• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Misfires on Bank 2

B

BillinABQ

NAXJA Forum User
Location
Albuquerque, NM
Just bought a 2000 XJ 4.0 Sport.
Check engine light on. Engine stalls randomly.
Pulled codes and got P0335,P0300,P0304,P305,P0306,P0174.
The P0335 code is a crank sensor circuit malfunction.
P0300 is a multiple cylinder misfire.
P0304,P0305,p0306 are misfires on cylinders 4,5,6....respectively.
P0174 is a Bank 2 system lean code.

Being that I just bought this thing, and have no idea how the previous owner
had maintained it, I bought new spark plugs and a crankshaft sensor.
After i replaced the crankshaft sensor, the engine started smoother and
did not die.
Next I removed the (what I thought old) spark plugs. The previous owner had replaced the spark plugs with Autolite plugs. I started with the #1 plug.
The first 3 plugs looked good, and still had perfect gap. .035".
The next three were black and fuel fouled.
I went ahead and installed the new NGK plugs and erased all codes.
I started it up and let it warm up. I drove it about 100 yds and checked for
pending codes with my scanner. P0174 was already pending and
within 1 mile the check engine light was already on.
I retrieved the codes again and that was the only code. I ran the misfire counter procedure on my scan tool and, as expected, cylinders 4,5,6 were misfiring....but no misfire codes at all, not even pending.

It seems odd too me that just those three cylinders were getting fuel soaked and misfiring.

Has anybody gone through this yet?

I will do more diag tomorrow as it is dark, cold and late...and I will keep posting.
 
Last edited:
Ok after further invetigation, and daylight, the previous owner replaced both Bank 2 o2 sensors, cleaned the throttle body out, replaced the Throttle Position Sensor, and what seems to be a new #6 injector.
Looks like I'm on the trail of the ghost he couldn't catch....

My fuel pressure was 48 lbs at idle this morning.
Im going to run more tests this evening. I'll keep posting.
 
Bill, is this the same "stall" type thing going on when we were out at the Puerco after I broke my Jeep?

I did not get a good look under the hood, but I would (just for fun) check the basics: Battery connections, grounds, compression check. I know I mentioned it when we talked, but you may have an 0331 head. Check for coolant in the oil?

Hopefully the guru's here will get you on the right track. If you are still at the shop playing with it after I close the store tomorrow... shout, might be able to drop by.
 
Concentrate on the P0174. Too lean. It was a good idea to verify the fuel pressure. Another thing that contribute to fuel/air includes the MAP sensor. This sounds kind of dramatic for an O2 sensor and sounds like the previous owner replaced them. I'd test the MAP sensor and be darn sure that the vacuum line leading to that sensor is pulling good vacuum. And perform a comprehensive search for a vacuum leak or exhaust leak. Idle RPM seem okay? More of a long shot would be a bad coolant temperature sensor; I'd test it just to be sure.

And yes, the 0331 head issue is still something not to ignore although it usually doesn't present like this and I would expect cylinder 3 to also be misfiring with a cracked head as it usually cracks between cylinders 3-4 where the casting defect is. What is your oil pressure running at? Have you checked your oil for milky substance? Take a look through the oil filler cap and see if you can see any coolant leaking into the head. And commit the following sentence to memory...."the #1 symptom of a cracked 0331 head is unexplained coolant loss".

Good luck and keep us updated.
 
Last edited:
-- back of intake gasket letting air into the rear cylinders?
-- o-rings for one of the rear injectors leaking?
-- faulty vacuum accessory in the rear of the intake that is disproportionately leaning the rear cyls?
-- torn diaphragm in the brake booster?

It seems that you are leaning out the rear and the ECU is compensating with extra fuel. I would look for things that would cause the rear runners of the intake to receive more air than the front runners
 
Ok......ready for it?
So I smoke tested the intake-good. I back fed smoke into the exhaust-good.
I cleaned all the connections to every electrical connector : every O2, TPS, MAP, every injector, IAC, coolant temp....every one i could find. Then I cleaned out the main PCM harness connectors at the PCM. I used some fancy electrical contact cleaner from Wurth chemicals, then used their electrcal contact oil on the contacts.

Then I cleaned out the throttle body, even though it looked clean, I cleaned the hell out of it anyway. I then ran some Mighty upper engine cleaner though the brake booster vacuum line, with the hopes of clearing up carbon build up.
I drove it home, about 15 mins down the freeway with the scan tool monitoring misfires, and every two minutes checking for pending codes.

When I got home there had been no misfires and no pending codes.
Maybe it worked. First thing the next moring I drove about 5 min to the closest parts store and bought some Seafoam.......I ran the Seafoam into the engine in the parking lot, and waited about 3 minutes. (well, until the smoke cleared) I then drove to work, keeping the engine above 2800 till about 4200 rpm.

No more lean codes. No more misfires.

Moral of the story......Keep your engine clean, drive the hell out of it.

Glen: the Crankshaft sensor was the culprit of the stalling out.
 
Right on, Bill. Glad it is looking up. BTW... not sure if you heard, but killer deals at work tomorrow. Bring in a full crew, we are hooking ya up. :)

Seafoam is great stuff... and fun too. :)

BillinABQ said:
Ok......ready for it?
So I smoke tested the intake-good. I back fed smoke into the exhaust-good.
I cleaned all the connections to every electrical connector : every O2, TPS, MAP, every injector, IAC, coolant temp....every one i could find. Then I cleaned out the main PCM harness connectors at the PCM. I used some fancy electrical contact cleaner from Wurth chemicals, then used their electrcal contact oil on the contacts.

Then I cleaned out the throttle body, even though it looked clean, I cleaned the hell out of it anyway. I then ran some Mighty upper engine cleaner though the brake booster vacuum line, with the hopes of clearing up carbon build up.
I drove it home, about 15 mins down the freeway with the scan tool monitoring misfires, and every two minutes checking for pending codes.

When I got home there had been no misfires and no pending codes.
Maybe it worked. First thing the next moring I drove about 5 min to the closest parts store and bought some Seafoam.......I ran the Seafoam into the engine in the parking lot, and waited about 3 minutes. (well, until the smoke cleared) I then drove to work, keeping the engine above 2800 till about 4200 rpm.

No more lean codes. No more misfires.

Moral of the story......Keep your engine clean, drive the hell out of it.

Glen: the Crankshaft sensor was the culprit of the stalling out.
Click to expand...
 
You must log in or register to reply here.

Similar threads

O
2000 XJ Failed Colorado Emissions high CO
2
Replies
27
Views
2K
Ken M
K
L
Multiple misfire Issue. P0300, P0301, P0302
Replies
8
Views
2K
HRDROKN
H
D
How to test PCM output/wiring for injector?
Replies
6
Views
2K
GravyDavey
G
R
2001 jeep intermittent misfire.
2
Replies
20
Views
3K
RetEBoogie
R
D
Chasing misfire and running out of variables.
2
Replies
21
Views
3K
deloxx
D
Back
Top