need help please!

car= 1997 Nissan Maxima

symptom= diag code Cyl #1 misfire...only under load(slight uphill drive or mid range acceleration)

have dones= coil swap(remained cyl #1 after test drive), plug replace X6, injector replace(new), intake mani gask replace(new)

same "symptom" before and after all "have dones"
help me out guys im stumped!
thanks
B

 

Check compression

 

tech2000-
sorry i did not include that in my have dones.
i did simple comparison compression test cyl 1 compared to neighboring and adjacent.
compression is not the issue. excellent suggestion based on my given info though thank you. any other ideas?
ty
B

 

Com'On guys i need some suggestive brain storming! help a brother out

 

Other things that can lead to this problem.

Faulty Computer
Coil or Coil Packs
Crank or Cam sensors
Faulty O2 (Oxygen) Sensors

 

maximus909-
wouldnt crank/cam/o2 sensors throw a separate code?

 

It would, but sometime the crank sensor will have intermediate problems. Have you tried just power off the ECU? also you would need to possibly trace a bad connection to the ECU.

 

yeah i have disconnected the batt terms and also used my scan tool to reset code/ecu.
it seems like a fuel issue the way its only under load. correct me if im wrong but if it were to be pump/filter related it would more so be a random misfire because of lack of pressure to entire fuel rail? crank sensor... adjusting to timing of spark i get...but again a full random misfire i feel like because all cylinder timing would be effected. thank you for the debate. its makeing me think harder

 

Are your plugs NGK?

 

ngk platinum laser blah blah sumthin sumthin...gapped at .044
10$ a piece is all i really remember hahaha

 

How clean are the electrical contacts to the coil on thar cylinder?

 

coil has been eliminated...read code, swapped two coils, cleared code, test drive, read code= same

 

Check the connector harness for the coil packs, or injectors could be corroded. Also did you check for vacuum leaks?

 

have dones= coil swap(remained cyl #1 after test drive), plug replace X6, injector replace(new), intake mani gask replace(new)

the harness is in great condition. no corrosion no loose wires

 

Please check the grounding wires for the injectors. They are attached to the engine with screws. Chances are that you will find oxidation there. Clean with fine sandpaper.

 

get some starter fluid/brake cleaner and spray it towards your throttle body and have someone start your car in the process.

 

Well my 98 just started doing this with #1 Cyl throwing a primary coil code, So I'm going to try Some NGK coils, I know the Hitachi's are the OEM but I'm curious about the NGK and I'm sure they'll perform even better than the Hitachi(s). Rockauto offers the Hitachi with a 1 yr/12,000 mile warranty, while the NGK offer a 3 yr/36,000 mile warranty...I'm going perform a compression test and check everything that I can, first being the crank sensor or the Crank pulley interrupter stubs that break the magnetic field of the crankshaft sensor....If it's continually the same cylinder no matter what I'm pointing my attention to the Crank dampner first....I'll update you folks of the findings.

 

CMax, are you just bringing ack an old thread which you feel is similar to your current issue regarding coil for #1?

I would want to investigate the electrical resistance of the wires leading to coil #1. Also continuity.

A bit of corrosion at a contact can increase the ohms resistance. That could trigger the code for
# 1 all by its self. Or it's possible that a wire harness has some damage which causes it to leak power where we don't want it, there will not be a strong enough spark to fire the plug consisantly. Especially when the engine is under load.


Is the problem worse on a moist day, or after a rainstorm the next day? If so, I have a story for you.

Question: Do all the spark plug electrodes look brownish, not blackish, and no greasy oily crusty ones, especially on #1?
​​​​​
I feel that you have isolated the problem to something between the ecu and a good coil and spark plug. So since the coil and plug are good, there is no point buying new. Especially not 6 new.

I would look at the contacts in the plug which attaches to coil 1. Make sure it is clean. Then if you still have problems, what appears to be left is the wires from the coil to the ecu. Or perhaps issues in the ecu it's self.

