- This topic has 13 replies, 7 voices, and was last updated 10 years ago by
.
-
Topic
-
Alright. I’m working on a 2003 nissan sentra se-r specv. it has the qr 2.5 4 cyl with the fly by wire throttle set up. The car ran great, but had a small issue where the idle would randomly drop then pick back up. So yesterday i did an oil change, cleaned the air filter. (k&n style) disconnected the battery to clean the corrosion off, and took of the maf and cleaned it with maf sensor cleaner. (I live on a dirt road, so it was a little dirty.) I put it all back together and did the key/pedal dance so the computer relearns the pedal position, throttle body position, and idle air volume relearn. The car starts and runs well, but once its warm, the idle isn’t as smooth as it used to be. When I press in the clutch and start to slow down the rpm’s drop to 1000, slowly climb to 2000, drop back down to 1000, climb back to 2000, then drop to idle. If I let it sit long enough the idle does what it has done in the past and drop down to 500 before kicking back up, but today it actually stalled out. Check engine light never came on threw any of this. I suspect that the maf is about done, or I need to take it to the dealer and have them do the relearn with there scanner. That or since i disconnected the battery, I may need to put it threw a few drive cycles so it gets back to where it was. What do my fellow techs think?
-
Replies
-
I am not a Nissan tech, but will give you my opinion about MAFs….
MAFs can be very touchy… especially with what you clean them with… Certain manufacturers do not even recommend MAF cleaning with any type of spray solvent (even though it is MAF Cleaner, made for that particular job)….
I must say this, I am not a fan of K & N filters (even though you say that is just the style)… have seen them cause issues with MAFs…..
I would have hoped your engine performance would have got better after the MAF cleaning… Even if you re-set the ECU (disconnected the battery) then I can see how there would be a notable loss of performance until the computer re-learns the fuel trims…. Since it got worse after the vehicle was operated, then there it is…. Most likely a MAF issue…
If you are confident that you have cleaned the throttle body correctly and there is no throttle plate issue going on, I would definitely consider the MAF to be suspect…
I would replace with OEM filter and OEM MAF… Disconnect the negative battery cable for 1 minute and take her for a long drive…
JMHO….
-Karl
I didn’t choose the k&n, it came on the car. I do plan to get rid of it however. I didn’t do anything to the throttle body at all. The maf is the only thing I touched that effects anything aside from the battery. Which is why I’m leaning towards it. I have read that these cars are picky about the maf in general, that makes me lean that direction more. I just wanted to double check my diagnostics before i spent money on a part I already cant afford. lol
update as i drive it its getting better its still doing it just not as often or as bad im gonna run it threw a few more dive cycles and see what it does
Drive by wire Nissans are a PITA when you start being nice to them. I won’t even change a battery on one without a memory saver installed. If the problem doesn’t correct itself a trip to the dealer or to someone with the proper equipment for a relearn is in order.
yeah i need to get a memory saver the things you take for granted at a shop then miss when you leave if i was still at a shop i would just drive it with the scanner collecting live data
I had this problem on another car and it was the idle air temp sensor that was not reading right with the k/n set up but for the relearn just drive it some it should get back to norm all of the ones I have done came back after a few trips.
The saying goes, “if it ain’t broke, don’t fix it”. This type of maintenance can be tricky as you have found. The only additional thing I will offer here is that if there are any leaks in the air tube after the MAF it can cause performance issues. Make sure there are no leaks there.
It may also be relearning base idle after you disconnected the battery. Keep driving it as you say and let us know if it gets better.
Good luck.
