QuasarDecimari

Fantastic engines, horrible to work on. Get ahold of a factory service manual PDF, and start reading up on the procedure to see if it’s something you want to do yourself. I was blown away that the dealership quoted me $2000 to do my engine timing on the VQ... I did it myself and rebuilt my engine while I was in there for $1200, but even timing alone took over 8 hours to get to. Sent from my iPhone using Tapatalk

I was waiting for you to come along with input! From the looks of the second posting, it seems rather important. The user explaining it gives quite a bit of detail about the impact it makes. Maybe I’ll go ahead and get out the grinder and some steel, see if I can’t make an extended bracket. (I swear the search feature on Tapatalk Mobile is absolutely useless. I tried searching for threads related to this and it just finds stuff completely unrelated...)

If he does he’s in luck. Changing the timing chain on the VQ is such a pain. If it wasn’t built so that you have to remove the entire upper oil pan just to take off the front cover, it would be a lot less terrible.

I can definitely run some tests as soon as I can, to see what sort of impact the valve has, especially with a lift. My take on it, while some things are always questionable, the engineers put it on there for a reason, not just for extra accessories. If tests are conclusive that the valve does indeed enhance rear braking with a lift, I can’t imagine it’ll be hard to make a writeup on a bracket that could fix this. I could probably design and fabricate one in a day.

That’s exactly what I was thinking when I figured out what the valve was for. I knew by lifting it, that valve became obsolete. Not a bad idea. I have it fastened right now at max, and I remember when I did that and went for a drive afterwards, I could tell a slight difference. My front bumper didnt nosedive as bad and braking just felt smoother, like it wasnt going to launch me out of the windshield. I could always conduct some tests with braking times and how level the vehicle stays when braking, if anyone is curious enough.

Hey everyone! A while ago, I was checking up on my rear axle's gear oil, and I started looking more closely at the strange device attached to the rear axle carrier. The one coming from under the body, attached to the axle by a spring. After a few minutes of scrolling through the factory service manual, I found that it's the load sensing valve. Essentially, the design of this valve makes it so that the vehicle can detect when there is a lot of weight in the trunk of the vehicle, or you're pulling a trailer, as the spring attached to the axle relaxes tension and the lever on the valve pushes upward, changing the valve position. This, in theory, allows the vehicle to distribute a little more braking power to the rear brakes. However, this only really applies if your axle is still the same distance from the body as it was when it was stock... Mine being 7" taller than stock in the rear, I can imagine that isn't going to do anything anymore, with how stretched the spring is. My question is, how important is the operation of this valve? I have temporarily secured it so that it remains pressed in all of the time, to try and see if I can get more smooth braking in the rear, but I don't assume that it does much in the longrun. I added a picture from the FSM of the device and its operation.

Also, depending on your year, you may either have a hall effect sensor or an inductive pickup sensor. One looks like a magnet, similar to a crankshaft position sensor, the other is like a tiny gear. Both are fragile and expensive to replace, so use caution when removing, and always be sure to gently clean them off before reinstalling. If it is the magnetic pickup sensor, avoid putting it near anything else magnetic while it is off the vehicle, to avoid damaging the sensor in case it isn’t really your problem. Sent from my iPhone using Tapatalk

It’s a huge pain to get to, if I remember correctly. Look at your transmission/transfer case, and follow it to the driveshaft. On the top side of the transfer case, right before the output shaft (connecting to the driveshaft), should be the VSS. However, there’s some controversy and I’m not entirely sure that one is it, as I could never remove it to do what I wanted with it. There are diagrams in the factory service manual, but they’re very vague. Sent from my iPhone using Tapatalk

Good points, and the MAF is nice and clean, fairly new (I baby the heck out of this engine, most external parts are new). Someone on the Facebook page for this group actually made a huge point I hadn’t considered, the PCV valve. While it’s also new, looking at all the symptoms of a bad PCV points mostly to this. While it doesn’t explain the loss of fuel pressure, or the exact reason for a single cylinder misfire, I have noticed a small amount of oil around the valve cover gaskets (only 14,000 miles on those too), oil in the spark plug tubes, and weeping around the bottom of the engine. Taking the little filter off the Valve Cover PCV inlet tube (the one connected to the throttle side of the engine), I noticed blowby residue (yellow sludge) in the tube, and the filter was saturated. I wonder if excessive pressure is building in the engine’s crankcase, and it’s not able to let off pressure from blowby, causing the rich fuel smell, and performance lag. Plus, excessive pressure would explain the source of the weeping along the engine.

