Dr. John
SILVER Star
You didn't say what carb you have. With a stock carb, this would be a classic Decel Fuel Cut Solenoid issue.
Backfire saga continues and tacho to zero (1 Viewer)
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I’m betting on this. If you unplug the tach wire from the coil, the emissions computer won’t give you issues.
I dealt with this for months.
Gretsch
SILVER Star
So curious here. Could you elaborate on how an FCS malfunction produces backfire? I dealt with a stumble/no power thing for months as well which did turn out to be the FCS (more precisely the solder joints at the EC controlling the FCS). I never had backfire however. My issue was the FCS would close when it shouldn't thus causing the engine to run rough or cut out altogether during normal operation. Since the purpose of the FCS decel system is to prevent unburned fuel (as I understand it) from entering the exhaust during decel by stopping the flow of fuel into the system, are you suggesting that the FCS/EC can malfunction in a way that allows it to not close during decel, thus causing backfire? Not doubting anything, just am trying to understand whats actually happening. Thanks in advance.
Dr. John
SILVER Star
What I think mine was doing, was... cutting off and on intermittently at all speeds. I was getting severe stumbles and backfires from Hell. It acted more like an ignition problem, where gas pools with no ignition, then backfires when spark returns. So...I don't know exactly where the backfires come from. I had a fresh MSD dizzy, new plugs and wires. I went through the decel system; checked the vacuum switch, the solenoid, resoldered some questionable joints in the "computer", cleaned electrical connectors, and replaced vac hose. All good now. You can make a jumper and easily bypass the system by connecting the solenoid's ground wire directly to a chassis ground instead of it being switched by the computer. This keeps the valve open all the time and you WILL get the normal burbles and pops on decel.
See my post on the last page.
FYI. Had a 77 international scout that would stop running in the rain and just backfire if you tried to start it. Turns out the plug wires were just old and cracked. When it was wet and humid from rain or snow it would short out the wires and stall the engine. Back then I didn’t know much about cars and was poor highschool kid. A can of wd40 would solve that problem. Can’t remember if I ever replaced those wires 
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- #27
Ok so just to be clear as there seems to be many carb and ignition combinations.
Im based in Australia. Most 60s are diesel over here.
I don't believe my 1983 2F has a computer of any sort on it. The carb is now a 3F desmoged, It did have the choke breaker diaphragm on it which I have disconnected as I thought it was making the truck lurch as you took your foot off the throttle. The only other addition to the carb thats fitted is the diaphragm for the vac secondary.
Yesterday I changed the dizzy cap and rotor (rotor looked different). Went to start and no spark. So I went back to the original coil and still nothing .
Everything is getting power including the coil, dizzy igniter and idle cut jet.
But nothing at the HT leads. I think.
Im thinking the igniter in the dizzy is the problem, tho I can't seem to find a wiring diagram for it so im not sure its wired up wrong.
It seems to be getting 2 x 12volt power sources and no negatives to the coil.
I bought points and condenser for it but this dizzy won't accept them so im stuck at the mo.
I checked the resistance on all the plug wires, just like everything else it all looks good and pretty new.
Im based in Australia. Most 60s are diesel over here.
I don't believe my 1983 2F has a computer of any sort on it. The carb is now a 3F desmoged, It did have the choke breaker diaphragm on it which I have disconnected as I thought it was making the truck lurch as you took your foot off the throttle. The only other addition to the carb thats fitted is the diaphragm for the vac secondary.
Yesterday I changed the dizzy cap and rotor (rotor looked different). Went to start and no spark. So I went back to the original coil and still nothing .
Everything is getting power including the coil, dizzy igniter and idle cut jet.
But nothing at the HT leads. I think.
Im thinking the igniter in the dizzy is the problem, tho I can't seem to find a wiring diagram for it so im not sure its wired up wrong.
It seems to be getting 2 x 12volt power sources and no negatives to the coil.
I bought points and condenser for it but this dizzy won't accept them so im stuck at the mo.
I checked the resistance on all the plug wires, just like everything else it all looks good and pretty new.
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- #29
This is the dizzy I have I think
Does anyone have this fitted and can tell me the correct wiring connections for it as I am now not sure ive replaced everything correctly.
And just found this thread. Sounds like my problem could be this dizzy?
forum.ih8mud.com
Does anyone have this fitted and can tell me the correct wiring connections for it as I am now not sure ive replaced everything correctly.
Electronic Distributor Fit Landcruiser 2F 4.2 3F 4.0 FJ40 FJ60 FJ80 Carbi" | eBay
1990 - 1992 Land Cruiser FJ80. - 1980 - 1989 Land Cruiser FJ60 / FJ62. - 1975 - 1979 Land Cruiser FJ40. - Fits all 2F & 3F engines that are carburettor / not EFI. - This isElectronic Ignition System Distributor.
www.ebay.com.au
And just found this thread. Sounds like my problem could be this dizzy?
Electronic F & 2F Distributors
And if that doesn't work just go to this link cause I'm a tard when it comes to figuring out Woodys secret code things.
forum.ih8mud.com
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- #30
Just thought id tie this off.
Im pretty sure I found the problem. While checking continuity of all wires I found the neg wire from the dizzy to the coil a bit sketchy. So I pulled both wires off the ignitor and tested on the bench. And both were off, so I cut the insulation right up against the spade connector and it fell off, same with the red positive wire. That soft silicon sheath on those wires really is pretty crappy. I trimmed and re crimped the wires added a bit of solder and the truck fired right up.
Ive been driving for a few days now and no hesitations no backfires and no blips on the tacho, so happy days I think.
Thanks to all on here, cheers
Mark
Im pretty sure I found the problem. While checking continuity of all wires I found the neg wire from the dizzy to the coil a bit sketchy. So I pulled both wires off the ignitor and tested on the bench. And both were off, so I cut the insulation right up against the spade connector and it fell off, same with the red positive wire. That soft silicon sheath on those wires really is pretty crappy. I trimmed and re crimped the wires added a bit of solder and the truck fired right up.
Ive been driving for a few days now and no hesitations no backfires and no blips on the tacho, so happy days I think.
Thanks to all on here, cheers
Mark
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- #32
Is your ignition a kit mate. I will be looking for an upgrade of some sort soon probably. This aftermarket dizzy I have seems good but im thinking I need something as a spare ignition cos of the inherent remoteness of travel here.
Chinese version of 70's GM HEI. If I did it again it would be Davis Unified's version of HEI because of quality components and they supposedly matched the timing curve to the 2F. .... Anyway they are simple to install, no guessing, but I suggest putting it in 180° off and arranging the plug wires accordingly (Just because the plug wires fit better that way). I'm thinking the Stock Dizzy is more reliable and less maintenance.
