mortelec

I picked up a very clean 03 loaded maxima for my daughter that had a driveability problem. I got it home and plugged in my scanner and came up with misfire code on 2 cylinders and cam sensor code on both banks. Thinking I had an easy fix I replaced 2 coil packs, cleaned the vvt solenoids and put in both cam sensors all oem Nissan parts. It started up idled nice and smooth but road test my bubble was burst. Once the rpm's get over 2200 it would fall on its face. After a couple mile drive a slight rattle has shown up. Now it won't rev past 2500 rpm's and the oil light started flickering at idle and it sounds like crap at rev up. Compression test was 155-160 on the firewall bank and 180-185 on the front bank. This video is holding the pedal to the floor. Is it worth a teardown and rering or do you experienced Nissan owners think their will be more problems inside other than a rering and bearings. I am pretty setup mechanically in my shop but not sure if its worth the time and I should just cut my losses and move on. The part that's hard to swallow is the car is extremely nice condition with every option except nav I think.

maxinout93

not too sure but maybe the maf is preventing it from revving over 2500rpm.

mortelec

That was crossing my mind. I also wonder if the oil light flicker is because if low idle rpm.

Child_uv_KoRn

iTrader: (7)

Some seem to read the pressure lower and it will flicker at very low rpms.

Rear (I can't read) precat is toasted and tore up that bank it looks like.

Delete cats, replace maf, reset ecu, use 40 weight oil and check for consumption.

maxiiiboy

It seems like your daughter's car is in Limp Mode. If you search this forum, you'll find 24 threads dealing with this issue.

Child_'s advice of "Delete cats, replace MAF, reset ECU" may be right on the money. However, you may also try checking/replacing the ECT (Engine Coolant Temperature Sensor) and the TPS. If this feels like replacing too may parts too quickly (it probably is), ask your Nissan dealer to diagnose the problem for you. If he is willing to do that while charging you nor more than 1 hour of labor, take it.

mortelec

Should clearing the ecu bring it out of limp mode? It doesnt seem to. I plan on going through the test chart today on the maf. Dang the oem ones are $600.

maxiiiboy

No, no - don't pay $600.
You can buy the OEM MAF here http://www.rockauto.com/en/moreinfo....431954&jsn=348 for about $250.
Even better, buy only the sensor (excl. housing) for ~ $77: http://www.rockauto.com/en/moreinfo....431954&jsn=346 . This one is not made by Hitachi, but I would trust Delphi; and it looks like a lot of people do.

mortelec

Well the MAF appears to be within specs the first video. Unfortunately the 2nd video sounds like it might be too late now. Glad I didn't pay alot for it I think its going back on craigslist. The car is worth fixing I've just decided I don't want to commit the time to do it.

Child_uv_KoRn

iTrader: (7)

Where are you located?

mortelec

Minnesota

sebastian2041

Wel i had this problem last week... I got the cam sensor reading of my obd i decided to reset it and see if they came back just to make sure and guess what they didnt comeback but a thermostat problem did( not related) i called my mecchanic he said we would clean the vvt and maf that they were most likely the problem...I then noticed the oil light flicker and it got me thinking maybe its low oil and that my car is just burning oil (as maximas are know for)so i added 1/4 of oil and then the car ran fine and no more light flickering

Ps i didnt know if my car was low on oil because the reading on the dipstick pissed me off since it wasnt clear, worth mentioning i recently change the oil and filter about 2000 miles ago which now worries me how bad ita buring it, if it has a lead or whats wrong!

mortelec

Good info. I did drain the oil and filled with new and the light hasn't come on. Also cold start I can rev to 4000 + but quickly fades and then can't get past 2200-2400. Not sure what to think.

sebastian2041

After adding oil to my car the problem was solved instantly the car was revving the old way no more stayinng 2.5k rpms i am worried that there is something wrong tho because the oil was just changed not to long ago..this week im supposed to be getting it sorted out! Im also trying to fix other annoying problems! Such as my cars first thousand rpms are really slow! And then it once up in speed the last thousand rpm are also really slow! This problem with the accelaration and top speed have been annoying me and is what leads me to believe my solenoids might be bad or the i need to clean them The maf sensor might need to get cleaned. I hope it makes the car run the way i want it since it feels lazy at time. My mechanic did drive my car said it felt slow and told me to order spark plugs and ignition boots not coils so maybe thats why it runs weird

