looking for some internet diagnostics problem with my g37s issue...

[purbeast0]

earlier today i was driving my 2008 g37s, manual, and after about 20 minutes was on some back roads going up a hill in 5th gear. i noticed that the car wasn't pulling as hard as it normally should and was kinda scratching my head. i then downshifted to 4th gear and i noticed that 4th wasn't pulling either. i also noticed that i didn't hear whistle that i usually hear when pulling between 2k and 3k RPM.

i then noticed a "service engine soon" light started to flash on my dash. it wasn't all the way on, it was just blinking.

so after i got up the hill i tried going back to 5th gear, and it was doing the same. so i decided to pull into a side road.

when i turned i was in 2nd gear, and when getting into gear, it felt like i was switching into 5th or 6th gear, because it was just picking up super slow. i then came to a complete stop and i decided to turn around and just go home. at this point i also turned off my a/c to see if that would help anything to let the car work less.

so when i went into 1st gear, it like jumped big time when i switched into second. and in first it was hardly pulling too. like it felt similar to trying to start from a stop in like 3rd gear. after 2nd gear i got into 3rd and then 4th and was on my way home.

like a minute later i noticed the light wasn't blinking anymore. so i tried to give it gas like i normally would. and now it was pulling fine. i was also hearing the whistle when it pulls between 2k and 3k like i normally would. i then pulled into another side road to turn back around to go back the direction i was going before, and everything was back to normal and working fine.

so when i drive home from the place, whichi s a good 30 minutes or so, after letting my car sit for like 2.5 hours while i was fishing, everything seems fine now. it seems like nothing happened at all.

so does anyone have any clue wtf happened? i'm worried that something might happen in the middle of driving now because this had never happened. my car has JUST under 60k miles and i've never had an issue with it. i do believe the warranty expires at the end of september, so i still have like 2 months left with it so i might just take it in.

one other thing to note - this morning i changed my oil. and this made me think that i did something wrong or something, but i kept redoing the oil change in my head, and no, i didn't do anything wrong and just did everything as normal and nothing was leaking when i was done.

so any ideas?

 

[jlee]

Hook up a code reader to it and see if there are any historical codes stored.

 

[Jimzz]

Yea duh, pull the codes. Can't tell you much anything till you do that.

 

[purbeast0]

well i'm not very car savy so i don't have anything to be able to pull any codes or anything. the light also isn't on anymore so i don't know if there is anything that would be reporting wrong with it currently.

i did just try this here to view the self diagnostics:

http://www.myg37.com/forums/g37-sedan/195183-service-engine-soon-light.html

and there was nothing in the error log and everything said "ok" next to it, so still have no clue.

 

[Imported]

It probably won't be the solution, but check your battery terminal connection. I had a similar power loss issue once during an autocross in my G35 and that was the reason.

 

[LTC8K6]

Something went wrong and the ecu reduced power, I think. Whatever it was went away and the ecu resumed normal operation.

Maybe you got some bad fuel?

 

[purbeast0]

Something went wrong and the ecu reduced power, I think. Whatever it was went away and the ecu resumed normal operation.

Maybe you got some bad fuel?

i did fill up yesterday at a different station than i've ever filled up at before. i was in a totally different part of town for a funeral and had to get gas. that would be really odd if that was the case.

i'll check the battery terminals too but i've never messed with them since having the car so i don't see how they could have moevd, but worth a check.

i did check tonight and i still have the warranty until september 15th so i think i'm going to get it looked at anyways just since it will be covered anyways.

 

[manimal]

bad crank sensor or both cam position sensors on those can put the ecu in limp mode. pretty common. VDC light will come on as well as two others usually.

Saw one a few years ago that had weird issues. They ended up taking it to dealer who replaced the flywheel and clutch because they said it was warped. I never saw the parts or the car apart just did a quick diag so I take what dealers say to people with a grain of salt.

Go to autozone and have them pull codes. Where do you live OP?


edit could be accelerator sensor as well. sadly thats a whole assembly though.

 

[radtechtips]

bad crank sensor or both cam position sensors on those can put the ecu in limp mode. pretty common. VDC light will come on as well as two others usually.

