Any Ideas to why/how this is happening?

 

Maybe a bad ignition switch.

 

When did it start doing this? Did you do anything to the car? Did anything happen to the car? Did you have anything done to the car?

We need at least some details.

How long does it stay running? If you put the key back in and jiggle it around, does it turn off? Can you drive it while it's doing this (short of the steering lock)? Do you have any aftermarket electronics in your car, most notably a remote start?

All of this is information that really should be provided.

 

This started just after my car died on my way to school, 2 weeks ago...apparently one of the injectors was pouring gas into one of my cylinders causing the engine to fuel-lock.
No aftermarket electrical stuff; the last mod I did was the NRP spacers on the manifold...to which I had to bend the ignition harness out the way(maybe the harness is damaged?) but that was about 2 months ago, and the car just recently went to $hit on me when that injector lost its small O ring and the gas kept flooding the cylinder.
The Nissan dealership says that the REF ckps may have shorted the ECU...would the ECU have any part in telling the car to shut off?
If I step on the gas after I pull the key out, it starves the engine because it opens the throttles body, so a lot more oxygen but the fuel stays the same, a minimal amount of fuel. So the injectors seem to keep injecting fuel just a little bit after I pull the key out, and the spark plugs keep firing as if they are not being told to stop.

 

Most of the power is (rather, should be) shut off from the ECU when the key is turned off. The only thing left then should be backup power, which shouldn't let the engine run.

So it doesn't rev at all (or very little)?

Does it do this every time, or it easily reproducible?

 

It does not rev at all, just stays at a very unstable and weak idle, until I either push the gas pedal or pop the clutch in 1st to kill it.
It has done it every time so far after I got it to run again, except 1 time when it actually did shut off, but did not shut off like it should, meaning it took about 4-5 seconds after I pulled the key out to shut off completely. But every other time it just stays on at a very rough 450 rpm idle.

 

bump any more thoughts? Is my ECU responsible for the spark timing and what not?

 

Yes, the ECU is responsible for running the engine.

Again, if you mess with the key, does it stop at all?

 

Okay, I started it up, then turned it off, and it killed it! So I tried it again-same thing. This was while it was parked. I thought I'd take it for a spin around my block. (Idle isn't as rough as before but still pretty rough to where the engine shaked the exhaust pipes and I can hear it shaking where the Y pipe has the flex section attached to the engine, it rattles pretty bad when I turned it off.) When I parked it again and tried to turn it of, it stayed on...and I jiggled the key it does nothing to turn it off, so I floored it to kill it.
So it's good that it turned off before I took it for the drive, but whenever it did turn off, it rattles the exhaust.
Any ideas?

 

sounds like it isn't timed right or it's misfiring also.

 

I pulled 3 codes:
0603
1302
and that 1403 again...
This time I pulled no REF CKPS code...
Cylinder 6 is the one that flooded in the first place.

 

Swapped the 6 cyl coil pack with 4 cyl, reset ECU and took another ride around the block. Now I pull 2 more codes, with the same 1403 code:
0201-Primary Ignition Signal (1302, maybe my EGI harnes is ****ed up, would that short the ecu?)
and
0701-multi cyl misfire

Any help here?

 

its a 99'...

 

Did you re-ground your Upper Intake Manifold? (two wires at the front of the UIM)

I didn't and had a similar issue (meaning same CEL's).

 

Ya...I did ground the uim...BTW, when i turn the key off, and press the gas, the engine wanna die. But if I turn the key back to the on position again, while the engine is still "running", and it lets me hit full throttle if I want to...
I'm thinking that my EGI harness might be damaged, no? And that might have messed up the ECU.

 

off topic...why is Ford advertising on this forum? Anyone gonna trade their Maxima for a mustang

 

Could it be deiseling? leaky injectors plus lots of carbon deposits??

 

asand1-I think that when engine diesels it eventually stops once the fuel inside is burned off. This keeps going until I drop the clutch or gas it to open the throttle. Thanks for the possibility though

 

Exactly my thoughts.

 

Quoted from Wikipedia:
"An automobile engine that is dieseling will typically sputter then gradually stop rather than continue running as if the engine was not switched off at all — the latter would usually indicate an electrical fault."
So my electrical is all messed up somehow...great
I'm initially waiting for a CKPS REF to come in the mail and put that on to see how it goes. I initially just threw that code p1335, but now I have all these other codes...feels kinda intimidating...