Hello Everyone! Curious if anyone has a similar experience or advice for this situation I’m having. I’ll give my vehicle details and cut to the chase. 2001 Nissan Pathfinder LE 3.5L VQ35DE 196,000+ Miles Engine Overhaul @ 182,000 Miles (Timing, head gaskets, plugs, and so on changed) Summary: The engine, whether hot or cold, rough-starts/misfires for a few seconds (first 1000 revolutions), then levels out and runs “fine.” Short Story, for those who don’t like to read: •Rough Start/Misfire in first 1000 revolutions •Cold or Hot engine doesn’t affect it •Very strong fuel smell in exhaust •Runs perfectly smooth after it levels out •DTC only showing Cyl. 4 Misfire •Ignition coils •Spark Plugs NGK Laser Platinum @14,000 miles, gapped to 0.044 •New Fuel Filter •Changed injector on Cyl. 4 •Compression in range on all 6 cylinders •Not losing coolant •Oil smells like gasoline, but isn’t milky Slightly more detail: The issue started within the last 500 miles. I cleaned out and overhauled the engine about 14,000 miles ago, with new head gaskets, studs, seals, and so on, and up until these past couple weeks, it has been running great. The engine rumbles a little, inconsistently when starting (the issue doesn’t occur every time), but it does start instantly with no problems. Just for the first 10-15 seconds of running, it rumbles and idles rough, then levels out and runs perfectly smooth. There is a slight power bog at higher loads, but this rig is also lifted on 33s. I waited until the computer would finally throw a code, which showed up after 4 rough starts. The DTC only gave information that Cyl. 4 was misfiring, so I cleared the code to see if it remained consistent. Over time, the light came back, and the code remained the same (P0304), 3 times. I ran a full bottle of seafoam and some premium Shell gas in the tank for good measure, but the issue remained. Naturally, I pulled off the intake manifolds and started to check for signs of failure. When relieving fuel pressure, the FSM asks that you pull the fuse to the fuel pump and run the engine until it sputters out. When I pulled the fuse and went to run the engine, it attempted to start for a moment, then died instantly (usually it runs for several minutes until it dies off). I decided to change all the coils with new ones, as well as changing the Cyl. 4 injector with a brand-new (NAPA) injector. Looking at the spark plugs, they didn’t show abnormal wear, the gap seemed a little larger than when installed (being now 0.047). Noticeably, however, the plugs were wet with fuel, and smelled really strong like gasoline. No other strange buildup was noticeable on the plugs, so they were reinstalled, but the plug for Cyl. 4 was swapped with Cyl. 2 just or good measure. The engine was then reassembled, and started. I took it to get a full tank of 91 Octane fuel, and it ran fantastic the rest of the day, with no starting issues. 24-hours later, the problem returned, and the idle is rather high (900-1000 RPMs in park/neutral). I’m lost as to what the issue could be, but I do have a few ideas. So, does anyone have any advice or ideas? Seen this problem before? I’ll be happy to answer any questions, or try most any tests I can. In the meantime, I will drive a different vehicle, and leave the battery disconnected in the Pathy in case the computer just needs refreshed. Thanks everyone!

Funny enough, I’ve got these issues occasionally, though I usually just blame having 33s. What’s your conclusion to these symptoms? They’re quite specific, so you definitely know of a problem haha. It doesnt happen as severely as the OP says it, but I know what he’s talking about. If I give it gas after shifting from R to D and not giving it a few seconds, it’ll go into limp mode as well.

Super sorry to hear it [emoji22] Now’s your chance to put a more powerful engine in it haha. How many miles did it make it? 22+ years with general maintenance is pretty darn good! Sent from my iPhone using Tapatalk

Definitely swap those bushings haha, it’s going to be worth it by the looks of it (and really help narrow things down if it isn’t the fix). If you have the cash, buying the whole arm assemblies with pre-pressed bushings will save you a crap ton of work. I otherwise had to use a press and large impact sockets to get those suckers in and out of the arms. With a big press, it was easy. Never would have gotten it done without one, however.

That was the case for me too. I did a bunch of mods but never used 4WD at higher speeds other than crawling on trails, so I didn’t know there was a problem until later. One of the problems with a high CV angle is that the front end lifts a little bit under torque, which causes and even more severe angle for the axles to put up with. While not enough to bind, it’s still pushing the limits of their smoothest operating range. Thats a har one to troubleshoot though.