Saw one a few years ago that had weird issues. They ended up taking it to dealer who replaced the flywheel and clutch because they said it was warped. I never saw the parts or the car apart just did a quick diag so I take what dealers say to people with a grain of salt.

Go to autozone and have them pull codes. Where do you live OP?


edit could be accelerator sensor as well. sadly thats a whole assembly though.

If you have jiffy lubes they will usually do it OP

 

[Zivic]

possibly a problem with the throttlebody/drive-by-wire setup. I had an issue with my nissan with something stupid like 5k miles on the car.

in regards to the blinking CEL... I was under the assumption, if it's blinking you best pull over, like NOW.. blinking means something really bad is about to happen. when it stays on, it kind of means 'check at your leisure'

 

[Wingznut]

A blinking Check Engine light indicates a misfire. The fact that you were losing power, substantiates this.

Flashing Check Engine Light - CarMD.com

I'm fairly certain the method you found on the G37 forums will not retrieve history. And since the CEL isn't currently on, that procedure won't be of much help. The easiest way to retrieve codes is to hit up a local parts store. Most of them will hook up a scanner at no charge. Afterwards, feel free to disregard their advice of what to buy in response to the code, as they are just making a guess.

And a guess is pretty much what anyone on this message board would be doing, as well. Most likely, you'll have to get a qualified technician to properly diagnose it. Unless you can determine that there is something incredibly common regarding your specific situation.

As for your warranty, be prudent on knowing exactly what it does and doesn't cover. No warranty on a seven year old car covers everything.

 

[Zargon]

what wingznut said.


you are probably on the original spark plugs....Nissan's service interval on them is ~75k miles

 

[purbeast0]

okay cool my gym i right next to an advance auto parts and i have had them check out my previous cars before. tonight i will see if they can pull the codes and see what they get.

there were no other lights on though, it was just this one that was on. and yeah the car not really feeling "right" made me pull over pretty quickly. i'm just glad it seems to be okay now and working now, and hopefully it will be okay until i can get whatever is wrong fixed.

i guess there isn't much more info i can find out until i have them grab the codes tonight. i'll post back with the codes when i get them.

 

[BlitzPuppet]

Yep, only time I had a flashing SES light was right after I did a plug change.

Turns out I cracked the insulator on one of the back plugs (hardest one to get to, of course). Would drive fine, but would misfire if I gunned it at highway speeds.

There were no codes in my case.

 

[purbeast0]

so yeah, had them scan my car just now at advance auto parts, and there was no information given. since the light isn't still on, there were no codes that it pulled. there was also no history or anything like that of what happened. so yeah ... basically no clue wtf happened lol.

 

[phucheneh]

so yeah, had them scan my car just now at advance auto parts, and there was no information given. since the light isn't still on, there were no codes that it pulled. there was also no history or anything like that of what happened. so yeah ... basically no clue wtf happened lol.

No. This is not how it works.

If there was a severe misfire condition (typically what causes a flashing CEL), there was at least one DTC stored. It doesn't matter if the light is no longer on. It will remain stored, at the very least, until power is removed from the ECM (i.e. battery disconnected). On a lot of modern cars, even disconnecting the battery will not clear history DTC's, as there is keep-alive memory ('KAM') inside the ECM (which is 'engine control module,' if that's not clear).

When your car was lacking power, was it a simple matter of 'push gas pedal and nothing happens'? Or did the engine actually seem to run poorly/erratically? People tend to describe misfires with terms like 'bucking' or 'jerking.' Mild misfires can be hard to identify, but missing bad enough to trigger the flashing CEL should be very noticeable- clear interruptions in the normal rythm of the engine. The more you try and open the throttle while the engine is under load, the worse it usually gets.

How many miles on your G37? Ever had any maintenance done other than oil changes? How often on said oil changes? CVVT (variable valve timing) problems are common on those engines...it can come about randomly, but usually it's the result of infrequent oil changes.

 

[purbeast0]

No. This is not how it works.

If there was a severe misfire condition (typically what causes a flashing CEL), there was at least one DTC stored. It doesn't matter if the light is no longer on. It will remain stored, at the very least, until power is removed from the ECM (i.e. battery disconnected). On a lot of modern cars, even disconnecting the battery will not clear history DTC's, as there is keep-alive memory ('KAM') inside the ECM (which is 'engine control module,' if that's not clear).

