Diesel combi pete

I have just brought an old t reg escort van, I have two black keys with it, one for doors and ignition and one for fuel tank. How can I tell if these keys have a code inside of them. My other y reg van has no chips in and the immobiliser has been disconected. the van I have just brought, the alarm /immobiliser flashes it it on and then flashes and go's out when turned off. everything on the van then works with no alarm going off, the only trouble is that the key will not turn the engine over and when I turn the key there is no sign of any power drain at all. spasmodicaly the engine will turn over but not often, I have checked all leads and earths.
Dose anyone have any ideas how to take ths system off the van. I was wondering if it is just a matter of unpluging the alarm unite and jumping all the pins in the plug over. This could be a nice van if I weld it and get it back on the road but if i can not start her she will have to go for scrap.. Any help truly appreciated Cheers. Pete