This is what Alldata pro states is a code P1300






DTC P1300
Catalyst damaging misfire multiple cylinders Drive cycle C:Signal out of range - above maximum.

ALLDATA Editor Note: The Emission Relevant Misfire for multiple cylinders is found under code P0300. See: P0300

Possible causes by suggested order of priority:

• Fuel pressure too low.
• Crank synchronization problem
• Ignition coil fault
• Fuel contamination.
• Engine mechanical fault.

Fuel Pressure Too Low.
CHECK THE FOLLOWING:

• Fuelling adaptions show enrichment.
• Check fuel pressure with fuel pressure gauge. POSSIBLE FAULTS
• Fuel filter blocked.
• Fuel pressure regulator fault.
• Fuel pump fault.

Crank Synchronization Problem
CHECK THE FOLLOWING:

• Sporadic reference mark error count raised.
• Reset count possibly also raised.
• Crank sensor fault is set. POSSIBLE FAULTS
• Crank sensor wheel physically damaged.
• Crank sensor out of position.
• Crank sensor faulty. DIAGNOSTIC HINTS
• Raised reset count with a zero reference error count may indicate a 12v supply problem.
• Diagnose fault with raised ref error count as a crank sensor fault.

Ignition Coil Fault
CHECK THE FOLLOWING:

• Misfire counts high for all cylinders using coil 2 (1,4,6,7).
• Misfire counts high for all cylinders using coil 1 (2,3,5,8).
• Misfire counts high for all cylinders. POSSIBLE FAULTS
• Problem with 12v supply to coil pack 2 (cylinders 1,4,7,6).
• Problem with 12v supply to coil pack 1 (cylinders 2,3,5,8).
• Problem with 12v supply to both coil packs.
• Coil pack 2 faulty. DIAGNOSTIC HINTS
• Raised misfire counts on paired cylinders 4+7, 2+3, 1+6, 5+8 indicate a problem with one coil drive or secondary circuit.
• Raised misfire counts on groups of four cylinders 1+4+6+7 or 2+3+5+8 indicate coil pack problems.
• Raised counts on groups of four cylinders 1+3+5+7 or 2+4+6+8 indicate a bank fuelling problem.

Fuel Contamination.
CHECK THE FOLLOWING:

• Misfire counts equally high for all cylinders.
• Fuel pressure measured with fuel pressure gauge reads normal.
• Abnormal fuelling adaptions.
• Engine running very rough.
• Visual check of fuel in fuel line (take sample). POSSIBLE FAULTS
• Fuel contaminated.

Engine Mechanical Fault.
CHECK THE FOLLOWING:

• Raised air flow at idle.Cylinder compressions.
• Cylinder leakages.
• Valve timing (Faulty or worn CAM).
• Spark plug condition - check for oil or carbon fouling. POSSIBLE FAULTS
• Valve, Piston or CAM problems causing low engine efficiency.
• Engine running rich causing carbon deposits on spark plugs.

 

SO from what I am understanding for Alldata is you very well might have a #2 Coil Pack causing the mis-fire. I have read alot about how the coil packs give problems plus it is alot cheaper to try that than to pull the heads off again.
I have to tell you that I have had my head gaskets redone about 1000 miles ago and now I have that dreaded waterfall sound under the dash. What is driving me crazy is I have tried to bleed the system to no avail.If I drive mine for about 5 miles the sound just about goes away. I also think that it might be a build up of condensation on the evaperator and not draining. IS that a possibility

 

Great post with the Alldata details. Thank you for that.

Since it concerns 2 cylinders on the same coil, but not all 4, my first thought would not be the coil, but maybe the wires. I may try to swap 6 with 5 and 7 with 8 to see if that changes the misfire to 5 and 8. That's if I can get my hands in... In my previous 2 DII's I had easy access in one and not so easy in the other, but I have not tried this one yet.

And no, my waterfall does not go away after 5 minutes... I wish!

Thanks!

 

That lower bolt on #7 on an HG job.

I could tell that someone before me had wanted that bolt out.

That person or party bashed in the firewall to gain clearance to the Head bolt near cylinder #7. That hard to reach lower bolt.

So, at least on my Discovery II

1) heads on at Factory. Yeah.
2) Fire wall basher renewed head gaskets some time in the past.
3) I renewed the head gaskets. I had a breach from #1 to the coolant jacket.

The other head gasket may have lasted, but I replaced it too.

 

Alldata Pro. Thas funny. You are on the right path with your diag of your number 6 misfire. Switch the wire with its opposite. If that doenst work, switch injectors, seeing getting fuela pressure on these things is supposed to be a monumental pain in the n*ts. If you do all that and it doenst move, then condemn the coil. And yes 2 of four could be bad. I see MB v12's that go bad all day long.

 

So... replaced the plugs. The #7 was actually a bit reddish on the ceramic tip; coincidence that I have the orange coolant?

Since I relaxed the plugs last weekend the misfiring has become more severe. I blame it on the wires not being able to provide enough power to the Bosch Platinum 4+ plugs. Magnecor 8mm are on the way and should arrive mid next week.

I did "gain" a code: 1319 since the plug change. Looking at RAVE I found "Low Fuel Level Check".

Repeated bleeding does not seem to get rid of the air in the system so I have decided to park the truck until I have fully diagnosed.

One more thing: I read on an article posted by Rovers North that combustion gas in the coolant should cause for "hard" hoses due to pressure build up. My hoses feel very soft like it's all air. Went by Pep Boys to buy a gas in coolant test, but they did not have one. Going to Autozone tonight to pick one up.

Keep you updated....

 

Don't put off what you must do.
No wishful thinking..

Sounds like the head gaskets are shot..
Or one is.

Use the Force Luke

Flickr: Landroverdude2's Photostream

 

No, no wishful thinking here... I just rather diagnose well before throwing parts (and in this case a lot of time I don't have) at it.

Did the "combustion gas in coolant" test yesterday. Was non-conclusive. Liquid changed to be a bit lighter, but definitely not yellow.

The coolant does get thrown up into the reservoir after the engine gets to operation temperature. Would there be any other reason that could happen? A small leak somewhere that pushes out coolant, replacing it with air when driving?

I plan on renting a compression tester to test the individual cylinders this weekend and also pressure test the coolant system to see if I can find a leak somewhere. If I find low compression on #7 and subsequently pressure test the coolant system I should have a wet plug on that cylinder after the pressure test right?

And again, no wishful thinking, just wanting to diagnose correctly before throwing a lot of time and money at it.

 

How can I avoid pulling the heads..
How can I avoid pulling the heads..

I went round and round.

I even put in Barr's leaks and drove it around hoping it would get better.
Always vomited out all the coolant when expansion tank was opened.
And, if left open more coolant came out.

The 3mm hairline crack in the head gasket from the cylinder to the coolant jacket.

Just start.
Take it apart..
No sense putting it off.

 

OK OK OK!

Just be prepared for a boat load of questions once I get started!

Here is one to get started:

- Any other jobs I should do while I am "in there"? The short block has only 30K on it and is still shiny (on the outside at least...). Got new plugs, wires are on the way, M1 301 oil filter, Shell Rotella 15/40, performed throttle body cleaning the other day.

I figure I should replace the T-stat (to a light spring?) as all coolant will be out anyways. Do a coolant flush. Do a thorough cleaning while it's all apart.

AND I will prep by reading RAVE and the countless posts on doing a HG job so I can make sure I have all parts & tools ready.

Thanks in advance for your help once I get started!