Crank but no spark (theres more!)

[BlueDNA]

Hi everyone,

First time and first post on this forum, so just wanted to extend a warm hello from Australia.

I have a strange problem with wrx and hoping someone could help. I own a MY99 and from yesterday onwards have had some really strange problems.

Yesterday when I tried to start my car (cold start), it would crank continuously without starting. When i tried to see if there was spark (taking out the ignition lead), there seemed to be spark, then the car started. Leaving it running for about 20 seconds, before it shut off again.

When i tried to start it again, it didnt work. Checked spark again and to my surprise there was no spark. Left it there for about 3 hours and there was still no spark. Checked spark properly with meter and there was definitely no spark.

This morning when i woke up and started it again, it worked okay without any problems. Left the car running for 20 minutes, shut off and cranked multiple times without problems. I have no idea what is going on nor have any clue as to what what could be causing the issue. Has anyone been in the same situation?

Some of things I've been thinking about include:
- Factory Brant Immobiliser: it seems to be powering the car okay, power is provided to car (can crank engine and hear power and fuel pump whind)
- Fuel pump: refer to above
- Spark:
- Ignition lead?
- Ignition coil?
- Spark plugs
NOTE: - pretty certain these should be okay, if it fails it wouldn't be temperamental right? (i.e. if it didn't work, it wouldn't work at all, it wouldn't be inconsistent...?)

- Crank angle sensor? (don't these generally malfunction on warm->hot starts?) the car didnt crank on cold start initially so wouldn't that rule out crank angle sensor?

Not sure if anyone has been in a simlar situation, but if anyone has, any light would be greatly appreciated.

Thanks,
David

[Donkey]

Unfortunately this is a US based site and we don't get the same vehicles as you do. My thought is to test the main coil pack or swap it for a know good one to see if thats the problem. Next would be to test the crank sensor. Usually this takes two people unless you have a remote crank switch (cheap mechanics tool). Its like a jumper cable that goes between the battery and starter main with a switch on it. After that I would check the oil pressure sender. From my understanding if that goes bad the fuel pump and ignition system won't work. Its a safety thing (roll over/accidents). If the ECU doesn't get an oil pressure sender signal nothing works. bAD grounds could also be a problem. Try getting a factory service manual as well. The diagnostic section are very useful!

[Drews]

^ +1


I'd check the specs on your coils and make sure they are getting a voltage that's within the tolerances.

[BlueDNA]

thanks for all the replies everyone.
The car has been starting fine since yesterday without any problems. A little concious it may happen again at any unexpected time...

I know that the specs for US and AU cars are different, but woudl it matter that was raining quite heavily on the day where it didnt start? (i.e. would MAF sensor be a concern?)

[Drews]

thanks for all the replies everyone.
The car has been starting fine since yesterday without any problems. A little concious it may happen again at any unexpected time...

I know that the specs for US and AU cars are different, but woudl it matter that was raining quite heavily on the day where it didnt start? (i.e. would MAF sensor be a concern?)

If something got wet it's more likely to cause a short somewhere. I know that on my subaru if your cam or crank shaft position sensors are off you wont get spark either.