Sidewaysste

I've put a multipoint LPG mirroring system on my LQ9. Above 2500rpm it behaves exactly as if it were on petrol, but below that I get a pronounced misfire. It isn't constant in that it does clear occasionally.

Are the LQ ignition coils known to be weak?

I've got iridium plugs at 0.9mm and Magnecor KV85 plug leads.

Does anyone have any suggestions?

jarheadl34

iTrader: (2)

I had a friend that ran LPG and if I remember correctly it took more ignition lead when on LPG compared to on gasoline. He used an MSD advance box with a rheostat type switch to add or take out timing as needed.
Jarhead

gofastwclass

iTrader: (2)

I've never done anything with LPG but truck coils are fine for lots of power in all sorts of applications from stock to high HP and high boost. People who love to spend money and have shiny new stuff tell themselves they need aftermarket coils but the factory coils have been well documented a multitude of times to be quite effective and reliable in heavy duty situations.

I seriously doubt the truck coils are too weak and would consider looking at the tuning end of things long before replacing hardware.

Sidewaysste

Well it turns out that the truck coils *are* too weak!

I dropped the gap down to 0.025" and the misfire disappeared. As I've no reason to think the coils are bad, this just shows how much harder it is to ignite LPG.
The obvious next question is - does anyone do any REALLY powerful coils?

G Atsma

Check with PanteraEFI, a vendor/sponsor here.

Sidewaysste

Thanks, will do.

JoeNova

The wrong spark plug can cause that same issue. Insufficient spark energy regardless of how powerful the coils are.
Either way, I agree. Contact Lance at PanteraEFI if you want better coils or top shelf advice on this.