Will not start---Update

[colinham]

I've checked the igition circuit and its working the problem is the fuel pump will not come on, first checked the DME relay with igition on and by pulling the relay from its socket on the fuse board I can hear the relay clicking in, put still no 12volt feed to fuse 34 which is next in fuel pump circuit, even tried fitting brand new relay but still no joy. Checking further found there was no 12volt supply to contact 30 on the DME relay which feeds the fuel pump contact inside the DME relay and therfore no supply out to contact 87b which feeds the fuel pump 16amp fuse ther should be as according to Haynes this contact gets a direct feed from the battery, what is between contact 30 and a 12volt feed ? Is this where the alarm system breaks into the fuel pump feed or am I on the wrong track. This is driving me mad trying to solve, any ideas or advice guys

 

[petrolhead944]

hi colin sound like the alarm is working then.what alarm is on the car.and as it got a imobiliser??

 

[Fen]

I agree (steady, Carl [][]), most likely the alarm. Trouble is the connections are designed to be tricky to find.

 

[peanut]

if you have no 12v+ supply to pin 86 on the DME relay I suggest you look at your ignition switch which provides the power. Failing that check your immobiliser which may disconnect this feed.
The 12v+ feed to pin 30 comes from another point possibly the battery ?

There are 2x relays inside the DME can Relay 1 and relay 2

When you switch the ignition switch on 12v+ is supplied from the ignition switch to to pin 86 on relay 1 which activates relay 1.
This allows the 12v+ from the battery which is on pin 30 to feed 12v+ to the fuel pump but it also feeds to pin 87 which activates relay 2
When relay 2 activates the 12v+ on pin 30 also feeds to the injectors .

If you remove the DME relays can and make up a 3 way linkwire and join pins 30, 87 & 87b together the car should start on the ignition switch. If it doesn't you should run a a 12v+ wire from a convenient point to pin 30 thus bypassing the normal feed.
If it then starts you have a fault with either the ignition switch or the 12v+ feed from the battery to pin 30 on the DME which could be caused by faulty immobiliser

As there is no 12v+ on pin 30 it must be the feed from the battery that is faulty somewhere . If the 12v+ from the ignition switch failed you would not hear the relay click when removing/replacing the DME can with the ignition switched on

 

[homesea]

How about the crank sensor dosent the DME look at that 1st to see if the engine is turning? If its not working then the DME will not fire the fuel pump.

 

[peanut]

ORIGINAL: homesea

How about the crank sensor dosent the DME look at that 1st to see if the engine is turning? If its not working then the DME will not fire the fuel pump.

yes it is important and I have already mentioned it but unfortunately Colin has now started a new thread here about the same problem so regretably all the advice given in the other thread is not available here.
Its very confusing to have two threads running simultaneously about the same subject