 

Yes I realize it's an old thread...The Spark plugs are all burning pale chocolate brown which perfect but the rpm drop per cylinder is pretty low @ #1 cylinder. I'll check the Connectors resistance or signal voltage but when I swapped the coil pack the problem moved with the coil pack so I'm kinda sure it's the coil pack #3 was faulty originally so I swapped #1 & #3 now #1 is the issue...I'll swap #1 & #5 and see if the issue is now at #5. I've had this Free Car for 7 yrs now and I'll test the coils (spark plugs are new) but the E3's I removed must've had .080 gap from the wear/erosion over a 7 year period and may have over strained all the coil packs trying to jump that spark gap. Weather doesn't affect the way the car runs, only a little load such as idle, with the a/c "On" and barely noticeable during idle in park....But I know I'm getting a few missed ignition events looking my timing light via the connector pigtails....So there's two cylinders I'm watching and I'm really thinking it's coil pack degradation #1 and now #4...So I'll do a few test and make that decision before this week is up...

 

CMax, I'm an older guy, 64.

I'm trying to follow along, however breaking up your sentences into paragraphs would help. Your discripion of moving coils around is as hard to follow as the whack a mole game. Lol. No offense intended.

You need to take ohm readings of your coils. That would tell about their health status. Perhaps you only need to buy one coil, or no coil.

You mentioned that you want to run a voltage test. Keep in mind, voltage alone is not all that is needed to fire the plug.

Voltage is similar to garden hose pressure.Like a garden hose, pressure is not all you want. You also want volume. Which is similar to miliamps. Because too few miliamps, but at the right voltage, would cause your miss. The plug would fire some of the time, but not all the time, like when under load.
The ohms reading, resistance measures how much flow we have like how much water comes from a he hose, at what pressure.

Should all coils read ok, the problem could be in the supply wire to the coil from the ecu, I would think.

A compression reading done while the throttle body is wide open would be helpful.

 

You couldn't follow me swapping coilpacks #1 and #3? The problem was originally @ the #3 cylinder now it's at #1 cylinder...That's obviously a coilpack...
I've taken readings of all the coil installed and in my inventory...They all appear to be good, I'll measure the voltage, amperage, and resistance of each connector and it's wire back to the ECU...
I'll get on it and fix it I thought I would see who all has tried the NGK coilpacks?

 

Cmax, I just had the same issue. I bought all 6 coils in a kit on partsgeek.com for $95.95 and just replaced them all, it was time.... #3 Cylinder was DEAD and after replacing coils and plugs, needed it anyhow, the beast is back to runnin great again... The 95s are notorious for #3 coil going bad. because of the heat from the intake plenum I suppose..... I have not tried the NK Coils but the ones I bought have 3 year warranty... https://www.partsgeek.com/ss/?i=1&ss...Y-K3&x=13&y=21

 

Yeah I believed I had a bad coil pack (C.O.P.) as well since when I moved it to another cylinder the problem transferred as well...I could barely find a 4th Gen in the 3 LKQ yards in Houston and decide to go to some salvage yards near Austin...and eventually found a gold mine...a 99 with what appears to be a new or newly rebuilt motor in it with 6 brand new C.O.P.'s (Hitachi), I'd tested them all and wow the numbers looked great! Tested my vehicles C.O.P.'s and found the #1 Coil over plug to test good when cold and the fail once warmed up....Replace #1 with Good used coil pack (C.O.P.) and problem's gone!!!! A/c On, In Drive, In Reverse, Not one freakin problem! So once I got back to my work apartment I changed the remaining 5 with the Good used C.O.P.'s, I'd found earlier that day and I'm all good to go....

 

Glad that you finally solved your issue.

One normally tests coils when cold, so they would have tested fine. Only to fail once the car is up to temperature. This is the kind of thing which drives us diy guys nuts.

I learned something new today. Might be useful some day.

Thanks again!

Th

 

I got plenty of spares to use as Lab Test monkeys, or as spares to carry in trunk along with that small box of Backup belts, coolant hoses, assorted of fuses and hdw. Just in case I run into any issues I got enough to save myself from being stranded in the middle of Nowhere, Tx...I had a neighbor tell something regarding Nissan versus Honda reliability...I'll start as a thread in The General section...

 

I can relate. I like to go on long drives into remote areas as well. Rather than carry extra belts and hoses, I replaced every single hose in the car. The radiator and water pump has been replaced as well.
Our cars requre that the front end is raised to work out the air bubbles so that it will cool properly.
Kind of hard to do when a hose breaks on level ground at the corner of tule and plumb.

I also replaced both belts. I monitor the belts and hoses from time to time.

I prefer to work on the car at my convenience.
Not when it breaks down at its convience.