I was towing a boat on flat ground and had a series of misfires and SES lit up, then went away. Up to that point, I had no issues on this new-to me Disco with 107K on it. I'd bought it from a friend who had new wires and plugs put on by a local Euro Shop.

Since then, I have been getting intermittent misses... sometimes at a light, sometimes while driving. there's no consistency that I can tell.

I pulled the codes, and got a P0440 - Bad Purge valve. checked the gas cap, cleaned it out with electrical cleaner, cycled it a few times, and ended up replacing it with the Hyundai part from the Hyundai dealer. It still is missing occasionally. today, was missing and flashed SES and then stayed lit.

I pulled the codes again.

P0300 - Random Misfire detected
P0304 - Cylinder 4 misfire
P0307 - Cylinder 7 Misfire
P0308 - cylinder 8 misfire detected
P1300 - catalyst damage misfire multiple cylinders Drive cycles C - Signal out of range above max
P0305 - cylinder 5 misfire

the P1300 was from the number of misfires and flashing SES which stopped almost immediately after it started.

I came home, pulled the SAI pipes and intake stuff, pulled all the plug wires and ensured they were attached to the coil pack correctly and were seated, as well as checking torque on plugs and that connection. everything was good, and seated firmly.

So I am wondering if this is just where I need to get the magencor 8mm? Other suggestions out there? the wires are a brand called Spark Transfer International. I"ve never heard of them, but they aren't the ones I have heard of...

Thoughts?

 

STI wires (Spark Transfer International) are good wires, at least they have been good to me. Mine are only the 7mm tho, can't speak for the 8.

 

STI and Kingsborne IGN790 have worked well for me.

 

OK, thanks. That's good to know as I'd never heard of them before....

 

I swapped in the Kingsborne 8mm ones as well to cure a misfire. They're less than half the price of magencor or STI if I remember correctly. The wires are a pain but you can do them without removing the intake manifold.

Might as well throw in some NGK Iridium plugs while you're there.

 

Thanks for that, Boston4! appreciate that info.

I did notice the forum linked me to another thread that I hadn't seen before https://landroverforums.com/forum/di...ncluded-24758/ in which Rovin4Life mentions

"when the misfire is 1 6 or 7 4 or 5 8 or 3 2 its a coil. even if a wire is bad then its managed to ground thru the coil and ruin both paths.

although this is far more common on a 03 and above because they got rid of the ground wire at the coil ."

As I am getting 4,7 and 5,8 misfires, I thought that was interesting.

I'd never heard of this before as an indication that the coil is going....

 

Here is the diagram for the coils:


As you can see, 5/8 and 4/7 are on different coils. I suppose it's possible that both failed simultaneously but seems unlikely.

This thread is tremendously detailed in tracking down the causes of misfires. I'd recommend reading it: https://landroverforums.com/forum/di...-thread-64462/

 

reading that thread now.. thank you.. pretty well written and pretty funny...

you're right.. it is unlikely that those both failed at the same time....

 

In reading this, I am wondering if seafoaming it is what's actually caused this... that's when it started... I might do the seafoam intake cleaning again and see if it cleans that up... and clean the MAF

 

I did clean the MAF with MAF cleaner, and didn't make a difference. I did notice the car ran just fine the MAF connected and pretty well with it disconnected too! A little surprising.... the PO had an incredibly dirty Air filter which has since been changed out.

I grabbed a can of ether to spray around the vacuum hoses to see if there were any changes in idle. I did find that I hadn't reconnected the purge valve to the throttle body, so I am certain that wasn't helping anything! Sheesh. Reconnected that and tightened down the valve cover breather hose as it was loose.

I did another seafoam intake cleaning and other than fun leaving a smoke trail at my buddies house when I left, no real difference.

I cleaned and scotch-brightened the gas cap and filler neck.

I also climbed under the rig and looked at the 'push' connections to the evap system by the filler neck, etc. in thinking back to when this first occurred, it was after I had to take the disco through the bushes with the boat trailer at the launch since I got parked in by some clown... I spent a bit of time looking under the rig to see if there were any vacuum lines that got pulled out as a result of the offroading with the trailer, but other than the one by the filler tank, I didn't see any obvious ones.

It is running a bit smoother with the purge valve and valve cover lines tightened back up, but not perfect.

For general consumption, I do have Champion RC11 PYPB plugs, and wasn't seeing that as a brand this forum likes. Happy to change those out.

But I am thinking that I will drive this for a bit and get through this tank of fuel and make sure it's refilled with 92+,

Happy to hear any other suggestions or where I can drill a hole to let the evil spirits out of this.....