91 jeep yj wont start

If the injectors do not fire, fuel in the rail does not matter since it's not getting gas into the engine. Look to see if your check engine light comes on, when you turn on the ignition. If it does not, then your ecu computer is in need of repair since it's not sending either a spark or fuel injector signal to fire up your jeep.

try a new coil.some times a new coil will fail

If the check engine light does NOT light up on the dash when you turn on the ignition, then your ECU is in need of repair. The engine will only start after the check engine light comes on and the ecu is what controls that. It's likely going bad, causing the delayed start problem typical of early 90's jeeps. Repair or replacement services for your jeep ECU are available on ebay.

it sounds like distributor check for spark when it wont start if there ig no spark then its faulty

sounds like you are working on a car FSM free?
why do that?
95 YJ
early wrangler
i have 95 yj fsm and 93, the 93-95 are a year class range.
very simular.
here is a free 93 fsm with full schematics in chapter 8w
wiring chapter, clik
pdf 76 is page YJ 19 actual
and as you can see its cave man simple 2 wires.
minus to ECU ignitor driver. transistor (inside ecu)
and
+ goes to
a142 sheet 5 (pdf 62)

im not sure what part A<B<C is, a fuseable link, is my guess
and is blown. but that be a bingo spot for sure.
the full manual is there.
see spark chapter.
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service

posted over 100 times, this link, its not new.

Check your engine to see if ,it has a yellow or blue spark and if it does then check your fuel filters and fuel pump to see if they are working or not.

Can you explain more so I can help. What do you mean still wont turn on, engines doesn't start or starter motor doesn't turn. Have u taken out a spark plug and connected it to the cable put the end of the spark plug to a ground and make someone turn on the engine for a few seconds you should see some blue sparks. Carefully use gloves. If no sparks, spark plug is bad next thing to check instead of putting the spark plug in the cable put Philips screwdirver put the screwdriver near a ground not touching about one inch make someone turn the engine for a couple of second you should see the spark jumping from the screwdriver to the ground, If there are no sparks ignition coil or spark plug cables are not good. But u say u changed ignition coil so maybe your cables are not good. There is a connector near the ignition coil disconnect it and turn ignition switch on measure the voltage you should have in between 12vdc + or - .5 vdc if no voltage present there is a blown fuse, Check for it

No spark and no fuel pressure? That sounds like a bad ECU. I would check the ignition coil, and the signal coming from the ECU to the ignition coil. Then I would check the voltage going to the fuel pump. Next, check the timing belt and make sure the correct timing is set.

When you turn your key to the ON position, you should hear your fuel pump pressurize for a few seconds.


I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

Sounds like a bad distributor control module. You blew-up your muffler because there was no spark.....lots of fuel in the exhaust....then an intremittent spark......BOOM!
Once the module cools off, it works again, because the crack in the circuit board re-connects....until it gets hot again, and opens the circuit........no more spark. Replace the module.

It would be great if you could find the Ignition Control Module!!! From my experience on my Jeep...90 YJ 4.2 liter carb. it does not have one...Computer controlled only...