Injectors - no fire

So my 1993, 4.0 XJ has been sitting for about 2 a year and a half and now won't start. I have narrowed it to an injector issue but not sure if it is the positive or negative side.
To get to this point here is the troubleshooting I've done:
- I can hear the fuel pump prime
- Tested fuel pump by pulling fuel line at the rail and jumping the pump relay (fuel flowed quite good)
- If I spray starting fluid/spray gas into the throttle body it will run until I stop it.

This leads me to believe that it is either a voltage supply, ground wire or ecu issue.

Not sure which step to try next.
1) See if I can find where the positive line (GRN/ORG i think) sends power to the injector from and test that. Not sure I have the right wiring diagram - the one I have shows power from the distributor to positive side of injector)
2) Borrow a set of noid lights to see if they light up on any of the injector lines. If no light then trace wires from there.

If anybody has thoughts, suggestions, complaints, etc. I'm totally open to listen. I'm trying to get this back to running to either sell or use around the land we're going to buy - it's be better than a UTV because it has AC.

Noid lights is where I would start. Good luck, a fire but no injector pulse condition is very hard to figure out. I can recall it coming up a few times before, but can't remember how or even if it was ever resolved. Prepare the parts cannon.

Unclewolverine said:

I can recall it coming up a few times before, but can't remember how or even if it was ever resolved.

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Yeah, the searching I did here and the Google did not give a lot of good results.

Unclewolverine said:

Prepare the parts cannon.

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Unless we decide to keep it I won't be spending much, if any $$ on it. I'd rather cut my losses and part it out than fight with it in 100+ degree weather just to get it running and sell it.

Thanks foir your input!!

You need a fuel pressure gauge to properly test the pump.

Injector B+ comes from the ASD Shutdown relay in the PDC. The PCM then grounds each injector to fire.

You can try swapping relays around.

could be the camshaft position sensor not sending the signal to the PCM. its the flat plastic piece under the rotor button that is under the distributor cap. My friends 95 XJ did the same thing.

Saudade said:

You need a fuel pressure gauge to properly test the pump.

Injector B+ comes from the ASD Shutdown relay in the PDC. The PCM then grounds each injector to fire.

You can try swapping relays around.

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I figure as fast as fuel was flowing there would be enough to get a sputter out of it but it does absolutely nothing.

I did swap relays but I can't remember if I did the ASD or not, iot's been a couple of weeks.

Da XJ nut said:

could be the camshaft position sensor not sending the signal to the PCM. its the flat plastic piece under the rotor button that is under the distributor cap. My friends 95 XJ did the same thing.

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I will keep this in mind! First I've read about this being a possibility.

Ditto on the cam sensor.
Try unplugging and replugging it a
few times to clean the contacts.

But he can get it to run on starting fluid, which implies a good crank and cam sensor. ASD relay would be my first guess, and I would check for +12-volts to the injectors.

lawsoncl said:

But he can get it to run on starting fluid, which implies a good crank and cam sensor. ASD relay would be my first guess, and I would check for +12-volts to the injectors.

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I did wonder if the crank/cam sensor would stop spark but don't know enough about these and haven't fully studied the wiring diagram.

cam sensor only sends signal for the injectors, Crank signal works the coil pack for ignition to the spark plugs. cam sensor is for the fuel injectors only.

Da XJ nut said:

cam sensor only sends signal for the injectors, Crank signal works the coil pack for ignition to the spark plugs. cam sensor is for the fuel injectors only.

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Not true. Both are needed to set the timing. The crank sensor is the main sensor to determine crank position and synchronize the spark and fuel. The cam sensor is needed in addition to the crank position to determine which stroke you're on. If either are not working, it will affect both spark or injection.

(The exception is the older Renix Jeeps where the computer seems to take a guess if the cam shaft sensor isn't working, and it' really got a 50% chance of guessing correctly)