2002 Mazda running horrible
If it's like most yes. The coils should be supplied with battery voltage and are switched by the ECU to fire. I don't really think that's your problem. As I asked before a short video clip of what happens when yu start from cold may help to reduce guessing. The secondary firing voltage is a different ball game.
Last edited by Charlescrown; Nov 1, 2025 at 02:41 AM.
If it's like most yes. The coils should be supplied with battery voltage and are switched by the ECU to fire. I don't really think that's your problem. As I asked before a short video clip of what happens when yu start from cold may help to reduce guessing. The secondary firing voltage is a different ball game.
the coils are NOT the issue only something later after you solved the main issue you can come back to the coils
Last edited by Callisto; Nov 4, 2025 at 09:12 PM.
Hey guys sorry about the previous post about measuring voltage on coils. Your messages before that did not load so I didn’t see that you guys ruled that out. Thank you so much for the insight. I will send a video of starting asap. Also. I do have a snap on ethos pro scanner I can use anytime I’d like. Is there certain live data things I can look for that can help me pinpoint the possible issue. Thank you guys!
Also one more thing. It’ll crank and crank and crank. I pull the fuel pump fuse. It’ll crank and start right up and run until it’s out of the fuel in the chamber. So it’s gotta be a over fueling flooding issue correct?
Sounds like that but it's strange that it won't fire till you pull the fuel pump fuse. I would have thought it would have a gut full of fuel by then and still take some cranking to start. It's almost like the fuel pump is causing a voltage drop but I would think that would blow a fuse. Not familiar with your scantool so it might take some time for me to decifer the data. What I do see is many sudden sharp changes in what I would have thought should be stable.
Hi I have checked all possible places for any kind of permanent dtc I believe there’s an option for it but it says there is no dtc. I will keep looking though. Is it possible timing off causing because the spark plugs are firing at the wrong time?
Lets do this. Disconnect one of the coils and try starting the engine. Now you have just created a DTC relating to that cylinder. See if the ECU reports that?


