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Unread 08-15-2013, 03:06 PM   #1
stacy1993joop
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1993 wont start have 12 volts at coil

i have searched and checked and replaced the caps in the ECU, changed the coil and it started and ran for 10 miles and stopped running while driving it and wont start again, checked all fuses, switched relays in power box by battery, turn the key and get a cel +hear the fuel pump run but no spark out of the coil or plug wires,have changed the crank position switch and im going to replace the ignition switch because its only 13 bucks. if that doesn't do it Ive got a distributor on its way. is the cam sensor in the distributor? & if that doesn't do it what should i do next?
and when towing it home last night with the emergency flashers going w/ head lights on the head lights started to blink off for 30 sec. and come back on is this normal.
sorry if i am rambling on.

thanks Stacy

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Unread 08-15-2013, 04:42 PM   #2
Que89YJ
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That headlight is not normal. Are you sure you don't have an alarm system? The distributor should come with the cam sensor installed. Did you check for fault codes?
http://www.jeepforum.com/forum/f12/h...codes-1257145/
You need to see if you are losing fuel or spark. Check the fuel by depressing the valve on the fuel injector rail and see if fuel shoots out. Check spark by putting a screw driver in the plug wire and hold it close to ground and look for the arcing.
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Unread 08-16-2013, 08:56 AM   #3
stacy1993joop
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I checked codes and have the normal codes 12, 33, 15, 55
i have fuel
don't have spark at the coil. (but i have 12volts at coil female plug w/key on)
i have replaced and checked-
coil (3 times first one started the jeep and drove for 20 min and then the jeep died from no spark)
new distributor
new crank position sensor
new ign switch
3 caps in the computer
checked all the fuses w/ meter everyone of them just not one the forums say to check
unplugged the VSS
have 12v to coil when i meter across the coil plug with key on
grounds look good.
i have metered pin 3/9/11/& 12 for 12v & grounds
checked the ignition switch red and yellow for power and thats good


can i hot wire it some how?

Last edited by stacy1993joop; 08-16-2013 at 10:06 AM..
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Unread 08-16-2013, 09:18 AM   #4
Que89YJ
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The ecu supplies ground for the coil. If you are getting power to the coil and no spark then the ecu is not switching ground. That usually points to a cam/crank sesnor issue. You replaced the crank, did you replace the cam/pickup in the distributor yet?
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Unread 08-16-2013, 10:05 AM   #5
stacy1993joop
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Yes I replaced the distributor and the crank sensor.
should i try another crank sensor? is the metal bracket on the crank sensor a ground or just a bracket?
does the crank sensor need any adjustments or does the flywheel trigger need cleaned?

what computer pin fires the coil and what is the Chain of events as in computer pin 11 first to crank sensor to coil to distributor? so i might jumper wire the circuit and see if that works. or is that a dumb idea?

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Originally Posted by Que89YJ View Post
The ecu supplies ground for the coil. If you are getting power to the coil and no spark then the ecu is not switching ground. That usually points to a cam/crank sesnor issue. You replaced the crank, did you replace the cam/pickup in the distributor yet?

Last edited by stacy1993joop; 08-16-2013 at 10:28 AM..
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Unread 08-16-2013, 11:28 AM   #6
Que89YJ
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No way to jumper around the crank/cam syncing. When you turn the key the sensor voltage is applied and as the engine is turned it pulls in the fuel pump realy and looks the the pulses created by the 2 sensors to figure out where the position of the pistons and the cam is at. When it sees the 2 in sync it starts pulling ground on the coil through pin 19 on the ecu. The way you are describing the issue it sounds like you either have a short/open in the sensor lines for the cam/crank or a bad ecu. I have seen an ecu fail in the exact way you are describing. Hank here on the forum went through hell with an exact type of issue. I think you need to see if there is anyone with a 91-95 wrangler or XJ with the same engine trans type in your area and just try a swap to see if it works. If you do need a new ecu I can point you to the right place.
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Unread 08-16-2013, 01:48 PM   #7
stacy1993joop
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I have a renter that has a 95 or 96 Wrangler and i know its a 4 cyl and five speed will that work if i swap his ECU
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Unread 08-16-2013, 04:48 PM   #8
stacy1993joop
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ok so i swapped the ECU from one jeep to the other and my jeep wouldn't start so i put my computer in his jeep and it started no problem & ran good. so my computer is good , also swapped the old coil from my jeep to his and it started so the coil is good also so im heading to get another new crank sensor to try on my jeep.

what should i try if that still doesn't work?

the motor is greasy from the owner before me taking the PVC valve off and it looks like it has just been building up a nice layer of oil for some time.

this is very frustrating
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Unread 08-16-2013, 04:57 PM   #9
Que89YJ
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Pull the cap off the distributor A's make sure the rotor is spinning when you crank it.
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Unread 08-16-2013, 05:09 PM   #10
stacy1993joop
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yep its turning
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Unread 08-16-2013, 05:19 PM   #11
stacy1993joop
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i bought this jeep not running and the PO said someone tried to steal it and they ripped out the alarm and it hadn't ran since that time. but i called the alarm manufacturer and they said the only thing that they could of tied into on the jeep was the yellow start wire off the column and it showed it. but was reconnected and tested ok

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Unread 08-16-2013, 09:34 PM   #12
Que89YJ
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That is a big piece of info. You have power to the coil and the ECU. So the next step is to check cam/crank sensor power, ground, and continuity from the signal on each to the ECU connector. You sound like you can handle a meter so can you reading the wire diagrams? If you cant I will walk you through it. How much did you pay for the jeep? We can get you going. I have a decent handle on the electrical as long as you are patient.
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Unread 08-16-2013, 10:47 PM   #13
DirtKar
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You are a good man, Que. I'll be watching this thread to see where it ends up.

The headlight flashing seems like a decent clue and very alarmish depending on the frequency of the flashes they produced. Were the flashes rhythmic (alarm?) or would they be described as random(faulty/intermittent ground)?
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Unread 08-17-2013, 07:04 AM   #14
Que89YJ
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I am betting the ground.
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Unread 08-17-2013, 08:18 AM   #15
JWELK
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Another possibility is a "spread" pin on the ECU. Also check the "ground' wire from the ECU to the coil. Do you have access to an oscilloscope? If yes, you can check for pulses on the above "ground" wire. You might be able to see a "flicker" of meter movement if you have an analog VOM. The "ground" side should be at 12 volts with momentary pulses to ground.
You don't want to know how I discovered these things.

Let us know,

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