When your car was lacking power, was it a simple matter of 'push gas pedal and nothing happens'? Or did the engine actually seem to run poorly/erratically? People tend to describe misfires with terms like 'bucking' or 'jerking.' Mild misfires can be hard to identify, but missing bad enough to trigger the flashing CEL should be very noticeable- clear interruptions in the normal rythm of the engine. The more you try and open the throttle while the engine is under load, the worse it usually gets.

How many miles on your G37? Ever had any maintenance done other than oil changes? How often on said oil changes? CVVT (variable valve timing) problems are common on those engines...it can come about randomly, but usually it's the result of infrequent oil changes.

it felt like i was pushing in the gas pedal, and it was picking up as though i was starting each shift in 6th gear. it was just picking up VERY gradually. then a few times when i was in 1st or 2nd gear, just as i was pressing the clutch it jerked quickly. i also noticed when i was at a total stop, my car was definitely idling rougher than normal and felt shaky.

there are just under 60k miles on my car. i got it with 21k on it. i haven't done anything to it other than oil changes and i've been changing my own oil since i was at about 40k miles. i have a reminder in my car for 5k miles, and once that goes off, i'll change the oil that weekend. this time i was at about 5500 miles before i did the oil change. i put 5w-30 synthetic mobile 1 in it as far as oil goes.

i'm not sure what a DTC is, but he was using the obd2 connector thing that i've seen used in my other cars to get the codes. and i saw it and it showed everything as "ok". is this DTC something that a special connector is needed for? or should that have shown it on there?

 

[jlee]

Diagnostic Trouble Code

 

[phucheneh]

DTC = diagnostic trouble code. You retrieve them by plugging the scan tool into the 16pin DLC ('data link connector'), which is the 'OBD2 thing.'

I'm guessing operator error on the end of the parts store guy. You can get your own code reader for cheap.

http://www.amazon.com/Autel-MaxiScan...keywords=autel

Competent little generic OBD2 tool. Has code definitions, reads freeze frame. Parts stores sell similar stuff, but the prices are usually awful...probably closer to 100 bucks for a similar tool.

If the problem is so bad that the car was idling rough in neutral/clutch disengaged, I would avoid driving it until you get it fixed. First step is just checking the DTC's. One or more misfire codes is likely to be present; the question is will there be anything else? I would hazard a guess than this is, in fact, a CVVT problem (not from neglect on your end, but merely a fluke thing), which is causing the camshaft timing to get stuck in the wrong position.

Other possibilities would be a bad MAF or maybe a bad throttle assembly. Maybe low fuel pressure from a bad fuel pump (unlikely) or an ignition coil just shit itself (unlikely). I could guess all day, but it means nothing until you at least find out what codes are stored.

 

[LTC8K6]

Are we talking about the same light? Is the Service Engine Soon light the same as the Check Engine light on a Nissan product?

Bad fuel could cause a temporary misfire.

 

[halik]

Flashing CEL = do NOT drive the car, you're getting continuos misfires *. Unless you like paying for new cat converters among other things.

* bosh motec has the threshold around 10 misses in 1 second

 

[SithSolo1]

bad crank sensor or both cam position sensors on those can put the ecu in limp mode. pretty common. VDC light will come on as well as two others usually.

I had one of the cam position sensors go out on my G35 and it didn't just reduce power, it shut the engine off...while going 40mph. Fun stuff However after I got it started again and until I had it repaired, I did notice reduced power. I had both my cam sensors replaced just in case and haven't had another engine issue.

I've also had a lose battery cable but didn't notice a lack of power, it just harder to get the car started.

 

[Zargon]

I had the same issue on my Xterra actually, now that you mention it.

they aren't expensive, and a minor PITA to replace(on the X, probably a larger PITA on a G series, much smaller engine bay)

 

[Wingznut]

Are we talking about the same light? Is the Service Engine Soon light the same as the Check Engine light on a Nissan product?

Yes... The terminology is pretty much interchangeable.

 

[rh71]

Sounds like an issue we had with an old Accord and it was the O2 sensor. Just another opinion in case it hasn't been researched on OP's part.