Video of my S12 sounding drunk... help!
 

JackieFan asked for me to upload a video so I have...

http://www.vimeo.com/11904610

ive bought a set of those ignition spark testers: http://www.halfords.com/webapp/wcs/s...goryId_165469#

the result was that im getting a spark to all the cylinders...

ive the dizzy cap and all fine...

unplugged and plugged in injector leads...

replaced the coil lead...

replaced the coil which had cracked somehow...

checked the spark with that HT tool and all the plugs light up...

next on the list is checking the spark plugs...

what else could it be?

Stoned post! ok so you have spark, and its misfiring. fuel and compression tests next.

get an automotive bulb a resistor with the same impedance as the injectors [sevice manual]and some wire, disconnect the injectors and connect each injector wire in turn to the bulb, and crank the engine. light = ok, and vice-versa. Give that its running atall can assume with reasonable safety the ecu is fine, and inconsistent readings here wouldindicate some bad wiring

for the injectors themselves, download the service manual and refer to the fuelling section for the test [you'll need a multimeter]

oh... where can i get one of these british shed inventions? :-)

Maplin/RS and your local motor factor [not halfrauds]

i have a multimeter already... what about the other invention? is is called something as a complete device or do i buy parts?

sorry im on a learning curve here.

cheers

erm, well theres a special tool which consists of those bits, god knows what they called it though. I'm not into paying excess if i can heath robinson something together. the resistor and you multimeter on continuity mode would do the trick in most cases too.

Is it just my PC or does it sound like that's not missing once the engine actually gathers pace?

You could also try checking the ECU for fault codes.

http://www.nissansilvia.co.uk/vbb/sh...ht=fault+codes

lo-fi web video doesnt help, but it does seem less pronounced, hence the compression test.

i got the plugs out today...

no.4 is slightly rusty on the top and blackened at the spark end
no.3 was wet from oil, blackened and not so tight as the others
no.2 was blackened
no.1 was blackened and was impossible to get off as it was on so tight


http://img269.imageshack.us/i/22052010392.jpg/
http://img269.imageshack.us/i/22052010392.jpg/
http://img525.imageshack.us/i/22052010391.jpg/
http://img525.imageshack.us/i/22052010391.jpg/

but this is probably due to sustained missing from trying to fix it? its no.3 i am concerned about. i split a load of oil on the rocker cover through filling up with oil the week before, then after that run it sat for a week which is when it buggered up after 3-5 mins of warming up... maybe the oil heated up and got in there?

also the spark plugs are set to .70mm. in this post alundra shows a picture of the 'stock' plugs gap to be 1mm: http://www.nissansilvia.co.uk/vbb/showthread.php?t=5027

was number three finger tight or thereabouts? if it was loose it could cause low compression and a miss that improves with rpm...

Oil on one plug is a little concerning, so would be worth a compression test if tightening the plugs properly doesnt yield results.

no.3 was medium to take off with a tool, so pretty easy.

what do my plugs look like? ive been reading when they look like that along with the white tops its a problem with the fuel mixture i.e. too rich.

what are the spark gaps for NGK Rs? they are .70mm.

cheers

how old are the plugs?? i think for piece of mind i would change them anyway, ive had similar trouble before with a dodgy spark plug, also was the problem there brfore you changes the plug leads, as our forklift at work used to run on 2 cylinders, untill you revved it, and that was leads.

just quickly about the plugs.

being an NGK r really doesnt say much about the plug. Its detailed specifications are buried, encoded in the part number, for example bcr6es and bcr7es. the numbers relate to the heat range of the plug

a 0.7mm gap shouldnt cause any problems although for mild tuning is a bit narrow. From memory until you're running aproximately a bar then a 0.8/9 mm gap did people fine with the heat range 7 plugs.

they are bcr8es plugs. ive set them to .9mm...

the car is running 1 bar of boost.

i will put them in today and fingers-crossed it will work.

I'd put them back to .7 tbh otherwise you might get the spark blown out at that boost.
A compression test is what I'd be doing first on this car.

ye, 0.7 on 8s is right for that boost

well just put it back together...

started it after 20 seconds of cranking...

it began missing, but then kicked into life with all four going... after about 20 seconds of being on all four, it started to resist and drop onto three, then it wasnt long before it stalled.

whenever i put my foot on the accelerator it began to die.

why would it be so hard for it to kick into life and then die after 20 odd seconds of being fine?

Do a compression test and post the results.

thanks

do i need a 10mm adaptor for the S12? the kits all seem to be 14 and 18mm.

same thing applies to compression testers as to spark plugs...

check inside the dizzy cap. i have had the center contact jump out before now

Yup i fitted these to this car last summer, Have faith David!.:p All correctly torqued up too..

Do a compression test. But get all the plugs out first.
Try using a decent 16mm deep sparkplug socket,UJ and extention bar. It will get them all out

Aslso check no split oil has gone in the injector contacts

yep john you did a good job considering the state the car was in before.

i couldnt be bothered to get a compression test. but it wasnt that anyway...

there was water and oil inside the dizzy! i swear i checked! it must be a crappy cap or something, so going to replace it. the oil came in from me spilling oil on the rocker cover i think...

after driving another car around for a while and driving my silvia, ive noticed my chest has got hairier. :1la

cheers for the help.