92 Turbo miata runs with bad CPS sensor but not A Good one?
05-08-2022, 03:29 PM
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92 Turbo miata runs with bad CPS sensor but not A Good one?
Howdy yall!
1 month of cps problems on my 92 Turbo Miata is making me swallow my pride and make my first forum post.
long story short(ish), my 92 mega squirt 2PNP Miata starts and runs with the cps senor that came on the car. Idles fine, and with <10% throttle she runs fine too! But with any load or any high rpm the engine misfires like crazy! I am talking gunshots and heavy sputtering on my fresh rebuild :( .While doing this the tachometer acts like it has the worst case of Parkinson's dipping and diving all over the place (dipping down in rpm dramatically and then returning right back up sporadically). This only happens when the car is misfiring, and almost every time the Megasquirt desynchs rpm.
My first go to was to replace the CPS with one of my spares, which the car decides to not start with. My next adventure was double checking wiring, and made my own harness to the ecu for the cps (good continuity to and through the ECU and correct voltages going up to the cps), still no start. Finally in a feat of rage I threw back on the cps that came on the car and low and behold she fired right up!! Is my spare bad? Had a friend drive the same trim, factory, year and even month Miata over to my place, took off his still hot cps, and put it on my car... back to no start. Seems that my money pit only starts and runs with the bad CPS sensor?? Now I am at a loss.
Below I have a list of my mods and tests, and replaced parts I've done recently, I also took a few logs of the "bad" cps, and a few of the known good cps, I will also include a copy of my tune as soon as i get home today.
toyota 1uz coilpacks, brand new fuel pump, fuel pressure was tested and is correct, all sensors calibrated correctly, aem series x wideband, gm iat sensor, cx racing v2 turbo kit, rx8 yellow fuel injectors, basemap from DIY autotune, compression test was 160 cold on all cylinders.
Any and all input is appreciated!!! Thank you guys so much!!
1 month of cps problems on my 92 Turbo Miata is making me swallow my pride and make my first forum post.
long story short(ish), my 92 mega squirt 2PNP Miata starts and runs with the cps senor that came on the car. Idles fine, and with <10% throttle she runs fine too! But with any load or any high rpm the engine misfires like crazy! I am talking gunshots and heavy sputtering on my fresh rebuild :( .While doing this the tachometer acts like it has the worst case of Parkinson's dipping and diving all over the place (dipping down in rpm dramatically and then returning right back up sporadically). This only happens when the car is misfiring, and almost every time the Megasquirt desynchs rpm.
My first go to was to replace the CPS with one of my spares, which the car decides to not start with. My next adventure was double checking wiring, and made my own harness to the ecu for the cps (good continuity to and through the ECU and correct voltages going up to the cps), still no start. Finally in a feat of rage I threw back on the cps that came on the car and low and behold she fired right up!! Is my spare bad? Had a friend drive the same trim, factory, year and even month Miata over to my place, took off his still hot cps, and put it on my car... back to no start. Seems that my money pit only starts and runs with the bad CPS sensor?? Now I am at a loss.
Below I have a list of my mods and tests, and replaced parts I've done recently, I also took a few logs of the "bad" cps, and a few of the known good cps, I will also include a copy of my tune as soon as i get home today.
toyota 1uz coilpacks, brand new fuel pump, fuel pressure was tested and is correct, all sensors calibrated correctly, aem series x wideband, gm iat sensor, cx racing v2 turbo kit, rx8 yellow fuel injectors, basemap from DIY autotune, compression test was 160 cold on all cylinders.
Any and all input is appreciated!!! Thank you guys so much!!
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