Hello there, I've been having some problems with my 94 YJ 2.5L Jeep Wrangler. I bought it broke. It was a crank all day, no start. then one day over the previous winter I decided to try it again. To my surprise it started. Ive been testing things & replacing things.
So far I swapped out my gas tank with a good known to work fuel pump. I took the original tank and put it on the side. I put a new fuel filter in it.
I also replaced some fuses under the dash & PDC as they were blown when I bought it from the previous owner. I know there was one 10 amp in the PDC that needed replacing
This week I have replaced the spark plugs as I pulled them and found they were pure black with the smell of gas. It didnt take the new plugs long to look the same and smell the same with gas. They also look wet from gas. That was just a few quick starts and letting it idle.
The ECU seems to be okay as the check engine light does come on.
One problem I have found amongst my search over these months of fiddling with it was the power to the coil is 0.04. I checked the battery and i have 12.7 volts on that. I go directly to the coil wire (Key on) and I get 0.04 on the multimeter. I believe I have the multimeter set up correctly as I get a correct reading on the battery. I have tried to get some tests on some sensors, i.e. map, crankshaft position sensor, O2 sensor but I havent been successful at it as I think I using the wrong settings for ohms.
I have cleaned the throttle body on it. I have also cleaned the IAC sensor.
The jeep does have a wire mishap somewhere around the PDC/battery area. I know it cut out all power to the computer and everything was completely dead. I notice when I shake the wire loom that those wires lead to the front axle diaphragm is when it cuts power to everything. I havent been able to locate that yet and it hasnt happened lately. But then again I havent been using this thing as I work on it as funds & time allow.
I test the fuel pressure with this known fuel pump to be good and pressure held after shutdown and it also held over night. I did swap the fuel pressure regulator with a good used one I had laying around. I also pulled the vacuum line on the fuel pressure regulator while I had the testor on the rail. It jumped to around 39lbs off. And then returned to 31 or 32 when placed back on.
I have posted a recent video of when I try to start it for the first time of the day. Once it starts it seems to start much easier. No so many cranks to take it to fire up. But after it sits for a long period its back to usual with long crank times. I also noticed it is hesitation on a quick rev of the gas pedal. But if you ease it, it acts normal.
I put a new alternator on it as over time the original froze up on me. I also put a new serpentine belt on it. I just recently cleaned the screens on the valve cover along with a nee valve cover. The 4 bolts on the back of the valve cover were loose. When I bought it the motor and underneath was covered in oil. So over the months I have been cleaning everything up. Its looking much better than it once did now if I can only fix the problem to get it running better. lol!
I have enclosed a couple photos as well. One is how I have everything set up for testing the voltage to the coil plug. One is of the old plugs that came out. One is from after shut down showing the pressure held. One of is a blue wire that has been spliced with connectors on it by a previous owner.
A few things when funds allow in the future would be to replace the spark plug wires, cap, & rotor. I also want to buy a timing light to check the timing. Otherwise Im not really sure what else to do here and was seeking some advice on where to look next.
I did notice the front axle diaphragm is leaking. It looks like the whole housing is compromise some way. I see a gasket there but also see blue rtv added along with two large radiator clamps tied together to hold the thing on. I do see the housing has all 4 bolts on it as well. I have yet to dig into that. lol !
Here is the video link of how its acting.