Great work, thanks for the summation.

 

Hello everyone:

I also did the following after researching the boards:

-Changed out the stock Champion RN11YCC plugs to Champion RC12MC4 (318) gapped to .032.
-Changed out recently replaced (5 months iirc by po) 7mm wires for a set of Kingsborne 8mm wires
-Made sure to re seat all the wire connections at the coil and at the plugs
-Split a can of Seafoam between the gas tank and the intake manifold via a vacuum line.
-Cleaned the MAF
-Cleaned the throttle body

These did not fix my P1316 problem so I also did the following:
- Complete clean and flush of the oil system (trying to see if I could get the potential vlave freed up)
- Changed coil packs out from my donor truck
- Swapped out all O2 sensors

Unfortunately none of this helped my P1316 problem. So I used the following technique to pass emissions so I can continue to drive the truck this year (I plan on rebuilding the engine and transferring it into my other D1 this year). Prior to this I tried to pass emissions 3 times. I finally studied the situation enough to figure out how to do this:

Clear the code (s) from the ECU using your code reader. Drive the truck until you get 5 out of 7 readiness parameters up (In Georgia you are required to have 5 ready at a minimum). In my case it took about 30 minutes of vairiable driving to get the 5 up and set per my Actron reader.

Once you have 5 ready, get home and shut it off (my code would come back after the truck idled for a few minutes when I finished driving it). At the next opportunity after the truck is completely cool drive it to the nearest emissions station. Make sure it is not fully up to temp (i did this by gliding it with the engine off about 50% of the way to the station which is 4 miles from me. Once I got to the station I turned it off immediately. The tech plugged it in, no codes, 5 parameters ready. He turned the engine on and idled for a minute, again no codes and I got a pass.

I suspect I do have a sticking valve, so I am in the process of removing the heads off my donor and getting them rebuilt so they are fresh when I pull the motor and rebuild the bottom end next year.

Hope this helps someone.

 

Have you done a compression and leak down test of the motor? I think the leak down should point out which cylinder you are having the stuck valve issue on if that is indeed the root of your problem. If you could figure out which is the sticky cylinder maybe you could pull the rocker cover and target the sticky valve with a penetrating solution and possibly enough would get by to free up the stuck valve. Another idea would be to park that cylinder at TDC and the remove the valve retainer and spring and push the valve in enough where the penetrating solution can work its way into the valve seal on the offending exhaust valve. Since the piston would be at TDC it would keep the valve from dropping too far. This is all theoretical as i have not had to go this far but "should" work, at least in my head. I'm not sure of the actual clearances in the combustion chamber with the head assembled so ymmv.

I was talking with the smog station owner and he said that in CA you used to be able to pass if you didnt have 2 of the 7 readiness codes set but they changed it to where you can only have one readiness code not set and still pass. One work around i've seen here in CA is that you register your auto in a county that doesnt have biennial smog checks, just checks for changes of ownership. You have to have a physical mailing address in the county so if you know someone that lives up in the sticks where they don't have the biennial smog checks that is one work around. Fortunately

 

Is there a sticky on how to clean the MAF? Or just hit it with some cleaner?

 

I used the CRC brand MAF cleaner. You can pick it up at most auto parts stores. Unplug your maf, undo the hose clamp holding the intake tube to the maf body and disconnect the maf from the air box. Get an old towel or some scrap cardboard and then using the straw thing that comes on the can spray copious amounts of cleaner into the opening in the maf body that houses the hot wire. I sprayed mine out really well, used about a half a can of the cleaner. Shake it out a bit to get any residual solvent out and then let it air dry, I let mine dry out for about an hour before putting it back in the truck.

 

If you were to pull the valve covers off and do cleaning would that have any effect?

 

I had a sticky valve. The exhaust valves are the culprits. Mine was on number 8. All kinds of techs told me it was something else. I ended up dong it myself after telling some LR techs what was wrong and having them drive it for a week or so (not a dealer). Just pull the heads, take them to a good shop and have them go over them and do a valve job and replace your head gaskets while you're at it. It does happen to these trucks. Seafoam will not help. I think the PO may have been running regular gas in it.

 

P1316 error code can be written when the O2 sensor is not working. I unticked the rear O2 sensors and experiment soon granted me an error code P1316.
I have a 1996 with the release of Range Rover P38 4.0 SE (NAS).

 

cannot get the ignition key out of my 1997 discovery when placed in park' any reccomendations.

 

I know this thread is old, but wanted thank you for this write up.

I just purchased a 97 Disco I last night for $1500. Of course; when I test drove it, as well as drove it home last night, and to work this morning, no CEL was on. Go to get the IM/Safety done during lunch, and the CEL pops on. Had my buddy hook up his ODB2 reader to Torque and it gave the P1316 code.

Guess I've got some work to do.