull 22 on decel just not at idle. No codes. Its not as bad as it was when I first put the car together in June though.


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## ldaledub (Oct 14, 2007)

i dont know if its been said but when the no start issue happens have you tried unplugging the injectors getting in the car turning it over to see if it will kick over then get out of the car plug them back in and see if it starts then?... i have this issue ive decided i m getting to much fuel on start up and the car is flooding out. aeb with unitronic tune for ie street cams ill have to write them an email or call bc its been an on going issue ever since the install. i know its a new file and they probably havent worked out all the kinks yet.


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## burkechrs1 (Dec 1, 2008)

I found my problem. I was running a 4bar on Uni Stg 2. Switched in the 3bar and it hasnt happened since. 

Either lucky coincidence or that was it.


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## Mindfault (Feb 2, 2010)

The wierd thing is is that it will crank right over if being jumped. Also i switched the battery out with a different one, it started 3 times fine, tnen it does the same thing.


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## Charlie_M (Mar 23, 2011)

Mindfault said:


> The wierd thing is is that it will crank right over if being jumped. Also i switched the battery out with a different one, it started 3 times fine, tnen it does the same thing.


 Check your grounds; stud under the battery and ground strap to the motor.


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## Mindfault (Feb 2, 2010)

The grounds are good. The wiring is good i dont know what else. Need to put a kickstarter on this thing


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## buckeyeshine (Dec 10, 2015)

*Replacing CTS Worked!!*

I want to thank those who suggested replacing the Coolant Temperature Sensor to fix the problem of my 2001 Jetta VR6 not starting when it was warm. It would start fine when cold, and also when at operating temperature, but would not start if for example I stopped somewhere for 1 or 2 hours from operating temperature (cooled down but not cold). It took me awhile to figure out it ONLY happened when warm, and not when HOT or COLD. 

It would crank and crank, I would have to bury the accelerator and finally it would start. Besides being inconvenient it was embarrassing! You could smell the gasoline from the driver's seat with this process. 

I had checked fuel pressure, fuel pump etc. to no avail. Based on an almost identical situation in this thread suggesting replacing the CTS I went that path and after one week now it has started every time all conditions. Maybe I should wait a couple more weeks before declaring victory but it was quite consistent in its' failure to start when warm and has been starting flawlessly since so I am confident, or heading for a big fall. 

This car has ran great almost invariably since I bought it new way back when over 14 years ago, and been a good friend!

Good luck and thanks!


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## taquechel (Jun 15, 2016)

buckeyeshine said:


> I want to thank those who suggested replacing the Coolant Temperature Sensor to fix the problem of my 2001 Jetta VR6 not starting when it was warm. It would start fine when cold, and also when at operating temperature, but would not start if for example I stopped somewhere for 1 or 2 hours from operating temperature (cooled down but not cold). It took me awhile to figure out it ONLY happened when warm, and not when HOT or COLD.
> 
> It would crank and crank, I would have to bury the accelerator and finally it would start. Besides being inconvenient it was embarrassing! You could smell the gasoline from the driver's seat with this process.
> 
> ...



Hi there,

i have the exact same problem in my Jetta TSI. Did the replacement really did the trick? I am going tomorrow to the dealer and I need to convince him to change it

regards!


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## pink_cthulhu (Mar 6, 2017)

*09 VW GTI not starting when warm*

I know its been awhile since this happened, but I had a real hard time finding an answer to this, so I wanted to post the answer, at least what it was for me. My 09 GTI has two fuel pumps, a high pressure fuel pump and a standard. The high pressure is used to start when the car is cool, and the standard is used when it is warm. I replaced the standard fuel pump, and that fixed the issue. Apparently it was going out, and had a hard time starting, but it wasn't bad enough yet to notice after it started.


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