Help, 1.8t cranks, wont start

[stemiched89]

Hello,
I have a 99.5 1.8t, have been daily driving it since we purchased it a few weeks ago. I go to work at 5am every day and it has started every day without any issue. When I went to start it Wednesday morning after it only being parked over night, it would not start. Cranks but wont start.
Replaced the battery and the same battery starts my other car.
Capacitor is reading 12.2V
Have spark

I have read elsewhere it could be the crank sensor? is there any way to diagnose this before purchasing and crawling under the car for what it "might" be?

Im sure someones going to mention buying a vag come and a bentley, which i plan on buying both, but at this current time i simply can not afford either.

Thank you,
Stephen

[Scottydo]

You sir need a VAG-Com. Beleive me its well worth the price you pay for a good one. We need the codes to help you out with the possible problem.

[SN95Audi87]

Scan the ob2 port for codes, most likely its the crank sensor. It gives people problems when the temperature drops below 25 degrees, atleast that is what I observed with mine. Anytime the temperature was below 30 it never cranked up smoothly.

[woolveren]

Check whether the fuel pump is coming active when you turn the ignition ON, listen to a small high pitched noise from the rear.

[stemiched89]

i had read elsewhere that if u have spark then your crank sensor is fine, although everyone continues saying crank sensor despite me saying it has spark...

as well i can hear the fuel pump

ill have an obd2 scanner coming in the mail tomorrow hopefully.

[Seerlah]

If you have spark, fuel, and compression then your car will start and run. Take the fuel rail out (injectors still in), crank the car and see if gas sprays (prep for gas to spray).

[Scottydo]

Believe me you will still get spark even if you have a bad CPS. Been there done that.

[stemiched89]

so the scanner is showing no codes, i was only able to check one spark plug yesterday. as soon as i get someone here to help me ill check spark, and oil. i do hear the fuel pump priming. is there a way to check compression without a compression tool?

[Seerlah]

No. Check for fuel.

[stemiched89]

alright so here is what ive done with nothing but the same results.
disconnected fuel rain and put in on position and fuel sprayed out
pulled all spark plugs and there sparking in a pattern
sprayed gum cutter into air box and made no difference
unplugged crank sensor and it made no difference, still sparked
there was blow back while i had the spark plugs out
checked all fuses

[Seerlah]

You have spark, you have fuel, now check compression. You can rent the tool for free at Advanced Auto and AutoZone. You just place a deposit that you get back when you return the tool. Only other thing I would check is your fuel pressure. Checking for spark, fuel, and compression are the free checks. After that I would spend the money on a fuel pressure gauge for your car.

[stemiched89]

if i had blow back, shouldnt that imply i have compression?
ill try to get to harbor freight tomorrow to pick up a compression tool

[Seerlah]

No (not in the sense of what we are looking for). That is simply any air being drawn into the combustion chambers being pushed out through the spark plug hole. There is a huge difference between 50psi and 150psi (air in your chamber). But you would not know unless you do a compression test. And you don't have to buy the tool. I rented mine from Autozone for free every time I checked mine.

[stemiched89]

alright, so this morning i went out and cranked the hell out of it. eventually it did turn over. it is a few degrees warmer today then the past couple, so it definatelly seems temperature related.
another page was mentioning coolant temp sensor. i believe im going to change that, and replace the crank sensor soon for ease of mind

[Seerlah]

Good choice.