HELP! Problems with AUTO

[SFerinTEXAS]

plug off vacumn line to egr. If that system is the culprit it should run better just not efficient.

Not counting a stuck open egr valve.

Have a 4.2 fd v-6 that plagued me with a #6 missfire code.After a few years it became almost undriveable.Found out some egr passages in the intake were clogged causing uneven fuel mixtures in the cylinders throwing missfire codes.
after the repair its like a new motor

[ViperRon]

TC The 2004 Xterra has a history of the bearings in the distributor going bad and causing the issue you are having. This is a common problem but also people have been lured into replacing it with no change. On your model there are 4 oxygen sensors on the manifold pipe that read to ensure clean burn and change fuel flow to injectors and timing change to adjust performance according to outside environment. These in part take the place of old fashion manual choke. The other part, EGR Valve, works in conjunction with these to supply heated air from exhaust to the intake to assist atomization of gas and air. As mentioned the EGR can clog and stick causing the same issues but often times have sensors that monitor open close position and give specific error code if it does not move. If it were totally clogged you would normally have seen performance and power go down hill over a period of time. The knock sensor is a safety and monitor feature to ensure smooth rotation of the engine that helps identify miss or power loss from cylinder that can be caused by anything plug, wire, sensor, computer, distributor, EGR, Map, burnt valve, etc...

I can not find it online search but either auto parts store or dealer should have the OHMS readings and wire position for the oxygen sensors in your system so you can read them with a meter. It may be in the manual or on sticker under hood. Most have a resistance range like from 2 to 4 ohms when not in use. You should also check to ensure 12 volts gets to them with key on and the connectors are not melted or burnt a common issue. You can check these for free. You can check them outside the vehicle with a torch to ensure they change but that is a bitch to do at times and you can screw them up with too much heat. You can pop the EGR valve assembly off the manifold and check to see if its clogged for the price of a gaskets (cheap) but it's a bitch some times and bolts shear off causing you to wish you had not touched it. You should check all vacuum hoses for leaks and poor connections for free but be careful some break darn easy after use and the right hose isn't cheap. I don't think its plugs or wires or distributor cap you would have found that before putting up the note.

Beware of dealers and some repair shops as they many times sell the manifold pipe catalytic converter and oxygen sensors all as one big bill expense for this.

[IanDMacDonald]

Screw all this diagnosing crap, buy a new truck TC!!!!!!!! Get the new Tahoe! Lol, jk. Pain in the butt, I know.

[vedgar]

Simplified diagostics for misfire.

Since the check engine light was flashing, the misfire was what we call a dead misfire. (Not intermittent) Cylinder 2 is the culprit and the knock sensor code can be ignored at this time. Check to see if you have spark at the end of the plug wire (plug in another spark plug and ground it. Second, pull #2 plug and see if it is wet. If wet, replace it . If not wet , use a stethoscope and listen to #2 injector. It will tick lightly if it is working correctly (compare to others). If it does not tick and the plug is dry, replace the injector. If it ticks and the plug is dry it may be cleanable. Not to be forgotten, make sure you have good compression on that cylinder. Good Luck
Vance

[TopCatGr58]

Problem Solved: FEEDBACK!

Hey again folks,

Thanks again for all of the brainstorming ideas and info. Fortunately, the misfire plug was #5 which was the front right one on this V-6, and I was able to get access to the injector electrical connector WITHOUT having to pull the intake plenum/manifold, just pulled the Dist. Cap and wires out of the way. Tested it with the Ohmeter, 12.4 ohms, within spec with the others I checked....so it wasn't FRIED.

Pulled the Spark Plug...had a little color on one side of it, but not a definitive streak!



THEN...looked more closely at the other side of the electrode!


The OEM's were Double Platinum....these were just "single" platinum....and so I guess that partly made for the wear at only around 40K since install!?

Then I looked more closely at the plug cap....for the #5 and 3 clyinders, it uses these 12" long hard bakelite/plastic tubes to be able to reach down thru the intake plenum to the plug! The one on the right is the misfiring #5.. it looks like it might have had a crack/imperfection in the casting and that darned "Electrickery" found a way out the side and to the engine....there was some sort of brace/bracket very close to that location down on the engine... so I am assuming that it was shorting out the side of the cap!?



SO...I decided to bite the bullet, and replace all of the plugs with Double Platinums, the plug wire set, AND the Dist. Cap and rotor....I had been cleaning the cap periodically by scraping off the arced/corrosion that builds up on the inside flat side of the cap plug pins that the rotor arcs to when distributing the power!



