EFI Help

[tony]

G"Day all you tech heads outhere

can any one ster me in the right direction,

89 RR 3.9 efi #5 cylinder is not firing (would have to be the one under the plenham)hardest bugger to get at.

OK so what we"v done so far we have spark at lead, spark at plug,
swoped injectors round #5 still not firing

elect conector on top of plug looks OK tight fit no corrosion,fuel rail good no corrosion.

Not being very good with electrics were would you go from here.........


if I had the dollars the cape maybe??????but in all seriousness any advice gratefully accepted

Tony

[DirtyDawg]

Have you tested it with a multimeter? see itf power is there...

[tony]

Originally posted by DirtyDawg
Have you tested it with a multimeter? see itf power is there


It could be said that I am electrically challanged (that would be an understatment)

Should there be 12v at the injector or only when its triggered??(and then should it be 12v)

the only constructive comment I can make is that I'v seen no smoke comeing out of any boxs (you may have guessed what I know about electrics you could write on the back of a postage stamp)

but thanks for your quick reply

Tony

[crossy]

i've seen plug in l.e.ds that sit on top of the injector, you then plug the lead into this. they light up when firing. from repco i think ???
the duty cycle would be too low for a meter to pick up on, try the multi on ac mode, but the reading will be low and meaningless. best to use a cro or take it to an efi mob for a quick test. Also I would think the injectors are batch fired with the loom split in two alternate banks. if this is so check continuity between one plug and your problem one. if you have a good circuit - your problem is likely to be elsewhere...

good luck and have fun https://www.aulro.com/afvb/

[DEFENDERZOOK]

<span style="color:blue">how did you diagnose that #5 is not firing.......?

have you tried a different plug and a different lead on that cylinder....?



tell me this and then we may need to go to step 2.....
compression test.....</span>

[tony]

G'Day Tony

Well your bloods worth bottling,indeed if you are ever out my way drop in for a beer.We went to step 2 and guess what theres no compression in that cylinder.
Dont know why I jumped to the conclusion that the injector was stuffed.
without doing the basic stuff first.

Thanks

Tony

[RaZzA]

sorry to bring up this old thread - but I was wondering what the cause was of the compression loss?

I only ask as I have the same year model as your self https://www.aulro.com/afvb/

[p38arover]

I wonder if the compression loss is due to a stuck valve. Is there a lot of tappet noise from that cylinder (indicating excessive valve lash)?

Ron

[tony]

G'Day Ron

When we pulled the head off the exhaust valve was chiped,there was no indecation of any forign bodies in the chamber just a big crack in the base of the valve.

There was no tappet noises or any other symption (other than no compression) and not fireing on that cylinder to indecate anything wrong.

Tony

[p38arover]

Oops! I didn't notice it was 3 month old thread!

Ron

[RaZzA]

yeah like I said - sorry to res it - but if I ever come across it I know what to look for https://www.aulro.com/afvb/ well - one of the things anyway https://www.aulro.com/afvb/