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Thread: Trouble after Head gasket replacement Code P1316 and oil light on

  1. #1

    Question Trouble after Head gasket replacement Code P1316 and oil light on

    Hi, everyone I just found this forum trying to research the oil light and the fault codes on my Disco 98.

    I got it very cheap, a couple of weeks ago, with a blown head gasket.
    I just finished replacing the head gasket and it took a little bit to get it started, after idling for about 15 minutes while bleeding the cooling system, I noticed that the Oil light was still on, and I got a check engine light with code P1316 and the P0300 code "Pending"

    (Please excuse me if I ask something stupid, although I'm handy, I don't know mechanics, and this is my first shot at an engine)

    While reading all over about the P1316, I found that should look at cables, coils and plugs as common sources of this code, the plugs look decent when I installed, but I did not check the gaps, so I will do that, I read that the cables should have around 7k Ohms per foot so I will check that too.
    But one thing that caught my attention particularly, was a video on youtube (I know is not the code or a land rover)
    https://www.youtube.com/watch?v=OyvdWeyDHf4
    Now, the thing is that the guy who sold me the LR, gave me a brand new gas filter and said he never got to replace the old one, I'm guessing, maybe he had the problem before the blown gasket, my question is should I do the filter? Does that make sense?
    Is it worth to buy one of those gages to check the fuel pressure?

    Now, on the other hand, I'm worried about the Oil light, that wont come OFF, I know that it has enough oil, and a brand new filter, but I can't find information on how to troubleshoot that issue. (I don't want to mess the engine while trying to fix something else)

    Thanks in advance for your comments or ideas.

    __________________
    Disco 98
    175k miles...

  2. #2
    Join Date
    Oct 2007
    Location
    Kelseyville, Ca.
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    2,410
    Hi and welcome!

    Having a misfire code pop up after replacing the head gaskets could be due to any number of things, especially if this is your first head gasket job and you're not familiar with all the intricacies. Hopefully it's something simple like a vacuum hose that didn't get put back in the right spot or perhaps switched plug wires or even switched injector connectors. Can you tell if it's running on all 8 cylinders or not? Does it seem to idle smoothly, or rough? Did you rev the engine any while bleeding the cooling system or did you keep it at idle the whole time? You could have a vacuum leak at the manifold or plenum, a spark plug that got some crap on the electrode essentially fouling it (did you replace the plugs, or did you leave them in the heads during removal and reassembly?) Did you remove the plug wires from the coil packs or remove the coil packs complete with wires? Also, have you cleared the codes, and did they come back, or did you not start the engine again due to the apparent loss of oil pressure?

    So now, on to the oil pressure issue...
    Did you change the oil when you did the HG job, or leave the old oil in there and just change the filter? From the way you worded you initial post, it sort of sounds like you just changed the filter. Did you fill the new filter with oil before installing it or just put it on dry and let the pump fill it up? When idling, did it all sound normal or was there a lot of valve clatter/ticking going on?
    If there's no oil pressure, it might actually have run the entire 15 minutes at idle without seizing the engine but you would certainly have heard a lot of noise from the upper end of the engine as the hydraulic lifters wouldn't have pumped up. It's possible that you simply have a bad oil pressure sending unit, they're known to fail. It's also possible that during the reassembly process you pinched the sending unit wire between the head and the A/C compressor bracket and it's grounded out, it's a single wire that comes out of the loom that runs along the passenger side of the engine on top of the manifold, the same loom that carries the injector wires. If it's simply disconnected then the oil pressure light wouldn't come on at all, it works by grounding the wire when the switch is closed (engine not running/no oil pressure) oil pressure overcomes spring tension inside the switch at about 7 psi and opens the circuit turning the light off.

