Topic: Fuel pump removal, easy/hard? problems keep coming am i in over my head???

[stan98tj]

so after i replaced the detonated piston, honed out the cylinder walls and put the engine back together, i took it to a mechanic to have it inspected and figure out why my 2.5l 98 tj is still starting hard and why my gas miliage is between 7.5-9 mpg..he tells me my fuel pump is shot and needs to be replaced for $850....can't swing it.  I wanna attempt to replace the fuel pump myself but im not sure if im getting in over my head or not...has anyone replaced one...is it a hard job, anything to look out for or tips you could give me would be appreciated. This is just so frustrating...ive had it for a month now and drove it all of 1 week before it broke down
(by starting hard i mean i cant start it-cold or hot-without putting my foot all the way down on the gas where it may or may not start the first go around and should i not press my foot all the way down then i have to wait about a minute before trying again...usually it starts then)

[Jeffy]

If you were able to replace piston and do all of that work then replacing a fuel pump is easy and should save you $$$ from his quote.  You have two choices.  One is to replace the in-tank pump.  The other option is to add a inline pump and just leave the stock pump.

To get to the stock pump, you'll need to drop the tank which isn't too hard.

[omnisi]

Should be pretty much the same as this.  I used it to do my mod... just swap out the pump instead of cutting the vent tube...

http://bigredheep.com/~jeepwra/forumnews-id-3934.html

[jagular7]

If you have a 98 TJ and press on the pedal to get it started, then I'd say there is probably nothing wrong with the fuel pressure. Problem is probably the idle air valve on the throttle body. The throttle body looks like a carburator, but it just lets air into the engine. When at idle, with the throttle plate closed, the air idle valve feeds the air to the engine. I'd take it to another mechanic to get another opinion if you don't like to analyze and perform the work yourself. Take it off, put in on the bench and clean it up with non-carb cleaner. Use a toothbrush and get into the crevaces as best you can. Q-tips work great for the inside corners. If you start to take items off it, they have gaskets to them and you may damage them.

To add, there is a crank sensor which tells the computer when to throw the spark to the cylinder. Your spark may not be strong enough to start the engine from a cold start. Coil, distributor cap, wires, and spark plugs would be a good start of getting it tuned right. Check the fuel pump pressure also.

I have a 97 TJ and provided a little info about gaining a larger gas tank for the 4cyl by trimming a little return tube within the gas tank.

Heck, do a quick self check by turning the key to the run position 3 times (not start but run). On the 3rd time, leave it on 'on' position. The OBD (on board diagnostics) will tell you codes that will lead you to the problems.

[aw12345]

If you have to floor it to get it started then its very well possible that its getting flooded. Like a leaky injector.
Either way buy a fuel pressure gauge measure the fuel rail pressure idling and while driving at full throttle if it maintain the correct fuel pressure the pump is ok and does NOT need replacement. If that is ok pressurize the fuel rail and see if it will hold fuel pressure if need be block or pinch the return hose. If all of that is ok it goes back to your original problem that made your engine fail. So all I can say is happy hunting, but do find whats wrong or you will toast the engine again. If it goes back to injectors or you cannot find anything else wrong maybe time for some of those snazzy ford 19# injectors

[omnisi]

. If it goes back to injectors or you cannot find anything else wrong maybe time for some of those snazzy ford 19# injectors

I think its 24# injectors for a '98 if Im not mistaken....thats what I put in my '99....

[jfrabat]

he tells me my fuel pump is shot and needs to be replaced for $850....can't swing it.  I wanna attempt to replace the fuel pump myself but im not sure if im getting in over my head or not...

First off, I dont think that the problem is a fuel pump, but for your information, I am really a rookie mechanic (just started toying with the Jeep about a year ago!), and the first thing I was forced to do was to upgrade the fuel system because of a fuel pump problem and a broken fuel rail that was leaking fuel into the exhaust manifold (NOT GOOD!).  Based on my experiences with the '94 2.5L, for which I replaced the fuel pump assembly, replaced the fuel rail and fuel pressure regulator, and replaced the 4 injector with the Ford ones, that this is most defenetely a fairly simple job (I did it with only my wife helping me partially for lowering the tank).

And all the changes I made were not even close to $850!  I paid $44.45 for the O2 sensor, $171.50 for the injectors, $108.90 for the fuel pump assembly (complete assembly!), $46.96 for the tank fill and return hoses (I decided to change these as well, although it was really not necesary), and $69.95 for the fuel rail (including the fuel pressure regulator).  I dont remember what the fuel filter cost, but I also replaced it (but those are fairly cheap if I remember correctly).  The rubber gasket for the fuel tank was about $8, and I also bought new lines for the two small lines that go on top of the tank (the rollover things; I forgot the name).  So for about $450 I did much more than what they are charging you $850 to do.

The only difficult (as in time consuming; not so difficult really) is getting the tank back in place (you will need a floor jack to do this).  Just remember to tighten everything up real nice, because if you were to leave the tightening rings loose, you will have a VERY SIGNIFICANT fuel leak, and you will need to lower the tank once again to get it fixed because there is not enough space between the tank and the body to get your hand in there (trust me about this one, and dont ask how I know!).

In my case, for your reference, the problem was that on hot days, after the engine warmed up, the engine started sputtering.  I never did have a problem starting up, but since I changed almost the entire fuel system, I think you can get a good idea of the costs. 

As for times, lowering the tank and changing the fuel pump took me about 1 day worth of work (but I was going very carefully).  The second time around (when I had to fix the tightening collars), it tood me about an hour because I already know what I was doing.  The fuel rain and injectors will take you one hour or so even on the first try, as it is easy to reach it, and there are not so many screws to get out.

So my advice to you if you have problems with the fuel system, is to change your injectors to the mustang ones (I dont remember if it was the 24# or 19#, but you can search here for Jeffy's post and find the right ones), and if you still want to change the fuel pump and fuel pressure regulator (and change the filter while you are at it), go for it.  Also you may want to increase your fuel capacity, and if you are already lowering the tank to change the fuel pump, better do it then, as I did it before with the tank in the Jeep, and got a couple of bruises to my arms as a souvanier (the space is very tight with the tank on, but it would be a joke with the tank down!). 

Just remember go online and do some price hunting, as there are some good deals out there that will save you some money...

Felipe

[stan98tj]

thanks so much for the info..will update soon. goes into a jeep dealership on monday to have em check it out.