Just changed out all the injectors on my son's 95 maxima because number 1 injector was bad. After I was done test drove the car, it was hard to start but after it started it ran like a dream, no misses and plenty of power. Parked the car and 2 hours later my son couldn't get it started. Very hard to start had to hold gas pedal to the floor and when it started ran ruff. I checked after I got it started and now the number 3 cylinder is misfiring, and it is not the coil. Could it have been a bad new injector our was there something I needed to do after installation?
It was a pain to take the plenum off and will check injectors at harness again before I go through disassembly again. any ideas as to this issue? 70.000 miles, new plugs, new #1 coil pack, all new injectors, new fuel filter, new air filter. and all advice or help is much appreciated.
Thanks John

 

Yes, it's entirely possible that one of your new injectors is bad. Been there, done that.
When you say new injectors, do you mean refurbished injectors from Ebay, or?

 

No ordered a new set from parts geek.

 

When installing injectors, it's best to put a very light coat of lubricating oil on the o-rings so the injector "pops" right in very easily with little resistance. Perhaps the o-ring is now damaged.

 

Did you buy this set of 6 for $80.95?
https://www.partsgeek.com/catalog/19...l_injector_kit

 

Yes they were hard to seat. used the metal cap and turned the screws on each side 3 turns or so at a time till seated. would that cause a fuel smell like flooded? and thank you for your fast response brother.
and yes that is the set

 

This is my 16 year old son's car, he saved and bought this for 2000 and it is in very good condition. I seen the car sit in a garage all winter every winter for 10 years, so when it came up for sell I told him he should buy it. all service records are there and thought it would make him a good car. so I'm worried that it might nickle and dime him to death.

 

Yes, you could have damaged the o-ring. They are not supposed to be hard to seat. They should slip right in with the help of a little lubricating oil. They way you described it by using the metal cap and tightening the screws, you essentially forced them in. This is not good! No tools needed, or force; they should pop right in with your own hands. Then install metal cap and screws.

Since that is the set you bought, my assumption is that those injectors were re-built or re manufactured at that price point. No way are you getting OEM injectors at that price point. Interested that they are labeled as "new". Perhaps they are knockoffs?

Now the Beck Arnley's at $68.99 each are more in line with OEM pricing for new injectors... FWIW, JECS are original equipment injectors for our cars.

Hopefully you just have a bad/damaged o-ring and not a faulty new injector.

 

I kept the old ones and all but one ohm-ed out to 10 to 12 only the #1 ohm-ed out to 0 so I should be able to use one of the old ones or at least the o-rings off it, correct? Man I hate that I have to take it all apart again. took me about 3 hour to do, maybe it will go faster next time. the worst part is it is #3 injector

 

Well, on the bright side, you're getting to know your son's car. You should be able to have that manifold off in less than an hour now.
The last thing you want to do is have to go back in there a third time. I would either run to your local parts store and see if they have a direct o-ring replacement, or buy an o-ring replacement kit from them. The kit should be less than $10. I suppose re-using an old o-ring is an option as Plan B, even an old good injector. Just be sure to pick the best one of the bunch and lubricate this time. And be sure to observe and take out the injector carefully as it may tell you that it was installed incorrectly and it's an o-ring issue. If there are no clues, there is still the chance the injector itself is bad.

More food for thought: If it's the injector and not the o-ring, you may want to consider taking a good known new injector from cylinders 2,4, or 6 and swap with cylinder 3. This may sound crazy, but if the problem persists, at least on your third attempt, the injector is a piece of cake to service.

 

Thank you so much, you have been very helpful to a old shade tree mechanic, Sure is a lot more involved than sanding and gaping some points, LOL. I'll post my results tomorrow when I'm done. Maybe it will help others.
Thanks again.

 

Just so you know next time, or even this time.....

Always replace the front 3 first and when they've proven to be working as they should, transfer them to the rear bank (carefully and lubed as The Wizard suggested) Then do the front three and make sure they are all functioning properly. Why? Because it's much easier to swap out the front 3 and replace malfunctioning new ones. Quite typical for Chinese manufactured Injectors. And you get to practice seating them properly and keeping the O-Rings intact.

