New M56 woes

[thewifesM56S]

Just bought a '11 M56S w every option including the illuminated door sills and trunk mat. New set of Continentals and the interior is flawless. Had to have it! And the wife deserved something luxurious. Even though I couldn't drive it till it traveled 1500 miles home to me. Have had a few issues and thought they were minor till today. Quick rundown. Dealer claims they performed a 90,000 miles service and installed new front brakes. The brakes squeal at low speed stops w light pedal pressure. Hard, aggressive stops are as they should be and feel like they'll pop your eyes out. It has had a couple troublesome starts needing four presses of the start/stop button and a quick tap of the throttle gets it going and now a service engine soon light saying it has a faulty MAP sensor. Any ideas and what's the location of that sensor. And does it have 2 since it has two intake tracts. Gonna try to address brake noise tomorrow by spraying backs of pads w anti-squeal. Hopefully they replaced pad shims or reinstalled factory hardware. I usually do all my own work since I'm so OCD and anal about everything. I was extremely trusting w this purchase and want this to last like the Pathfinder. SE V8 w 218k+ and will outrun and surprise a lot of unsuspecting victims. I'm a true believer in Nissan's 5.6

[Ilya]

Welcome to the forum!

Check the FAQ in my signature which has a link to the FSM (factory service manual). MAP should definitely be listed there.

[Debonair]

Welcome! I had to replace my rear rotors to get rid of some brake squeak on my 11' M56. I did this after doing pads front and rear.

[Altered]

Definitely check to see if it is front or rear, I had squeaking rear brakes and the dealer replaced the pads with Nissan Blue pads + resurfaced rotors now all is well. Not sure if they have updated pads for the Sport package brakes on the S models.

Regarding the MAF sensors I've heard people have cleaned them, my dealer doesn't recommend this and they aren't too expensive to replace. I believe they just have to reset the idle after replacing them.

[Debonair]

Here is the MAP sensor location, #19. MAP sensor sensor is a Manifold Absolute Pressure so only one is needed (only one manifold).

[thewifesM56S]

Map sensor will be cake. Thanks for the diagram. Really appreciate it. Any ideas about the hard to start issue. It happened just now to my wife so now it's a marital issue. Thanks again and I'll post some pics once we get a decent day/week w out rain. Louisiana gives us a free rain shower w every freshly washed vehicle.

[Altered]

Ahh, I was thinking that the post referred to the Mass Air Flow sensors, never mind. That diagram is of the V6, is the V8 the same?

[thewifesM56S]

Yeah just noticed the intake gasket. It is of the 6. Quite possible that the 5.6 could just have just one also. Check engine light hasn't come back on yet. But it hesitated to start for me also. Maybe weak battery in the key, but I'm not getting anything on the message center.

[thewifesM56S]

And it's not really a squeak in the brakes. It's almost like a school bus that needed brakes a year ago and now the kids refuse to get on. It causes neighbors to stare. Really obnoxious. Will def address/inspect tomorrow morning.

[Debonair]

Ahh, I was thinking that the post referred to the Mass Air Flow sensors, never mind. That diagram is of the V6, is the V8 the same?

Just one is needed. Here is the 5.6L, #22.

[thewifesM56S]

Thanks for the diagram. Just wondering if the hard to start issue could be dirty throttle bodies like I've been reading about. Couldn't hurt to clean them. I may also change out plugs while I'm in there. Any recommendations. I swapped my OEs in the Pathfinder for Bosch +4 iridium. Def smoothed out the idle and acceleration seemed stronger. Any tips or opinions are always welcomed.

[Debonair]

Dirty throttle bodies usually only cause start-up issues if they are horendously bad or if the car is already warmed up (heat soak). Like you said it won't hurt anything to clean them. Just don't unplug them or force the blade open.

For plugs I believe it's NGK for 5.6 and the Denso for 3.7, both iridium.

[thewifesM56S]

What happens if I do unplug them and force the blades open? I'm a habitual line-stepper. And my OCD won't let me put it back together if the whole throttle blade isn't clean. Should I disconnect the battery and then unplug? Would the Bosch +4s be a bad idea? I know this engine is direct injection, are the heads different than the 56DE? Just wondering? Whatever y'all get the best performance using, I'll try. It's still raining here so no chance on touching the brakes till I'm done working tomorrow. It'll make the day go by quick knowing I have something to work on. Any recommendations on what to clean the calipers with. I don't mind scrubbing if that what it takes. The previous owner took great care of the inside so all I got worry about is the mechanical issues that come along w a 90,000+ mile used car. Brake noise would drive y'all to suck starting a shotgun.

[thewifesM56S]

And is heat soak that big of a deal on these engines? Or is it really a problem w the push to start. I've never had an issue starting the Pathfinder after shutting it down. Especially after running it hard. I always have and always will. Since day one.

[Debonair]

#1A - What happens if I do unplug them (#1B) and force the blades open?

#2 - Should I disconnect the battery and then unplug?

#3 - Would the Bosch +4s be a bad idea?

#4 - I know this engine is direct injection, are the heads different than the 56DE?

#5 - Any recommendations on what to clean the calipers with?

#6A - And is heat soak that big of a deal on these engines? (#6B) Or is it really a problem w the push to start.