Definitely on board with onespiritbrain. It might be able to be narrowed down that way. And yeah, depending on the size of your tires altogether, 0.5mm just won’t cause that much trouble due to the angular velocity and rotation of the tire, a difference of 0-0.5mm is so tiny that the differential or TCase won’t see it when it’s geared in proportion. That CV angle sounds like a bit of a flag however. Is this the first time you’ve experienced this after the lift? Did you lift it recently, and now that you’re using 4WD you notice it? Or have you had the lift for a while and this only now started?

Some things don’t hurt to pack with new grease after a while. Not sure what year you’ve got, but most are the same in the topic of where can be greased. I like to keep my front driveshaft greased, I pack grease into my hubs whenever I have them open, tie rod ends if they’re not OEM (my MOOG ones have grease fittings), U-Joints don’t hurt either. If you do any mudding or water crossing frequently, keeping your drivetrain packed with hi-temp marine grease is good practice too. Sent from my iPhone using Tapatalk

Oh god, I had a small hole about a centimeter across in a boot once, and the mess it made from the grease was horrendous. I cant imagine the mess if they were pumped full :O Sent from my iPhone using Tapatalk

Correct, the only time it would REALLY matter is with the tcase in gear, as it requires that near-perfect 1:1 between the front and rear. How bad is your CV angle? More important, have you done an SFD? I’ve been able to go smooth on 2.5” of lift in comparison to the subframe (and by that I mean I had 6.5” spacers, but only a 4” SFD. That’s changed now) without any major vibration in the CVs. So we’re good there. Have you looked for play in the driveshaft flanges? Specifically to the transfercase? I’ve heard of cases where the bearings are shot to the output flange and it causes a bunch of balance issues. This is also a good point. A U-Joint setup requires similar angles on both ends of the shaft for it to operate smoothly. If one end is too high or at an extreme angle, it’s gonna be a rough ride. Sent from my iPhone using Tapatalk

Also, if you have the time and a good press, changing those Differential Mount Bushings really doesn’t hurt. I did that and I’m glad I did, makes it feel a bit more controlled in 4WD. Originally I could move the diff up and down by hand by pushing up on the pinion side, so it was time to be done anyways haha.

Take a look here: Rumble and Shake in 4WD? https://r.tapatalk.com/shareLink?share_fid=45554&share_tid=43858&url=http://www.nissanpathfinders.net/forum/index.php?/topic/43858-Rumble-and-Shake-in-4WD%3F&share_type=t Just in case you want to give it a good read, I was having the same issue as you for a long time, and that’s my thread on it. It was a very large discussion, so reading through all of it might take some time, but I ended up posting my results and fix, analysis, and all that in the final post. I even used a go-pro under the chassis to find the problem myself, and unfortunately, the result only lead me astray. Like I said, read through it, we really touched on every possible option for what would cause the issue. There’s 132 replies worth of information and troubleshooting, so get a list ready! Good luck!

Unfortunately it doesn’t look like it. I did some research on the fans to see if they cross reference with each other or have the same mounts, they’re a bit different, and it doesn’t look like it would. I can’t find dimensions for the clutch or fans online anywhere, so I can’t say for sure, but none of the 3.3L fans I looked into say they would fit a 3.5L, and vise versa.

Keep us updated on the results when you get to driving it again! Hopefully that’s all it was. Sent from my iPhone using Tapatalk

Like you were saying, a real flush is the devil. Which would mean a machine would pump new fluid in until all the old fluid is pushed out, but this can easily kick up clutch pack material and debris to clog more things up. If you’re going to aim to change all of the fluid, like I said, drain some, fill some, run it for a bit, drain it, fill it, repeat until it’s pretty clean. This way you’re not forcing new fluid through the tranny, and instead just letting it work the old fluid out itself. I did that around 20,000 miles ago and it’s going nice and strong.

This doesn’t hurt either. When I changed my transmission filter, I filled up the tranny with fresh fluid, ran it for a day or so, and the next day drained it all out again to refill, hoping to get as much old fluid out of the torque converter and so on as possible. It actually improved the smoothness of shifting a lot. Sent from my iPhone using Tapatalk

Bigger tires unfortunately do really add that extra stress to the transmission, especially the shift points, as the wheels are now turning at a different rate relative to your vehicle speed than originally programmed from the factory. Other than regearing, which will only help a little, the only other fix I know of is to install a speedometer adjustment chip like the one from 12OClockLabs, which can be a tricky animal of its own that also kinda messes with the transmission.