my s 12 wont start please help
 

hey i would appreciate any help, i have a 87 s12, i have tried every thing, plugs, timing, fuel pump, injectors, pickup sensor, compresion, air, now it fires for just a second or at least trys, and after that in just turns over, took imobiliser out and and checked power ecu, now when ignition is on the small light in ecu is on, and when you turn key, light goes out? havent got a clue.
im a mechanic myself and other than a blown ecu im stumpd, this is my first s12 so any help would be great. thanks.:)

Have you definately got a spark and is fuel coming through giving you wet plugs?

yes have spark and fuel while turnin over.

Cam timing
Valve clearances/Rocker shaft
Ignition timing
Vaccum Leak,
Air flow meter
Ecu
fuel pressure regulator
Bad Fuel

Thats about all the possabilies i can think would be possable

I had the exact same problem, everything checked out ok.. i would bet £10 that if you heat the plugs with a blowtorch or on an arga then pop em back in it will fire up :) .
Also on mine the switch on the throttle had stopped working so my timing was way out so that could be worth checking.

i checkd the switch and seems to be working, power and continuity checks out? also i think ive just blown up the coil with all that starting. there is now a crack in the side and it sparks when it wants, so does any body know where i can get one at a reasonable price, and maybe plug leads?:(

Try taking out the fuel pump fuse and then turn it over for a while and put it back in. Also under the Air box is two plugs around 6/8 wires. Check these as one of mine was rotten and was causing all sorts of probs on mine. Also Paul (silviagod) had a prob with his FPR on the rail so check the pressure!! Good luck!

I don't think coils are generally available except from Nissan ££. I have heard of people in the states using erm MSD Blaster ignition coils?? which are supposed to give a stronger spark. Should be cheaper than the Nissan item i expect. I pulled a coil of a scrapper a few years ago for a few quid.
Plug leads are available from most motor factors but the boots are too short so not as good as the Nissan items but much cheaper. Someone more knowledgeable pls correct me if i'm wrong :)

Are you sure it's the crack in the coil not fouled plugs etc. that's causing the sparking problem ?

Hi, i'm new. Sounds like you know your stuff all right. I'm a mechanic myself and i'm puzzled. Check the ignition timing with a timing light, you might have a spark but the timing could be wrong. Also check the main relay, it connects your ignition and fueling to the ecu, if it's faulty, the ecu won't know how to balance the ignition to the fueling, upsetting the timing, and the car will not run. This would usually bring on a fault light which may be the light see on the ecu. Only other thing i can think of is that the ecu has blown but it's unlikely. Hope you sort it mate!

Hi, i'm new. Sounds like you know your stuff all right. I'm a mechanic myself and i'm puzzled. Check the ignition timing with a timing light, you might have a spark but the timing could be wrong. Also check the main relay, it connects your ignition and fueling to the ecu, if it's faulty, the ecu won't know how to balance the ignition to the fueling, upsetting the timing, and the car will not run. This would usually bring on a fault light which may be the light see on the ecu. Only other thing i can think of is that the ecu has blown but it's unlikely. Hope you sort it mate!