right i've got the 16v lump in the mk3, i've got the mk4 engine loom, fusebox, imobilizer, transponder all hooked up to the engine just so i can get it started before i start splicing the looms.

but alas i am having a huge headache, the engine turns over and sparks, it'll fire up with easy start down the throttle body but that's it. i'm hardwiring the fuel pumps straight from the battery at the min so it's getting fuel to the engine bay but the injectors ain't doing any thing. now i'm guessing this is some thing to do with the immobilizer, i've got the key stuck in the transponder ring so that should be fine, but when i take it out of there it still does exactly the same thing so it can't be working surely?

every thing seems to be plug and play except one wire from the transponder/immobilizer box thing which is grey and white with a brown plug on it, any idea where this should go?

also which relay is for the fuel pump on the mk4 fusebox?

also does it matter if the mk4 had had a flat battery for the last 6 months or so? would this fuck the ecu up or out?

cheers for any help this is doing my fucking head in

Edited 19 May, 201016 yr by McLOVIN

sounds like what you said, the immobiliser! had this problem changing an ecu in an audi the other day, £20 and was flashed to suit the key

i dont think it's immo related, you would not get any sparks if it was the immo, the fuel pump should prime though irrespective of wether the immobilizer is active

the spare wire you mention normally goes to the airbag controller iirc

does the immobilizer not just cut the fueling? my mate had a skoda octivia that if you used the spare key to try and start it, it would fire then cut straight out. if it was the spark it cut then it wouldn't even fire?

that was my trail of thought any way, probably wrong

and my fuel pump isn't connected to fuse box because i forgot to get that plug from the doner car

does the immobilizer not just cut the fueling? my mate had a skoda octivia that if you used the spare key to try and start it, it would fire then cut straight out. if it was the spark it cut then it wouldn't even fire?

yes that's right, it will start and run for about 2 seconds then die becuase it switches off the fuel pump relay (j17), the ignition coil is also fed from that relay too.. you mentioned that it runs on easystart, so that kind-of eliminates the immo becuase it will only spark for about 2 seconds if the immo is active(on)

that can't be the case tho mate because it still sparks without the key near the transponder ring

how would i go about checking the injection system to see if there are any issues with that?

are you getting fuel to the fuel rail? you should be able to hear the fuel pump priming, failing that, connect it to the black wire from your ignition barrel, that will switch the pump on when the ignition is flicked to position 1 or 2.

once you know your getting fuel to the fuel rail, check each injectors spray pattern by puttting each one in a jar and turning the fuel pump on manually, mark the jars with measuring lines ie 50 / 100 / 150 / 200 mLs and record how much comes out after x amount of seconds, they should be equal, it should be an fine mist spray, and they should close instantly without dribbling.

did you try my technique as posted on CP, i reckon your onto a winner with that one

not tried that one yet saf but i think your on to some thing with that one

the pump isn't priming off the fusebox because i forgot to get the plug with the fuse box wiring on it from the doner car. Atm i've just got a live going to the pump. I have no ignition either, just hotwiring the loom (forgot to get the black box aswel).

you forgot a lot of stuff. . . . .

Pikey it, simply earth the fuel pump relay and it should work. (temp solution)

it's alive! fucking fuel pump relay was screwed

woohooo =]

thanks every one for the help you've given

so it wasn't immo related then??

glad you got it sorted though mate... as an aside, dont buy relays from the dealership, genuine vw relays are about £28 which is an absolute rip-off.. i got a handfull of spares at the scrapyard for £2 to keep in the wagon

Wow all of this will be really helpful to me over the next week or so... Cheers everyone for answering alot of my questions :)

Just to add to this it wasn't the relay that was fucked. I bridged the relay as rich suggested and it worked but with the fuel pump constantly live with the ignition on. Changing the relay didn't solve the problem so I just ran it like that for the best part of a year, when I did finally get a chance to dig into the wiring again to try and find the problem I found that while cutting the 6n loom up I had accidentally snipped the wire from the ecu to the fuse box that controlled the fuel pump. So take care when snipping those wires

Just to add to this it wasn't the relay that was fucked. I bridged the relay as rich suggested and it worked but with the fuel pump constantly live with the ignition on. Changing the relay didn't solve the problem so I just ran it like that for the best part of a year, when I did finally get a chance to dig into the wiring again to try and find the problem I found that while cutting the 6n loom up I had accidentally snipped the wire from the ecu to the fuse box that controlled the fuel pump. So take care when snipping those wires

I'll be extra anal when checking all of my valver loom then. Do you have a hybrid ECU situation going on then or is all the engine management dealt with by the 16v ECU?

Nah it's all the oem ecu and management mate

Has anyone ran a poloace chip on a hybrid?

Not that I know of, I did ask if the chip would be suitable on one but not sure he fully understood what I was going on about

As in the valver OEM ECU?

Had a look at all the wiring today, let me get this straight, do I just need the loom controlling injection, ecu, immobilizer and transponder from the 16v and the rest can be done by my original loom? Which loom do you have controlling oil senders and coolant sensors etc?

Cheers

Harry