2002 Infiniti I35 MAF Issues

[wst_3]

I have a 2002 Infiniti I35 with 180k on it and for the past 3 months I have had to replace the MAF 3 times. The dealer has done all the work. First it was just the MAF replacement then a week later the MAF went out again. The dealer replaced it free of charge, then a week later it blew again. I took it back to the dealer and the mechanic told me that because my front valve cover was leaking on my alternator and it may have shorted out my alternator because it was charging at 14.1 volts most of the time. I had the front valve cover gasket replaced and the alternator and had the car back a week and it blew the MAF again. This will be the 4th MAF that the car has needed in 3 months. Any suggestions on what else it could be. My car has been at the dealer for 2 weeks now and I don't know if they cant figure it out or if something bad is wrong with the car. I though it might be the ECM but the tech said that the ECM either works or doesn't. Any help here would be greatly appreciated!

[elwesso]

Welcome to NICO!

That sounds really suspect. How do you know the MAF is actually failing and it's not something else? Normally, I would say that if something is gonna short or "blow" like that, it would do it pretty much immediately, within minutes, not a week.. It would be interesting to swap your MAF onto a known-good car and see what it does. My inclination is that the MAF isn't bad, but something else is causing your issues.

Could there be a bad ground or something of that nature causing this issue?

[wst_3]

Its all real weird, the tech at Infiniti said he has never heard of this kind of problem with an I35 before. I though it might be a ground too.

[NutriaforBreakfast]

On you-tube Fluke has presentations on how to use the multimeter
to trace electrical problems. I would learn how to use a multimeter
and try the basic electrical checks first before putting it in the shop.

[loystock]

I agree that the problem is not with the MAF sensor itself but lies somewhere else. Most likely it is the harness from ECU going to the MAF sensor. A wire in the harness could be shorting another or touching the car frame intermittently. Please note that the ECU provides current to heat up the MAF element and based on the measured airflow, meters the air-fuel mixture. Also check the main ground points of the engine harness. Make sure they are clean and secure.

I'm not sure why the alternator was replaced. The spec for the charging voltage is 14.1-14.7 VDC. It was at the lower end but I have seen alternator output as low as 13.8VDC without any problem.

[NutriaforBreakfast]

As your alternator ages, it can actually produce AC current instead of DC
current as rectifiers and diodes age. I think this is called "ripple" voltage. This AC voltage is not good for the electrical components wanting DC voltage an
can short out your battery. Not sure if this is what is wrong but is just a
suggestion.