BigDave01

2006 Maxima SL auto.

So I got an intermittant misfire that started about 2 weeks ago on cyl 3. This is what I have done since and nothing has helped and it stays on cylinder 3.

• replaced all coils with new
• replaced all spark plugs new
• switched fuel injector 3 and 2
• new injector pigtail on cyl 3
• new pigtail on coil cyl 3
• compression check good all cylinders between 142-145
• new intake gaskets
• new plenum gaskets
• did an idle air motor relearn

Its still there at cyl 3 nothing changed. It primarily just does it at idle and as soon as I give is gas it seem to run fine. Its worst when in gear stopped with ac on.

All that I can think of at this point is the ECM?

Please help if you can im extremely frustrated.

steezmuffin686

I'd advise cleaning the grounds....sounds like a intermittent connection.

BigDave01

I forgot to mention that I also checked all the grounds I could find.

-on timing cover
-behind battery on fender
-in cabin by ecu
-battery

The problem also is a bad ground would kick a p0300 and this is staying consistently on cyl 3 p0303.

Some days I can drive all the way to work 25 miles with only half dozen misses, other times (majority) it immediately starts misfiring randomly and often as soon as I start it.

BigDave01

I also did confirm that spark is steady and consistent so I have ruled out ignition, which leave only fuel.

steezmuffin686

Lol, well then. I'd guess either rodent damage, or corrosion of terminal plugs and or wire fretting. There is always a bad injector to be the culprit


...just noticed you did pigtails etc...hard to say then. I'm still leaning towards a ground. Unless the injectors are grounded via the Pcm

SR20Power

iTrader: (1)

Okay, it's GREAT you did all of that. Now take a multimeter and check the voltage in the pigtail. You will get the voltage that should jump up and down between a certain range (search it) this indicates the "firing" of the injectors. You can just do Cylinder 1 or two and write the the voltage range and do the same thing for the 3rd cly. And obviously if you are getting something way off then there you go. Do it for all.. why not!
You could have a break in the pig tail wire somewhere. If thats the problem you can find that by using a multimeter to check for resistance (Ohms) between the connections and somewhere on the wire going back to the ECM.

I always suggest electrical trouble shooting before replacing anything, typically you'll end up sending money you didn't need to. But at the end of the day you did perform a tune-up.
Good luck!

BigDave01

Couple additional checks I did with no change:

-replaced cyl 3 injector pigtail
-checked resistance at ecu for all injectors and coils all read exactly same respectively
-tore top end apart again and swapped around injectors again
-checked volts at each injector and all even

Strange though is right after doing all that I took on drive for 15 min not a single misfire, shut off and restarted 10 min later and back to misfiring again.

Are the injectors grounded through ecu or do they all go to ground at the engine? (If they go to ground at engine I was going to run a new ground wire from pigtail directly to the ground on front of motor.)

BigLou55

iTrader: (6)

If you swapped injectors around and coils and you still have a misfire at #3 I would point to your wiring harness. Can't remember the number but there is a TSB that discusses wire breakage in the engine wiring harness, particularly around the bend near the passenger strut tower. Although I have a 5th gen the harness takes the same route. I had an intermittent misfire issue and I pretty much did everything you listed and still could not find it. I started moving the harness around one day while the car was running and BOOM! it misfires. Kept at it until I found the exact spot in the wire that led to #3 (yea I had a #3 misfire also, weird right lol) ignition coil. To fix my issue I just spliced in wire from a spare harness I had laying around and solved (that was 40k miles ago). It took me a month to figure out the problem, hopefully it doesn't take that long for you. Good Luck.

maximatech12

Woe 142 is low! You may want to consider a new car! Pour some oil in it to see how much it increases. It's supposed to be around 175-180 the minimum psi is 142 your right there! you could swap it with a nicer engine. Just make sure you take all the precautions and check the TSB's.

BigDave01

It's still within specs and other than a misfire has lots of power and every cylinder was within a range of 3 psi. Remember this was done cold as I wasn't going to burn my arms and hands getting to operating temp then tearing apart.

BigDave01

I have been so frustrated I went and bought another car while I figure this out. Now that I can not worry about having to drive it everyday I plan an doing what you have said and check the wiring harness around passenger strut area. I will also try to check the operating volts to the injectors to see if I can see a variation.

If neither of those work I was going to splice in new wire all the way from ECU to injector.

Does anyone know if the injector grounds through the ECU or through a dedicated ground? If it's not through ECU I will add its own ground wire also.

