Anybody know about Ford DIS ignitions?

nola mike

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Started getting some surging, initially worried a drivetrain issue. Then felt like a misfire, eventually got a CEL for #3 misfire. Replaced plugs, which definitely needed it but then started getting misfires in all of 1 bank's cylinders (4/5/6). I put a timing light on the plug wires and got very intermittent spark out of the offending cylinders. Other side was consistent. I'd like to get this in shape enough to pick up a "free" (ha ha) wave runner tomorrow, it's a few hours in each direction.

I don't even have my crappy Chilton's manual with me, so no idea of the specifics of the system. From what I can tell it's a distributorless waste spark system. I don't know which sparks are wasted/which cylinders are firing at the same time. It's a 4.0L OHV engine, 97 Ranger.

I compression tested both banks and they're 130psi (dunno if my gauge is accurate, but whatever).

So...Can the coil pack fail like that (intermittent on one bank)? Position sensors must be working, ICM must be working unless it has different output wires for the different banks. Same with wiring. Anything else it can be?
 

matt167

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Yup. It’s a waste spark system so it sparks every time. With limited tools I’d put a coil on it. If you had a scanner or a scope. You could watch it. But being intermittent it might ohm okay and still be bad. I don’t think coils for that are too expensive. I buy most of my car parts from rock auto where I find them stupid cheap for reputable brands
 

nola mike

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Yup. It’s a waste spark system so it sparks every time. With limited tools I’d put a coil on it. If you had a scanner or a scope. You could watch it. But being intermittent it might ohm okay and still be bad
Seems that the port side sparks twice as often as the starboard side. I'm definitely dropping some sparks on the starboard side. Had my wife pick up a new coil on the way down here, I'll throw it on in the am.
How would scanner/scope help me here?
 

matt167

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Seems that the port side sparks twice as often as the starboard side. I'm definitely dropping some sparks on the starboard side. Had my wife pick up a new coil on the way down here, I'll throw it on in the am.
How would scanner/scope help me here?
You could watch the spark with a scope. Scanner you could watch pids… but for something like that, it’s a pretty safe bet to toss a coil on it
 

nola mike

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You could watch the spark with a scope. Scanner you could watch pids… but for something like that, it’s a pretty safe bet to toss a coil on it
Ah, well, it wasn't the coil. The spark actually doesn't look like it's dropping anymore, but I guess that wasn't the main issue. The misfire seems to start in cylinder 5/6 and then eventually throws a "random misfire" code, along with a lean code on that bank (this is the opposite bank from where the spark was dropping). I figure that the lean choice is because of the misfire. So more low hanging fruit is plug wires. I could swap and see if the fault follows, but 235k miles wouldn't be a bad idea to replace. After that I guess we'll need to see if the misfire is too much fuel or not enough. Won't be able to bring the sweet wave runner back today. "All it needs is a battery!"
IMG_20240518_130726.jpg
 

nola mike

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Ah, well, it wasn't the coil. The spark actually doesn't look like it's dropping anymore, but I guess that wasn't the main issue. The misfire seems to start in cylinder 5/6 and then eventually throws a "random misfire" code, along with a lean code on that bank (this is the opposite bank from where the spark was dropping). I figure that the lean choice is because of the misfire. So more low hanging fruit is plug wires. I could swap and see if the fault follows, but 235k miles wouldn't be a bad idea to replace. After that I guess we'll need to see if the misfire is too much fuel or not enough. Won't be able to bring the sweet wave runner back today. "All it needs is a battery!"
View attachment 398256
Just an update, finally got the new wires. I ohm'd out the other ones, and 1 wasn't in spec, but tried swapping them and it didn't work. Went to put on the new wires and noticed that at some point I mixed up 5 and 6...so there was at least part of my problem. Dunno if the original problem was coil, wires, or both, but we're back in business. Hopefully got another couple of 100k miles left.
 

Scott Danforth

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the manual pump says it needs more than a battery. 1717407790938.png
 

nola mike

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This is going to be a project for my 13 year old. He's convinced he can fix it by watching youtube (me: "how are you going to fix this when you can't adjust your bike gears?").

But he's saving his money for parts and gas. Inside actually looks pretty clean without water intrusion. Looks like a dead simple carb'd 2 stroke with good parts availability, and looks like a fun toy when working (unstable, maneuverable and tippy). Hoping this will be a good thing for him to learn on. God help me, I'm on board with this plan. My wife is not quite as enthused. Oh, trailer also needs a bit of work:

IMG_20240519_124231.jpg
 

Scott06

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This is going to be a project for my 13 year old. He's convinced he can fix it by watching youtube (me: "how are you going to fix this when you can't adjust your bike gears?").

But he's saving his money for parts and gas. Inside actually looks pretty clean without water intrusion. Looks like a dead simple carb'd 2 stroke with good parts availability, and looks like a fun toy when working (unstable, maneuverable and tippy). Hoping this will be a good thing for him to learn on. God help me, I'm on board with this plan. My wife is not quite as enthused. Oh, trailer also needs a bit of work:

View attachment 398971
I think that is invaluable experience for a kid his age. I started screwing around with cars helping my dad, which led to me restoring old cars, learning to weld & rebuild engines/trans. When I started working in the beverage production industry in late 90's this experience helped me immeasurably in my profession, especially being confident in figuring out out machines work.
 
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