Pulling my hair out - Saxo VTR non starter

[johnny99]

No need to get complicated. Does the feul pump kick in, it should run for 2-3 seconds when the ignition is switched on. Have you got feul at the fuel rail. Is there a spark at the plugs.

John

[Paceracing]

I would say your airbag is a good starting point. It probably does communicate on CAN as it, along with the other restraint systems, (seatbelt pre-tensioners, are PRS - Primary Restraint Systems, Airbags are SRS - Secondary Restraint Systems - (which is why you see labels for airbags saying 'SRS')) need to all fire in synchronisation in the event of an impact. It will almost certainly talk to the ECU at the very least from a diagnostics perspective should a fault occur in any of the restraint systems.

[graham bahr]

most of the small peugoet/citroen cars like 106, saxo etc, have a big relay mounted under the ecu, its got about 16 pins, its a tachometric relay, it uses the rpm signal from the crank sensor to switch on the ignition coil, fuel pump etc, so if that relay is faulty or the crank sensor doesnt work you wont get power to the col etc, even though the ecu may be powered up

[GORDON STREETER]

Originally Posted by johnny99

No need to get complicated. Does the feul pump kick in, it should run for 2-3 seconds when the ignition is switched on. Have you got feul at the fuel rail. Is there a spark at the plugs.

John

In his first post he said that there was no power to the coil pack if you read it, and the fact that the rev counter works when cranking shows that the CPS is working and the ECU is powered up at least .
I would assume when he also said that the fuel pump is OK he was getting fuel at the rail

[NMMotorsport]

Again thanks everyone for thier responses.
So now i have something to try. The airbag system i removed, i dont have the little wiring loom for it. Just an empty 4 wire connector, 2 of them being a 12v supply. What should i do with the other 2. Tried linking out, putting a 55ohm and around 110 ohm resistance across it( only resistors i had to hand). Is there anyone on here who races the saxo vtr and has already totally removed the airbag system??

[NMMotorsport]

Hey everyone

Firstly I would like to thank everyone for all the input into my problem, has really made me dig deep with the car and as a result I have learned plenty of new stuff.

Secondly, the car now runs, after numerous different directions of trying to find the problem I went back to the start. To keep it simple I started checking the loom and making sure things went where they should as per Haynes manual wiring schematic (which I might add tends to not give you the full picture and as usual colour cables not quite right and some items just not on the diagram) As the end result I found a supply to the fuel pump relay with only 10V on it, according to the diagram it should be spliced into another 12v supply at the relay which surprise surprise had 12v on it. So as simple as a bad joint. after repair car now runs as it did and at last I can carry on with the work I had planned.

So again just to thank you for helping me on my way, really appreciated.

Jon

[GORDON STREETER]

English damp weather ! never happens where I am at the moment . As Johnny99 said you should have gone back to basics and I assumed you had !
Joking aside I'm glad you found it and found out a bit more about the problems you can have with todays marvelous electrical systems !

[NMMotorsport]

Cheers gordon
I did do the usual twice before this but this was more about learning the car than anything tbh. Frustration does tend to cloud your judgement. But thanks for the help.

[indigorallye]

www.106rallye.co.uk
Good technical forum for all your TU engined issues ;-)