Mechanics

SPARK AT COIL BUT NOT PLUGS

1993 Jeep Cherokee

Electrical problem
1993 Jeep Cherokee V8 All Wheel Drive Automatic 93000 miles

I have no spark at spark plugs but when I remove coil wire at dist. Cap and put a plug in it it has great spark. Even open up gap on test plug a long ways and it still sparks from coil. Have replaced crank sensor, PCM, Plugs, Wires, Cap & Rotor to no avail. Timing is on anyone have an idea what to do next? Is it possible the rebuilt PCM is firing coil when rotor is inbetween contacts in cap?
Avatar
Rev4rev
March 2, 2008.



Common sense would say its the cap and rotors

but if you had replaced the cap and rotor and new wires
the only thing left is the distributor
pull cap off and ask a helper to crank for you watch the rotor if its spinning

BMRFIXIT
Mar 2, 2008.
Also tried to hold distributor shaft with rag while I has someone crank it to seee if gear was slipping but it turned fine against the resistance.

Tiny
Rev4rev
Mar 3, 2008.
See if you have spark at the coil and it strong
start at the coil then the end of coil wire before the cap
and if its strong place it on the cap
(in the middle of the cap is for the coil wire )
if not then its the wire no good or the coil week
replace as needed
no spark out of the cap indicate bad rotor and or cap
spark has to go some where
let me know

BMRFIXIT
Mar 3, 2008.
Also checked that rotor was pointing in the correct position when on TDC and it was.

Tiny
Rev4rev
Mar 3, 2008.
You have to understand electricity
you say that you have spark at the coil
that spark has to travel throw the wire to the cap in the cap on to the rotor out the rotor to the cap and to each wire by firing order
simple as that
now electricity very lazy and will take the easy way out
that’s what you should be checking for
PS : you are cranking the engine watching the spark arcing from the coil is that correct
or you’re using a test light to test the power at the coil wire connect.
Let me know

BMRFIXIT
Mar 4, 2008.
Dont overlook the obvious like bmrfixit said. Have you replaced coil? I replace these coils so often. I will even replace this coil when im doing a regular tune up because they fail so often. This is the only ignition system I will do that because of the frequent problems. Something to think about

Tiny
Mastertechtim
Mar 4, 2008.
Changed most other thing else so I will change the coil even though it ohms ok. I checked spark at Dist. Cap end of coil wire and it will jump a 1/4" gap easily. That is why I am convinced it is firing when rotor is in between dist cap contacts leading to spark plug wires. Just cannot figure out why.

Tiny
Rev4rev
Mar 5, 2008.
If you have spark at the coil wire and no spark coming out the cap its the cap and rotor
if rotor is running like you said before

BMRFIXIT
Mar 6, 2008.
Red is the coil wire


http://www.2carpros.com/forum/automotive_pictures/99387_jeep_v893_2.jpg


BMRFIXIT
Mar 6, 2008.
Triple checked spark plug wiring and it is in order.
Tested cam postion sensor and it tests good.
Coil did not fix.

Tiny
Rev4rev
Mar 6, 2008.
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