hello I need some help I have a 2002 Disco II. I had my head gaskets changed recently now I have a flashing engine light that comes on and off at no set point. I have engine codes P1117, P1300, P0300, P0301, P0303, P0305, P0307.

so far i have changed the
*Plugs
*wires
*coil pack
*O2 sensor upflow and downflow on Bank 1
*MAF sensor

any help would be greatly appreciated

 

I would look more towards the cam and crank sensors. They are what control spark and fuel. I have NEVER seen a P0300 fixed by replacing plugs and wires. It's not a secondary spark problem, it's a control issue. Check the wiring near the cam and crank position sensors, it's possible, if this started after work being done, a wire got pinched, a connector isn't on tight, or maybe cracked or broken, etc.
Now you say this condition comes and goes? That sounds like an intermittent bad connection of some sort at a control sensor. Good Luck and keep us posted on your progress.

 

You know what, now that I think about it a little more, that P1117 code is an even better clue to this problem. That's a coolant temp. sensor code. You may want to start there. That sensor also works off of the 5v reference circuit along with the cam and crank sensors and could also be driving your mixture rich. That's the sensor the computer uses to control cold start. It may be thinking it's cold, if the voltage is dropping out on that sensor. Check that sensor and make sure it's plugged in good and tight and check the wiring really good on that too.

 

Every time I have seen misfires all on one bank it's been the O2 sensor. The only logic I can make of that is that with the O2 not functioning the computer either dumps too much fuel or not enough to those cylinders causing the misfires I know you installed new ones on Bank 1 but try swapping the upstream sensors side-to-side and see if the misfires move to Bank 2. I have had more than one O2 sensor be bad right out of the box.

 

He makes a good point here too. With a P0300 code, your best information will come from the scan data for the O2 sensors and the fuel trims. If you see that one of your O2 sensors shows no activity, it is either stuck or you've got a wiring problem to the O2 sensor. I would take a good look at the scan data before replacing anything. If you have no activity on one O2 sensor, you can swap it with the one from the other side. If you still have a "stuck" O2 reading, then you know that you have a wiring problem and the sensor is not reporting info. to the computer correctly. I usually back probe the signal wires on the O2 sensors and make sure that they're running under and over stoich, which should be somewhere around 450mv typically.
I didn't realize these misfires were all on bank one. For some reason I thought I saw an eight in there? Maybe the 3+poor eyesight? That P1117 code may or may not be related, but this can cause a rich condition too (or lean for that matter). So you'll want to figure that one out too. The easiest test to do for that is to unplug the sensor and make sure you have 5 volts. Then you can plug it in and back probe the other wire and monitor the voltage to be sure it changes with engine temp. If it's stuck at one constant voltage, then you know the sensor is no good. If you don't have 5v there, then it will be in the wiring or engine computer.

 

okay I will try checking the O2 sensors tomorrow and the temp sensor also. thanks guys

 

hey i was just thinking my cousin did the head gaskets for me and when he did I had him change out the radiator. He said something to me about a sensor that he would have to fabricate a bracket because the radiator didn't have a place for it. does this sound like it could be the sensor you are talking about.

 

I don't know exactly... It doesn't sound likely, it sounds to me like maybe he's talking about the probe-type sensor (at least I think it's sensing something) that, I believe, is part of the A/C system. There would be no way to make a bracket for the temp. sensor you're getting a code for, it sticks right into the coolant, so you couldn't just make a bracket to hold it and have it work properly.

 

where is the sensor you are talking about located?

 

I can't remember on the Disco. I haven't had trouble with mine in forever. A lot of cars have a few different ones. If your gauge is working correctly but you're getting a temp sensor code, it's probably got one for each function. There are also temp switches for the cooling fans on many vehicles.
I think mine was in the intake manifold, if I remember right. Anyway, mine was so bad that I had a wandering idle when it got hot because it was still trying to run cold start functions. I think the fuel system kept dropping in and out of open loop too. That sensor can cause all sorts of trouble!
Anyway, there's one (I think) in the radiator right near the top hose and one in the intake manifold. Don't quote me on that, I work on way too many different vehicles to remember everything and my truck is not here at my house right now.

Were you able to get any data on the O2 sensors and/or fuel trims?