94 jeep wrangler yj 4cyl no start

Ive been doing maintenance on my dads old jeep so my brother can take it to Dallas…it ran fine just doing routine maintenance on it making sure everything was in order… long story short one night some one stole the battery removed it properly and didnt damage any wires… i replaced the battery a few days later and now the engine will not start… ive already replaced fuel fillter, sparkplug wires, coil, sparkplugs, i cleaned off the crank shaft sensor its also had an oil change and now it just wont start… ive been able to get it to start with starter fluid, it runs for a few seconds and then dies…the last thing i noticed is after considering droping the fuel tank i checked if the fuel bar had gas in it… i removed the black cap and drained some fuel but not emptying it… i tried starting it a few times and then checked it a while later and noticed that no fuel came out this time all this leads me to think something is wrong with the fuel sending unit… any suggestions or test to run?? anything would be great and much appreciated.

Find the fuel pump relay and put a jumper from pins 30 to 87 and try to start the engine. If it starts and runs that relay may be shot or the computer is faulty and fails to trigger the relay. To make the correct connections remove the relay and read the pin numbers on the relay and jump from the slots in the relay housing that match the relay labels.

Here’s a long shot. Some vehicles won’t start after you replace the battery. Unless the computer was kept powered up in between. The reason is that the computer is always monitoring the engine, and making adjustments for changes it notices. LIke it might notice the throttle body is getting a little clogged, so it will open the throttle a little more at idle, so the engine runs smoothly. So the computer is learning by doing, to keep the engine running well.

All those “learned” parameters are stored in the computer memory. Which is all erased when the battery is removed. So the computer doesn’t remember how to keep the car running. In some cases the only way to start the car is tow it to the dealership, where they can program it with some special parameters that will allow it to start. Once it starts and runs, after a couple days it will relearn all the parameters.

And I recall that early 90s Wranglers ran the fuel pump ground wire into the cab, grounding against the floor near the clutch pedal. That ground can become corroded and fail resulting in the fuel pump failing to operate.

i checked the fuel relay its fine… im thinking its the gas pump im not getting any gas in my fuel rail and i just replaced the fuel filter i also cleaned the injectors they had a little build up but not much fairly clean… when i put the key into the on position i hear the fuel pump click once. is it suppose to click more is there an easy way to check if the fuel pump is good without dropping the gas tank??

A failed fuel pump would be too coincidental for me. Sure you can pressure test the fuel system, I would be looking at fuses, fuseable links and anti theft systems first, just in case the batttery removal was not up to par. Also double check pos and neg on the battery along with connections. I had 1 case on a side post battery the rubber protector was not actually allowing contact. Does anything indicate you are getting power from the battery? dome lights etc? Maybe a bad battery,

I don’t think a 94 would have the issue of not starting if the battery is disconnected.

A fuel pressure gauge hooked to the fuel rail will tell you if the pump is running. It’s normally a humming noise…the chick may be the relay.

After you replaced the fuel filter, did it run at that point?


Did it run fine before the battery was swiped?

It could be that when they swiped the battery they shorted out the system and now you have a fusible link that’s bad.


ive checked all fuses and relay, i have power, engine wants to start just never will it worked fine before the battery was stolen now it just wont get fuel, it has no anti theft system and when i say no fuel i mean like not a drop… is there anything else other than power to the pump that would be causing me not to get gas aside from a failed pump ive read on a few forums it could be the PCM but im really hoping not

It may be equipped with a fuel inetia switch that if popped usually as a result of a collission would prevent fuel getting to the engine.

@Yosemite is probably right, a 94 wouldn’t usually suffer from the ECM learning problem. I think that problem was more common w/Fords and GM, models in the late 90’s, early 2000’s. But it wouldn’t hurt to verify by asking at the Jeep dealership to see what the techs there think. Visit at a time when they aren’t busy and someone there will likely offer up some free advice.

You think it is a fuel problem? I’m presuming this vehicle has an electric fuel pump, fuel rail, and electronic fuel injection, as most did in the 90’s. If the pump is running, the fuel rail should be pressurized at spec. Is it? Did you make the measurement? And just b/c the fuel rail is pressurized, that doesn’t mean any gas is being injected. For example the ECM won’t inject gas unless it detects the engine is rotating. So there could be a problem with whatever detects that, like the crank position sensor. There’s a tool that can detect if the injectors are being pulsed, or a stethoscope-technique can be used to hear the injector “click” when it is pulsed. Have you done something like that yet?

An engine pretty much has to start if it has spark at the right time, fuel, air, and compression. Since this all started with the battery removal, focus on the things that require electricity, the electric fuel pump, and the ignition system. You have to narrow down which of the 4 above functions isn’t working.