Been having quite the time getting my 1994 D1 back in running shape after a head gasket change. Amazing how many things can creep up when you upset the stability of an engine after 145k miles.

Most recent trouble is a very rough idle and low power at speed. Diagnosed as "no spark" at cylinders 1 and 6, confirmed by timing light and spark gap tester as well.

New spark plug lines, new spark plugs, new distributor, new coil. No check engine light. No weird readings on oxygen sensors or MAF or TPS via RoverGuage. Injectors are all opening fine (via noid light check). Replaced distributor and distributor rotor. Engine timing was done a few weeks ago via a professional shop who said cylinder 1 was firing (as they needed it for setting the timing).

Can anyone think of a reason why cylinders 1 and 6 might selectively not spark? Could be an issue with the new distributor after a few weeks I guess? Something about cylinders 1 and 6 being 180 degrees offset has me thinking that might be the case...

Any and all thoughts would be appreciated!

 

Did you replace the cap and how old is the coil

 

Dizzy D1's are picky when it comes to caps, rotors, and ignition amplifiers. Even though it's remotely mounted the ignition amplifier can just start acting up especially once the D1 is warmed up. You said you replaced the dizzy did you go with a Lucas replacement or the Pertronix D175510? Going with the aftermarket unit eliminates the issues with the OEM ignition amplifier (aftermarket has the amplifier built into the dizzy) as you simply run the Red/Black wires from the new dizzy straight to the coil and bypass the OEM ignition amplifier, but you should also replace the coil to the Flame Thrower unit as the Ohm's are different vs the OEM Bosch coil.

 

Thanks guys really appreciate the quick replies. New Lucas coil and cap. Verified coil resistance was in spec. However the plot thickened this evening when I took the cover (not cap) off the distributor.

What I found that concerned me was the accumulator / reluctor gear only has 6 teeth. My old unit (and a really old one I kept from a while ago) has 8 teeth. I’m fairly sure you need 8 teeth in there to trigger the pulse charge for the spark. This would explain not having spark on 2 of 8 cylinders. The cap that came with it has 8 spark positions. Hmm.

Double checked the part number and labeling from the unit I bought and everything says 3.9EFI v8 on it… starting to suspect a mistaken assembly. Maybe someone at the mfr put a 6 cylinder diesel reluctor in…

Photo attached. Anyone have domain knowledge to confirm 8 teeth are needed? I have a message into the distributor but they’re in UK and pretty sure they will make me return it to confirm faulty. Probably a month until I hear back and another few weeks after that to get a replacement.

Best4x4 I’ve been considering a Pertronix unit and flame thrower. Every once in a while I read that people have bad luck with them which made me skittish. Sounds like you’ve been satisfied?

 

I can pull the cap off mine tomorrow and look but 8 makes sense.

I have been running flame thrower coils for years with no issues on my 3.9's and the last 20k miles on my Excursion as well.

 

That is the issue NO DOUBT good find! Here is a pic from a 95 D1 dizzy I have pulled apart. I've seen a lot of the aftermarket dizzy's and no real serious issues to report. Most of the issues were do to the wires being poorly ran/connected to the coil. There is also the quite large DUI HEI unit which some folks run. The OEM setup is good, but there is better stuff out there no doubt. My dizzy in my 95 went out, and I had a good spare. If I didn't have the spare I'd have grabbed up a D175510 and Flame Thrower coil. If the spare dies = that is my next move for sure!



The reluctor gear pictured = you can have it if you wanna just swap it out and see how it goes. Like I said that part is from the original dizzy that went out in my 95 D1 (pickup coil was covered in metal filings, and the magnets were busted all to hell on it. I just tore it down to inspect it. No plans to repair it as I'd just go with the aftermarket unit if the other one dies.

 

If you're lucky, you could swap the old 8-tooth gear into the new dizzy. Just don't pull up on the shaft, or the centrifugal mechanism falls apart. Then you'll need to dig in even deeper. I'm surprised it even ran at all. On the bright side, you probably found which shop to avoid in future.

 

Awesome thanks guys. Shout out to Best4x4 for unearthing that 8 tooth reluctor! I’ve got an old rusty one here I’m going to try to clean up and see if I can get the existing distributor to run in situ. Really appreciate the offer and will let you know!

Found a “power spark” aftermarket unit and coil for fast shipping so pulled the trigger on that as backup. Not sure when I’ll learn my lesson and buy Pertronix… probably after spending 1k in crap distributors and coils.

I’ve been trash talking the 14CUX system for the last few weeks to anyone that will listen to me. But after uncovering this faulty distributor issue I have a new found respect that it managed to run and compensate for the poor timing and loss of power. Probably explains why it wants to idle itself at high revs currently

Thanks again and will report back!

 

The old system is reliable and robust in my experience. Just lacks all the new tech finger pointing at the faulty components

 

No problem at all