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· Throwing Money at It
1995 Land Rover Discovery
Joined
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72 Posts
Discussion Starter · #1 ·
Ok, bit of a frustrating problem here. Some time a while back, I loaned my D2 out to a friend for a week. She took it on a minimum maintenance road, kicked up a rock, and broke one of the coolant lines from the expansion tank. She then drove it until it overheated, which toasted my driver's side headgasket. I got the truck back, replaced the line, and determined that while the gasket was leaking coolant outside the engine, none was getting into the oil and none was going into the cylinder. I continued driving the truck for some time, until I had a massive oil leak while on a road trip. I determined the oil leak was from the rear of the intake gasket, and replaced the intake gaskets with genuine parts, to get me home. About a month after the intake gasket job, the truck developed a severe misfire on the way to work one day, so severe that it wouldn't start after work and I had to leave it in the lot. The next day I had a friend drive me to work, and the truck started right up, so I drove it home. On the way home, it again developed a severe misfire, so I parked it and started buying parts(this was in January). Over the last few weeks, I tore it down and replaced the headgaskets, had the heads machined and checked for cracks, and replaced the spark plugs and wires(Delco plugs and STI wires). Yesterday I got it all buttoned up and started it, and the misfire was immediately present and as severe as ever. I pulled the codes, and my scanner was showing misfires on 2, 3, 4, 6, and 8. I cleared the codes, and started the engine again with the MAF unplugged, and the truck ran noticeably better, with only a slight miss. The codes now showed a cylinder 4 misfire. I pulled the plug, it was very sooty but sparked fine. I've experimented with it a bit, and come to the conclusion that with the MAF unplugged, it misfires a bit but holds an idle and runs. With the MAF plugged in, it will only continue running if I keep my foot on the gas and hold at least 2500 RPM. With the MAF plugged in, the misfire will change in severity continuously, sometimes running almost correctly and sometimes stumbling so badly it will die no matter what I do. The specific cylinders misfiring seems to change, but number 1 is the only cylinder that hasn't thrown a misfire code with the MAF plugged in or unplugged.


How should I go about diagnosing this? Would a bad MAF and airbox lid really cause these issues? I'm hesitant to just start throwing parts at it without having any idea what I'm doing.
 

· Throwing Money at It
1995 Land Rover Discovery
Joined
·
72 Posts
Discussion Starter · #2 ·
Also worth noting that all the plugs I've pulled so far were very soot covered, but an inline spark tester and sparking them outside the engine showed good spark.
 

· Throwing Money at It
1995 Land Rover Discovery
Joined
·
72 Posts
Discussion Starter · #5 ·
I did not shim, I didn't even think about that. I'll order a set of shims asap. That said, I had good compression on all cylinders, so I don't know if that's the issue.
 
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