I have a 1990 Montero In My backyard It ran fine when I put it there I was doing the brakes Over a three week period I went to start and Nothing. It turns over but doesn't catches I have charge the battery up and nothing. Is there a way to check the fuel Pump? is there any fuses for the fuel Pump? I have a 1988 Trooper it did the same thing I finally figured Out it was two Fuel Pump Fuses under the hood.

How Do I check the fuel Pump?
How DO I Check If I'm getting A Spark?
Any Help Will Do. I have A backup Computer and Distributor Also I can try That too.

To test for spark, you can remove one of the plugs and with it's wire attached hold it near the block while cranking the engine. It should arc when you do this.

I'd check for spark b4 checking fuel. I don't have an easy way to check if the fuel pump is working. Others will though.

like off roader said, check for spark, my guesses right now are-

coil
power resistor thingamajig next to the coil
ecu.

its got to be something simple. from my experience, ecus and dizzys dont go bad from sitting for 3 weeks. fwiw, id go through the electrical system and make sure that every thing is clean and that your electrical connections are properly seated. as for the fuel pump, you can hear if its working. if your really curious... you can pull up the carpet in the cargo bay (phillips screwdriver), remove the access panel (12mm socket or wrench) and the fuel pump is right there(you can pull it and check the sock in the tank, youll need a 8mm and be very carefull because if you break one of the studs... you swear... alot). if you pull the pump, its kind of a pita to get it seated again... and dont even get me going on the rubber gasket. but, i would doubt that your problem is fuel... i think its electrical... something simple that could easily be overlooked. since it has been sitting though, if schlack has built up... you may want to consider removing the air intake where it hooks up to the planium and try a little bit of starting fluid. it worked for me to make mine burn out a couple of quarts of oil that got into the intake when i rolled... made it burn it, would do the same for schlack.

I would start by checking spark and gas. Make sure your plug boots and coil wire boots are seated all the way on the plug and on the cap. Crank the engine over for a few seconds and pull a plug and see if it is wet with gas. If it has gas on it, wipe it off and put the plug wire on it and ground the plug and have someone crank it over and see if it sparks. Yellow orange spark is weak, blue white spark is strong. I have seen before where truck had spark but it was very weak and did not run. Also make sure all electrical connections are tight. Make sure there is gas in the truck. I have seen before a guy tried for 3 hours to get a car running. I asked if he had gas, he said yes, it turned out his gas gauge was broken. You never know. It has to be something simple.

Since I have a couple of Monteros in my back yard. I took the ECM out of a 89 Montero and put it into the 90 and it started right up. I guess the ECM is bad. I have to open it up and take a look. Now I have two great running GEN 1. I like the GEN 1 better then my 99.

I believe the 89 ECU is different from a 90 ECU.