Ok so my girlfriends 96 disco has no spark in the #5 and #7 cylinders. I pulled the plugs and the #5 plug end was smashed up and squished. Figured that maybe whatever was in the cylinder could have blown out, but I'm not sure. The end of #7 was stark white. I replaced the wires and drove it and it didn't misfire the first time I accelerated, but after that it started misfiring again. I tried to do a compression test, but the tester wouldn't read anything. And I know it would atleast read something if the head gasket was blown. I know how to work a tester on my eagle talon, anything special about the disco that I missed?

Anybody know why its misfiring? I really need to know because I can't figure it out.

Thanks,
Brian

 

Someone with way more experience will give you the right answer...but maybe it's your wires?

I had cylinders 1 and 6 misfire...I changed all wires and plugs...and now it runs great.


edited for spelling

 

did you compression test all cylinders or just #5 and #7?

 

i tried to test all the ones on the drivers side and couldnt get a reading and all the wires on both sides have been replaced. Could two different coilpacks have gone out?

EDIT:
It also threw the p1313 and p1316 codes. And it only threw the p1307 and 1305 cylinder misfire once out of the three times that I read the codes, deleted them, and tried to fix something and test drive the car then repeat (hope that makes sense)

 

Did you install new plugs? What brand of plug wires did you use?
If your compression tester wasnt screwed in all the way you may not get a reading.

 

This is just a general observation, not Rover specific, but good to know. Old, worn out plug wires may still work when the engine is cold and first started, and the richer mixture that the fuel injection or carbeuretter choke gives, but when warm will start malfunctioning. I had this happen to me, after I had my 1948 Chrysler engine completely rebuilt, and couldn't for quite a while figure out what the missing problem was. Finally changed out the plug and coil wires and it ran as smooth as silk. Rover Specific content: Land Rover Discovery vehicles are known for being very hard on spark plug wires, and many people recommend replacing the old wires with Magnecore 8mm wires, which should give excellent service life. A spark plug wire can look just fine, and yet not work when the engine is warm and at operating temperature.

 

Ok so I hurt my shoulder and couldn't work on the car these past couple of weeks. Could the problem be a bent valve, because you shouldn't get any kind of reading on the compression tester if a valve is bent. AND I DID REPLACE THE SPARK PLUG WIRESwith the brand napa recommended (don't remember the type).

 

Ok, before you start yanking the headds off to look for a bent valve, order a set of Magnecor plug wires, return the ones from NAPA after the new ones come in.
99% of mis fire codes on Rpvers is because of bad plug wires. Even though you have brand new wires from somewhere else Rovers eat plug wires for lunch.
I have put plug wires on my truck and they were bad after one day of driving.
www.atlanticbritish.com, www.expiditionexchange.com, you can also Google them and buy from whreever you like.
A bent valve is not very likely, it is posible, but not likely.

 

I'd do a leak down test before I started pulling the heads off. Did you replace all the other plugs too? Are you sure that there's no compression in the one cylinder?