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ecm code


sledneck07

Well-Known Member
Joined
Dec 13, 2009
Messages
91
Vehicle Year
1991
Transmission
Manual
well to start off my 91 4.0l with auto blew a head gasket. had a 94 4.0 and manual in the shop. so i swapped both engine and tranny so now i have a 94 engine with all 91 sensors, ignition and and fuel system and a manal tranny with the 91 auto ecm. it misses and backfires when it has a load on it and accerlation, but no load it revs up good, has a slight miss at idle but no worse than before. also i have a snapping sound (like when you hold a spark plug aginst the block to check spark, or a broken plug wore arcing) at idle and goes up and down with engine speed. i hooked a scanner up to it and it comes up with a code 86 0=4-3 SS FAULT/C=FUEL AT RICH LIMIT. anybody know what this means? also changed fuel filter in may and just changed plugs and wires. also if this helps in have other info from the scanner

TPS 1.01 - 4.65
ECT .61
IAT=ACT 1.71
IAC 31% - 66%
O2S1 58mv - 952mv
BARO 96
IAT 53*C
ECT 90*C
OPEN/CLOSED LOOP (OPENS AND CLOSES PROPER)
VREF(V) 5.01
CANP=PURGE OFF

any help is greatly appreacitaed
 
One of your emissions sensors are not readin properly, its running rich and probly has a mild timing issue as well. If its running rich it will default to 10* timing. Check your MAF o2 sensor and anything else that affects the air fuel. TPS, etc. The other thing could be a bad coil. DId you use the old coil on the newer motor? It might be a firing order thing as well. Or maybe a plug is not connected all the way. You got hte motor swapped and running so your obviously not an idiot, just go back to the basics. Start at point A and check one at a time. Its an electrical problem not fuel or starting. SO focus your search on anything ignition associated. Start with the coils. Or work backwards from the cylinders would prolly be easier.
 
with the spout disconnected timing is at 10* and with it connected its at 20* and advances when the throttle is snapped. as i said new plugs and wires yesterday and today. to the best of my knowledge the firing order is the same, the coil pack is new in i beleive in febuary. but i suspose i could test the coil and check spark. im just wondering what the code 86 0=4-3 SS FAULT/C=FUEL AT RICH LIMIT is, mainly the 0=4-3 SS FAULT. is the ecm reading a missfire or short or something of that sort on cylinders 3 and 4? as the plugs serve as the coil ground (if i rember right). i can also check the values tomarrow but i lost my manual so if anybody has the values and could send them my way that would be great otherwise ill do some looking to find them or my book.
 
so i talked to a mechanic and he said its most likley an intake leak. the o2 sensor is reading its lean so the puter is jacking up the fuel rate. not gonna be sure tell i take a peak at it tomarrow but ill post my findings
 
I had an exhuast leak when I swaped in my 4.0. Couldnt get the clamp tight enough. It was sucking in fresh air and giving the o2 a lean reading. So it was adding fuel and making it run rich
 
well ill be darned it was an intake leak. i guess it goes to prove that you awlays start easy and go up from there. dang i fell dumb. problem solved thanks for the help. also the snapping noise is an exhaust leak that i found when i was changing the oil.
 

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