My light only flicker in low rpm like when slowing down or shifting make sure you add the right amount of oil because although people suggest 5qts i fee like it might be more since i recently added five quarts and then t need more!

mortelec

This one I can hold the pedal to the floor and only get around 2200 rpm's. The maf seems to be in spec according to my scanner data. Possibly the precats but being in Minnesota the only way they will come off is a torch that's why I'm probably sending it down the road.

sebastian2041

Oh i see i know that these cars have pre cat problems but never got to in to it probably should tho! Although for me its not biggy since my dad is a metal fabricator so getting it out will be easy and putting a new one will also be easy and cheap

Now you make me think that my pre cat might be why im burning oil... Interesting

MadMax SE

I will link the thread but i recall someone saying that their precats got clogged and that let to backpressure into the cylinder. if that backpressure builds up in thr crank case it can force oil past the oil rings, thats if the precats are the cause. use a nice 10w30 to see if it burns slower, penzoil platniun is sone great stuff for these vq's

maxinout93

[QUOTE=mortelec;9107021]This one I can hold the pedal to the floor and only get around 2200 rpm's. The maf seems to be in spec according to my scanner data. Possibly the precats but being in Minnesota the only way they will come off is a torch that's why I'm probably sending it down the road.[/QUOe

Kinda in the same boat with the exhaust work, nobody seems to want to touch my car because of the rusted y-pipe bolts at the pre-cats. They give me one price to replace it, them if bolts break which more than likely they will the price goes up.

sebastian2041

i been using mobil 1 synthetic 5w 30 the car only has 110k but next oil change ill move up and see

mortelec

After sleeping on it I may pull the precats this week if I get a free day and see what they look like. Its not going to be easy looking at the bolts but I've got a torch. Ive exhausted pretty much all other possibilities I think. I'll report my finding .

Child_uv_KoRn

iTrader: (7)

Soak with lube for days and remove the whole manifold.

Yeah, they can definitely clog from oil burning after they cause the oil burning.

I used the new pennz plat 5w40 in my sister's de-k and it burned a little after 5k. That engine doesn't burn at all (been using mobil 0w40).
If it's a moderate burner I'd go with castrol blend. For a heavy burner I'd probably get my hands on the cheapest 50 weight until winter, then use the cheapest 5w40.

It pays to stock up on hundreds of quarts at year's end for 1-2 bucks

Adamk8824

my mass airflow died, no codes, coudlt rev above 2500 RPM or close to it.

I used a mas airflow sensor from a 2001 and used a resistor from digikey and my car is fine. Costed 120$ instead of $450.


I honestly think you need new injectors (all 6). That sound is the sound my car makes from bad injectors leaking, it knocks slightly. Replace the spark plugs while you are in there. .044 gap. the pre cats do not cause limp mode.

so to sum it up, new injectors, new spark plugs, new MAF sensor. almost guarantee that will fix every issue your having.

mortelec

BAM Child uv KoRn all I can say is you the man! Your knowledge is greatly appreciated. Got ambitious tonight and tore off the front cat and pipe. Couldn't get the back cat off but what.... the front cat was was empty. WTF I thought ended up cutting the pipe in front of the last cat and wouldn't you know there is all my front cat guts. Looks like the main converter is plugged solid also. So my question now is if I delete the pre cats what is that going to do to the o2 sensors?

Adamk8824

Oh shucks. Looks like i have another costly repair in my future.. sighhh.

Donkeypunch

I think you 3.5 guys get broken precats because of the oil burning situation.

Child_uv_KoRn

iTrader: (7)

This is exactly what happened to my first 3.5...except it killed the motor. You got lucky b/c the front bank was saved when it disintegrated completely and caused this big problem (the rear is tougher so it's just getting sucked up and eating the cylinders/rings). Many people on here disbelieved my report (and the precat failures in general), but this is pretty conclusive lol.

So, you've got it. Gut the rear and main cat and you should be good minus oil consumption.

The clog is definitely limiting the rpm, but it is suspect given how maf failure reacts, too. You'll find out after you fix everything. Grab some junkyard mafs (for freesies) if you need one.

