After spending several days on my 'Mada, she's finally back on the streets. I posted in Problems my symptoms, but here's a summary:
Cutting out under load, loss of power overall, missing. Initially able to kill it, wait a few minutes, and start back up and that would "clear" it up for a bit, but the period kept getting shorter and shorter until she would barely go.
Error codes: Initially P0420 and P04390 (Catalytic converter efficiency), but eventually P0300 (multiple cylinder misfire).
Troubleshooting: Initially I thought it was bad gas, then the gas cap. Replaced the gas cap. Finally came down that it was the fuel pump/filter. I replaced that, but it didn't solve the problem. However, I feel something was wrong with the pump/filter, because it wasn't until I replaced it that I could isolate the real culprit: failed catalytic converters, specifically the cats closest to the engine.
Seems the cat on the passenger side failed and disintegrated, blowing back and completely clogging the secondary cat downstream. The driver side upstream cat was in pieces, but only a little had made it down stream.
Needing to get her back on the road, I gutted all cats and cleaned out the pipes. She's now running at full power, and maybe a little bit more. I don't feel like the pump was a waste because I still feel there were problems in that area, but no doubt it was the cats failing that ultimately caused my problems.
I'm still getting P0420 and P0430, but with no cats, that's to be expected. I'm going to research the best approach to replacing the upstream cats, whether to have a shop cut the old ones off and weld new ones on or just replace the exhaust manifolds. Unless I can find a shop that will do them relatively cheaply, I'm leaning towards replacing the manifolds. They're around $340 each from Courtesy.
EDIT: The downstream cats are in the section of the exhaust connected to the exhaust manifold/upstream cat and before the Y. Easy replacement (bolted both ends), and I'm hoping they aren't too expensive. I did run into a problem with gaskets: none of the parts stores in my area (Autozone, Advanced, Oreilly's) had the right gaskets and tried to sell me the paper ones instead of metal. They also didn't have the flange gasket. If you tackle this job, don't wait until you're ready to go back together before getting the gaskets. I'm thinking I'll get mine from the local dealer or courtesy.
By the way, the locking ring on the fuel pump is a major pain to get off without the tool, but I found a way to do it: The pump assembly is actually spring loaded and pushes against the bottom of the tank and the lock ring. I found that by spraying the lock ring with WD-40 and having someone apply some downward pressure to the pump assembly, you can get it off with a hammer and a brass punch (to avoid sparks). It comes off relatively easy that way. Likewise to put it back on.
Just wanted to let you guys know what I ran into. She's got 128k on the clock. I don't know exactly what caused the cats to fail, but I'm guessing they got clogged and then blown out. I'm thinking it would be a good idea to monitor your exhaust as you get to 100k on.
Cutting out under load, loss of power overall, missing. Initially able to kill it, wait a few minutes, and start back up and that would "clear" it up for a bit, but the period kept getting shorter and shorter until she would barely go.
Error codes: Initially P0420 and P04390 (Catalytic converter efficiency), but eventually P0300 (multiple cylinder misfire).
Troubleshooting: Initially I thought it was bad gas, then the gas cap. Replaced the gas cap. Finally came down that it was the fuel pump/filter. I replaced that, but it didn't solve the problem. However, I feel something was wrong with the pump/filter, because it wasn't until I replaced it that I could isolate the real culprit: failed catalytic converters, specifically the cats closest to the engine.
Seems the cat on the passenger side failed and disintegrated, blowing back and completely clogging the secondary cat downstream. The driver side upstream cat was in pieces, but only a little had made it down stream.
Needing to get her back on the road, I gutted all cats and cleaned out the pipes. She's now running at full power, and maybe a little bit more. I don't feel like the pump was a waste because I still feel there were problems in that area, but no doubt it was the cats failing that ultimately caused my problems.
I'm still getting P0420 and P0430, but with no cats, that's to be expected. I'm going to research the best approach to replacing the upstream cats, whether to have a shop cut the old ones off and weld new ones on or just replace the exhaust manifolds. Unless I can find a shop that will do them relatively cheaply, I'm leaning towards replacing the manifolds. They're around $340 each from Courtesy.
EDIT: The downstream cats are in the section of the exhaust connected to the exhaust manifold/upstream cat and before the Y. Easy replacement (bolted both ends), and I'm hoping they aren't too expensive. I did run into a problem with gaskets: none of the parts stores in my area (Autozone, Advanced, Oreilly's) had the right gaskets and tried to sell me the paper ones instead of metal. They also didn't have the flange gasket. If you tackle this job, don't wait until you're ready to go back together before getting the gaskets. I'm thinking I'll get mine from the local dealer or courtesy.
By the way, the locking ring on the fuel pump is a major pain to get off without the tool, but I found a way to do it: The pump assembly is actually spring loaded and pushes against the bottom of the tank and the lock ring. I found that by spraying the lock ring with WD-40 and having someone apply some downward pressure to the pump assembly, you can get it off with a hammer and a brass punch (to avoid sparks). It comes off relatively easy that way. Likewise to put it back on.
Just wanted to let you guys know what I ran into. She's got 128k on the clock. I don't know exactly what caused the cats to fail, but I'm guessing they got clogged and then blown out. I'm thinking it would be a good idea to monitor your exhaust as you get to 100k on.