Reading the threads here on the P0087 DTC's. I'm having a intermittent issue where the engine is running smoothly as a sewing machine and then suddenly, it starts "chugging". It happens as I'm driving home and placing it in reverse to back into my garage. When I get out of the car my garage smells like gasoline with smoke residue also. Scanner displays P0087 (low fuel rail pressure), P0300 (random misfire detected and P0304 (cylinder #4 misfire).

I first replaced the high pressure fuel pump plunger/bucket. The original bucket was not damaged and the cam lobe looked normal without any visible wear and seemed to be getting good lubrication. I cleared the codes, cycle started it 2-3 times and the engine ran normal again for about 500 miles and the issues comes back.

Then I replaced the relay on the left side panel under the hood. Cleared the codes and the engine ran normal again for about 500 miles and the issues comes back again.

This engine had the timing chain recall performed on it at about 85K, it now has 120K. Any thoughts would be surely appreciated.

Your problem is at the #4 cylinder. It's either:
1. A bad coilpack
2. Bad spark plug
3. Your injector staying open

The first 2 possibilities are quite easy to confirm & troubleshoot. Switch the #4 spark plug and/or coilpack with one or 2 other cylinders and see if the problem persists as P0304 or if it moves to a different cylinder.


For example, I'd switch the spark plugs between cylinders #4 and #2.
Then switch the coilpacks between #4 and #6.
Keep in mind that the last coilpack on each bank (cylinder #7 and #8) are different than the other 6.

If the P0304 code goes away and becomes P0302, then the spark plug was the issue.
If the P0304 code goes away and becomes P0306, then the coilpack was the issue.
If the P0304 code stays, then more than likely you have a faulty fuel injector. An injector stuck open would result in low fuel rail pressure.

I start with the simple checks and advance to professional help as I become limited in skill, tool or time.

This is great advise! I will attempt to do this during the weekend if time permits but at least I have a starting point. Thank you and I'll post with the results.

Have you run a can of SeaFoam through the fuel system? I had never used it before my first Infiniti, and learned about it on this site. I add a can just before filling up at the gas station when I'm having issues. It is amazing on how it cleans up fuel delivery issues in Infiniti's.

I did an upper engine/intake clean with the SeaFoam stuff (2-cans) a couple of months ago when I installed my dual oil catch cans along with replacing both PCV's.

With the mileage on it, and having to remove the intake manifold anyway, I'm going to replace all the Injectors, all the coil packs, spark plugs and the 8-intake gaskets.

I'm hoping that will eliminate to issue. If not, I may have to replace the high pressure fuel pump which cost between $800-$1,400.

Unless someone has a cheaper or experienced suggestion, that's what I do and keep my fingers crossed.

C6Joe1957 wrote: ↑

Sat Oct 10, 2020 4:27 pm

Unless someone has a cheaper or experienced suggestion, that's what I do and keep my fingers crossed

I feel like my suggestion is as cheap as it gets. You are using parts that you already have and are only moving them around.
The intake manifold does not need to be removed to address the coil packs or spark plugs at all.
If you were to get to the injector, sure!

With the mileage on it, and having to remove the intake manifold anyway, I'm going to replace all the Injectors, all the coil packs, spark plugs and the 8-intake gaskets.

From experience, I'll tell you that yes, spark plugs are a wear item...eventually. Coil packs and injectors aren't, and I recommend you don't mess with them unless you are willing to install proper good quality replacements (OEM is usually the best for stock cars). If you install substandard parts, you might end up with way more issues to chase down.

I'm hoping that will eliminate to issue. If not, I may have to replace the high pressure fuel pump which cost between $800-$1,400.

Once again, if you started replacing parts without narrowing the issue down, you are just throwing parts at it.

I suggested the coilpack - spark plug troubleshooting method because I figured it wouldn't take too long, plus it's free. I assumed you were attempting to do this yourself, with the main intention being to save some money like most of us do. Throwing parts and crossing your fingers is counterproductive in that sense.

I'm not saying that it is guaranteed to not be an issue under the manifold. If you troubleshot it, you might in fact end up right there.
However, why replace 7 coil packs, and 7 injectors that you didn't have to?
What if you replace all those -plus the HPFP- and find that the issue is in the cylinder itself or in the ECU?

If you prefer to not troubleshoot it like I had suggested and you are willing to throw money at the engine in random parts, it might be prudent to just take it to Infiniti for a diagnosis. Of course you don't have to have them fix it, but for approx $150, they'll usually come back to you with the fault pinpointed.
It saves you time & money in the long run.

