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Pulled the plugs on the car and found completely clean trailing plugs. Car has a powerFC, but is otherwise stock. My first step is to grab the multimeter and start ohming out the coil harness to the ignitor, then back to the ECU. Any other place I should focus attention? It would be weird that both trailing coils are dead at the same time, no? Can the powerfc turn off the trailing coils? I dont know much about the history of the car at the moment so I'm digging through it myself.
This picture is the rear rotor but the front looks the same. I'd say the plugs have at least 2000 miles.
Yeah, start with the coil pack harness and then check the coils. The shop manual has an ohm test for the coils that I've found is on the money - if it fails that test, the coil is bad or failing.
Could also possibly be bad spark plug wire, but I'd imagine you wouldn't have 2 bad wires both on trailing. Unless they are some really cheap crappy wires or something.
While the harness did ohm out correctly, the harness is falling apart, with open breaks and exposed copper. The coils all (Leading, T1 and T2) ohmed out at 1.2 ohm. Which is above the 1.0ohm specification of the FSM. Doesn't entirely explain it, because the Leading coils were firing fine. I'm going to go double check my ohm meter and make sure it's working correctly. It's not a cheap POS, but it's not a Fluke either.
make sure you touch the probes together to get the internal resistance of the meter first. whatever that number is, subtract it from your reading to get actual.....
Yeah after taking that into account the coils appear to not be the cause of the problem. But the harness had exposed copper when I took it apart. It was fully baked, and the wire sheathing fell apart.
and did you check the R from the coil plugs to the wiring connectors. There should be infinite resistance on the trailing coil
that said, both not working may tilt fault to the igniter, or the harness from the igniter to the coils.. Check the continuity on your harness from the igniter, then try to get your hands on an igniter that you know works
well.... hold up now... if your harness is in that shape then i would stop troubleshooting completely until it was replaced. electricity and wiring is magic sometimes. we cant say for sure one way or the other if your deteriorated harness isnt the entire problem.
KD Rotary back in the day sold an "Anti Detonation" device. It later turned out to be CNC aluminum discs which were pressed into the trailing spark plug holes. It would have been hard to see them in there, or even know they were installed, because the spark plugs were placed on top of them.
KD Rotary back in the day sold an "Anti Detonation" device. It later turned out to be CNC aluminum discs which were pressed into the trailing spark plug holes. It would have been hard to see them in there, or even know they were installed, because the spark plugs were placed on top of them.
Hah! Well this engine was rebuilt by KDR. Brilliant. I love this forum. I'm going to grab my borescope and double check it. Thank you. I thought those plugs were too clean, even for not firing. I'll post the results.
I've run into only a handful of KDR motors that had this, but the clean plugs was a tell tale sign common to all of them. Glad you were able to get them out. Ive been able to pull them from intact motors by pulling out only the trailing plug and rotating the motor to generate a compression cycle.
The way these plugs were designed, they are a press fit on to the electrode of a new trailing plug. After a few heat cycles the plug opens up and fits loosely so if you remove the plug it won't pull out the cap with it. I put new plugs in the engine without starting it and removed them to check with a borescope and the aluminum anti detonation plugs were stuck firmly on the end of the new spark plugs. Had to use pliers to pull them off they were stuck on pretty tight. Both of them came out this way.
Again - thank you, I would have been replacing everything in the ignition system chasing my *** without having known that!
Ah the infamous "anti detonation device" strikes again. It was a two bit attempt to avoid detonation before advances in tuning and engine management were what they they are today. Glad it was an easy fix.
but the clean plugs was a tell tale sign common to all of them.
Reading through this thread and looking at the pictures. This was my observation. "Squeeky Clean Plugs". There is no way plugs could be put into a working rotary engine and run for a 1/4 mile and come out that clean, Never mind 2000 miles. Something didnt add up.
Wow, that is a great find! I remember when these came out, it was SUPER hush-hush. Because it was a dumb idea . Back then people were trying ANYTHING to get modded motors to last, though.
WOW that is just crazy - but if the intent was to disable trailing ignition, why not just do it electrically? Remove the trailing plug wires & unplug the trailing coils from the wiring harness. Same result, but then several owners later you won't have the current owner wondering WTF is wrong with my trailing ignition.
I believe I have some of these in my trailing spark plug holes. I was inspecting with a borescope just trying to inspect rotors and apex seals and then fell onto this thread. How are you suppose to remove them?
There are two ways. You can turn the engine over with the plugs out and the fuel pump off, the compression will blow them out. Or (the easier way imo) take a fresh spark plug, run it down into the hole tight, then back it out. It should come out with the plug like pictured.
01-21-20, 02:29 PM
. Back then people were trying ANYTHING to get modded motors to last, though.
