05 Mazda tribute- intermittent stalling
DTCs: None Repair history: Alternator replaced a year ago. Unknown brand.
This vehicle has a very intermittent stalling issue. It is a dead stall like you are turning off the key and it starts right back up every time. Sometimes it will not happen for two days, but mostly when it happens the engine is cold. Sometimes happens right when you move the car and other times after you drive for a minute and come to a stop.
It NEVER has stalled while driving, but while driving it will intermittently jerk as if it were a misfire. Also the security light will come on when this happens.
I highly suspect alternator noise and when the jerk happens while driving it can be seen in the alternator AC signal and sometimes also appears as distortion on the crank sensor signal.
In the attached capture, is the alternator AC glitch enough to make it jerk?
Can anything else on the vehicle cause this AC glitch except the alternator?
I have never been able to duplicate the stall while the scope was running thus far. I have the vehicle to drive until I figure it out.
I only work on electronics so I cant help too much but I will say this just because its so common you may want to take a look. On these 05-06 3.0 escapes, the coil system is poorly laid out inside the pcm. Sometimes the coils cause to much feedback into pcm and the drivers inside will over heat, which then overheats the drivers controlling IC. Usually this kills the controlling IC and a few coil…
I would use a scanner and graph the engine data pids, then drive it when it's cold. When it acts up, look thru the data pids for any clues.
This is a Ford COP primary coil winding volts with negative 81 volts in the burn time which could spike the PCM. With a 4 or 8 channel scope you could scope 4 or 6 COP primary voltages at the same time and drive it till it acts up.
Damon, a couple of thoughts. 1. I realize it's intermittent, but you could disabled your alternator and maybe bolster your battery situation for a good test drive. I realized that it might not do it in the time that your battery or batteries would last, but if it does it then you'll know for sure that it's not related to the alternator. If you do not want to disable the alternator you could…
I don’t think that a .4v drop is enough to cause a system shut down. Especially knowing the the system is at about 14 volts. 13.6 is more than needed to run any module or engine component. So, I wonder is the glitch the result of the fault causing the stall? I would use an amp clamp to see if a sudden current draw is associated with the voltage drop. The description of the fault occurrence…
I think this describes your issue to a tee.
Damon, the references here to the RF issue and the TSB sound fascinating and I'm perched at the edge of my seat to find out if that is the quirky cause. However, you'd have to wonder why it would take so long to show up. That said, if it's not the issue, I would go back to simple and back to basic. Granted the security light “on” is a little off key here, but your description (ie dead stall, no…
I identified a bad coil and installed it today. So far so good. I will drive it one more day before calling it a fix. I will post my results and captures. Thank you all for your help. I would have never thought a coil could cause all this!
"I would have never thought a coil could cause all this!" - I have read it at least five times. You'll see it again. Usually it's a Chrysler product.
Damon, what was the other trace in your scope capture? Wondering if a primary trace would have "timed" to the alternator blip and indicated which coil to investigate? Just the repeatability would have been curious. Great post!
The two traces in that capture are the crank sensor signal, and the ac voltage taken at the battery terminals.