 

Okay sooo...
After swapping the coil pack from cylinder 6 to cylinder 4 and vice versa, I am still throwing a cylinder 6 misfire...which means it is misfiring for reasons other than a bad coil pack. Any ideas what could be doing this, could the harness be broken? What other possibilities?

 

Okay changed the oil, there was HELLA fuel in it; it almost had the consistency of water
Put some Mobil 10w30 in it and now it runs okay, and when I take the key out it kills the engine again like it's supposed to
thanks.

 

Can I assume you'll keep an eye on that oil for awhile? You may have a leaking injector.

 

She ran pretty good for about 3 days, now it won't start...I remember that the last time I started her up, I had to crank the engine over about 6-7 times just to get it running..now it won't at all..
one time I had to wiggle the ecu harness to get it running, wonder whats goin on now? I pulled a 0101 camshaft sensor code. great.
So I measure infinite resistance across the sensor, so that means that the sensor is bad right? It seems so simple device I don't see how it can go bad.
Could this be the reason no start?

 

This maybe unrelated but did you check the oil for fuel again?

 

How do i check for fuel in the oil? just by smelling it? The oil smells like oil not like gas.

 

Based on your earlier post I assumed you knew how to do that but if you had the correct amount 3 days ago and now the lever is higher then you certainly have something getting into the cranckase. Certainly if it is fuel it should smell like gasoline and if it were coolant it usually creates a frothy mess.

Perhaps a bit more on point, I have noticed that my ECU plug is flexible enough that if you rely on just the center bolt to draw it together the two ends bend outward and as such don't neccessarily make good contact with their respective connections. I have fixed many a code and random problem by simply pushing in the two ends of the connector to improve contact.

 

The plug? I'll try that then thanks jd! And The oil is the same level as it was 3 days ago btw...and it's not watery.

 

well the connection is tight so I don't think that's it. I wonder how long I had this bad camshaft sensor because the pcm never showed it on my cel before, and I just checked the codes to make sure and it was reveiled...would it be responsible?
And it ran just last night also, with the exception that it took about 6-7 cranks to start it. Now it won't start at all...

 

worst part, my friends honda civic key can turn my car on and off... absolutely not what i want to happen...however...it is a kool thing because u can leave the car running take the keys lock the doors and go into a store or something

 

haha that is tight though...a locked running Maxima in front of a 7 eleven lol peeps like

 

i had this exact same problem with my 95 mustang gt! the not starting and starting then staying running its nothing major.i cant remember the exact part name its in the steering colum. damn it i cant remember the name ill think of it..... on the problem the ley issue is a broken ignition lock my girls 01 focus does the same thing...

 

not to add to the array of holy offtopicness, but my first car, a Bonneville, did something similar, but only if the headlights were on. that is, with the car running, turn the headlights on. turn the car off with the headlights on, pull the keys out and everything, and the engine would still be running, and would run like normal too. the car acted like i never pulled the key out! it would only turn off if i turned the headlights off.

whatever could have caused that problem could be causing your problem, but in another flavor. maybe some wire somewhere is chafed and is touching some ground or something, i don't know. that car is long gone, and i never figured out what it was.

hope that helps...

 

ok so I got another camshaft position sensor and she fired right up!
Originally the dealership wanted $3300.00 just to fix her, I spent $78-on a new injector, and $100-for a new camshaft sensor...
$3300 Nissan? I should go back there and strangle the jerk.
Oh and apparently i had washed my cylinder that was locked, so i put a bit of oil in the spark plug hole to build up another oil seal along the wall.

 

Sounds like their "fix" was to put in a new engine!

 

Not even close, that price was for as he told me, "further diagnosis & teardown labor" and possibly that I needed a new ECU which would be an additional cost..
Well I just got home and I threw another code, a first one for me. 0412, upstream o2 high voltage fault. Maybe my electrical is ****ed after all.
Before this whole ordeal, I always had a constant 0512, downstream o2 fault...now I have an upstream.

 

IMO you have two categories of problems- one is the electrical issue to continue to throw spark to keep running after the key is off, and the second is the fuel that dumped into your crankcase. Watch that like a hawk, b/c that's a really good way to smoke bearings- load of engine w/o sufficient oil viscosity and strenth to protect them. Sorry, but I have no answers, only to point out that I think you have two different rabbits to chase.

 

I changed the oil last week, plan on doing it again real soon as well.

 

And while it was all apart I went and painted my spark plug cover:

 

looks pretty ! good job