If you had the oil jet/timing chain recall work performed at 85K miles, the HPFP lifter bucket was already changed, as that was on the list of parts to be replaced. That would explain why the bucket looked ok. If you're at 120k and those spark plugs are original, yeah I would change them for sure, as you're past the recommended mileage for that item. Then drive it for a while and see it that helps with the misfire issue. If it doesn't then do as EdBwoy recommended; swap coil packs.

Thanks again for the advise by all, unfortunately this past weekend I was unable to perform any of the test do to call ins at work. I have ordered 1 OEM coil pack, a complete set of 8 OEM spark plugs and 1 EOM direct fuel injector just in case.

The previous owner took meticulous care of the car and gave me a manila folder with all services records that is about 1-inch thick but I could not find any reference of the sparks plugs being replaced. So when the new parts arrive, I'll swap the spark plugs between cylinders #4 and #2. Then switch the coil packs between #4 and #6. Hopefully that will reveal what my issue is and I'll be ready to make the repair.

I'll do the test and report back mind findings, what was needed and the results. BTW, EdBwoy, your YouTube M videos are amazing and helpful! Thank you all.

Update.

I moved the #4 cylinder coil pack to #6 cylinder along with swapping #4 spark plug with #2 and cleared all DTC's. Upon startup, the engine chugged so I shut it down. The scanner read P0306 which is cylinder #6 misfire. So I crossed my fingers and removed the switched coil pack from #6 cylinder and replaced it with the new coil pack and Walla!

The engine started up normally with a high, 1300 rpms instead of "chugging" which was promising, but at the same time blowing out of the exhaust pipes, was a heavy and smelly white smoke from the residue of the excess unburnt fuel.

Once the fuel residue burned off, the engine idled normally at 750 rpms and so I took the M out for a 25-mile rip from my house and onto the freeway and back.

The engine ran perfect and normal as before the issue with full power and so now I can drive it to work tomorrow.

I want to thank everyone here and especially EdBwoy for your advise. You got to love a happy ending.

Great news and good troubleshooting - glad to hear you've resolved the idle/power issues. Quick question, I see you are from Olympia - are you in Olympia, WA? I'm in that same area.

kmiles wrote: ↑

Mon Oct 19, 2020 1:51 pm

Great news and good troubleshooting - glad to hear you've resolved the idle/power issues. Quick question, I see you are from Olympia - are you in Olympia, WA? I'm in that same area.

Yes, I live in Oly, WA. I've seen a couple of M's around where I live but never get the chance to chat.

You're welcome, and I'm glad you're back on the road and can use the car to commute in confidence again.

Please keep us updated if anything funky happens. I am especially very curious about the low fuel rail pressure code.

***
Also, what was your opinion of the 2 spark plugs you removed to switch around?

EdBwoy wrote: ↑

Tue Oct 20, 2020 1:24 pm

I am especially very curious about the low fuel rail pressure code.
***
Also, what was your opinion of the 2 spark plugs you removed to switch around?

After changing out all the spark plugs and the faulty #4 coil pack, I cleared the DTC's after the initial start where the engine ran normal again. After the test drive there were no DTC's. So, I'm a bit puzzled too as to why the 087 code showed before?

As for the spark plugs, almost all the plugs were at a smaller gap after removal. .038-inch verses .044-inch. They looked okay so I think they might have been newer than I thought and also, it did not take much effort to unscrew them from the well when removed.

I wasn't sure if you had had enough time to cover the 500-ish miles it previously took the car to exhibit those symptoms.

Anyway, if the codes have gone away, then it's all good. Well, mostly.
I would need to verify exactly how the M56 is programmed, but it seems to be running on "if in doubt, flood it out" logic. Basically, if the coilpack was firing as it was being asked to, but the o2 sensor was still reading a lean mixture, then that bank might have been forced to dump more fuel to compensate.

If excessive and over a long enough time, then it is possible that the fuel rail pressure could drop below some predetermined range and throw the low pressure code.
That's the part I was curious about - Is the pressure lower because the source isn't feeding fast enough, or because the rail is being depleted too fast? If the issue is excessive dumping, that could be a catalytic converter killer.

Reading fuel trims might be quite beneficial to check out the system behavior & history.

This is neither here nor there, but as a matter of principle, I don't erase my codes. I correct the problem and use the code reader only to watch.

EdBwoy wrote: ↑

Thu Oct 22, 2020 9:41 am

That's the part I was curious about - Is the pressure lower because the source isn't feeding fast enough, or because the rail is being depleted too fast? If the issue is excessive dumping, that could be a catalytic converter killer.

Thanks again for your feedback. I'm now curious also in what you are saying in that it could be a catalytic converter killer. During my research to find a cause for my issue, I found references about the fouling of primary up stream and secondary down stream O2 sensors.

Could there be a correlation?