    So, we need some answers to the above questions before we can proceed. Or perhaps there's some useful info in all this that will help you find the problem(s).
    '91 RRC-4.2, R380, LT230, GDE bumper with Smittybuilt 8K winch, Custom 3" lift, 33's, Equipe trailing arms, Rock Ware sliders, Custom diff guards, Maxyedor HD steering, TT/Detroit, Rovertracks axles
    '61 Series II 88"
    '95 D90
    '94 RRC County LWB

    "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves." -Will Rogers

  3. #3
    Thank you so much for your answer.

    Before I started the disassemble, I read the codes, basically showing the ones I still get, plus misfires on a couple of specific cylinders, Catalyst Damage fault banks A & B, a pending Knok sensor 2 circuit/range performance bank 2, pending 02 sensor bank 2 circuit 1. (did not noticed if the oil light was on)

    I erased the codes and proceed with the gasket change,I did remove all the plugs from the heads, and they looked on decent shape, I left all the cables connected to the coil pack and marked their position on the block, a couple of cables where a bit loose on the pack and missing their hoods (so I figure, it will be best to change them and have them all new)
    I honestly don't know how to positively tell if its running on all cylinders or not, but is seems to idle smooth.
    I'm fairly sure that the injector connectors are in their correct order, but one thing I just did, was to pinch the shredder valve, expecting some gasoline to come out, but I did not get any, is that normal?
    How much pressure does the system has when its pressurized?
    When idling to bleed the cooling system, the engine was not making any loud weird, or clack-ing sounds, I just let it idle for about 10 minutes (no revving)

    Like I mentioned the guy who sold it to me, gave me the fuel filter, and I don't know if that could be part of what is causing the code, I look at the old filter and it seems like has never been changed.

    Now, regarding the oil, I did drain all the oil out of the engine, and when I remove the head covers there was virtually no sludge, so I guess the truck was fairly well taken care of. (no I did not fill the filter with oil, is it better in general to do it? (I always do my oil changes))
    I do remember the cable you mention, because I disconnected it, and cleaned the connector because it was covered with greasy stuff, I'm quite sure I connected it again, although one of the words in your answer made me feel chills... "pinched" And I guess its a possibility, so I will double check that.
    In the meantime I ordered a pressure sensor replacement, because I figure that would be the logical first step.

    I hope I answered your questions, and again thank you so much for your help.
    Last edited by Tito De Hoyos; 09-29-2016 at 02:46 PM.

  4. #4
    Join Date
    Oct 2007
    Location
    Kelseyville, Ca.
    Posts
    2,410
    So, regarding the oil pressure sensor wire first: Disconnect it from the sending unit and give it a gentle pull while watch the wiring harness about it. If it won't budge and it doesn't cause the harness to move a little, then chances are pretty good that it's pinched.

    It's always a good idea to fill your oil filters before installing them. The oil goes to the filter first before circulating to the rest of the engine and the time it takes for an empty filter to fill is time that the engine is essentially running with no oil except for the traces left between the bearings and the crankshaft, etc. You have to do it very slowly as the level inside the filter drops as oil seeps into the filter media, so you have to fill it, wait a bit, fill it again, etc. Don't fill it quite all the way to the top as you'll lose some when you turn the filter to it's 45 (or thereabouts) angle to install it. And use a good quality filter, DO NOT use Fram as it's gone from one of the best filters on the market to one of the worst. Genuine Land Rover, Wix, Napa Gold (which is made by Wix) are good ones, as well as the K&N HP-series. I prefer the K&N or the Wix, and I use the longer filter that was standard on older Rovers.

    So, from there, we need to verify that you are indeed getting oil provided the sensor wire is okay and not grounding out. The simplest thing I suppose is to remove the oil filter and see if it's full of oil...since you didn't pre-fill it, if you're not pumping any oil through the engine for some reason, then it stands to reason that the filter would be empty. I strongly suspect that you'll find it full. You could also remove a valve cover (the passenger side is easiest to get to) and see if you have oil up there, since you just changed the head gaskets then it was probably clean and dry in there when you assembled it, after 10 minutes of running with normal oil pressure it should very oily now, with oil pooled in the low spots (especially those recesses where the front and rear-most head bolts sit. If the filter is empty however and/or no oil is to found under the valve cover, then you certainly do have a problem!

