No power to coil (I think)

JoeSpit

JoeSpit

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Dec 9, 2020
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island of maui
hey gang, so on my 00 wrangler 2.5L has had a few issues lately that i thought was my fuel pump going bad (which it was) so i replaced it and everything started running worse. At first i thought it was something with the fuel system, like maybe a leak in the line and even re-replaced the pump incase that was a dud.

Ususally it would just take a WHILE to start and run fine, until the other day when it would loose power while on the highway and it was only able to manage to just barely putter back home. So like i said i rereplaced fuel pump and lines and that all has good pressure now buuuuut still wont crank!

Turns out i've got no spark. I dont even have power going to the coil. I've replaced relays and all fuses seem good. I checked (but didnt clean) my grounds (because thy looked fine)

I'm kind of at whits end here. I dont have any idea what could be the issue. Crank sensor is fine (checked it with a meter) engine cranks, fuel pump...pumps, just no power to the coil.

From what ive read it could be PCM buuut wouldnt everything else not work? is there some other fuse or relay to check? it was all running pretty fine before i decided to switch out my dying fuel pump (had to do the prime on/off 4x trick to start, and it always ran fine) I cant imagine my electrical system to just get wonky outta nowhere (unless i shorted out something, but again wouldnt everything not work if i shorted PCM?)

HALP MEH!

Mahalo
 
UPDATE: i got it to turn over finally buuut i have to do a series of turning the ignition on/off.

i had noticed when i was testing coil with a spark plug, when my helper (8 year old son) rapidly switched on/off i got shocked. so i tried that with everything together and sure enough on the 8th quick on/off it started up with a good idle.

I still do not know why it does that and why my coil has no power when trying to start it under normal conditions. anyone have any thoughts?
 
Have come across several of the 2.5 coils that were cracked on the backside out of view and showing signs of failing. Also check to see if the factory ground is still installed from the coil bracket to the frame.
 
Last edited:
TJ4Jim said:
Have come across several of the 2.5 coils that were cracked on the backside out of view and showing signs of failing. Also check to see if the factory ground is still installed from the coil bracket to the frame.
Click to expand...
i tried using a new coil but no luck. Granted i didsnt bolt it down i just plugged it into harness and distributor
 
If you have no power to the coil then there's probably no power to the fuel injectors since they are on the same circuit same fuse. I think it is #19 in the battery junction box. It will be a constant 12v with the KEY ON.
If voltage is present then we'll move on to the ground side which is PCM controlled.
 
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JoeSpit said:
i tried using a new coil but no luck. Granted i didsnt bolt it down i just plugged it into harness and distributor
Click to expand...
Like any other electrical device your coil must be grounded, plugging it in like you did the coil will not function.
 
When iu test the wires going to the coil, with ignition on it will read 0 and when it cranks it only goes up like .5 volts. i can smell that its pumping fuel, and while my coil is a lil worn its still in good order according to my meter.

i get a lil lost when reading about tracing the wires through the harness back to the ECM., plus im really hoping its something more simple like the ignition switch. Anyone know a way to test the ignition?
 
so i found a hack to start it where it will work in 2-3 tries:

if i crank and then quickly let go of the key, on the let go it will start. So me thinks its ignition related.

So now the question is, is it the cylinder/actuator or the actual ignition switch?

Also also this thing that is connected to the ignition (pictured black cylinder with a wire on both ends) gets suuuper hot. I'm not sure how that narrows it down or what it even is.

Any thoughts?

dash.jpg
 
aaaaaaaaaaaaaaaaaaaaaaaans the problem was..........


Dirty ignition contacts!!!

out of desperation i doused everything in contact cleaner and it now starts up everytime on the first crank!

thanks gang for playing along in this guessing game. Now time to return the new coil, relays, spark wires to orieliys
 
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heres the timeline.

- The fuel pump that came with it was getting loud and taking a bit to crank. If i cycled on/off 4 times it would start right up, So i replaced the fuel pump with a Delphi assembly and everything worked fine for a few days. then one day after a longish drive it lost power on the highway and i was able to sputter it home. My thought was bum fuel pump.

-I change out for another Delphi pump but then it wont start because i'm not getting proper spark. After messing with relays and testing a new coil to no avail, i notice it will start if i let the key spring back from cranking quickly, then after cleaning the contacts on my ignition starter switch it works fine, i know I'll have to change out the switch but i just gave it a spray here and there if it was getting fussy, that worked for a week.

- now i keep getting sputter stalls only after i drive for about 10 minutes. If i start the car i can rev all day and no sputter but after i drive a bit it stalls out and i have to let it cool for like 25 minutes before i can drive it again for another 10 minutes.

I changed out the ignition switch, the fuel lines seem to have pressure (alot of comes out when i depress the check valve) the only thing that seems out of place is when i test the power going to the fuel pump it will read 10.5-11volts. Back when i installed second pump and had no spark i was also getting low voltage readings on wires going to coil.

I've glanced over wires and there doesnt seem to be any bad ones. My grounds seem okay as everything else will power up (headlights, radio, etc) it only stalls when i drive which makes me think its something with the wiring perhaps around the area where it goes over the trasmission, maybe when it heats up from driving.

Has anyone gone though something similar or any thoughts, or maybe i just got 2 bad fuel pumps in a row?
 
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