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This video shows you what it's like to see this 1991 Jeep Wrangler YJ which has a similar fuel system to other Jeeps like the Cherokee XJ, and see how to fix a common problem with these SUVs.
Long crank time
Long engine crank time
Engine slow to start
Engine takes a long time to start
Hard starting
Slow cranking
Extended crank time
Engine Starter takes a long time
Slow starting
Extended crank time
takes a long time to start
hard to start
The problem with this vehicle, is that the fuel line check valve, which is located on the fuel sending unit that's inside the gas tank fuel tank, is not working properly. So what happens is, that after the engine is turned off, the fuel pump also turns off and stops working. Since there is no more fuel pressure, all of the gasoline fuel that is inside of the fuel lines, drains back from the engine, through the lines, through the fuel filter, and back into the gas tank. This is because the pump isn't keeping pressure on the fuel anymore.
Then, the next time you go to start the engine, it takes a really long time, because you have to wait for the fuel to make it all the way up to the engine from the fuel tank. This stinks, because if the check valve was working properly, it would close after the pump is turned off, and it would hold the fuel in the line, so it's there and ready to go the next time you want to start the engine. But this is not the case.
So you can always try to use the key to "prime" the fuel system, which is something that the engine computer ECM PCM also tries to do as well, automatically. Every time you turn the key to the ON position, the computer also turns on the fuel pump to prime the line. But the computer on these older Jeeps only primes for 1 second. This is obviously not enough time for the pump to refill that really long fuel line. That's another reason why it takes so long to start. So you can always cycle the key ON and OFF a few times, but the computer will only try to prime twice, which is a total of 2 seconds, again, not enough time to prime the entire line. Plus, when the one second prime ends, the fuel just drains back again! Stinko!
So you can fix this in a few ways. Put in a momentary "priming" switch, which turns on the fuel pump while you press the button. That way you can manually reprime the line each time. But this is costly, time consuming, and makes it difficult when someone else is going to drive your car. You can also fix it the right way, and go buy another fuel sending unit. But this is the most expensive way to fix it, because the sending units can cost upwards of $200!
Instead, you can install a oneway check valve like it was done here with this Jeep. The check valve is installed just after the fuel tank, which keeps fuel in the line for most of the distance from the pump to the tank, including the fuel filter. These 5/16" fuel line valves only cost about $2 on eBay, which is so cheap, it's totally worth the price, even just to try it and see if it will solve your problem (which in this case it did work, and it works great. Yeah!)

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