If none of this works it must be ECU?

maximatech12

The compression is low!
Send the ECM in for testing. They hook it up to a machine. Apparently if you don't replace cat after emissions code the cat deteriorates and the damages engine. I would assume it's a pressure compression issue. Some folks tried gutting the cats but I would replace it immediately if I got the emissions code. I'm considering replacing mine because of P0430

BigDave01

I tore apart again and checked resistance from ECU connector and every injector was the same, and had someone jiggling the wiring harness all the way up and down. So I believe the wiring is good.

I checked with a noid light and found that cylinder 3 fires but at low rpm it fades out to almost no light at all or just bright enough to see something at idle ans seems to vary in brightness (dim with ocassional brighter patches) at idle when in gear. When you rev it it gets bright.

I checked cyl 6 and it was dim but steady at idle and when put in gear it brightened slightly. When reved it also got bright.

Based on these, I believe the ECU going out. Any opinions? I havent used noids lights much so dont know if the dimness at idle is normal, but other ones I tested were not as dim as cyl 3 which is misfiring.

Anyone have any experience with ecu testing and repair companies? I found a couple online but dont know how good the are.

Foreignecurepair.com
Protechautosystems.com
http://www.ebay.com/itm/Nissan-ECM-E...xU9ymf&vxp=mtr

maximatech12

For the P0306/P0300 it could be exhaust issues... These cars have a 3 way catalyst that deteriorates...
Apparently the 2002 owners were complaining of this issue creating premature engine failure. A few members in the previous generation were advising Max owners to gut the Catalytic converters because of this...

maximatech12

I just replaced my plugs but before I had to make sure they were NGK. If you used Bosch or motor craft you could wind up with misfire codes

oldngivout

iTrader: (8)

Any updates to this situation?

I am struggling with a Quest 3.5 doing the exact same thing...

BigDave01

Well I sent computer in and they said it had a short on the injector driver and they said they repaired it but once installed no change.

I have to send it back to them. Its very frustrating because I drove it for 10 miles yesterday before the first misfire then went back to doing it like before. Just no consistency. I am goi g to try cleaning the maf again though I dont think it will have any effect.

I am also going to replace the camshaft sensor on that rear bank.

I still feel like its a fueling problem, just haven't figured it out.

I took it in to a mechanic and he put it on his scanners and couldn't see anything wrong. Ignition and injectors seemed to be working fine. He thought maybe a timing chain skipped a tooth. I don't think that is likely because if it did the misfire would always be there and wouldn't go away. And that is not the case because it will run fine sometimes abd even when it is , isfiring it is not regular it bounces all over.

Geronimo

It could definitely be timing. I had a similar situation on a Subaru and it turned out to be timing related even though it only started misfiring when it was warm. Ran great otherwise but one cam gear out of four was a tooth off.

maximatech12

you can get Nissan Data Scan II and hook up to the ECM it will give you injection pulses in milli seconds on bank 1+2. Tou can get real time measurements for the timing. Where it's supposed to be is printed on a sticker under the hood. Mine is 15degrees. You just get a cheap VAG-COM cable. If you get pulses it's not shorted.
did you replace the injectors with hitachi or jecs ?
I don't know if this can happen but could the tube seal leak oil into where the spark plug is ?
If its intermittent it wouldn't be a bad timing issue

BigDave01

I checked and there is not any oil in the tube.

I don't have access to the Nissan Data Scan II. I did check with noid light and they all lite up except it seemed like the light was dimmer at low rpms for the cyl 3.

I didn't replace the injectors I just. Moved them around d to different cyl and the misfire stays at cyl 3.

I will double check timing but my scanner I think shows it at about 15-20 at idle. I can check this next week when I get ECM back for the second time.

maximatech12

Sounds like your ECM is fine. you would see it's burnt if it was shorted and you'd get a P0605.
If they test the injection circuit within the ECM they may not get continuity because of the way it functions.
How could it just happen sometimes?
if there was a short within the injector circuit you would have more issues than what your explaining right?

BigDave01

Got repaired computer installed and no change.

I also ran continuity checks on wiring to injectors and coil and tested perfect.

But I tried pulling the MAF connector an voila idles perfect. It killed it when I did when it was running but if I do it from off it starts and runs perfect.

Also when I clear the codes while its running it immediately begins to misfire again.

So does this mean its the MAF?

maximatech12

MAP is measured in Grams per second? You can scan the load in real time if you have the right connection. the Nissan engineers list The MAP as a possible cause to a misfire.

Also if it misfired after clearing the codes it may have been in "fail safe" mode because of the misfire. In fail safe the injectors fire simultaneously as opposed to sequentially. I'm not 100% sure as to exactly how long after an engine issue is detected it functions in "fail safe".