If you find the #3 is bad, put a good one from the even bank in there and the replacement in the front, should it need to be replaced yet again.

Hope you replaced the rail hoses and clamps, injector seating grommets, the PCV Valve and Grommet, Knock sensor and Fuel Pressure Regulator while in there, so you can really be done for a good long while without having to go in again and deal with the gasket kits. Might also do the Valve Cover gaskets while there. You're already 2/3 of the way.

 

I had my injectors rebuilt by Injector RX in Houston.
They do a great job. They also provide the o rings.

I'm guessing that you did not oil the o rings before installing them. Lack of oil will cause the o ring to rub or catch inside the casting they are supposed to slide into. The o ring will rip or get distorted. That would cause an air leak, and starting difficulty.

You need to know that our cars have a tube from the intake manifold to the egr casting. It tends to clog over time, and would need to be cleaned.
That chore is difficult unless the intake manifold is removed. You might want to think about dealing with that if you need to remove the manifold. You should clean out the egr casting as well.

Be sure to check the knock sensor for cracks while you are in there anyway.. That's another possible issue which is much easier to deal with while the manifold is off.

All this might seem like a pita or fluster cluck.
I'm just mentioning this because it will need to be dealt with sooner or later. The car's mileage is low enough that you might not need to deal with this yet.

The intake manifold is one of the more difficult repair issues we encounter.

This is a good solid car once deferred maintainance issues are dealt with. Many of us have over 200,000 miles on ours. They are quite reliable as a daily driver. Your son's car has very low mileage. I'd say that you made a good decision buying the car.

The current injector issue seems to be due to a defective replacement injector or an installation error.

The car is over 20 years old. The injector's tend to leak at this age. Many of us have had this issue, and many more will. But once it's done, the car can be good for many, many more miles.
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Okay update, Like you stated the o-rings were cut in 4 of the six injectors. I replaced the o-rings lube them up and they seated with lite pressure from my fingers. Put everything back started car had white smoke at first and it cleared and then started to run rough again.
I coded the car and have P1320 code? So frustrating. But the injectors are good now. Ant advice for that code?

 

This is an oxygen sensor code.

I understand that you did not have this code before you removed the upper intake manifold again?

A possible other cause of this issue is an air leak.
Did you re-use the upper intake manifold to lower manifold gasket?

Re-check your work for any loose hoses or cracked ones.

Seems to me that you might have overlooked something during re-assembly. Quality control issue. Been there, done that. This is not exactly easy stuff. Hang in there.

 

Could have killed the O2 when running rich earlier. I know I've wiped one out quick on another car when I ran it super rich. Hard to say though.

 

Same thing happened to me 11 months ago, had bought all 6 injectors from rock auto. Once installed, It took a while for the car to start and then it started to misfire a bit with white smoke, had turned it off shortly after. The Injectors came in faulty and needed to be spray tested to make sure the spray pattern is correct. Remember who knows how long those injectors have sat.

 

Good point.

I'm going to guess that the oxygen sensors might be reporting the previous over-fueling issue. If I'm right, the ecu might react to that by creating a mixture which is too lean. That would mean stumbling and missing.

Perhaps the issue will go away once the car has been driven a bit. Dont drive it for too long though, or it might harm the cat.

 

However, I have driven it misfiring a bit for 20 miles or so after the Injectors were installed without white smoke coming out from the exhaust in hopes it would smoothen out but never did. May of have damaged the Catalytic a bit but nearly a year later, it's still working. Also draining the gas from the cylinders is recommended as well. Oil change..coolant change too..

It was smooth for maybe 10-20 mins but then eventually it started to misfire again and CEL came back on after the computer does drive cycles. I was so confused. Mind ya, I had to go back 3 times before It was all corrected.

I never advise driving it if white smoke is coming out. Also had replaced both o2 sensors at the time as well as they were both running rich..

 

I thought that P1320 is the primary ignition fault??

 

It is, and nothing to do with the O2 sensors as previously mentioned.

It is possible for this code to be present in an active state (stored as an active DTC), without there being misfires present on the engine. I would clear the code and see if it comes back.

How is the max running now?

