hi, i'm new to this site and would really, really appreciate some help.
i'm sure you guys have probably heard this all before but i've tried to search through older posts and even printed out the diagnostic tests out of the tech archives aswell as any other wiring diagrams i can find but i'm no further forward.
i have a 94 m reg 3.9 efi discovery auto. its been working great until the other day when i went to start it and it did, for a second or 2 then just cut out. however, before this, a mate of mine borrowed it for a few days and before he parked it up he did say it was wanting to cut out at lights etc. anyway, now it just cranks over and makes no effort to try and start.
there's no aftermarket alarm/imobiliser fitted. i haven't tampered or been messing around under the bonnet before this occurred. however since, i've checked all the plugs(NGK's with good leads)and watched for a spark on a couple of them, which i think is good enough, i even swapped the coil with another v8 i have and that starts with either coil. i've took the fuel pipe off at the rail and turned ignition on and fuel pump works. i couldn't check the pressure at the schrader valve on the rail as i don't have the equipment. i believe fuel is getting in the cylinders as the plugs do get wet and smell of petrol. i got a multimeter reading of some kind at an injector plug just for a quick check.
i read on one post that someone had a similar problem and they finally diagnosed a faulty temp sensor so i took mine out and heated it with a lighter and got a reading on the dash, tried to start it then too, but with no luck.
back to the diagnostic tests. i have a wabco ecu (big silver thing behind glove box) number 446 044 040 0, amr 1097,(i hope this is the right one as i cant see no other obvious one). this has a 35 pin plug, therefore this leaves only the one test on ecu fuel injectors from the archives.
first step, pin 10 and ground. less than 11v check cables... done. this is a white wire with a grey trace and i have no volts. the one next to it, pin 9 (white wire with a red trace) has battery volts on ignition. all the other pins on the ecu plug have no power and i am unable to get hold of a wiring diagram that suits my disco, wire colours or anything (or blank spaces on the plug 2,3,20,28,29. or does this not matter??). i've seperated the ecu plug and there's no corrosion at all. i've made a few checks visually and with a multimeter around both foot-wells and i cant find any obvious problems with relays, even replaced what i think is the main relay with a new one.
does anyone have a wiring diagram that might match my vehicle? am i looking at the ecu plug right? is it possible to have jumped a tooth on the timing when it was started up, or im a just talking silly?? i'll be able to check this with a light while cranking won't i?
i hope this isn't too long winded and like i say, any help would be greatly appreciated.
thanks. Tony