    You didn't mention that you had these codes before doing the HG job, so whatever caused them is still most likely present. It could be a very clogged fuel filter or a weak fuel pump (or both) A fuel pressure tester is only about 15-20 bucks from Harbor Freight, you should have around 30-35 psi with the engine running. It's normal for the pressure to bleed off over time when it's sitting so if it's been a day or more since you last ran it, it wouldn't alarm me any to see no pressure at the Schrader valve. You can turn the key on, wait for a few seconds and turn it off again and that will prime the system for starting, if you check for fuel at the Schrader valve again and still don't get more than a dribble, then you have a fuel delivery problem. I'd go ahead and check that and then change that filter. You said it was hard to start after the HG job, if it's still hard to start that could be an indication of low fuel pressure.

    As far as those ignition wires go, it sounds like they're due for replacement. You might have spark jumping which could be the cause of some of your problems. One trick is to wait till night and start it in total darkness, then look for any flashes of light around the plug wires which would indicate spark leakage.

    Sounds like you still have a bit more diagnostic work ahead of you.
    '91 RRC-4.2, R380, LT230, GDE bumper with Smittybuilt 8K winch, Custom 3" lift, 33's, Equipe trailing arms, Rock Ware sliders, Custom diff guards, Maxyedor HD steering, TT/Detroit, Rovertracks axles
    '61 Series II 88"
    '95 D90
    '94 RRC County LWB

    "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves." -Will Rogers

  5. #5
    Thank you again, I never thought about the logic on having oil in the new filter, but I think is a great tip, anyway, if I got this right, the sender works by grounding itself either with oil pressure or by mistake if you pinch the cable, so if I disconnect the cable and the light goes out, that means that is not pinched, and if after that I take the oil filter and has oil in it, it will mean that the pump is working but not necessarily providing the correct pressure.
    But at least I will know that the engine is not running dry. (and I will replace the sender and hopefully that will take care of that problem.

    One question, am i right assuming that I can replace the sender without emptying the oil?
    And I guess the same goes for the filter, although there will be more dripping here, correct?

    On the fuel side, I will check the pressure but I wanted to ask, what tester do you recommend?

    Option 1 Or Option 2

    And yes I will definitely change those plug wires.

  6. #6
    Join Date
    Oct 2007
    Location
    Kelseyville, Ca.
    Posts
    2,410
    Option 1 on the tester. The second one is for testing low pressure fuel pumps for carbureted engines, it only has a capacity of 10 psi which is way too low.

    You don't need to drain the oil to change the sender, only a little bit of oil might come out when you take it off, but probably just a few drops. Yes, you'll lose a little more oil when taking the filter off but only a few ounces, no need to drain the oil for that either.
    '91 RRC-4.2, R380, LT230, GDE bumper with Smittybuilt 8K winch, Custom 3" lift, 33's, Equipe trailing arms, Rock Ware sliders, Custom diff guards, Maxyedor HD steering, TT/Detroit, Rovertracks axles
    '61 Series II 88"
    '95 D90
    '94 RRC County LWB

    "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves." -Will Rogers

  7. #7
    Quick update...
    I got the fuel pressure gauge, but I have not tried yet, maybe I wont have the need to use it this time.
    After turning on the key for a few seconds I went to check the shredder valve, and got almost nothing, so I went ahead and changed the fuel filter. (it was a pain without taking out the tire because my 27mm socket wont fit, and it's the biggest one I have (next thing in my wish list I guess))

    After replacing the filter, did the same test, put the key on the on position for a few seconds, and boy, what a difference, I got a good stream of spitting gasoline, I don't know yet if the fuel pump is sending the correct pressure, but at least I know that more gas is getting to the rail, plus the truck started much easier.