#1A - Unplugging them generally requires the Idle Air Volume Learn procedure to be performed. Not impossible, just an inconvenient.

#1B - The blade is motor driven (vs. cable and spring like non-drive-by-wire vehicles), so force of any kind MAY damage the electric motor. Some people have done it without issue I believe.

#2 - This might work. You can always unbolt the throttle body from the manifold, the back side, and then reinstall; this is how I clean mine. There is a good guide for it HERE.

#3 - I don't think so as long as they meet all the required specifications. Give them a shot and let us know how they work out.

#4 - I have no idea.

#5 - Brake cleaner and a metal bristle brush. If they are very dirty and/or rusty a wire wheel on a die grinder or drill. Use eye protection.

#6A - Not that I know of.

#6B - My guess based on what has happened with my car and others on the forum would be your battery. If it looks original or old it is probably at the end of its life.

[Altered]

Regarding the heads I've seen the exhaust port shapes are different between the two, happened to read that on a Titan forum before. Also direct injection would mean there is an injector port in each cylinder, so I doubt the DE would have the same combustion chamber design.

Also, wouldn't a metal brush or wire wheel damage the finish on the calipers?

[Debonair]

Also, wouldn't a metal brush or wire wheel damage the finish on the calipers?

Oh yeah - I was thinking of the non-sport, unfinished calipers. Metal bristles is a no-no on the painted/coated Sport calipers. Good catch Altered!

[k67p67]

I believe the non-sport calipers are coated to prevent rust. If you use a wire brush on them, I'd bet they'll show a lot of rust in short order.

[Debonair]

I believe the non-sport calipers are coated to prevent rust. If you use a wire brush on them, I'd bet they'll show a lot of rust in short order.

Maybe but I have seen some pics of calipers from snow states. They don't look coated to me.

[thewifesM56S]

Cleaned and greased everything last night, sprayed backs of pads front and rear. Upon tearing down the rear I noticed 2 things. Whoever had done the brake job on the rear did not install the shims that come w the new pads. And they're actually Akebonos not a nonagenarian brand pad. After all this, of course it still squeals. I had the guy at Discount Auto Parts pull up a picture of the Akebono pads they can ordering they're the same as what's on the rear but have shims. $54 isn't bad and they can be overnighted at no additional charge. Gonna change hardware also, seeing it's only $9. And it failed to start once, the second time I tapped the gas and noticed it said "connection w key has been made" on the main screen. Bad remote battery?

[thewifesM56S]

Damn iPhone autocorrect somehow typing no name = nonagenarian

[thewifesM56S]

Correction, Advance Auto Parts. They offer 2 different Akebono pads. ProAct ultra premium and Street Performance ultra premium for $10 more. Anyone have experience w the Street Perf.

[SOPM8]

No experience with the Street Performance but I just completed a full brake job (rotors and pads) on my M37x using the Pro-Act Premium from Advanced Auto and so far no problems.

[thewifesM56S]

Installed the new Street Perf. Akebono pads, still have high pitched squeal backing down the driveway. ????????FML????????
Seafoamed the engine, 3/4 of the bottle in the vacuum line off the brake booster and the rest in the gas. Let it marinate for 45 min then started the smoke show. Cleaned the throttle bodies and changed the batteries in both remotes and it still hesitates to start every 5-6th time I drive it. If it fails to start then I restart and feather the gas and it runs fine. Sometimes it'll throw a check engine and it says it's the MAP sensor. Will that prevent it from starting? It never sounds like a weak vehicle battery when it doesn't start. Any ideas or pointers would be great. Don't mind working on the car, just hate throwing unnecessary parts at it.

[adeedpb]

Did you resurface or replace the rotors?

Have you replaced your PVC valves?

[thewifesM56S]

Have not resurfaced the rotors. The pads I replaced were brand new, just missing shims. Shims are only available w the new pads, so I got a new set. I figured the rotors were turned since it had new pads. Have not changed the PCV valves yet. I guess it couldn't hurt but never thought that would affect random starting issues.

[thewifesM56S]

Mr. adeedpb, you will def. be enrolled in the cheese of the month club. After changing both PCV valves, This! Car! Starts! Every! Time! Thank you sir! Gonna get the rotors turned this weekend and see if you're 2-0.

[adeedpb]

My sudden onset of dyslexia slightly tarnishes my glory :p I must have been thinking about plumbing.

[Pimperish1]

Mine does the fail to start thing as well. Started the first winter I had it. At first it was mainly during cold months then at random. Doesn't sound like the battery is weak at all. It cranks and stalls out. Like you said if you tap or feather the gas right after it starts, it purrs like a pit bull. Told the dealer about it and got the standard "unable to reproduce" line (just like when I complained about the a/c compressor humming, to find out there was a bulletin put out three years later ). Never threw any codes with it so nothing to chase with. I've come to just live with it.

[thewifesM56S]

I notice a rattle/hum w the a/c on. Usually at a low idle or when I first start the car. It doesn't change w fan speed but goes away when I completely turn off climate control. Have only put 3k miles on it and still finding a few little kinks here and there. For some reason I can't stop sitting on the porch and starring at it. Can't wait for a few extra dollars to roll in. The wife wants me to spray it nebula blue pearl. She loves the way the S8 looks on the DYC videos on YouTube. I'm leaning towards the red.