You just need defoulers to trick the ecu. There's lots of threads on it.

maxiiiboy

Nothing, really.
You front/upstream O2 sensors will operate just fine. And they are the only ones that count.
Your rear/downstream sensors will complain that the pre-cats are not doing their job. Unless you live in CA or NY, you can ignore this complaint and install anti-foulers to get rid of the annoying CEL light.

Amazing pictures. Save them. And send a copy to Nissan and tell them what a lousy job they did on this car, and in this area in particular.

sebastian2041

Time to start saving up money for this repair... Or gutting

Child_uv_KoRn

iTrader: (7)

Yes....HEADERS

dwapenyi

iTrader: (3)

If anyone should be blamed, it's the EPA, and whatever the equivalent of the EPA is in europe. You will note that all emissions related equipment is warranted by a separate, federal emissions warranty. Also, this same exact issue (disintegrating precats debris sucked back into the combustion chamber-> debris scouring cylinder walls->oil consumption increase->eventual complete loss of compression->toasted VQ) is happening on some older Toyota MR2s.

Pre-cats just suck

sebastian2041

Now time to read up on headers was thinking about it before now more... Cost? Gains? Sounds? So much to learn 😳

Child_uv_KoRn

iTrader: (7)

All three

maxinout93

yeah that rattle noise def sounds like one of the pre-cat material was rattling around inside the housing. glad you found the problem, now you should be good to go. Just keep an eye on the oil levels.

how did you remove the front one? Did you have striped bolts? I need to invest in a torch myself, these people here are giving me a hard time with my rusted exhaust lol.

sebastian2041

I have a rattle noice too but only when car starts uo for less than 5 seconds it rattles then goes away its quiter if the car is warm

NmexMAX

iTrader: (22)

In some cases Nissan manned up, but not for failing pre-cats, but rather for cracking manifolds. I got my VK56 manifold repaired for free under the 8yr/80k emissions warranty. But, the pre-cats were fine, it’s just on the VK56, the precat is embedded into the manifold therefore nicely being covered under that portion of the warranty, whereas on the V6 Pathy, this was not the case, though those cats/manifolds weren’t failing nor cracking.

And then there’s me, my car burns oil and I’ve had headers since she was 2 years old with 40k which was about 12 years ago and 130k miles ago. Began burning around 20-30k ago.

Child_uv_KoRn

iTrader: (7)

Yeah, precats are useless. But it's legal to dump mercury in some places (without oversight) so that's good. Good job, EPA.

NmexMAX

iTrader: (22)

lol savage.

sebastian2041

Or be one of those douche with a truck rolling coal

mortelec

So heres my hindsight now. I got the car with bank 1 & 2 cam sensor codes, 2 different cylinder misfire codes. Cam sensor codes were the vvt solenoids stuck. Misfire codes were 1 completely dead coil pack and 1 intermittent coil pack. My theory is the cat fell apart previously and the dead cylinder helped finally plug up the rear cat with the motor running poorly. Today I gutted the rear cat. I did it in place but wouldn't recommend it. Took a couple hours. I ordered a new rear cat for $110, welded in a new flex braid pipe and put in non foulers in the y pipe. If the car runs good I think I did pretty well. It was a fully loaded 1 owner car that was very well taken care of. I'll still have less than $1000 into it. This is for my daughter who just got her license.

Child_uv_KoRn

iTrader: (7)

Nice job!

Just don't forget to check the oil every week
As you know, women will drive a car till it's D - E - D dead.

I did a clutch job for one where the throwout bearing was destroyed. There was nothing left inside. It was just a ground down shell in pieces! And of course, she had no idea what happened. It just quit starting one day
Had another with no oil in her truck. She was driving it around for days! Good ol nissan hard body.

dwapenyi

iTrader: (3)

From what I've observed on these forums, the pre-cats seem to fail past the 100K mile interval, so as far as Nissan is concerned your on your own.

Must be because you have the first version, the 1.0 of the VQ35, which is essentially a stroked VQ30. So I guess there were some teething issues which got ironed out in the later VQ35s

Another thing is, I guess in the older days, when you stroked a motor, there wasn't as much need to worry about how far it will rev. This is a 24 valve DOHC V6 with a 6500 RPM redline. I'm sure the Nissan engineers must have been a bit hesitant about stroking it AND keeping it reliable.