Fired it up, and was hitting on all 6 cylinders again. The check engine light is still on, but not blinking....went to the auto store, same codes as before, they stated that I'll have to drive it for 30 or so miles and once the ECM realizes that it's behaving again, it will clear itself and turn off!

SO...it looks like my fuel injector was having an ignition problem....sounds familiar doesn't it! Happy camper again!!!

T.C.

[MPittma100]

Misfire

High TC,

No doubt you have gotten rid of the problem with the "tune up". Next time (if) you have a misfire code, switch the plug that caused the code with any other cylinder plug. Remove the code (with scan tool) and see if a reoccurring misfire code follows the switch. When a misfire occurs, a code for it will show up quickly.

Not sure if the auto parts outlets scan tools have the code removal feature, but they are available.

When you have multiple codes, they are prioritized in order by the software. Normally the first code is the one to be concerned with.

If your engine light does not turn off by itself, you will have to have it cleared. You may check your vehicle manual and find out that you can clear the code manually. Some vehicles will clear via battery cable and/or computer fuse temporary removal.

Hey again folks,

Thanks again for all of the brainstorming ideas and info. Fortunately, the misfire plug was #5 which was the front right one on this V-6, and I was able to get access to the injector electrical connector WITHOUT having to pull the intake plenum/manifold, just pulled the Dist. Cap and wires out of the way. Tested it with the Ohmeter, 12.4 ohms, within spec with the others I checked....so it wasn't FRIED.

Pulled the Spark Plug...had a little color on one side of it, but not a definitive streak!



THEN...looked more closely at the other side of the electrode!


The OEM's were Double Platinum....these were just "single" platinum....and so I guess that partly made for the wear at only around 40K since install!?

Then I looked more closely at the plug cap....for the #5 and 3 clyinders, it uses these 12" long hard bakelite/plastic tubes to be able to reach down thru the intake plenum to the plug! The one on the right is the misfiring #5.. it looks like it might have had a crack/imperfection in the casting and that darned "Electrickery" found a way out the side and to the engine....there was some sort of brace/bracket very close to that location down on the engine... so I am assuming that it was shorting out the side of the cap!?



SO...I decided to bite the bullet, and replace all of the plugs with Double Platinums, the plug wire set, AND the Dist. Cap and rotor....I had been cleaning the cap periodically by scraping off the arced/corrosion that builds up on the inside flat side of the cap plug pins that the rotor arcs to when distributing the power!



Fired it up, and was hitting on all 6 cylinders again. The check engine light is still on, but not blinking....went to the auto store, same codes as before, they stated that I'll have to drive it for 30 or so miles and once the ECM realizes that it's behaving again, it will clear itself and turn off!

SO...it looks like my fuel injector was having an ignition problem....sounds familiar doesn't it! Happy camper again!!!

T.C.

[TopCatGr58]

Hey Mike,

Well, if the plugs/wires weren't so hard to get to I wouldn't mind trying swapping stuff around. But the friggin' engineers have designed these things with so much crap in the way....the intake EFI plenum and such, putting the #6 plug around the back of the engine next to the firewall where you have to be a contortionist to be able to access it , the plugs so deep down into the engine due to the double overhead cams, that it's almost not worth it to try to do that type of diagnostic approach. I miss my old Pontiac 350 V-8 with just the PVC valve ;p... but we do have cleaner air now!

The other good thing is that this has helped me to be able to diagnose the same type of error codes that I am having with my sister-in-law's 2002 Nissan Quest with a V-6. I'll be able to check the injectors, and hopefully they'll OHM out properly, and then it'll just be a matter of replacing the wires and possibly the dist. cap/rotor as well, we've already replaced the plugs recently.

T.C.

[IanDMacDonald]

T.C. I've found that those peeps @ AZ or wherever have no idea of the capabilities of a CAN/OBDII scanner. I have my younger bro's GM Techtron scanner to play with, plus my own collection. Part of the collection is an ELM 327 bluetooth scanner. I pair it to my phone and can do anything I want with an app like Torque. Plus, if you have a Ford product, there is a program called "Forscan" that can control the whole car from unlocking your doors, to turning off individual injectors. I also have a Mitchell On Demand and All Data account at my disposal. Pretty handy stuff.

[MindWebs]

multiple types but very nice!!

http://www.amazon.com/Version-Blueto...+327+bluetooth

http://www.amazon.com/iSaddle-Blueto...+327+bluetooth

yes they do require a "smart phone" or tablet with wifi and bluetooth.

there are free programs available, to check codes and reset faults.

have used them for 3-4 years now. great little tools. and cheap!!!

