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Crankshaft sensor keeps going faulty

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Hi guys. I am running a 36-1 toothed wheel on my crank with a hall sensor mounted .051" away. Engine is a 4age 16v. The issue is the sensor keeps going bad. Car would pop and bang and cut and then it won't start back even when left to cool down. The ECU is an aem ems4. Could it be a setting in the ecu or a bad batch of sensors. This is the second sensor in 2 weeks i have changed.

Thanks Kurt

Are you confident you're supplying the correct voltage to the sensor? Unless you're dealing with a knock off chinese sensor then this certainly isn't normal. There could be issue with some of the settings in the ECU but this would normally result in the engine not going at all. What sensor are you using?

Hi Andre. It's actually not me that's doing the tuning. I live in canada now and the car is in Barbados. I built the engine and I installed a new crankshaft pulley that has the trigger wheel made on to it. The sensor is from a Mitsubishi. It's an oem sensor. The part number is g4t07171. The car was working before the engine was rebuilt and the owner told me that only 3 things that changed is the crank pulley, the air gap between the trigger wheel and sensor and that he had a bulk head connector installed for the engine look. So he had the sensor bracket i made machined to bring the sensor closer now being at .030" rather than .051". I personally don't think that is the problem, but as you know I am thousands of miles away and am relying on his tuner to make all the necessary checks. I personally think it's a wiring issue because the tuner also said that he could not get the cam sensor to sync or something so he had to make it wasted spark. The coils are the individual Toyota coils.

To be honest I'm not impressed with the Aem software, it's too complicated. I'm not a professional tuner but all the standalone ecu's I have worked with are so much more sensible and user friendly.

Not sure if this helped. Thanks Andre. IlI'keep you updated with what they come up with.


If the old sensor stops working and swapping a new sensor is the only way to fix it, that makes me wonder if the sensor is getting mechanically or electrically damaged. The sensor could be scraping against the trigger wheel if the wheel is out of round, or the bracket allows too much movement, but that should leave a visible mark that a mechanic would notice. I'm not familiar with that sensor or the car it came from, but a quick internet search suggests it's a 3-wire sensor so it probably needs reference power from the wiring harness. Check factory wiring diagrams to see if it should get 5V power or 12V power, sending too much voltage could cause a sensor to fail over time. I did see some sensors (probably knockoffs) from alibaba.com in the search results, so you may want to try one from a different supplier.

I think the software for the EMS4 wasn't too bad compared to others that were available in 2009, but agree it feels pretty old now.

So the owner of the car reinstalled the original sensor and it started. He checked the supply voltage to the sensor and is getting the required 12v. I am going to team view with him tonight to check out the settings. Keep you posted with what I find if anything.

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