starts, idles nice, cuts out

[91 TSi GP]

Ok i'm getting annoyed because I can't figure this out. My cars been fine but 2 days ago I went to start it to move it and it started and cut out like 7 seconds later.
what the symptoms are is I start the car it idles nice I can even rev it. A few seconds later it just shuts off. No shuddering or anything just straight off as if I shut the car off. I can even be in mid rev and it shuts off. Then afterwards its not wanting to start but it will but die instantly like its almost getting flooded.
any input or ideas?
Forgot to mention there is no CEL

 

[____Kurt____]

Any chances of water in the gas?

 

[casuprock]

Bad AFR sensor? Those take a bit to warm up to temperature before ecu goes into closed loop- could explain why it idles on startup and borks after warm up.

 

[doubleclutch99]

Can you start it right back up? or do you have to wait to restart it?

 

[minimoose]

Honestly sounds like a security thing. Do you have the key fab?

 

[91 TSi GP]

Water in gas.. maybe? It hasn't been driven alot in the past year but has had the same tank of gas in there the whole time. It doesn't have any security system on it. Im in retard mode this morning what is an AFR sensor? And restarts are a bi*** right after. Acts like its getting flooded almost...

 

[doubleclutch99]

I'm pretty sure the AFR sensor is going to be an o2 sensor. have you checked the plugs to see if they are wet ?

 

[95DSMawd024]

check your injectors

 

[DOHCTA]

try logging the coolant temp, i heard of a similiar problem and the coolant temp sensor was slightly unplugged getting mixed readings and shutting off the engine.

 

[doubleclutch99]

try logging the coolant temp, i heard of a similiar problem and the coolant temp sensor was slightly unplugged getting mixed readings and shutting off the engine.

That's a very good possibility.

 

[Ricardo18]

Here is a list of potential issues in order of likelihood:

Bad ASD relay. This shuts off your injectors and spark. (Try replacing with a spare, or buy one from the shop with all intentions of returning the unit if this isn't the issue), but these shutdown the motor as if you turned the key off when power is disconnected.

crank sensor going bad. You can check your sensor voltage as the motor is being started or whenever its turning. You need a second person for this part . This should be a square wave going from one set voltage point to another (maybe 5v to 0) and just going directly from one to the other, skipping all values in between.

cam sensor going bad Same check that was done for crank sensor.

I would say water in the fuel system, but you get no stuttering or warning of an inconsistent fuel mixture, suggesting your fuel flow is constant and uninterrupted by content.

I don't know of the coolant temp sensor issue, but you could disconnect the sensor by unplugging it, and turn your car on. It should default to a "rich" setting, and throw a code, but it will keep the car running and can be easily eliminated with that test.

O2 sensors usually throw a code if your AFR ratio is messed up, but again, there isn't any stuttering or missing at idle. AFR messing up will definitely cause misfiring.

I can't think of anything else that it could be . A quick check-put it in drive as soon as you start up (no applying gas, just allow the car to roll) and see if it still shuts off. If it doesn't, the problem could be ecu (maybe tcm if AT).

Good luck.

 

[JusMX141]

Fuel system issue....either the pump is dying, the filter is dirty, or your MPI relay is on the fritz.

 

[DOHCTA]

There are a TON of great ideas to help narrow down the problem. I doubt you'll find time in one week to test out our theories, but none the less, it interests me to know (subscribed) and hope you resolve the issue quickly with little problems doing so.

 

[Gruff511]

i have the same exact problem in my 420a. i turn it on and itll shut right off after a couple seconds. i get no CEL and everything is good..ive had this problem for over a year now and the only thing i havent replaced are the injectors and i AM getting rich AFR every time it dies so im down to the injectors..you can try checking your injectors as well. could be an ECU issue too.

 

[91 TSi GP]

Thanks for all the input. I was stupid busy this weekend because me and my girlfriend had a huge luau party. Tomorrow im gonna try and sort this out. I have a few ideas and im going to try some of yours. Ill defiantly keep you posted

 

[91 TSi GP]

Ok guys I got home when it was dark so I had about no time to fiddle tonight. However I was starting to think the power transistor was bad. I replaced it with a spare and im still having the same symptoms. The more I think about it it has to be a spark issue. If it was fuel it would stutter before it died but it just cuts out like it looses all spark. The fuel filter is brand new and I can hear the pump running. Tomorrow im going to test the coils.
Is there anything else you can think of?

 

[97ebaygst]

It's your cam sensor I'm sure, because I had the same exact problem. changed the sensor and it runs fine now. I think what happens, correct me if I'm wrong, is when the car first starts its going off a closed system and once it gets started it notices it can't read the cam sensor, which is needed for the car to run then cuts the car off.

 

[91 TSi GP]

Figures the one extra part I don't have! However shouldn't I be throwing a CEL if the sensor is on its way out?

Ok got to mess around with some things tonight and your not going to believe this one... I kept testing things and everything was passing. Well I knew my fuel pump oring was messed up because my field pressure would bleed off. So I pulled my pump out and took a peek down in the tank.





I was out of gas WTF! Canceled my tune and everything for my tank being empty. I mean seriously! A week trying to fix this and all I needed was gas. Yes my fuel gauge wasn't working for a while now by the way.

 

[DOHCTA]

How much of your hair did you pull out? Lol

 

[Gruff511]

I was out of gas WTF!

Haha wish my problem was that easy of a fix i dont know why but in my car when the fuel gauge is all the way down Past empty till the needle stops i still have a good 5 gallons in my tank!
i guess thats how i drove on empty for a couple days

 

[talon95boost]

i had a problem like this on my 2g gsx the symptoms were the same but it was the MAf (mass air flow sensor) glad yours was a little simpler .

 

[91 TSi GP]

Ok it gets better. I had my sending unit in the back of my DD to solder a wire at work.
Well last night my FU**ING DD got stolen! I will start a thread to vent later tonight. Stand by