Cleaned tb's - CEL keeps returning
 

Hey guys,

Cleaned my tb's 3 weeks ago, they were mildly dirty but I need notice an overall improvement.

Removed the neg battery cable when I did, also cleaned my filters and MAFs.

It was fine afterwards, didn't need any reprogramming or resets untill 2-3 days later when I got a Service Engine Soon light and the idle was 1100rpm. Also, the car seems to keep coasting on its own from 1500rpm with no throttle input.

Did a reset, all the relearning procedures and that seemed to fix it. For another 3-4 days..

Every time I reset it, even just an ECU reset, it's perfect for 3-4 days and then out of the blue one day after 10 seconds of cold start I'll get a SES light again and high idle/coasting.

What's going on, does it need a dealer reset? Obviously, nothing is broken because it's perfect for a few days...

Thanks:dunno:

When it is 'perfect' for a few days, what are your the idling rpms? Is it really getting down to 650 rpm? For whatever reason, the learning abilities of the ECUs in these cars can be rather challenged to say the least. Some get by with no problem, some have to be brute forced EVEN WITH a Consult system! :icon43:

If you do end up heading to a dealer, you might consider Nissan instead of Infiniti; should save you a bit. Also, call around. Some dealers have a blanket fee of at least an hour, but others will just charge a 1/2 hour or so.

When I reset it, it's completely fine and stable around 600-800rpm. Not sure it's exactly 650, but it's stable. Doesn't fluctuate or stumble or anything, engine braking is good too.

What code are you getting from the SES?

Haven't checked yet sadly, I know that's the first clue. But I've been resetting it everytime because it's annoying when it keeps going without throttle. I should leave it on and go to the nissan dealer next time.

Yeah, that's generally a very bad idea to just reset a code without reading it first. It's definitely a practice that can come back to bite you in the a$$. In all likelihood though, your car was/is just throwing a P0507 code, which is for idling too high.

It's still coming back after a few days on cold start.. it's P0300 random misfire.

vacuum leak? Have you checked all the intake pipes?

I did, doesn't seem to be a sign of vacuum leak anywhere..

This might sound weird but when was the last time your changed your drive belts or your battery? Does the belt look glazed or stretched?

I originally had the issue where the SES light would go on and off every week or so. I ran the code and it came up as P0300 which could mean 100 different things from minor to horrifying. Also my idle would dip a hundred rpms or so whether it was at 650 with SES off or 1100 with the SES light on when coming to a stop or stoplight. So i cleaned my throttle bodies (very dirty) and cleaned my maf sensors and cleaned and re oiled the K&N filters on my nismo intake, the throttle dips went away but the SES light would still kick off and on ever 5-7 days or so.

Then i took my vehicle in to infinitti for service, and all they did was replace the battery because the OEM failed the test (still started the car fine) then they replaced the drive belt and flushed/filled the manual transmission fluid. Since that service I never saw the SES light again and its been 3 months and 1500 miles since... Im knocking on wood that it doesnt come back but it looks like it did the trick for me. I read a hundred other posts where it was caused by something else though, whether it be fuel injectors, ignition coils, 02 sensors, etc. Its a hard code to narrow down. Good luck man!

I'm actually really glad you said that. Because I suspected the battery too, and everyone around me said I was being silly. It's just weird that it started after I cleaned the intakes/tb's, so that would seem the obvious culprit.

But my car has been a little hard to start this winter, and still sometimes if I don't drive for a 1-2 days. It starts, always.

What hit me now is that the only two weeks I never had a SES light was when I had my girlfriend over, and I was driving a lot of miles every day to go places and take her to and from the airport. I joked that the car misses her because the SES returns after she's gone. But it could very well be that the battery is better because I drive a lot.

nice, yea that sounds like it could be it. So Infiniti dealer quoted me 155 for a new OEM battery.. I was like ehh.... and cruised over to advanceautos website and applied some coupons and grabbed a Optima Red Top for $170, chose in-store pickup and called it a day. Im intending this to be the last time i have to buy a battery for this car before i trade up for a new one...

Well, one day after a new 150 dollar battery, its back. Argh!

How did you check the vacuum leaks? by eye :/ . Or did you spray carb cleaner all over them and see if the idle changes?

Sprayed cleaner, can't find nothing.
Went to Nissan today hoping they could find more clues than just the P0300, but no.. They did reset the tb's and idle and learning parameters. But I have a feeling it will be back.