no cel ever, weak spark
Thread Starter
Junior Member
Joined: Jan 2018
Posts: 1
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no cel ever, weak spark
have a 89 bronco 4.9 5 speed 4x4..
cranks, some times farts, weak spark. no CEL ever. not koeo not ever. bulb is good.
checked alot of stuff. check out my post at http://www.fullsizebronco.com/forum/...-question.html
over fueling has nothing to do with it by the way
please help
cranks, some times farts, weak spark. no CEL ever. not koeo not ever. bulb is good.
checked alot of stuff. check out my post at http://www.fullsizebronco.com/forum/...-question.html
over fueling has nothing to do with it by the way
please help
Senior Member
Joined: Jul 2007
Posts: 3,805
Likes: 480
From: Cape Girardeau MO
Welcome to the site!
Browsed through your post on the other forum. Offhand, suggest if your spark is yellow-orange - not good, would like to see more towards bluish. If the spark is weak when observed in regular atmosphere, it will be weaker or perhaps non-existent under compression - increased air density requires more voltage for a spark to jump the gap.
Suggest to have a look at your ignition components that typically won't throw a code - there are resistance checks for the coil, but I no longer have my shop manual - IIRC, something like single-digit ohms across the primary, and on the order of 8,000-10,000 ohms across the secondary. Is the coil getting 12VDC supply? The plug wires also have resistance specs - like 3,000-5,000 ohms per foot max. Is the plug wire insulation in good shape - no leaking off to the nearest available ground as indicated by a light show in darkness? Are the cap and rotor in good shape? Perhaps stretching, but are the plugs Motorcraft copper core - I cringe about those super-duper-double platinum multi-electrode overhyped lightening-bolted whiz bang varieties?
At any rate, IMO, these are the things I'd chase down first. Good luck, and keep us posted.
Browsed through your post on the other forum. Offhand, suggest if your spark is yellow-orange - not good, would like to see more towards bluish. If the spark is weak when observed in regular atmosphere, it will be weaker or perhaps non-existent under compression - increased air density requires more voltage for a spark to jump the gap.
Suggest to have a look at your ignition components that typically won't throw a code - there are resistance checks for the coil, but I no longer have my shop manual - IIRC, something like single-digit ohms across the primary, and on the order of 8,000-10,000 ohms across the secondary. Is the coil getting 12VDC supply? The plug wires also have resistance specs - like 3,000-5,000 ohms per foot max. Is the plug wire insulation in good shape - no leaking off to the nearest available ground as indicated by a light show in darkness? Are the cap and rotor in good shape? Perhaps stretching, but are the plugs Motorcraft copper core - I cringe about those super-duper-double platinum multi-electrode overhyped lightening-bolted whiz bang varieties?
At any rate, IMO, these are the things I'd chase down first. Good luck, and keep us posted.