 

still having miss fire. : ( ,also cleared old codes, and the P1320 showed up.
I think I need to test the other coil packs.

 

Well.... it appears that I gave the wrong information.

I looked this code up myself, saw incorrect information, and ran with it.

My red faced apology.

Oops.

 

I wouldn't sweat it JvG, you were just trying to help.

 

JvG it's all good brother.

 

Can anyone tell me the pins I use in the injector plug in the wire harness I believe it has two rows of 4, to test the 1-3-5 injectors also what pins do I use to ohm the coil packs.
Thanks again update I found the injector test pattern on another post, pins 1-4 top row pin 5-8 bottom row injector 1 is pin 1 and pin 2, injector 3 is pin 1 and pin 6, injector 5 is pin 1 and 5. The plug is located
on the passenger side of the wire harness on top of the engine fire wall side. It is a grey plug on my maxima. still need advise on testing coil packs.

 

UPDATE Okay so today I tested thew coil packs and the injectors again and all tested good. I the started the car of coarse running rough, I pulled the #2 coil pack plug and no change pulled the #6 and same thing no change. All
other cylinders made a difference when unplug.
I pulled the #2 and #6 injectors to find that the o-rings were damaged. I installed the old o-rings and car ran better, but still not as it should. New code is P0300. I believe that I still have issues with those two injectors o-rings, so I ordered new O-rings and will keep you posted.

Thanks

 

P0300 is the generic misfire code. Keep clearing the code and with any luck you'll get a specific code like 0302, 0303 etc that will pinpoint exactly which cylinder is giving you problems.

 

Case and point made in my post above, and lucky you, 2 and 6 were the two O Rings damaged and not 1, 3 or 5.

Hopefully you paid attention to changing the 6 injector grommets, and other parts I recommended too.

 

Yeah dont do that. I had a mechanic who did that to my car and I had to take apart my engine to fix his mistake. Put the injector in the rail and then push on it with your thumb and twisting lightly back and forth till it sits in.

 

changed out the o-rings and all is good there, but still have a miss. Codes are P1320 and P0300 I checked everything and all tested good but still no difference on #1 when coil pack unplugged. switched coil packs and same thing same location. Injector Ohm's out good.
Is it possible that the o-ring on that one failed, It did seat fine with only finger pressure. Or could it be something else. It has no hesitation at all when reeving but at idle it runs rough, feel it more in gear.. Thanks John

 

So you confirmed that the cylinder which misses has spark as tecall.

I would disconnect the connection for the fuel injector.
I imagine there would be no diffence, it would still miss.
If so, either the injector is diffective, or the connection is not getting power.

The next step would involve switching the questionable injector with the one next to it. if the problem then moves to the previously good cylinder, the injector is bad. If the previously mis sing cylinder now fires properly, we know the connector is providing power., and the spark plug fires.

Should the cylinder STILL misfires afterwards, either the connector is not getting power, or there might be a compression issue.

Compression issues would be unlikely on our engines. Especially on an engine with only 70k on it.


to

 

Okay The #1 injector o-ring was torn again. I can not seem to get it to go in with hand pressure. Put another o-ring on it oiled it up and tried to seat it, got in only half way so I gently used the cap and screws to seat
it the rest of the way. Now I have no codes after test drive, seems to be running fine. I'll see how it starts after it cools down to insure it isn't flooding. One other question in the mean time, I noticed that the intake filled with gas while the injector was out, I removed all the gas I could before I put everything back together. I didn't notice that the other times, could that lead to the cylinder flooding and can it get into the crank case, IE should I change the oil?
Thanks for you patience through all this. also is it possible that an o-ring could be damaged enough to not cause a miss fire but allow gas to bleed through when engine is off? I'll post again in a couple of hours.
Update Okay with engine cooled down it will not start unless I push the gas pedal down. seems to run fine other wise. any thoughts???

 

The diaphragm in the fuel presume regulator can leak gasoline into its vaccum line, then into the engine. This would cause loss of fuel pressue, starting difficulty, and excess emissions.

remove the it's vaccum line, then sniff it for gasoline fumes. It the vacuum line might drip gasoline . If you see those issues, replace the fpr.

