hey!

working on my 99 Max -

its throwing a 0303 (cylinder 3 misife) and a 1320 (ignition signal primary circuit malfunction).

sure enough, cylinder 3 is misfiring - in fact, it doesn't seem to be firing at all. if i unplug the coil while the car is running, absolutely nothing happens.

tried:

swapping coils with cylinder 1. no change. the coil from cylinder 3 did have some oil on the tip that fits over the spark plug....
changed spark plug cylinder 3 (old one looked pretty black/maybe fouled). no change.

the exhaust from the car does not look weird/white or anything. but it is definitely running pretty rough.

now, i would suspect the injectors, but i changed them about....20-30k miles ago. im thinking its the injector because if the injector were working but there was no spark, id have a funny looking exhaust, correct? whereas a good spark but no fuel injected into the cylinder might not show up at the tailpipe. am i conceptualizing that correctly?

any thoughts would be much appreciated. man i hope i dont have to replace that injector again. what a pain in the ***.

Check that there is power going to the coil at the harness

After you swapped coilpacks from cylinder 1 to 3, you erased the codes, right? And cylinder 3 popped up again?

ya - codes erased, p0303 keeps comin up

which pins on the harness should be getting +V?

Regardless of how the exhaust looks, does it have a raw fuel smell at all?

Also, unplug and reconnect the #3 injector harness connector at least three (3) consecutively.

Maybe do the same for all cylinders.

Don’t ask … just do it.

i dont think i sense much of a raw fuel smell....but maybe my nose is not sensitive enough to that. it smells like exhaust! and maybe a little bit gasoline-y....but hard to say

otherwise, update:

i did not yet try plugging/unplugging all harnessed, but i will say in the process of troubleshooting this ive unplugged coils 1 & 3 a fair number of times with no results (except unplugging coil 1 affects RPMS and unplugging coil 3 does nothing).

i did, however, do a little funky test with a continuity tester. hooked it up to ground, took coil 3 out of the valve, leaving it plugged in, and used the continuity tester to see if i got a spark. sure enough, with the engine running, coil 3 will gimme a little spark when i bring the continuity tester close to it. it does not seem super strong, but it's there. tried the same with coil 1 and got about the same strength spark. so that means coil 3 is likely OK, as is the wiring harness - correct?

i am thinking my two options are - try to get a set of OEM coils and see if that does the trick (even if coil 3 'works' it may not be giving a good enough spark). ive heard many times that maxima coils have all sorts of weird problems, so maybe a new set is a good place ot start. because if thats not it, i move on to option 2, fuel injector replacement. which will be a HUGE pain in the ***........

any thoughts??

Wouldn't hurt to get a good used OEM coilpack from the jy and see if the issue goes away b4 diving into the fuel injector. My hunch though, is that your issue lies with the fuel injector. Hopefully you got some nice JECS injectors in there...

sounds good - will check the pick and pull....

if my maxima is a 1999, should i check for infiniti's too? are the coils the same part? which infinit make/model aligns with a 99 max, if any?

well got lucky at the pick and pull!

found a nice, beat-up 97 max. the hood was broken and i was able to prop it all the way up so it was easier to access. got 6 OE coils - all look in OK shape.

i tried replacing just the cylinder 3 coil - no change. damn. going to replace all 6 (they are Densos in there now) and see what happens!

seems so odd that the injector would be totally dead, not long after being replaced.......

I have the same issue, but with cylinder 2( so easier to mess with than yours

any updated?
how does ur car run? Cus i wouldnt have known anything was wrong with mine if it wasnt for the code... but same thing I pull the connector and it doesn't affect the rpms. But mine wasn't the injector either, swapped with cylinder 4, along with coil pack, and sparkplug.

Still on the hunt, u?

I've heard from a friend at Nissan that when one coil pack goes they tend to domino. Personally I have had to replace 3 different coil packs in the last 6-8 weeks. You can also do an ohms test on each coil pack as well as testing the electrical coming to the pack try try and isolate the bad ones. The video below details both. I believe he also checks the condenser. Hope this helps