Misfire, then non-starter this morning -- HELP!

[Bowlerwell]

Having cleaned the ISV yesterday to sort out the lumpy idle, I started her up this morning and had very rough running.

VAG-COM gave a lambda error (possibly because of the misfire).

Using the 'unplug the injector' method, I discovered that the misfire was on Cyl 2 and 4! (do they even share the same POS?)
The cables aren't long enough to swap POSs between cylinders, and I don't have a spare any more .
I took the coilcover off to check the sparkplug boots and spark plugs: no oily mess, plugs are tight, boots look fine. But just incase, I swapped boots 1&2, and 3&4.
Then the car wouldn't start at all!

VAG-COM now gives:
001250 Injector Cyl 2 - Open or short to ground
001251 Injector Cyl 3 - Open or short to ground
001252 Injector Cyl 4 - Open or short to ground
000515 Open or short to B+

I checked Fuse 28 and it's fine.

Further VAG-COM readings (after cranking) only give the 000515 Hall sender error.

I'm kinda suspicious of the hall sender error because it has never been a problem, and the car started a few times this morning (albeit with a misfire).
The injector errors explain the misfire, but only cyls 2&4 were misfiring first thing!

I'm struggling here to figure out actually what is wrong.
Please help!
JohnB

[sjw185]

Hello John,

Are the injector codes not from you unplugging them checking for missfire?
Your right with the Pos think one does 1,2,3 the other 4,5
You could try that trick of running water over the cam sensor?
Hows your fuel pump/relay?
After market alarm?
Disturbed any wiring on the bulkhead connectors when working with ISV?

cheers
Steve

[johne]

Given that the ISV is close to the POS's, I'd check that you haven't disturbed any of the connectors around there.

John

[Bowlerwell]

Thanks Steve, You're right, the injector errors will be from me unplugging them. Good call!!
I might try that water trick (but it won't explain the misfire...).
I may well have disturbed something on the bulkhead when doing the ISV... I'm not sure what would cause a misfire, then non-start...

[Bowlerwell]

Note: After re-fitting the ISV yesterday, the car did start and run fine. (although i didn't frive anywhere)

[sjw185]

When did you start getting missfire trouble?
Mine had a lumpy idle and turned out to be a dodgy injector after much plug, coil and pos changing
I tracked mine down by swapping coils and going for a blast and pulling plugs straight away to check colour.
Ended up changing injectors until the black plug changed cylinders.
You need it running first though

[Bowlerwell]

Misfire started this morning Steve. Car started and idled fine after ISV was put back in yesterday.
Non-start happened after I swaped coil pack boots between cylinders...

[johne]

Note: After re-fitting the ISV yesterday, the car did start and run fine. (although i didn't frive anywhere)

John, how long did you let the engine run for yesterday? If you didn't let it warm up fully and didn't drive it then all you've got is a fouled spark plug - happens with mine everytime if I just do something like start, drive out the garage and stop, only to resatart later.

I have the confidence to carry on driving and it'll clear as I get down the road but you might want to pull your plugs first and clean them.

John

[Bowlerwell]

Thanks John.
I'll take the plugs out and clean them.
I still have the cam sensor error... maybe it's just coincidence that it's gone? Does it connect on the bulkhead too? I might have knocked it when fiddling with the POS connectors this morning.

[johne]

Cam sensor connects at the bulkhead along with the knock sensors etc. It would be some coincidence if it happened to fail at exactly the same time.

John

[Bowlerwell]

Thanks John!!
I'll clean the spark plugs, change the boots, and check all the bulkhead connections after lunch.

JohnB

[Bowlerwell]

I have cleaned the spark plugs, and changed the boots back to the previous order.
I also had a fiddle with the connections on the bulkhead (although i'm not sure which one is the hall sensor).

Now it still doesn't start, but i get no errors on vag-com. not even 00513 engine speed.
I do, however, now get an autocheck warning for oil after cracking...

Any ideas?

[Tonks4x4]

The connector for the haul sender is the plug at the front of your engine that is fixed to a small bracket on your inlet manifold.

If you remove the coil pack and your plugs, put your plugs into the coil boots and then crank it over you will see if they are all sparking correctly.

[prj]

1. Clear all codes with VAG-COM
2. Crank for 20 seconds, see if you get any codes.

If you don't, make sure you have fuel and that the fuel pump is activated during cranking.
You can try taking the fuel rail off, aiming it away from the car and seeing if the injectors are spraying fuel.

EDIT:
Yeah, and check for spark as well, as noted above.

[Bowlerwell]

Thanks for the tips chaps. Much appreciated. I probably don't have any more time today to lookat this
Dimitri, will the injectors just pull off (with the fuel rail) or are they fixed down?

Thanks.