    I disconnected the oil pressure switch and the light went out, so I know the cable is not pinched, I'm still not sure if I have enough oil pressure or not, although the oil filter has oil on it, so before running the engine for a few minutes to see if the codes come back or not, I'm waiting for the OPS to get here tomorrow to replace it, and make sure I have enough oil pressure to run the engine...

    For the first time I move the truck to have it on a better position to change the fuel filter, and I think I will have to do the brakes, they feel too low, plus I can see the the disks have grooves. (Still need to get a 28mm socket first)
    I look all over the truck for something to remove the tire, but I cant find any tools or place to store them, I see the jack and the chuck but that's it. (any hint on where should they be?)

    I took the fuel filter apart and it looks black, and super brittle, I'n not a filter expert or anything, but it cracked like if it was thin brittle plastic.

    Thank you again TigerDan, for all the help, and will update this as soon as I replace the Oil pressure switch.
    Attached Thumbnails Attached Thumbnails Screen Shot 2016-10-02 at 1.01.07 PM.jpg  
    Last edited by Tito De Hoyos; 10-02-2016 at 04:16 PM.

  8. #8
    Join Date
    Oct 2007
    Location
    Kelseyville, Ca.
    Posts
    2,410
    Sounds like you're well on your way to getting it figured out. I'd say the oil pressure problem is looking more and more like a bad sending unit, interested to know if the new one turns the light off.

    As for the lug wrench, it should be stored with the jack, if it's gone, it might be somewhere else in the truck or else it's simply missing. Not uncommon. I use a 6-point 1-1/8" socket, it's a tight fit on the covered lugnuts used on DIs if the cover has been mangled by use of a too-large 12-point socket but it can be hammered onto the lugnut if needs be. Alternatively, a 29mm socket should be a slightly looser fit (if you can find one) just make sure it's 6-point.
    '91 RRC-4.2, R380, LT230, GDE bumper with Smittybuilt 8K winch, Custom 3" lift, 33's, Equipe trailing arms, Rock Ware sliders, Custom diff guards, Maxyedor HD steering, TT/Detroit, Rovertracks axles
    '61 Series II 88"
    '95 D90
    '94 RRC County LWB

    "There are three kinds of men: The one that learns by reading, the few who learn by observation and the rest of them have to pee on the electric fence for themselves." -Will Rogers

  9. #9
    Join Date
    Sep 2009
    Location
    Loomis, Ca
    Posts
    831
    I found my lug wrench under the rear seats with the jack handle.
    Trail Checklist:

    Rubicon (Buck to Tahoe in the rain/snow), Hell Hole
    ...

    96 DI 5" RTE, GBR 4.11's, ARB Front and Rear, 35" KM2's, custom front bumper, custom rear bumper, Roof Rack, Bottorf Sliders, Superwinch, RTE steering skid, Custom front diff guard...other and more to come

  10. #10

    Question

    Thank you sactodisco, unfortunately, I think mine are just missing...

    Now for the real bad news, I replaced the Oil pressure switch, and the Oil light still on, should I buy an Oil Pressure test kit like this one?
    I read somewhere that one thing to look at would be the Oil Pressure Regulator Valve does that make sense?
    Or the Pick up strainer?

    I also read this... (and I kept both the drain plug and the oil filter off during all the time it took to change the head gaskets.

    Has the oil pressure light been on all the time since you changed the oil? These pumps are fiddly, and if you drain all of the oil and remove the filter at the same time, you can lose the prime in the oil pump. Unfortunately, if this occurs, it entails pulling the oil pump, packing it with vaseline, reassembling it, and then refilling the crankcase with oil.
    I always change the filter first, (there is really no excess oil leakage due to valves in the filter), then drain the crankcase and refill. Be sure to fill the new filter with clean oil and smear a little on the o-ring before you screw it on.
    :-(
    Last edited by Tito De Hoyos; 10-05-2016 at 09:47 PM.

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