Apologies in advance: I am very new to the whole car-fixing thing.

So, I got a check engine light, ran the codes and got back a P0307 and P1316 for misfire on Cyl 7. Changed the spark plug and wires to Cyl 7. Then, I disconnected the battery for 20 minutes to clear the code.

But, after reconnecting the battery and starting up the car, I still have the CEL. Anyone have any advice/tips on how to proceed?

 

I guess you could, go back to the auto parts store and ask if they can clear the codes. Otherwise keep driving and if there are no more active codes, after a number of drive cycles, the codes will be cleared automatically.

What I would do is connect my code reader and clear the codes myself. Even the really cheap models can clear codes.

By the way, why are you changing only one spark plug?

 

Thanks for the reply. I just ordered a reader to do this.

I only have a misfire on 7, so I thought (and was told by a friend) that I should only change that spark plug. Is this not correct?

 

Of course one plug may solve the immediate code issue. If one is bad, others may be close behind. Personally I would blow out the sand and change all the plugs, same with wires. That way you are sure you have the best baseline conditions. Check the gaps on new and old, and analyze each old plug to get a sense of the condition of the motor cylinders. This tune up could pay for itself when the motor runs a bit better, you'll save on gas.

I use the Torque app on a tablet that connects to a blue tooth OBD plug-in module. It's very good at reading live data, O2 sensors and such, besides reading and clearing codes. It can be used on any OBD vehicle.

I'm glad you're back on the road.

 

Thanks. Might as well do them this week then.

Now another issue...I bought a cheap OBD reader off amazon and it wouldn't connect to the truck. However, the one they used at AutoZone was able to read the codes (but not the mileage or VIN). Likely the one I bought is just busted/defective?

 

Better to get a good brand OBD reader. Just compare the price to a tank full of gas, then it doesn't seem so bad. Although I have used the $5 ebay bluetooth modules successfully (probably $10 now).

The OBDLink bluetooth is really easy to set up and use, just press a button at the right time. I bought a 3 foot extension cable on ebay so I can see the lights flash. The signal is strong enough to read data while under the hood too. I think it cost $70 or $100. The Torque app cost me $5 to upload, then $5 to update a couple times over the years. I think I'm into it for $15 at this point. I figure I got my money back after only one diag and repair of an O2 sensor. I use it on all my cars. My mechanic bought a professional scanner for around 3 grand, it's a beautiful thing. He uses it on all his cars too.

 

Are you saying your scanner won't read the Disco at all? You have it plugged in correctly, right? Maybe it's time to return & try another one.

Early Land Rovers weren't covered really well even back in the day ....by Snap-on and others. They were kind of odd-ball. Of course you could read generic OBD codes, but not specific codes or do bi-directional stuff. They weren't even added to the Snap-on high end software until like 2011 or around there.

Hopefully you'll get your scanner figured out or replaced. Try it on another vehicle. Its almost impossible to work on and maintain any vehicle made in the last 25yrs w/o a decent scan tool.

Yeah, look at that spark plug. It could be cracked or just non-functioning. Or the wire bad (or valve,etc). You might also perform a compression test on that cylinder too (when warm). Could have low compression too. Some auto parts stores rent cylinder compression testers ...like OReilly's. If you do that, you might as well pull all the plugs and test all the cylinders (read how to do it "Properly"). Inspect each plug as you pull it out. Lay them out on a table according to how they came out of the engine. Observe the color, oil or wetness. Plugs tell a certain 'story' about how your engine is operating. Then write down the compression reading of each cylinder so you can remember what it is. You want to do like 4-5 puff's per cylinder (the same for each). You gotta do it when the engine is still warm (not hot). If the plugs are aged, worn and rotten, put new ones in. They're not that much at like a farm n barn type store, and make a difference in engine operation.

Let us know...

 

Yeah, it just said it couldn't connect. Tried over and over. Double checked the connection and everything, no luck. The AutoZone OBD scanner read the codes just fine, so idk. I've just ordered a new OBD scanner, we will see.

Thanks for the advice. I've changed the plug and wire. Car feels/drives/starts perfectly normal, even though I haven't yet cleared the CEL. But, I've only driven it 5 miles or so since changing the plug so I don't think the computer has re-cycled yet. Hopefully this new scanner can clear the code and we will go from there re: compression checking.

 

Just unhook the battery for a while, that should clear the codes. But then again, it would be good to see whaat the codes are too. In case they're different this time.

 

Did that actually, did not clear the codes :/