Dear Jim,

I have a 1991 Jeep Cherokee (4.0 L, straight-6) and I've been having major trouble starting it in the morning. It just keeps cranking and I have to keep pumping the pedal before the thing will finally start up. When the car is already warm, there's no problem starting it again. This has been going on for a while now, and I've had the fuel pressure regulator replaced and the whole multiport fuel injection system serviced. Do you know what the problem is?

-- Carey Gumm

Sounds like you've made some good guesses so far, bro, just not the right one yet. You know you're having a problem with fuel getting to the engine, but I'll bet it's something that's happening before any gas gets to the fuel injectors. Your particular vehicle has an electric fuel pump inside the gas tank. These units do eventually go bad, just like anything with moving parts, and yours has probably had enough.

Whatever the reason for it conking out, you'll need to replace the fuel pump and see if that makes this cold starting problem go away. The good news is your '91 Cherokee has a pump that can be replaced without removing the whole gas tank. The mechanic at the shop can just loosen the tank instead, and that should save you some labor on this one. By the way, there's also a screen filter that snaps onto the fuel pump -- make sure they replace that too.

There are a few more things to remember about these devices, bro, so let's just make it our...

Tip of the Week

You can help your fuel pump last longer by making sure the fuel filter gets changed often. Dirty filters make the pump work a lot harder to get the job done, and that's always going to shorten its life span. Keep adding those fuel injector cleaners, too -- one bottle every three or four tanks. Also, try not to let the gas level get too low before filling up. Most of us do this sometimes, but a nearly empty tank means more heat, and that's bad on a fuel pump's bearings. Keep the tank at least half-full to help cool things down.

Last but not least, try not to turn the car off and on again a few minutes later. You know how flipping a light switch on and off wears out the bulb? Same thing with these guys.

Buffalo Jim, owner of Allstate Auto & Marine Repair in Las Vegas, writes a weekly column. Send your automotive questions to him at buffalojim@lasvegasniftynickel.com. If Jim picks your question to answer in Nuts & Bolts, you'll also be the proud recipient of a deck of official Buffalo Jim playing cards, presented in a classy, tin box bearing his hairy image.