V6 Engine won't turn over

[g8dhe]

Either use a meter or maybe a 12v lamp between earth and the Green/Red wire that should go to 12v or light up if the start signal is reaching the starter itself when the relay operates, in which case its a problem inside the starter/contactors.

[nth]

I was wondering if there was a way I could kind of 'jump start' the starter motor? So if I make up a new wire and attach it to the little tab on the solenoid and spark it with 12V do you think that should operate the starter if the ignition is on?

The starter should operate & turn the engine over if you do this regardless of whether the ignition is on or not however the engine wont actually start unless the ignition is switched on. If the starter doesn't operate with a direct 12v feed try using a jump lead from the starter casing to the battery negative terminal to rule out a main earth fault. If the starter still doesn't operate then it is faulty. It goes without saying to ensure the gearbox is in park before doing this as it will bypass the inhibitor switch.

[BongoBonkers]

Thanks guys, short on time in the week but will get back on this job armed with your helpful advice asap. Will let you know. Thanks, so helpful.

[BongoBonkers]

So, I got it to start but it is still not fixed. The starter motor was rebuilt last week so I was reasonably hopeful that the fault is not there. I attached a wire to the solenoid tab on the starter and attached the other end to the positive of a small motorbike battery. Nothing happened. Then it connected the negative of the small battery to the bongo chassi, still nothing. Then I connected the negative of the small battery to the starter motor casing and the van started immediately. Once it was running then it behaved completely as normal and stopped as it ought to when I turned off the key.

I put a multimeter into the end of the wire that attached to the starter solenoid tab and got my wife to turn the starter key. There is definitely life there, as in it reads zero when the key is not turned and then reads approx 4 volts when the key is turned. I could not get any more than around 4 volts there though. It is not a very wide opening on the plastic connector so it is possible I am not getting a great contact with the multi meter probs but that does not sound like a high enough voltage? But there is definitely life there. I have 12 volts on the main starter positive connection.

So, it's a weird one. I would say I can rule out the starter, immobiliser and ignition switch? This is because the van does start and run and there is definite life at the starter motor when the key is turned, however only 4 volts.

Does anyone have any brain waves as to what might be worth investigating? I am thinking of some kind of poor earth connection somewhere? It began as an intermittent problem and got worse over a couple of weeks to the point of total failure. So logically it is something that has slowly degraded rather than instantly broken? Driving me crazy. Any help appreciated

[g8dhe]

The heavy duty connection is direct to the starter battery and should always measure 12 volts at all times, its not switched or fused so be careful.
The other smaller connection goes to the relay and the ECU, whilst the Starter relay isn't operated then a low voltage may well be seen feeding back from the ECU, however when the Ignition is turned to start then you should see a full 12 volts via the relay, if its not 12 volts then there is a problem back up to or beyond the relay.

Ah just seen you have an immobiliser, you can't rule that out as the relay/transistor that intercepts the starting circuit may have failed whilst the other circuits may be fine within the immobiliser.

[BongoBonkers]

Hi Geoff, thanks. When you mention 'the relay' in your reply, is there any way you can identify which relay you are referring to? And is there more than one of them? I think I am going to have to send it to an auto electrician but don't want to give up yet if there is a relay I can check / clean / replace. Thanks

[g8dhe]

Yes see my first reply to you with both electrical diagram and locations diagram A2-04 is the relay on the offside wheel arch. You said you had already opened it up ?

[BongoBonkers]

Hi, yes you are correct. We have opened H270 relay and tested it. It tested correctly but we also bought another one as it was fairly cheap in case there was some issue with the pins perhaps not making good contact. No luck there, still not working with either relay in place. I was confused with your reference to offside wheel arch and thought there might be another relay that I was missing. There are some electrics down by the throttle pedal that I thought you were referring to.

I have managed to get a local auto electrician to look at it on Saturday so hopefully he will get somewhere. I will of course report back in case you are curious.

Many thanks for all of your help, Geoff and all others.

[g8dhe]

Yes please do report back its the only way we learn of new fault locations and problems, otherwise we can only keep regurgitating the same old problems!