I'm gueasing that you might still have injector o ring issues.

I dip a paper towel in engine oil. Then I rub the oil into the hole where the injector will be shoved. I also oil the injector o rings generously. Failure to do this rips o rings.

I gently tap the injector in to place by placing a small block of wood or plastic on the injector, then tap the wood or plastic item with a hammer untIll seated.

I would definitely change the oil. It's contamunated with gasoline now. use cheap oil until you are sure that there are no more injector or fpr leaks.

 

Do a process of elimination. Double-check the electrical connector to the injector. If that's not it, then you will need to rule out that #3 injector. I would pull the upper intake and replace the injector, just to rule it out. Maybe get a lower cost injector from RockAuto. (I always keep a spare injector on hand for such purposes).. Its probably unlikely that the fuel filter in the injector is clogged, but its possible. Did you replace the main fuel filter after replacing the injectors before starting the car?

Note, when you install the injector, be sure to use plenty of oil on the o-rings, and pop it in by hand. don't use pliers or a hammer or you will risk damaging the o-rings (speaking from experience). You need to wiggle it and push hard by hand to pop it in. It will pop in, gotta push hard.

Don't be discouraged about removing that upper intake manifold. I can have mine off in 35 minutes (first time took half a day). A few tricks to make it easier: I replaced those 2 bolts on the back of intake manifold (near the firewall) with socket head (allen) bolts. Makes it much easier to remove and install. I also decided not to hook up that throttle body heater, and simply replaced those small coolant hoses with a long hose. The throttle body heater appears to also activate a thermal plunger which pushes the idle up high when cold. (my car is calif emissions, not sure if this device is on the fed cars) I disabled that by bending the cam on the throttle cable pulley away from it. Car starts and runs just fine without it even in the dead of winter I also put a longer hose extension on that 180 degree hose on the egr cooler on the back of the manifold. . These things give me more room to lift and swing up the manifold toward the firewall without disconnecting the little hoses. Also, upon install, I know that egr tube is a pain, but when installing the upper intake, put the egr bolts in last. I know it takes a little patience and finesse to get that gasket in there, but it can be done. I usually start with one bolt through the egr tube flange and through one hole on the gasket, get that bolt started, then swing that gasket up in place to put the other bolt through.

One more thing, while you have it apart, replace the fuel pressure regulator. Its attached to the rack, looks like a flying saucer with a vac hose attached. Be REALLY carefull taking out the old screws, many stories of guys stripping the phillps head out. It can be done, just make sure you got a good bite with a good quality phillps and push in hard before turning. They are the same screws that are used on the injection caps. I've heard some guys also replace those screws with socket head screws. Use a little never seaze when you reinstall.

 

Still working on issue will keep you posted. Thanks for the help everyone. Still have to hold throttle wide open to start, but doesn't sound like it is missing. runs great, gas mileage is good, coded out for a knock sensor, new one on the way with cable.
Is ti possible that the gasket on the tube with the two bolts near firewall drivers side fell out? would that cause the starting issue?

 

You may have idle or drive-ability issues w/o that gasket, but not starting issues. Sounds to me like you still have flooding injector issues. Once you have your o-ring situation figured out and 100% confidence that are installed correctly, don't rule out that one or more of those generic injectors you bought may be garbage.

 

I was afraid that one of the o-rings might still be bad, could it be torn enough to bleed down but not enough to cause a miss?

 

Most definitely. It's still "missing" as you drive down the road, but it's so slight that the ECU can compensate for it and you don't notice it. But at start up, the overwhelming amount of additional fuel that has pooled up is not within the acceptable range, and therefore starting issues.

 

If the egr tube gasket were missing, the car would start, and run very rough / missfire at idle, and you would hear a fairly loud hissing sound coming from that area due to maifold vaccum loss. (don't ask me how I know this )

I agree with other posters in this thread, you gotta rule out the injectors. Suspect fueling starvation issue, esp since you need to floor it to start it. Did you change the fuel filter?

If it were me, I'd be inclined to shoot some starting fluid/ether into the intake, then attempt to start without touching the accelerator pedal. If the engine fires immediately, then you know it's a fuel starvation issue.