[ViperRon]

TC I do understand about how hard it is to get to plugs and wires. I have a 2.5 Chrysler that I have to remove the intake to do wires or plugs on 3 cylinders. But if that is what had to be done to check for a miss I would. Those diagnostic testers are great at pointing to a problem but it still comes down to interpreting what it tells you. I had assumed you had checked wires and plugs first after a misfire error code. I will suggest that if your Oxygen sensors are over 50K miles you think about checking/replacing them because the burn on those plugs is quite severe for 40K unless the ignition is running super hot (High voltage)or the fuel is super lean. Would not want the next troubleshooting to be a religious piston from lean mixture.

[trbig]

I did have it read at the auto store, and put the error codes in my FIRST POST

Sorry. Don't know how I missed that. All I have in defense is that sometimes I do drink in the evenings... lol. Glad you seem to have sorted it out.

[TopCatGr58]

The other good thing is that this has helped me to be able to diagnose the same type of error codes that I am having with my sister-in-law's 2002 Nissan Quest with a V-6. I'll be able to check the injectors, and hopefully they'll OHM out properly, and then it'll just be a matter of replacing the wires and possibly the dist. cap/rotor as well, we've already replaced the plugs recently.

T.C.

Sorry I didn't provide the followup on this issue...the S-I-L's Quest. IT DID have a bad injector....of course the one under the Intake Plenum assembly! Replaced "it"....she didn't have the funds to replace ALL of them, the other 2 in that side of the engine ohmed out correctly! After replacing the injector, AND the plug wire/dist. cap/rotor set(did that first but didn't resolve the issue/miss) it was again hitting on all 6.

Well that lasted about 6 months....was informed today by SWMBO that the S-I-L's Quest was again acting funny, missing and such!

This was after I had moved my mom in with me from Fla, and among the things she had was an OBD reader consumer level via CarMD.com. I had used it a year ago in Ala. to diagnose a bad O2 sensor on her Chrysler 300. Well, I used it on the Quest.....but it said that there were MULTIPLE misfires detected both at low and higher rpms levels! It said there were lots of possible reasons for the problem!

Well, since I had already replaced the plugs/wires/dist. cap/rotor I figured that it probably wasn't any of that! I pulled the plugs along the front bank that were easy to access...they all looked fine, no fouling! Because I had learned to OHM check the injectors....and that they had ~80+K miles and 13 years of age on them, and I could check the front bank the easiest, I went ahead and pulled the power caps and OHMed them. 2 were ~20 ohms, 1 was about 100 Ohms...and so I figured/guessed that it was probably fried. Pulled it, went to the local AutoZone, they had one in stock for only $89.00 , got it and installed it, hooked everything back up, and LUCKILY the engine ran correctly again hitting on all 6.

Just like before, when it was previously fixed, it has to run about 30 or so miles without registering any MORE error codes, and then the Check Engine light went out all by itself! SO...I'm expecting it to do it again. So it was a relatively easy fix this time....due to better familiarity with the possible problem, knowing the proper diagnostic technique, and then being able to apply the fix/solution. I just hope the other injectors last for a while before they also fail! WHEN I have to go and pull that intake plenum, I WILL be replacing the other 2 injectors when one of them goes bad!

T.C.

[3Phase]

Thank you for the follow-up!

I have a friend that has roughly the same problem with a Toyota V6 throwing p0301 through p0306 misfire codes left and right. I let him know what you've done, now I get to laugh and watch him playing "find the real fault!" and chasing 'puter codes while I put Columbo back together.

.

[jimbyjimb]

Nissans? Side-feed injectors? It's the ethanol. Because the body of a side feed injector rests in fuel 24/7 and that fuel has excess moisture due to the ethanol the bodies swell and open up the coil. I had a Q45 I sold not wanting to spend 800$/yr on injectors for. The new ones by now, aftermarket, should have fixed this issue. I believe Python are the brand.

Z cars had the same problem. It's a good injector design but ethanol kills them. That's if your Nissans are the old side feed style. I'm not sure what engines/years had side feed vs top feed.

[jimbyjimb]

Oh schnapps, looked up the parts. TC, next time you pull the plenum, because you will have to again mark my words, replace ALL injectors and try to find a company with a warranty that guarantees they are ethanol safe. That job is not worth doing 1 injector at a time. Or find a station with ethanol free gas.

Nicoclub.com is your Nissan/Infiniti everything forum. Lots of info compiled on this over there.

Damn side feeds. I would have kept that Q too. Nice car. Injectors dropped like flies.