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Detailed fuel pump problem on my 93 - humming n worse

-If you do the JY run get the whole system, the regulator for sure. (here pull-a-part JY are pretty good source)

-Did that origional fuel pump get tested by you? The Orig owner may have goofed and its ok, problem some other part.

-That pump, lines, regulator, electrics, vaccuum- not really a whole lot of stuff to go thru. just have to dig thru it.

-on the polarity- as i understand it - they do just plug in But the wires from the plug to the actual pump motor inside the pump assembly are crossed.

Good Luck

orange
 
I see a lot of good suggestions. The loan a tool / tape guage to the window sounds pretty redneckish but could give me more information so I'll give it a try. :)

If i can get that pressure guage from autozone I could also do the capacity test at the same time.

I have not got around to work on the Jeep much lately but I appreciate your suggestions, at least now I have a few more cheap things that I can try myself.
 
Today I replaced the fuel pump relay, checked all of my vaccuum hoses for leaks, and checked all of my fuel lines. I have absolutely no pinched, dented, or in other way blocked lines. I flushed both the gas line and the return line from the engine back and blew them out with air..no clogs. They were/are clean.

I was wondering though, the gas line that goes from the fuel pump to the fuel filter (short foot and a half hose), is it directional? One end has a tighter turn than the other end, does that have to go to the pump or to the filter?

Also, if the vaccum line that goes from the tank to the Pollution Pump was leaking vaccum, would it affect the performance of the pump in any way? Below is a crude diagram, but the vaccum line in question is the top one on the picture. It goes from the 2 white vents on the top of the gas tank to a t splitter, then through a metal line to the front of the jeep and connects to the pollution pump.

21bljlz.jpg
 
wim hoppenbrouwers said:
Hallo Nick XJ. The fuelfilter is directional. 3/8"in and 5/16"out. :eeks1:


'92 XJ
Click to expand...

yes, but is the hose connecting the fuel pump in the tank to the fuel filter directional? As I said one end of the hose has a shallow bend and the other end has a sharp bend. Does the sharp bend connect to the fuel pump or to the fuel filter? or does it not matter?
 
Nick_XJ said:
yes, but is the hose connecting the fuel pump in the tank to the fuel filter directional? As I said one end of the hose has a shallow bend and the other end has a sharp bend. Does the sharp bend connect to the fuel pump or to the fuel filter? or does it not matter?
Click to expand...


it would only be directional if the ends/connections where different sizes. that would be so it could connect to the filter and fuel pump assembly. if they are the same and type fitting, then they are not directional. if you take it off and blow through each end, you should be able to get air coming out unless there is a check valve built in, which you would see.

as for the vacuum hose leading to the charcoal canister, i doubt a leak will have an affect on the pump. that line is a vent line. just reattach/fix the line/hose.
 
all of your symptoms are pointing to an overheating pump.

assuming that the shop really verified the proper voltage and the pump is wired correctly, there aren't many more reasons that it should be overheating. The checks you've performed and parts replaced rule out most of the other causes.

I would suspect a poor ground for the pump in this case. The best thing you can do (for little to no $$) is run an additional accessory ground to the chassis. It will never hurt to have a better ground and it can eleviate that as a cause. Also, verify a good connection from the pump body to the sending unit assemble as well and you can scratch a poor ground off the list for a couple bucks in wire and a little of your time.
 
try checking the connector from the main harness to the pump. its under the rear seat. may be corroded... michigan and all...
 
orange with blue strip, if you lift the back seat, towards the top(junction of top half of seat) you will see a little square cut in the carpet, your wires are right under there, if not stick your hand in and reach for center, you'll find them
 
dying to hear the final results on this, Nick I know you're frustrated, but watch your tone on here, everyone is just trying to help, they don't have to, so relax and be patient, and a few dollars for a paid membership when the problem is solved would be a nice show of appreciation.
 
Nick xj- 'tween jobs' is a Really BIG Stress. Hang in there!

If we can be of help with the Jeep, We are Happy to help.

Good Luck,

orange

-
 
Update finally!

I spent the weekend working on my Jeep. I purchased a fuel pressure guage to find out exactly what is happening. I let my Jeep idle for 45 minutes and the pump didn't hum at all. The fuel pressure was rock steady at 33psi. After 45 minutes I ziptied my pressure guage and took it for a drive while it was still hooked up. Sure enough 5 mins after driving the jeep the fuel pump started humming. I took it back home and checked the pressure guage. Now the pressure had dropped to 29-31 psi and was jumping back and forth. I revved the engine and the pressure dropped to 20psi, I revved it harder and it dropped even lower. So I have determined that my fuel pump is giving out after it starts humming, but I still have not figured out what causes it to hum.

At this point I figured i'd replace the fuel pump again just to be safe, so I dropped my tank, took out my fuel pump, and took it back to Autozone to get it replaced only to find out they sold the pump I ordered to another customer!

So I decided I would just bite the bullet and pay the difference for a better bosch pump. Turns out Autozone does not even sell any other pumps than AirTex. I called Advance Auto who said they had a bosch in stock so I returned the AirTex pump to Autozone for "store credit" (cuz they wouldn't give me money back) and headed for Advance. When I get there, they go in the back to find the pump and realize their inventory is off and they dont have one. When they tried to order one, it turns out the Bosch pumps are discountinued. Advance only sells Airtex, Bosch (well they used to sell Bosch), and an offbrand that they dont even have any information on. All the local stores are out of everything except Airtex, so I left Advance with nothing.

What I did find out is that I can buy a Bosch fuel pump from Chrysler for 90 bucks, but it has no sending unit. Unfortunately I turned my origional fuel pump in for the core and gave the Airtex pump back to Autozone....so now I am without a sending unit even if I did want to buy just the pump.

I called Napa and its 215 bucks for a rando Napa brand Fuel pump/sending unit combo...which I was told was way overpriced for what I would get. Soooo, does anyone know where I can purchase a fuel pump/sending unit combo that would be better than buying another Airtex?
 
i believe the napa unit is a carter. just fyi.

have you checked on the price of an oem unit at the dealer? (i mean the module not just the pump?)
 
Don't tel anyone, but here is a discount code for Rock Auto to save 5%. Put it in the "How did you hear about us?" 2D0FBE50D45C When I emailed them for a NAXJA discount code, they wouldn't give me one. This one is actually from a different anonymous forum.
 
Nick_XJ said:
....and headed for Advance. When I get there, they go in the back to find the pump and realize their inventory is off and they dont have one. When they tried to order one, it turns out the Bosch pumps are discountinued. Advance only sells Airtex, Bosch (well they used to sell Bosch), and an offbrand that they dont even have any information on. All the local stores are out of everything except Airtex, so I left Advance with nothing.
Click to expand...

I'm not sure which store you went to, but for future readers, the Bosch pump has NOT been discontinued and there are currently close to 100 of them sitting in Advance warehouses awaiting purchase.... sorry for the runaround that you seem to have gotten-- I just hate when stupid people in retail try to cover their incompetence with B.S.

rant over:peace:
 
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