ShadowGryphon

After a few months of not being able to work on the rx8 I was showing the video of the noid light test to a friend of mine and he noticed that the rpm kept dropping. As soon as he pointed it out I noticed that every time the rpm dropped, the noid light WOULDNT flash. So, while I trace down to see if its wiring or sensor related, I figured I would ask if anyone has ever had an issue with the trigger wheel or the ess sensor. If so, if there an aftermarket upgrade?

dannobre

iTrader: (3)

It is unlikely to be the trigger wheel...but the sensors do fail

There isn't any reason to go aftermarket. The sensors work well as configured.

Check that you haven't picked up crap on the sensor...I have seen them pick up nuts and small bits of metal and that makes them work poorly

ShadowGryphon

Ive replaced the sensor as well as cleaned it multiple times before and after replacment. Now, I did buy a used sensor, but it ohmed out ok. I guess I am going to have to check the signal with my o-scope to see of its sensor or wiring. What else would cause intermittent injector pulse? When I say intermittent I mean it'll pulse a noid light steadily and then stop for about 3-4 seconds, and then start up again.

dannobre

iTrader: (3)

Which injector did you have it hooked up to?

Rotary engine injectors are staged....not like a piston engine where they are usually all functional over the operating range of the engine

ShadowGryphon

I had it hooked to the front primary. Heres links to the two videos. The first has sound and shows the rpm readout. The second has no sound but shows how intermittent it gets.

https://youtu.be/-cys-Y3eMuM

https://youtu.be/FVlqYWp-3jA

dannobre

iTrader: (3)

I would think that the idiot light might be the issue...

Does the car start?

I would check the Injector wiring for sure.

if you have a scope I would use that before I trusted the light 😎

ShadowGryphon

No, the car currently refuses to start 9/10 times. Compression is good, coils plugs and wires are good (doesnt make a difference if oem or LS coils) fuel pump has been replaced, maf has been checked. It has fuel (atleast to the injectors), air, and spark. Once it eventually starts it runs perfectly.

I know the noid light isnt foolproof but I couldnt help that notice that every time the light stopped flashing the rpm readout dropped. Thats why I though ess or trigger wheel.

dannobre

iTrader: (3)

I would change the ESS.....try and borrow one from a working car. The shaft sensor is the trigger for both the injectors and the coils. Maybe follow the wire along the side of the A/C compressor and into the harness to look for issues. If you can scope it that should tell you as well

I would doubt it's the injectors...but wiring and the ECU are also possible.

Sounds frustrating 😐

ShadowGryphon

Ive already replaced the ess once. How likely is it that the used one I bought was faulty?

mazdaverx7

iTrader: (6)

Have you pulled the plugs after cranking to see if they're wet with gas or if they're dry? Just to help determine if there's a fuel delivery issue or perhaps a spark issue. I know you said your coils were good but perhaps there is another issue with the wiring. Have you tried to pull any codes from the car? Would be nice to run the car and monitor the live data and see if there's any values that are out of spec or anything that's spiking or dropping off.

dannobre

iTrader: (3)

The problem is that you replaced one that was unknown with another one that is unknown

The sensor doesn't fail very often..they are basically the same sensors that were on the FD motors and they usually live for years

That being said .....the most likely failure that would intermittently take out your spark and fuel would be something to do with that system. It could be the sensor, the wiring harness to the ECU...or the ECU itself

Easiest way to rule out the sensor and the cheapest would be to borrow one from a functioning engine...if it still acts the same look elsewhere. If it solves the problem get another one that works.....

Diagnosing intermittent electrical problems can be the most frustrating thing to fix.

It is way easier when they die completely...much easier to find the problem then

ShadowGryphon

Unfortunately I dont know anyone locally that would let me borrow a known working sensor. I am fairly certain I have spark as when using an inline spark tester it lights up. I just bought a Power Probe 3 for work so that should help track down any electrical issues.

mazdaverx7

iTrader: (6)

Where are you located? If you're in Ohio I have everything you need to include a rotary compression tester. I'm happy to help with a spare ESS if you were local.

ShadowGryphon

Unfortunately I'm in Mississippi. Thanks for the offer though.