no spark on a 20seh

[silvertornado_sr]

no spark

all wiring looks to be correct and everything in the right place but no spark any ideas ?

thanks mark

[mk1nova1.8]

checked your earths ?

[silvertornado_sr]

all earths look to be there also :(just con fusing the **** outta me now :(

[Lee]

Crank sensor? Dodgy leads / plugs / cap / rotor? Coil working?

Test the entire ignition system!

[silvertornado_sr]

crank senor been replaced
leads been replaced
coil been replaced
plugs replaced also
engine was working fine before being removed from the cav

now its in the nova just won;t start :(

[Lee]

Got a switched live and a perm live?

Bear in mind Novas have two switched live circuits. One is secondary (runs the stereo, heated rear screen etc) and goes to 0v when cranking.

[silvertornado_sr]

black wire off the single point inject is a switched live if not mistaken ? if not then that might be my problem ??

[Lee]

Are you running the SPi' original loom? Jesus, it must be a birds nest in there lol

Get a DMM on the feed and get someone to crank it. Thats the easiest way to find out.

[silvertornado_sr]

got most of it cut back lol but thanks for advise will let you know :)

[silvertornado_sr]

the black wire goes 12v and stays 12v when cranking :( so no idea what i could be now :(

[Lee]

ECU plugged in properly?

Check the coil is getting 12v when you crank.

Check the coil earth

[silvertornado_sr]

coil earth ???
ecu in properly
will check coil earth and how do i test if gets 12v when cranking ?

[Iain]

Multimeter on the coil black wire when turning it over.

[silvertornado_sr]

thanks iain ;) you gonna try poping up later see if you can work it out

[silvertornado_sr]

gets 12v for less than a second then voltage drops :(

any ideas

[Iain]

Try splicing it in to an ignition live wire which keeps 12v during cranking? Just to test if that's the problem.

[Sloth]

sounds like a crank sensor issue. i.e getting signal then ,losing it. have ya connected the single black wire near the coil on the loom?

[Lee]

SEH coils get their power from the ECU, not an external wire. Just unplug the harness from the coil and check there is power down the black wire (you may need to peel back the insulation from the plug itself)

Sloth, that black wire you're talking about is the switched live feed

[Sloth]

yer, ive missed it meself lee, hang on, was the shell a 1.0? if so the coil feed is useless, same as some of the spi switched feeds aswell......

[silvertornado_sr]

shell is a 1.2 merit did have a 1.6i in there until it gave up and have used the same wires as the 1.6i used if this helps ?

but as to iains suggesteion no spark also :(

[novajulz]

I had the same problem on my cav 2ltr 8v engine i had no compression on the valves so i stripped the head n took all 8 valves on regrinded them n all so polished then. once put bk together started first turn of key. If thats any help.

[silvertornado_sr]

has compression just no spark :S

[novajulz]

oh i see ok lol well i put an extra earth from the chassie by the gearbox on the the starter motor bolt used real thick wire. has he checked the gap on the spark plugs?

[Lee]

We still haven't established if the coil is working yet, dont jump the gun lol

Always start at the source when fault finding and work forwards ;)

[Iain]

Lee he said he tried 3 coils and all suffer the same problem. Whether he's tried them with the new working 12v feed or not though....

[belly257]

put the ignition live wire to the big black wire behind the fusebox

[silvertornado_sr]

well still stumped with this :( as iain said tried the 12 thing and still no spark :( only thing stopping me driving the lil beast :(

[Lee]

SO the coil is getting 12v then? In which case check the dizzy and rotor arm again, and the crank sensor comes back into play again. Might be worth trying another one. Also worth buzzing through the crank sensor wires to the ecu, but you will need a wiring diagram from a haynes, unless someone who has an SEH diagram can tell you what pins the crank sensor goes to.

[silvertornado_sr]

thanks for the advise lee :) just wish the thing would start so i could drive it :(

[silvertornado_sr]

going to check everything again and see what happens :)

[silvertornado_sr]

right think i have found the problem the igtion live wire i got wrong but can't find the right wire to connect it to as theres no black wire free need to know where to cut the black wire to feed the ecu ?

[Sloth]

behind fusebox. big huge black, use thick wire mate.

[silvertornado_sr]

can't find the one on the engine loom :( help

[novaxe]

check the coil m8