Well, I originally was having an issue that made me think the maf was having an issue. Then I saw it was filthy, So I figured I would try cleaning it. But today it finally threw codes.
p0301 cyl 1 misfire x2
p0102 maf a circ low input x2
p0507 idle control high
p0113 I.A.T. sensor 1 circ high input
Now the check engine light came on and I said f$%k it and followed nissans recommendation and unplugged the maf to see if it worked correctly. With the maf disconnected, it revved correctly but idled at 1500 rpm, so a few of these codes are from that, but the light was on before I unplugged the maf. I think the cyl misfire is why my rpm randomly drops at idle. unplugging the maf test tells me I may need a maf. I’m gonna move cyl 1’s coil to cyl 2 to see if the misfire moves. Which is probably my original issue. Looks like I need to figure out the misfire, new maf, and a relearn using nissand scanner, and I should be good.
[quote=”bonvo” post=94912]Well, I originally was having an issue that made me think the maf was having an issue. Then I saw it was filthy, So I figured I would try cleaning it. But today it finally threw codes.
p0301 cyl 1 misfire x2
p0102 maf a circ low input x2
p0507 idle control high
p0113 I.A.T. sensor 1 circ high input
Now the check engine light came on and I said f$%k it and followed nissans recommendation and unplugged the maf to see if it worked correctly. With the maf disconnected, it revved correctly but idled at 1500 rpm, so a few of these codes are from that, but the light was on before I unplugged the maf. I think the cyl misfire is why my rpm randomly drops at idle. unplugging the maf test tells me I may need a maf. I’m gonna move cyl 1’s coil to cyl 2 to see if the misfire moves. Which is probably my original issue. Looks like I need to figure out the misfire, new maf, and a relearn using nissand scanner, and I should be good.[/quote]
If your getting the p0507 the relearn was not done correctly. Thats
why the idle is so high. I never had any luck trying the relearn the
manual way. (on/off pumping the pedal ect…) Did you unplug the TB?
you should not have to do the relearn for battery disconnect. For the
misfire. May be time for a new set of ngk plugs. The original usually
go 100k.I didn’t unplug the throttle body, but I did unplug the maf. I plan to go to nissan to have them do the relearn as I don’t have the scanner they have to do the relearn myself. as for the misfire, the plot thickens! I found the plug had NO gap in it. it had been squished closed. Looked down the into the cylinder and there is no sign of damage on the piston. This may be an issue that is covered under warranty.
ok, it’s been a while, but time for an update. I cleared all codes and went to nissan so they can connect there scanner. The reason for the idle moving around is the car is running lean and the computer is trying to ritchen it to compensate. Well, I went threw and replaced the maf cause I knew that was bad. The new maf helped but its still doing it. I connected my fuel system cleaner and cleaned the injectors, checked the fuel pressure and it was spot on, replaced the plugs cause it needed a tune up anyway, used my lungs as a smoke machine and found no vacuum leaks. The only thing I can think of is I have an exhaust leak that is allowing air into the exhaust system before the o2 sensors, or the o2 sensors themselves. I did all of this without it throwing any codes, this is with me watching the live data on my scanner. (finally bought one) Then tonight it finally threw a code for lean conditon cyl bank 1. (didn’t write the code down I forgot) is there anything else you guys can think of that I’m forgetting?
here is a pic just for fun
[URL=http://s70.photobucket.com/user/bonvo/media/Snapbucket/D15BA943-orig_zps734d9520.jpg.html][IMG]http://i70.photobucket.com/albums/i100/bonvo/Snapbucket/D15BA943-orig_zps734d9520.jpg[/IMG][/URL][URL=http://s70.photobucket.com/user/bonvo/media/Snapbucket/23C28C31-orig_zpsa0dd3411.jpg.html][IMG]http://i70.photobucket.com/albums/i100/bonvo/Snapbucket/23C28C31-orig_zpsa0dd3411.jpg[/IMG][/URL]
i read this entire post because the subjects was calling all nissan techs lol. bear in mind nissan are usually very simple vehicles from my experience. there are 2 things i see that u should look at here and try to rule out first. that is the O2 sensor and the fuel pump.U already Ruled out the fuel pump. so the next thing is the O2. Try switching the upstream and downstream sensors and see if it make any difference
- You must be logged in to reply to this topic.