Hello Everyone,
Seems I posted in the wrong area for my first post (hopefully I have better mechanical skills than computer!)

New Member / long time follower with a desperate need for advice.

As short as I can here is my situation:
I have a 2001 Landrover Discovery 2
Truck was running poorly (smelly exhaust, rough idling and a banging noise) so took it to mechanic specializing in Land Rovers. Report was, truck needed new head gaskets, MAF and O2 sensors and was showing 14 trouble codes. After repairs, they would then determine if I needed new catalytic converters. Estimated cost was well above the value of the vehicle so I took on the project myself with parts ordered online. After removing heads, there was no difference in the appearance of any of the cylinders. I took heads in for cleaning, testing and machining with a good result. After reassembly, truck seemed to run fine in driveway until I took it around block and barely made it home. I had no problems with the work I did and since truck drives very similar to just before I took it apart, I think problem is unrelated to head gasket problem. As of today, I am showing the following codes P1884,P0303, P0305, P0307, P0301,P0300,P1300,P0155,P0135,P0134,P0154,P1590,P0 340,P0448,P0445,P0102. P0301-7 say misfire on all drivers side cylinders, so I disconnect a lead and tested for spark with one of the old plugs (replaced all plugs with new during head job) thinking maybe I had a bad coil pack. Spark was strong. Thinking I can't have almost every sensor fail at the same time, I went looking for a bad fuse and found the 15A engine management fuse blown in fuse box adjacent the battery. I replaced the fuse and no difference other than engine now faulters when I disconnected connection to MAF sensor (it didn't make any diffence earlier.) The banging noise turned out to be the heat shield on the drivers side catalytic converter had a broken weld which I repaired. I have not yet replaced the 02 sensors, but did clean them up prior to reinstalling (lots of accumulated soot). During my repairs, I cleaned the fuel injectors in an ultrasonic cleaner and replaced the seals (kept each injector in original place as I was not sure if it mattered). Exhaust is STINKY and leaves a sooty black stain on driveway until warmed up. Its now too dark to continue and I need a mental break - its gotten personal now! Any advice is welcomed. Thank you!!!!!

Update: I have ordered new o2 sensors and a MAF sensor which should be here sometime this week.

 

Did you check to see whether the fuse had blown again? I recall reading a thread somewhere recently where the same fuse kept blowing. I can't recall what/if anything solved the problem, sorry.

 

Black soot is a very rich running engine, basically it is dumping fuel. You could have dead catalytic converter, I believe but am not sure but an exhaust shop should be able to test them, you can order a complete Y pipe and do the job yourself a couple of hours. You are looking at 500 -1000 for the Y pipe with cats.

 

So many issues, get down to basics first, then we will figure out advanced.

First, list what all your codes mean, we don't memorize them here on the forums and we are not going to look them up.

Now to diagnosing. To start with, disconnect the front oxygen sensors. The truck will default to what is called open loop and run based on maf, rpm, and throttle position sensors. That will take care of the rich fueling for now as the computer is saying its lean when its not.

2nd, get the misfires resolved. Take it slow and use the process of elimination. Right now everything on the drivers side is misfiring. Those are not even on the same coil, 1 and 7 are on one coil and 3 and 5 are on the other. Doublecheck the spark plug wires and make sure you have them correct. Once you are double sure they are all correct, then use the process of elimination. It is unlikely you have four bad spark plugs, but if you wanted to eliminate that as a possibility you could swap left and right. Because all the misfires are on one side, it could be the following:

1. Rocker arm shaft not tight
2. Injector wiring not connected
3. Injectors bad (unlikely all four would be - maybe not seated?
4. Plugged cat? You can drop the wye pipe if you like and run open exhaust just to see if misfire goes away.

I am assuming the four misfiring cylinders are completely dead, no fire at all - CEL is flashing at you. If you can get it down to less than four misfires then you can start process of eliminating by swapping plugs, wires, coils, or injectors left to right.

Report back after you have done some or all of this.
2.

 

Thank you everyone for the info
I have not had too much time to do much other than replace the 02 sensors. This did not do anything other than remove the codes for bad 02 sensors. I did check for another blown fuse, and confirmed the leads are connected as prior to HG job. I did note some wear on rocker arm shaft when I had the heads off, but torqued them properly when reinstalling, so they are not loose. Prior to repairs, I had a nasty sounding banging that a stethascope showed was coming from the drivers side cat. I assumed the guts had broken apart and were banging around. When I had it out, I found the heat shield weld was broken and could not hear anything else moving around inside when I shook the wye pipe/cat. I repaired the weld but have a tough time believing the banging came from a sheet metal shield. When I rev the engine, it sounds like I have an exhaust leak through my air filter. I have been doing much thinking about what could be wrong and agree removing the y pipe and catalytic converters and run without to check codes is the next step. Right now, I'm thinking the cat is plugged. I will report back once I've tried this. Again, Thank you very much for the feedback!!!!!!!!

 

It’s certainly worth dropping the y pipe and giving it a try, but in my experience plugged cats (not in a LR) run fine at lower power.

 

True, likely would not see an issue at idle. Not enough airflow.

 

Been a bit since last post, so here is the latest. Engine did run well at idle, but not at speed. I removed the wye pipe/cataylytic converters and determined the drivers side was completely blocked (used a shop vac on blow mode to test). I'm expecting a replacement to arrive tomorrow and I have high hopes my problems will be fixed. Suprisingly, the scap value of the cats is the same price as new replacements ($800). I will keep you updated on results