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-   -   Car died at track day - shitty wiring or bad sensor? (https://www.miataturbo.net/engine-performance-56/car-died-track-day-shitty-wiring-bad-sensor-108920/)

Morello 12-28-2023 12:22 PM

Car died at track day - shitty wiring or bad sensor?
 
Hey all. Just asking for a quick sanity check here. My car died about 5 sessions into a track day a couple weeks back and I'm just now getting into fixing it. Composite logger is showing no crank trigger when it works (why does the composite logger not work like 70% of the time?), and the regular log is showing 0 RPM while cranking. I have 12V across the two outside pins on the crank position sensor connector, and I have continuity back to 2E on the ECU from the middle pin. Sure seems like the sensor bit the dust, but I did this VVT swap wiring like 7 years ago so it's also totally possible that one of my splices went bad.

I know the cam position sensors go bad with some regularity, but has anyone heard of the crank sensor going bad?

Ted75zcar 12-28-2023 12:38 PM

Yes, crank sensors are known to go bad. Replace with OEM, don't fall into the knock-off at half price trap. I buy mine from Jim Ellis IIRC.

Edit: crank sensor spacing is a known issue as well, bunch of threads/topics on this subject.

Morello 12-28-2023 12:44 PM


Originally Posted by Ted75zcar (Post 1644381)
Yes, crank sensors are known to go bad. Replace with OEM, don't fall into the knock-off at half price trap. I buy mine from Jim Ellis IIRC.

Edit: crank sensor spacing is a known issue as well, bunch of threads/topics on this subject.

Yeah, already checked the spacing. Is Delphi considered knockoff?

Ted75zcar 12-28-2023 12:49 PM

I don't remember if Delphi is OEM or not. I sourced several different sensors in ~2017 and did a bench characterization. The Mazda branded one is the way to go (at least for a 36-2).

LeoNA 12-28-2023 05:16 PM

Mitsubishi, but even the aftermarket units made by Mitsubishi are junk. I don’t understand why, just have had the same issue with new Mitsubishi units from Rockauto.

Morello 12-28-2023 10:15 PM

Well, I did what you said not to and ordered the Delphi unit for $45 instead of $170 for the oe from Jim. I will come back and eat crow if I come to regret this decision in a year.

(I’ve been running a car parts store CAS for years- hopefully my luck continues)

rjacobs 12-28-2023 11:39 PM

I killed a Beck Arnley crank sensor in my 01... I think it was acting up for at least one track day, if not 2.

Swapped to a real OEM sensor... Had to change my tune from falling edge to rising edge and then redo my timing offset... only thing tuner and I could think of is the sensor is in the housing backwards or the wires are wrong inside... somehow the knockoff didnt get it quite correct from an OEM sensor.

Morello 04-07-2024 07:00 PM

Update - I twisted the mounting bolt off, and then an extractor off in that. So the car has been sitting in my garage for the last 4 months untouched.
Time to start making some progress. Looks like the bolt is fucked in the oil pump, which is stock - not a bad time to upgrade to a boundary pump I suppose. Timing belt, water pump while I'm in there.

1. Should I stick with the stock trigger wheel? The only time I've ever had sync issues is on cold starts when cranking speed is kinda low. 36-2 is easy enough to add while I'm in there
2. Fluidampr also?
3. Where do people get their timing belt components these days? This used to be the ticket back in the day - is this still the case? FM is out of stock on VVT components

rjacobs 04-08-2024 11:18 AM


Originally Posted by Morello (Post 1648673)
Update - I twisted the mounting bolt off, and then an extractor off in that. So the car has been sitting in my garage for the last 4 months untouched.
Time to start making some progress. Looks like the bolt is fucked in the oil pump, which is stock - not a bad time to upgrade to a boundary pump I suppose. Timing belt, water pump while I'm in there.

You're going to have to pull the motor to pull the oil pan to do the oil pump... Its not just a "pull the front of the timing shit off and change the oil pump" operation.

I would see if you cant drill out and re-tap even if its a slightly larger size, or throw a time-cert in it. Might have to pull the radiator and some other shit in order to get a drill squared up in there, but far easier than pulling the engine.

Morello 04-08-2024 05:08 PM

I've already accepted that I have to pull the engine to get this fixed. The oil pump housing looks like cast aluminum, and drilling it out was a possibility until I broke the bolt extractor off in it. Much more likely to fuck up the housing than drill that out at this point. There's also not much meat to drill a larger hole into (see photo). The car has been running boosted for 7 years now - seems good a time as any to clean up some leaky seals and shit anyway.
https://cimg1.ibsrv.net/gimg/www.mia...391fc4b853.png


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