A Bit Of Wiring Help....

[Quarryman 1]

So I took out the old alarm from the 205. Problem now is the car won't start.

 

I stripped all the wiring back that ran to the battery and around it and am down to these 2 that go back through the bulkhead, the blue and yellow ones circled. Do i need to connect one to the battery?

 

The car is trying to turn over but i reckon the fuel pump is not priming, does the alarm break that circuit?

 

 

Another of bunch of wires that went back through the bulkhead but i reckon are just the power and sensors for the alarm box are here, i assume i don't need to do anything with them?

 

 

While i'm at it, does anyone know what this unconnected plug is for? It seemed to have connections down to the rad, thermostat?

 

[richsmells 2]

Can't help with the alarm, although when I tried to remove my immobiliser after it permanently immobilised the car, it was spliced into the fuel pump circuit and ignition switch. Pretty simple to reverse after tracing back the wires. Are you certain the pump isn't priming? Is there a control box behind the dash or centre console trim?

 

Brown plug is the fan test plug. Bridge the middle connector to one of the outers for high/low speed. Useful in summer if the rad temp switch fails.

Edited February 21, 2010 by richsmells

[DrSarty 100 1 Cars]

Immobilisors often work on a twin circuit, usually the fuel pump and the solenoid or coil.

 

That light blue wire, is the right colour and thickness from your pic that it looks like it should be the solenoid wire. However you say it's trying to turn over, which I don't quite understand. Is it turning over the starter or not? If not, I bet that's one circuit to reconnect.

 

Secondly, solid, thick yellow wires are usually power. I'm NOT saying connect that wire to live, but could that be the fuel pump, coil or even the ECU live feed? Way to check is - if it's cranking - then is it sparking? If it is, then it means the ECU and coil are getting power. You can check if the coil's getting power with a multi-meter.

 

Otherwise do a continuity check between that yellow wire and the fuel pump at its local connector. At the fuel pump it'll be a white wire (no. 76).

 

Otherwise your tachy relay could've lost its power feed. That controls the fuel pump. Switching the ignition on should hear the pump prime for 0.5secs. You can check that too with a multi-meter with the ignition on.

 

My feeling is that as it was running previously, and all you've said you've done is cut out an immobilisor, is that you've cut-out feed to the fuel pump, ECU, tachy relay or coil. And as I first mentioned, you may have the solenoid wire to reconnect too.

[CosKev 16]

Blue on my ph2 309 Gti was spliced in fuse box area by an old alarm.

 

This stopped fuel pump working.

[davepug205 7]

taking out the alarm will of broke the fuel pump wire, which they normally cut and run throught the immobilizer.

[Quarryman 1]

Thanks for the replies guys.

 

I'm not sure the fuel pump is priming, what does it sound like when you turn the key?

 

I'll do a continuity check between the two wires in the pic and the power to the fuel pump.

 

I'll also check behind the dash for more of the alarm, though I reckoned it would all be in the unit that I ripped out under the bonnet...

 

To answer the question above, yes it's trying to turn over the starter sounds healthy but the engine just isn't firing up.

[DrSarty 100 1 Cars]

I'm not sure the fuel pump is priming, what does it sound like when you turn the key?

 

Well it should make a hum noise. If you're not sure what to listen for, put your fingers on it and turn the ignition on or have someone else do it; you'll feel the pump motor run for half a second.

 

To answer the question above, yes it's trying to turn over the starter sounds healthy but the engine just isn't firing up.

 

Not being pedantic, but that means it IS turning over, not trying to. But now I understand; it's turning over or cranking but won't fire up. What about spark?

[Quarryman 1]

Well it should make a hum noise. If you're not sure what to listen for, put your fingers on it and turn the ignition on or have someone else do it; you'll feel the pump motor run for half a second.

 

 

 

Not being pedantic, but that means it IS turning over, not trying to. But now I understand; it's turning over or cranking but won't fire up. What about spark?

 

 

Cool, I'll check the fuel pump so. I can turn the key and feel it at the same time.

 

Apologies for my wording. Yes it is turning over. I'll check for spark later so.

[Quarryman 1]

 

Success!

 

So it seems those 2 wires were un-important. I tracked the yellow one back through the bulkhead. It went up under the steering column then down the side of the door to the back seat. Just when i was convinced it was going to the fuel pump i found to my surprise it was taped to another wire, back up the side of the door, under the steering column and hooked to the chassis, grounded!

 

The blue one hooks to the fuse box, i'll figure what it is at some other time.

 

The important connection was back on the other side where the alarm box was, i'd forgotten about. Two grey wires that had been spliced into the loom. Connected them, turned the key and it started up straight away!

 

While i was at it i ripped out lots of wiring that seemed to be left over from a phone kit.

 

Anyway, now it seems the oil pressure sensor doesn't seem to work, not sure if its related.

 

Thanks for the help guys!