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VWDoc
VWDoc, Independent VW Shop owner
Category: VW
Satisfied Customers: 6457
Experience:  20 years of experience working with VW's. Independent European shop owner and technician.
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1999 Passat: L..trouble starting..dies..idle until warmed up

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My daughter's 1999 Passat 1.8 L has trouble starting when cold, have to really pump the gas to get it to turn over - and then dies at idle until warmed up. No problems starting or running the rest of the day.

VWDoc :

Hello, I'm Jason. I will do my best to answer your question quickly and accurately using the information you have provided.

VWDoc :

I'd like to know a few things...

VWDoc :

first, is the check engine light on?

Customer:

Hi Jason,

Customer:

No, check engine light is not on

VWDoc :

ok, no problem, and you haven't had it scanned, even without the light on?

Customer:

I took it to a local garage last week and they did diagnostics - they thought it MIGHT be fuel pump, but couldnt say for sure

VWDoc :

usually in these cars, the pump either works or it doesnt....

VWDoc :

now, often there is a failure item that causes this condition, but does not leave behind any codes...

Customer:

that's what i thought - it cranks great when warm, only has problems after sitting overnight or several hours

VWDoc :

ok, at the rear of the cylinder head, there is a plastic water outlet...

VWDoc :

in that flange, there is a 4-pin coolant temperature sensor

VWDoc :

they often fail, and cause too much fuel to be injected during startup

Customer:

ok, i can have that checked, but problem seems to be not enough fuel getting to engine? she has to give it a lot of gas, it turns over, dies, she does it again, then will die within the first block sometimes - then all is great

VWDoc :

any black smoke?

Customer:

none

VWDoc :

and actually, I just recommend replacing it, as the parts are very inexpensive (about $35) and take 30 minutes to install

Customer:

I'll replace that for sure

VWDoc :

yeah, I don't stock a lot of parts at my shop, but keep about a dozen of those on hand

Customer:

can i get part from you?

VWDoc :

but....if that doesn't cure it...

VWDoc :

then some dedicated live data testing should be done to check air mass meter integrity, fuel injector opening time, and so on. This will have to be done using a dedicated VW scan tool, that all good Euro garages will have

VWDoc :

I buy them directly from the dealer, or www.ecstuning.com

Customer:

perfect, i'll get the part and see if that works and take next step to have it scanned at a Euro garage if it persists - anything else we should be doing?

VWDoc :

those are definitely the first steps

Customer:

Her a/c board melted (literally) down a few months ago and this started aboutt he same time - i originally thought it was because my mom put super cheapo gas in the car!

VWDoc :

wow. But no, doubt there is a correlation

Customer:

ok, then i'll stop razzing granma for being cheap!

VWDoc :

heh...ok :-)

Customer:

Thanks Jason, I'll get on the coolant temp sensor - appreciate your help!

VWDoc :

glad to do it, and thank you

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