Starting issue for my 2003 M45

[nuQ]

Well, boys...it's been a while. Bought my 2003 M45 in 2013, but it was a second car and didn't get much use. In the past 2 years it basically sat, but due to a hurtful breakup with a long time fiancee, and my relocating, it is back in action. The issue began when I cleaned the MAF (back in 2014) and neglected to hook up the wiring harness and started...obviously realized right away and hooked it up, but check engine light immediately lit up. Now I'm dealing with starting issues, which I assumed was the starter going. If the M is cold, it may start right away, and other times multiple clicks with no start. Sometimes once or twice, this morning, probably 20 times before it turned over.

I took it to autozone to have the codes read (and assumed a code for the MAF would come up), and all it showed was P0300 and P0507. These would indicate a cam shaft sensor and possibly the crankshaft sensor, as well. I did read somewhere that a bad sensor could affect starting the M. I definitely can tell there is a misfire, and a gas smell, which I think might relate to a bad sensor.

Is there a way to determine what is the actual cause of the starting issue? Could the MAF non wiring harness start up cause damage to one or both of sensors, which is causing the starting issue, or should the focus be on the starter itself? Would there be a troubleshooting procedure to determine?

Thanks in advance.

Jeff

[Ilya]

Welcome back, unfortunately under no so great circumstances.

I'd remove both sensors and clean them first. Sometimes they have a thin film of 'metal shavings' on them which affects their operation. If that doesn't help, then I'd replace both (assuming your mileage is quite high).

Having the MAF unplugged won't break those sensors. It'll just tell the ECU that it's not reading air, hence the rough idle and check engine light. In the 4th Gen Maxima, we used to leave the center unplugged on purpose for 10 seconds to perform some ECU magic if I recall.

[nuQ]

Thanks for the reply. Not high mileage at all for the year...117K original miles. Exactly how do you clean the sensors without doing harm?

[MaxBolus]

You may well have issues with the MAF and other sensors, but the clicking starter means at minimum you need to replace the starter.

[nuQ]

Is there any chance a key fob with an old and dying battery could effect the starting of the M? I was noticing that it was taking a couple pushes of the open lock button for it to work, so I replaced the battery yesterday. The M sat since yesterday afternoon, and when I attempted to start it today it cranked over on the first time...and three different stops where I turned the car off. Seems hard to believe, but that is the current situation. Thoughts?

[nuQ]

I take that back....it has nothing to do with the starting issue! lol

[EdBwoy]

Hello. Your specific situation sounds a little familiar. Have we communicated before, perhaps on youtube?

Anyway, I don't think the key fob battery should have much effect on the car starting. You should after all be able to start the car even with the key fob as dead as a doornail.

How is the health of the car battery itself? That could cause the general multiple misfire code P0300.
For the P0507 code, try the idle air relearn hoping it doesn't end with needing a new TB as this case - topic605184.html?hilit=P0507


Also, I haven't been able to fully figure this out but in various cars, if I uses the key fob to unlock the door and quickly insert the key and attempt to start the car, it would "miss". I thought it was some sort of security time lock, but every single time the cars did that, I would take the key out and after a moment it would work like normal.

[EdBwoy]

Jeff,

I finally got to your email, pardon the delay. Gmail didn't notify me and these days my weekdays have been triple-swamped to just check all my email accounts.

...I did the full procedure of erasing the check engine (ignition key, gas pedal, etc,)....did the accelerator re-learn and idle relearn...not sure if I heard the throttle body move, but the last step (idle relearn) seemed to go according to the instructions, but the idle is still at 1000rpm's, and I believe while in park, it should be around 700. When I put in drive with foot on brake, it will go down to about 800.

It seems to be getting to the point where it is getting harder to start while car is cold. If it's at operating temps, it will start, maybe the first time, but usually within 2-3 times. Otherwise you just hear click. I did just read that a bad camshaft position sensor can affect starting, among other things...misfires, stalling, complete shut down while driving, etc. [...] I really can't just throw money at the car and hoping for the best.

I'm pretty convinced that the camshaft sensor, and probably the crankshaft sensor (I believe they are the same sensor), and I'm thinking need to be replaced, but, is there any way to determine this might be the cause of the non-starting, or would it be safe to assume the starter is the culprit, in addition to the camshaft and crankshaft sensor? Is there a trouble shooting procedure?

Generally, the crankshaft, camshaft and MAF will cause running issues - that is staying running at a stoplight, staying running at startup etc... The car has to actually attempt to crank over and if the computer isn't getting good engine speed signal or air intake signal, then it will kill the engine or just wouldn't activate the fuel pump and injectors.

Since yours isn't even starting, look at the car battery. My 03 M45 had an original battery that lasted nearly 12 years, but it sure was a stretch. Get the battery tested at minimum, replace it to be certain. The starter needs a lot of juice to move 4.5 liters of air. Plus electrics and electronics die in weird ways, a dying battery might work every single time... until when you really need it to.
But even then (or before/after attending to the battery), try to treat the car slow - as I mentioned in my post above, my cars generally don't like the carjacker-speed sequence of events.

[nuQ]

When I get the battery tested, what are the proper specs?

[nuQ]

BTW...the battery is very new...maybe 3 months old. It was an inexpensive one from Autozone, so I'm wondering if it just doesn't have the cranking power needed by the M....?

[EdBwoy]

I can't recall the specs, but when I go to the auto parts stores, they can usually pull up what the car should have. Most times, what I buy has had higher CCA ratings than the factory units being replaced. They should have given you a decent battery, but again, a check wouldn't hurt.

They test the battery and can say whether something within that particular battery is off. I believe I have taken batteries with no marking and they can usually determine if it is good or not. Since they sold you this one, then it should be even easier to check the specs.

[nuQ]

Thanks!

[rbfastback45]

my 03’s start problem sounds the similar your problem.

sometime it take 3-10 key turns with just a clunk before it finally starts.

had the battery tested and it’s good an only a year old.

dealer told me it needed a starter.

took my car to a buddys shop to do the valve cover and get a quote on the starter.

he called me today and said the starter is perfectly fine it was just a loose wire.
he said the oil was dripping on it and had some type of loose connection.
said it starts every time now no problem an only took him 1 min to find it under the car.

[nuQ]

I've been dealing with the starting issues, and yet to have it tested, but will. I do notice if ANY electrical components are one when attempting to start it, will result in the click...i.e., the radio, HVAC, or even having my foot on the brake. When I took it for an oil change, I told the tech to look at the starter and he did say it was fine. They also ran the codes and came up with only the P0300 code...random misfire. Assuming the MAF is ok, would the next logical step be to replace the Cam and Crankshaft module? The gas mileage is killing me right now which is probably from the misfire...averaging less than 12 mph. Thoughts?

[Gene Ln]

with the fast idle do you have any check engine codes? when I bought my car check engine was on and it was fast idle 1000 rpm like you, I did idle relearn and many other things and after extensive research I found that the throttle body calibration was bad, evidently if you open the throttle plate by hand, such as when cleaning, it messes up the calibration and you need either to send it to a professional, or replace the throttle body. I replaced my throttle body and have never had any more trouble.