Offroad-Express

Hey guys. i got a commy 3.8v6 in my surf and wasn't liking the bad fuel economy so i changed the spark plugs as a hopefull fix. but when pulling off one of the leads the end broke off. ordered a new set of leads and bought a single lead just to get it going for the mo. but now it runs quite strangely, drove it from the paddock to the driveway and it stalled about three times
just wondering what the problem could be, i think i put the leads back in the right place.
Does anyone know the cylindar order? Cheers, Tim

numbered on the top of the coil packs dude.

cheers for that ben saw those but i know jack all about engines and i cant see any numbers on the rocker cover

gimmemud wrote:cheers for that ben saw those but i know jack all about engines and i cant see any numbers on the rocker cover

ahh righto... ok

the left bank (passenger side of engine) is 1 - 3 - and 5 cylinder, the drivers side bank being 2 - 4 and 6 cylinder numbered front to rear.

easy

awesome thanks for that, will see how it goes when my leads arrive tomorrow

well apparently its not the leads or spark plugs i think. put the new good quality leads in but the same thing. sounds like a two stroke and stalls randomly even when gas on . stupid truck mumble mumble...

You didn't accidentally disconnect the AFM whilst you were in there? Usually even with a bad plug or lead the motor will still run semi okay. You would need to have a few bad plugs or the leads around the wrong way for it to stall and run that badly.

Matt.

there is a 3 month old afm in there at the mo. the old one packed a sad and to think of it the problems seem similar. might have to check that, cheers.

mine did similar thing but it runs a map sensor and the vacume line to it had come off from the throtal body

to check if it is spark start it and disconnect one plug at a time, next trick when you find the faulty plug is to swap the coil it can be the coil pack causing the prob V6 Commodore hard starting and misfiring under load. There is another common issue Black wire with Yellow trace - inside the engine bay coming from EFI control unit (it may be different now). It is a Single wire that splits off to two wires. Hold wire, squeeze or move wire at join and the engine should increase in idle then settle. In some cases, the engine may stall. Repair connection the wires run to the Coolant Temperature Sensor and the Throttle Position Sensor.

The TPS can be faulty too

The commy's run a wasted spark so disconnected a single plug will affect two cylinders.

If you remove a plug make sure it's grounded so the spark has somewhere to go. Test each plug to make sure each one is firing.

Next it's time to move on to AFM/MAF and begin testing the sensors. You can probably pull codes from it at this stage to see what the ECU thinks is wrong.

Matt.

when i said afm i meant a 3 month old throttle position sensor. would you be able to tell me what the maf/afm sensor would look like and where it would be located. Also i ran it for a couple of minutes without one of the leads on and just the metal sticking out of the coilpack with it not being earthed (would that be bad?) just to see how the new sparks plugs were after i broke a lead. i know all the leads are around the right way and the spark plugs are nice and tight.

and i wish i was able to plug the ecu into a machine but when the engine was wired up they didn't put the plug back on it

post up a few pics of the engine bay someone can then draw a circle around it. /check the plugs and earths for the computer and sensors too. I would seriously think of going to an auto sparky to get this fixed and the comp plug wired for diagnostics

gimmemud wrote:and i wish i was able to plug the ecu into a machine but when the engine was wired up they didn't put the plug back on it

yea i have this problem to, pain in the ass a

my maf sensor is mounted separate to engine to the firewal with a vacume line running to a small pipe on back of throtal body (pointing at the firewall)

hey guys thanks for the help running back to normal now... well sort of.it was that vacuum line i must of accidentally knocked it when changing plugs and thought it was normal... but no.
Now the problem is that accelerating it sounds like a two stroke still and its a bit sluggish and it did some nasty misfires. Also i ran it for a couple of minutes without one of the leads on when i broke a lead last weekend, and just the metal sticking out of the coilpack with it not being earthed just to see how the new sparks plugs were, is this a bad thing?

may pay to pull plugs out again and give them a clean up, having no lead on and with it running bad may have fowled them up, worth a go anyway

Each coil feeds two plugs and they run wasted spark ie both plugs fire at the same time. For the wasted spark to work both plugs must be earthed.

If one plug is not earthed then the coil can't operate properly and is effectively open circuited. This can possibly damage the coil, the high voltage energy has to be released and will take the shortest path to earth which is often inside the coil destroying it.

Matt.

Mattman wrote:Each coil feeds two plugs and they run wasted spark ie both plugs fire at the same time. For the wasted spark to work both plugs must be earthed.

If one plug is not earthed then the coil can't operate properly and is effectively open circuited. This can possibly damage the coil, the high voltage energy has to be released and will take the shortest path to earth which is often inside the coil destroying it.

Matt.

So i suppose there is no chance in the plugs just being fowled
Is there a way to fix coilpacks (i'm a sparky) or do i have to fork out for a new one