ColombianMax

iTrader: (7)

Hey guys, I usually like to figure things out on my own prior to making a new thread but kind of gave up and decided to post and see what you guys have to say..

I have a 2002 SE 6 Speed with 180k. NO CODES whatsoever and none pending either. I bought it in May 2012 and it was shaking a bit at idle then but still seemed to have full power at all times. Coming from a 3rd and 4th gen, despite the fact that I believe the car is misfiring- its still running quite well and strong. I only use 93 Octane from BP, Shell, or Mobile.

Here's a list of things I've replaced not only to address this issue but also because they had to be done.

-6 new spark plugs from Nissan
-04 front and rear valve covers + gasket
-3 new coils from Advance Auto for the rear (originals seemed to be ok)
-2 new Bosch O2 sensors back in June


So there was no change when I swapped out the 3 rear coils, leading me to believe the 3 on there were still good so I put the original rears onto the front hoping the front would have a bad one or two but still no change.

I checked the injectors yesterday to make sure the resistance was within spec (13.5-17.5 per FSM) and they were all around 16.x however the lower intake had a smell of fuel.

That being said, its safe to say assume coils are good and injectors are electrically in spec. There are no fuel leaks in the hoses surrounding.. What alse could cause my car to shake lightly and be missing just a tad bit of power? Fuel pressure regulator maybe?

According to an Actron scanner- timing is fluctuating between 13-15 degrees at idle. Not sure if that's normal but thought I'd put it out.

Reizy

iTrader: (48)

Many have criticized Nissan's use of a "lifetime" fuel filter (or screen) on the fuel pump and even more have noticed a significant difference after changing it. With 180K and not knowing history of said filter, I would start there.

Galactica

iTrader: (5)

This. You may also see about your MAF and replacing upper 2 O2 sensors, just for maintenance (unless they've been done already).

Mints33

iTrader: (5)

Take out the MAF, and give her a good cleaning!

Pearl93VE

iTrader: (14)

I forgot all about the lifetime fuel filter, John. You may want to try that.

http://www.shiftice.com/fuel_filter.html

Did you do the ECU reset? If so, did it change anything?

ColombianMax

iTrader: (7)

Thanks for the replies.. I'm gonna start with the simplest today so I'm gonna go buy some MAF cleaner spray and see how that goes. I'm tired of poor MPG and the bit of vibration and the barely but noticeable lag. 19mpg combine city and highway.

About this fuel filter/screen.. whats the best place to buy this?

Is this is? http://www.autozone.com/autozone/par...ier=22063_0_0_

dfj240

iTrader: (1)

Best place to get it from is the dealer. That link is not what you're looking for. That is just the strainer for the pump. What you're looking for is the fuel filter itself, which is in-tank and really easy to replace. It's not expensive from the dealer either.

http://tinyurl.com/btad833

That's a link to the exact part you'll need from Tri-Cities Nissan.

I dealt with a VERY bad hesitation problem when I first got my Maxima, and went through quite a lot more than you have, and blew through a lot of money trying to solve the problem. It turned out to be a clogged pre-cat. If you only have minor hesitation and idle stumble then it's quite possible it's something else, but it might be worth it to you to check it out. Very easy to diagnose as it turns out, just need a vacuum gauge. If you're interested, let me know, and I'll run you through it. Some of the other guys here might even have a better diagnostic method for clogged cats too.

-Nathan

ColombianMax

iTrader: (7)

Hmm, so I havent had a chance to replace filter inside fuel pump, nor clean out MAF. HOWEVER, I got a CEL on Friday and it was a P0300 which is a Random Cylinder Misfire... My On-Board MPG calculator is telling me I'm getting 20MPG... which is probably closer to 16 BAAAH!!!!

Not sure the MAF or Fuel Filter would cause for this code. With my limited knowledge on the 5.5 Gen, I'd have to say this sounds more like Coils or injectors to me.. dont forget the LIM has a smell of RAW gasoline when the UIM is removed.

Ugh, this isn't fun!

Pearl93VE

iTrader: (14)

P0300 is so broad. Could be a number of different things at this point. Could be a coil intermittently going out, intake/vacuum leak, clogged cats, etc.

Hopefully you will spring a new code here like mine did within the next week or so to help narrow it down. A 'P030X' would be nice.

If you don't get a new code and keep the P0300, I would lean more toward something that is affecting both banks. (ex. intake leak) So I doubt it's going to be the injectors, especially if they were all within spec. I suppose you could check pressure on the fuel rail if you wanted to.

Does your oil smell strongly like gas? How about in any non-EVAP vacuum lines?

ColombianMax

iTrader: (7)

So I finally changed Valve Timing Solenoid gasket which was leaking nasty but before tearing anything apart, checked for more vacuum leaks. While there were no leaks, there one of the lil valves that bolts up to the UIM and has two vacuum hoses connected to it sounds like a vacuum leak but countless TB cleaner and no revving or abnormal idle so figured its normal.

I DID however recheck the injector resistance on all 6 AGAIN because that strong fuel smell just gives me a feeling that its the injectors. Last time when I checked the resistance, they were all well below 17 ohms (spec is 13.5-17.5) however they were cold. This time I checked them immediately when the car was still warm and 3 of the injectors tested at 17.6-17.8 ohms! I continued to work on the IVTS gasket and once done, engine was cooler so I tested injectors again and bam, they were below 17 yet again.

So now that I tested injectors warm, I'm thinking its definitely the injectors... What do you guys think?

Finchum

i was thinking a vacuum leaks on hoses or intake tract, but now that you tested the injectors, and talk of a fuel smell..........leaky injectors.

i recommend new injectors and changing out the fuel filter screen.

when I get around to messing with the screen I am going to research and see if i can eliminate it and put an inline filter in place.

Markusfisher

I know this may seem too easy, but id recommend doing a good old deep creep sea foaming. 1/4 bottle in gas, 1/4 bottle in oil.. 1/2 bottle in intake (brake booster hose.)

And i second changing the fuel filter.

ColombianMax

iTrader: (7)

Alright guys, so I got ahold of some VERY low mileage injectors that my friend had stored away in a lil box. All Ohm-ed out at 14.5-ish which is within specs. Replaced them and while the car does run a BIT better, it still isn't where it should be.

I swapped MAFs with a known working one (he gave it to me also) and the car is still not where it should be. So I connected the OBDII scanner and something stands out here.

Look at the ignition timing, As far as I know it SHOULD be at 15 degrees in IDLE. As per my limited knowledge, one of the only things that could retard your timing is a bad knock sensor or actual knocking in the engine to prevent damage. So I'm wondering if the knock sensor is bad... I removed it ealier to swap with a brand new spare 4th gen KS I had laying around but the plug is rounder on the VQ35 KS and couldn't use it to troubleshoot.

NOTE: There are ZERO codes and ZERO pending codes..

Pearl93VE

iTrader: (14)

I don't know if this is good for VQ35 as I haven't spent enough time researching... but you could try this before you throw money at a knock sensor...

http://forums.maxima.org/2747137-post13.html