ddenton749
Well-Known Member
- Joined
- March 27, 2002
- Messages
- 109
- Reaction score
- 11
- City, State
- Kennett Square, PA
- Year, Model & Trim Level
- '93 XLT
I can't find a vacuum leak anywhere.
It all started suddenly. The engine started running very rough. It would almost stall at traffic lights and I had to drive two-footed to keep it running to nurse it home. It is running extremely rich to the point where it blows black soot out of the tailpipe when I start it.
It will idle ok for several minutes then it will start to gag and sputter, then if it doesn't stall it will clear up and run ok for a few minutes. The exhaust smells rich. The CEL will come on and then go out again. It runs better when the engine is cold but then when it warms up it idles rough.
When it idles rough I can open the throttle a bit and the engine clears up and the power comes back. Then it will start running rough again.
I had trouble accessing the computer due to poor connections. When I did get it connected there where no codes stored. Weird since the CEL did come on.
I took the upper intake apart to look at the gaskets above and below the fuel rail - both appeared good.
416,000 miles on the original engine.
Compression test - good 180 psig in all cylinders.
Vacuum - 14-15 inHg.
Spark plugs black and dirty but all are the same.
I checked the vacuum components: hoses, brake booster, cruise control, interior vent system, cold air valve, trans modulator, fuel tank vent, etc., - all good.
Tuned up a couple of years ago but I didn't drive it at all last year.
Injectors are very old. I replaced them many years ago with junk yard injectors. I applied 25 psig of air pressure to them and they don't leak.
Coil pack is original.
MAF sensor is original.
Air tube between MAF and throttle body new.
IACV original.
TPS original
Fuel pressure regulator is original.
I have been having trouble with electrical connections lately. Most recently a dirty fuel pump fuse prevented it from starting. The cruise control will drop out sometimes when I hit a bump. Those kind of things.
Any and all suggestions and ideas are welcome.
It all started suddenly. The engine started running very rough. It would almost stall at traffic lights and I had to drive two-footed to keep it running to nurse it home. It is running extremely rich to the point where it blows black soot out of the tailpipe when I start it.
It will idle ok for several minutes then it will start to gag and sputter, then if it doesn't stall it will clear up and run ok for a few minutes. The exhaust smells rich. The CEL will come on and then go out again. It runs better when the engine is cold but then when it warms up it idles rough.
When it idles rough I can open the throttle a bit and the engine clears up and the power comes back. Then it will start running rough again.
I had trouble accessing the computer due to poor connections. When I did get it connected there where no codes stored. Weird since the CEL did come on.
I took the upper intake apart to look at the gaskets above and below the fuel rail - both appeared good.
416,000 miles on the original engine.
Compression test - good 180 psig in all cylinders.
Vacuum - 14-15 inHg.
Spark plugs black and dirty but all are the same.
I checked the vacuum components: hoses, brake booster, cruise control, interior vent system, cold air valve, trans modulator, fuel tank vent, etc., - all good.
Tuned up a couple of years ago but I didn't drive it at all last year.
Injectors are very old. I replaced them many years ago with junk yard injectors. I applied 25 psig of air pressure to them and they don't leak.
Coil pack is original.
MAF sensor is original.
Air tube between MAF and throttle body new.
IACV original.
TPS original
Fuel pressure regulator is original.
I have been having trouble with electrical connections lately. Most recently a dirty fuel pump fuse prevented it from starting. The cruise control will drop out sometimes when I hit a bump. Those kind of things.
Any and all suggestions and ideas are welcome.