93 maverick duel fuel carbereted missing when at normal temp

[Robo]

just trying to get a broader base line on where the engine is at.
more info gives us more to chew over and offer you a solution.
9.5 v after resistor is low no wonder it didn't want to start.
hows the battery and alternator?.
and as bro taslucas said earths

check voltage at ignition you should have 12v.
at coil starting voltage should always be 12v and, after you release key with resistor slightly less.
helps to preserve points from burning to fast.
but the pertronic modual is designed to run with oem type (resistor) coil.

putting the coil issue aside hows the plugs and leads.

[munzy42]

Bit more info for has, trip home was great, only missed a couple times. Climed the Adelaide hills 10 km very step no worries. A little cough and backfire at the top of the hill on gas. Ambient Temperature was 22. Started to miss a little about 1.5 hr's into trip, ambient temp 26. Pulled over for a coffee and 20 min snooze. No worries all the way home.

[munzy42]

Still lacks a little power so I've got new plugs. Colder ones and gaped them to 0.7mm as per ngk instructions. See how it runs tommorow on the trip back to the big smoke ( 4.5hrs of hard rock music)

[GQ TANK]

I had similar problems.

Removed the ballast resistor and changed the coil to a gt40 - still intermittent misses.

Found the advance ring in the dzzy was seized - cleaned and greased it - qworking properly.

Redone all the wiring connections as I found suspect crimped connections at the coil in particular the wiring going to the gas safety switch - fixed.


With the changes Im now getting better fuel economy.

[munzy42]

Signs are good, replaced the plugs with colder ones set to smaller gap, truck hasn't run this good since I got it. Doesn't hessite after stopping at lights, more power too. Old plugs looked fine when I pulled them out 2 weeks ago but today they definately showed signs of running too hot. Gap was also too big, close to .9 mm which the book says is fine for standard (.8 to .9) but ngk website said too big for gas. Haven't tried it on petrol yet.

[munzy42]

Yeh I thought my advance ring was not working, degreased it and lubed it with high temp grease, if I duck on the tube it was working fine. Tried with and without resistor , no difference. Was worried volts might be too high without, 13.4 volts when at idle. Now its at 11.4 at idle.

[munzy42]

IMG_20140405_180433.jpg the old pugs all show too hot like this.

[taslucas]

Good to hear you've got it sorted mate.
I mat check up on my dissy advance too cheers

[Robo]

Thats good news.
Keep an eye on plugs gap std type plug will wear faster than normal with lpg.
recon 5000 klm is good base line for rechecking plugs
Thats why I suggested use Iridium.
Ive had em for 5 yrs now, wear wise never had to clean or re-gap em once due to k's.
to me that truly "electronic set and forget", as it should be in a perfect world lol.
and that's not a fluke I run in in my GTR also same good results they are even older and higher k's.
If ya get the odd miss still on lpg, gap prob still the slightest bit large.
sometimes it can take a few goes to find the optimal gap setting.

Seeing that it had incorrect plug gap from previous owner,may indicates state of overall tune
Might pay to take it to lpg tuner for a going over..
that way you will have peace of mind things are as they should be.
tell him Iv'e gone over it,plugs timing is ** deg, etc etc think its ok, and I want my tune checked.
(after a second opinion so to speak).
he may check for lpg leaks & then put his exhaust analyser on it and set about his business.

Also does it have a upper cylinder lube system fitted like morreys?.
cheers

[munzy42]

Doesnt have cylinder lube system.

All so update from the big trip. Ran sweet for 1 hour, few misses, but not too serious. Stopped and fueled up. Ran good for another hour, then few misses, bit more than before. Pulled over for dinner, got timing light out ( bough a new one on Saturday but hadn't used it yet). Found timing to be advanced buy 15 degree. (this thing was serviced by Repco mt gambier for last few years). Adjusted to 11 degrees. Ran great for next 2 hours, no misses, power seemed a little less tho. Missed quite a bit driving through the Adelaide hills ( very winding and up and down steep hilly, great if I had a skyline, bit hairy late at night in a maverick). Wondered if it might be running a bit lean on gas, and that was making it run hot?