Good afternoon everyone,

We have a 2001 Disco II that has sat in storage for about a year and we're trying to get it going again.

Surprisingly, after charging the battery it started right up but after a minute or so upon slowing to idle, it began loading up and surging with a pretty rich smell at the exhaust. We drained the old fuel, which wasn't much at all, and put in 10 gals. of premium. Still has the same problem. Plugged in my OBD II and this is what I got in return:

P1590 - "DTC definition not found! Refer to your vehicle's service manual.
P1300 - "DTC definition not found! Refer to your vehicle's service manual.
P0303 - Cylinder 3 misfire detected
P0505 - Cylinder 5 misfire detected
P0707 - Cylinder 7 misfire detected

DTCFRZF P1300
FUELSYS1 OL_FAULT
FUELSYS2 OL_FAULT
LOAD_PCT (%) 4.7
ETC (*C) 124
SHRTFT1 (%) 0.0
LONGFT1 (%) 14.1
SHRTFT2 (%) 0.0
LONGFT2 (%) 16.4 ?
RPM 680
VSS 0
MIL STATUS ON
MISFIRE MON OK
FUELSYS MON OK
COMP. COMPONENT OK
CATALYST MON INC
HTD CATALYST N/A
EVAPSYS MON INC
SEC AIR SYS OK
A/C REFRIG MON N/A
OXYGEN SEN MON INC
OXYGEN SEN HTC OK
EGR SYSTEM N/A

I was surprised to see the misfire codes on the odd cyl banks. When the vehicle RPM is raised through idle and upwards of 4000rpm it seems to run fine. Also, when power-braking and putting the engine under a load it does not break but rather holds strong and steady. If left to idle, the surge and rich smell seem to increase until cleared by acceleration. Once at idle, it returns about 20 to 30 seconds later. Interestingly, if the AC is on, there is less evidence of the problem and it runs smoother, whether that has any validity or not.

I do have the three amigo lights, which were on long before we put it in storage, and lights associated with the 4x4 are on because I have the front shaft out. We had to drive it from our other house without this shaft because when inserted, there was a vibration as though one of the weights may have come off. It is a reconditioned shaft that was balanced and sent to us several years back. Without the shaft, the vehicle ran smoothly the entire 500 mile trip and once here, we put it in storage in the garage.

Based on the codes, I'm trying to determine if there is anything that would generally present a sequence of faults like this. If there are indeed misfires on the odd bank at an idle only, does this represent a fuel delivery problem of some kind? I'm also wondering about the MAF sensor and both the upstream/downstream O2 sensors after sitting all this time. Cleaning MAFs is an absolute disaster and I don't want to just start changing parts hoping to correct something that might be wrong. The code array doesn't make sense to me, so I thought I'd post it for someone that knows more.

From looking online, I managed to learn that the 1590 code appears to be an ABS fault, which is understandable since my ABS light has been on for some time now. Not certain how to approach fixing that problem. The 1300 appears to be tied to the multiple misfires. Inspected wires, which were replaced several years ago, and they seem fine with no evidence of arcing and thought if bad that they would produce misfires throughout the throttle range, but it seems to run quite smoothly above idle. Plugs also show no evidence of poor spark delivery, with a nice cocoa appearance on both banks.

Prep-wise, I've put new oil and filter in it and changed the plugs, which were overdue anyway, and a new air filter.

Any recommendations or advice about the code results would be greatly appreciated.

Thanks much!

Russell

 

Sounds like it needs a good ol' fashioned Italian Tune Up

It wouldn't surprise me a bit for it to run a little rough and even trigger misfire codes after sitting for a year. Just let it run for a bit and gently rev the engine and let it warm up and see if it smooths out. Let us know.

 

Yes! 2x above. Let it run for a while add seafoam in gas. Then, if misfires still occurs, tune up.
Gerry

 

That fuel system fault means it isn't going closed loop, which is why the fuel trims are out of spec. The oxygen sensor monitor @ Incomplete status sticks out. Eliminate the presence of any vacuum leaks by smoke screening the driver side intake manifold and upper plenum, in general. The fuel injector Orings could be a problem but easy to rule out. If you don't receive more specific feedback, try switching the front Oxygen sensors & consult the OBD again after the engine is thoroughly warmed up to operating temp for possibility of misfire switching banks which would confirm the faulty component. I would not suspect the coil pack itself right away as misfire monitor is online.

See 18-2-49 thru -54 of RAVE w/m to begin.

BtW: there is a 0300 & a 1300
The 0300 is your everyday multiple cyl misfire & 1300 is "catalyst damaging level" of multiple cyl misfire so I don't necessarily agree with "warm it up, clean the soot out"
You need to get to the bottom of this 1 in a hurry. I don't know what it takes to ruin a cat' converter but it does happpen & you will find info on the subject here should you choose to run the search function. I recommend running the engine for diagnosis purposes only, no more than absolutely necessary so long as p1300 withstanding.

 

If it's been sitting I'd replace the spark plug wires first thing vs diving deeper into it, or just to be safe do plugs, wires, and coil packs to completely rule out anything to do with spark.

Also since you aren't driving it I bet you anything if you tried the CEL would go nuts flashing & you'd have a very good chance of ruining the cats.

 

Misfires on three of four cylinders on one side indicates a bad O2 sensor on that side only. Replace the Bank 1 upstream O2 sensor and see what happens, or, swap the upstream O2s and see if the misfire moves to the other side.