Stumbling-Won't Idle Or Run Above 2500-Running Rich

427Cammer

Registered User
OK -- tech call going out to the SC experts -- car is a bone stock 1990 SC 5-speed.

Was cornering an off ramp which was bumpy with road patches -- no potholes, just lumpy/bumpy -- wasn't going too fast, but entertainingly aggressive in speed.

Suddenly car started bucking, and not wanting to run above 2500 RPM, nor would it idle without quitting -- could restart without too much cranking, but would have to keep throttling the pedal to prevent it from stalling.

RICH smoke is pouring out of the exhaust pipes, and it sucked down my fuel during my ride home (started giving me trouble 15 miles from home -- managed to limp it into the driveway) by several gallons -- no gas smell under hood or outside of car, not overheating, oil pressure is perfect, and the check engine amber light never came on.

Suggestions as to what to look for? I am not as savvy on these computer controlled cars as I am with carburetor tech, though I learn fast -- car acts like the float is stuck in a carburetor, except of course it is fuel injected.

Appreciate any thoughts you might have regarding this problem.

Scott
 
OK -- tech call going out to the SC experts -- car is a bone stock 1990 SC 5-speed.

Was cornering an off ramp which was bumpy with road patches -- no potholes, just lumpy/bumpy -- wasn't going too fast, but entertainingly aggressive in speed.

Suddenly car started bucking, and not wanting to run above 2500 RPM, nor would it idle without quitting -- could restart without too much cranking, but would have to keep throttling the pedal to prevent it from stalling.

RICH smoke is pouring out of the exhaust pipes, and it sucked down my fuel during my ride home (started giving me trouble 15 miles from home -- managed to limp it into the driveway) by several gallons -- no gas smell under hood or outside of car, not overheating, oil pressure is perfect, and the check engine amber light never came on.

Suggestions as to what to look for? I am not as savvy on these computer controlled cars as I am with carburetor tech, though I learn fast -- car acts like the float is stuck in a carburetor, except of course it is fuel injected.

Appreciate any thoughts you might have regarding this problem.

Scott

im no tech with these cars but know a fair amount about them... seems like it could be a dis or Intercooler tube leaking(any of the sc piping)
 
IAC = Idle Air Control vavle, that would cause a poor idle, not sure how it affects drivability though.
 
Sounds like a balancer that's about to fail and is causing a poor signal to the crank sensor, could also be bad crank sensor or DIS module.

David
 
Finally got time to work on Bird over the past weekend -- you are just going to LOVE the solution that fixed the problem . . .

SOMEHOW -- I do not know how, since only Ford has worked on the car in the very distant past, the upper IC tube became loose and was leaking badly UNDERNEATH and out of sight, at the blower cover end.

The collar nut was finger loose -- I spun it off with a flick of my fingers -- and the nut that holds the support standoff on the bottom-middle of the upper tube was missing -- and the IC end nuts of the upper tube were not tight.

Removed the upper IC tube, cleaned all sealing mating surfaces, and reassembled with orange hi-temp RTV -- I will be disassembling the whole top half of the motor in the near future, to replace leaky valve cover gaskets, and felt the RTV should hold on a stock motor for a couple of months.

Also, taking heed of some Randy's advise read elsewhere on this board, I tie-wrapped or hose-clamped every reachable rubber hose on the back side of the motor -- one larger hose attached to the bypass was very loose and likely leaking vacuum -- the hoses are factory original, and ALL need replacing -- project for later this summer when I do the valve cover gaskets.

Bird is idling smooth and quiet, once again -- initially, after sealing the IC tube and clamping/tie-wrapping hoses, the car started and had a very rough idle -- wanted to quit unless I feathered the throttle -- I had the battery out and disconnected while servicing the IC tube, so computer was forced to reset itself. After driving for a few miles, the rough idle went away.

Per XR7 Dave's suggestion, I was using an ebay-purchased used Ford trouble-shooting manual, which guided my steps in diagnosing my problem in a logical fashion -- what a GREAT manual to have -- thanks to XR7 Dave for the top-notch suggestion -- the steps that it described/used took me directly to my leaky IC tube problem, without any fuss or muss.

Apparently, as I was cornering through the bumpy cloverleaf, the motor was hopping in the chassis a bit, and was able to twist the already loose upper IC tube just enough to open up a leak on the bottom-side, out of visual sight.

FWIW -- my code-reader was only picking up a code 33 -- which has been a problem since before the idle problem -- EGR valve problem, which will get fixed when the valve cover gaskets and other behind-the-motor items get serviced/replace -- spark plugs & wires, fuel regulator, heater hoses, rubber hoses -- code-reader gave no other code notification, despite obviously leaky upper IC tube.

Scott
 
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