1196 Jeep Cherokee no power to fuel pump

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#1
I have a 1996 Jeep Cherokee Sport with a 4 Lt engine. It died one day in town and had it towed home. The fuel pump has no power to it, but the fuel pump relay and the (ASD) AutoShutdown relay are both working. There is power at the relay station and to the relays that is next to the battery that these two relays plug into. I have changed the crank positioning sensor and the ECM, which I read might be the problem. Still it will no start. I don't hear a whine when I turn the key and there is no pressure to the fuel rail. This is a 1996 which has the fuel regulator attached to the fuel pump in the tank.

If someone can tell me which wires to jumper, I can test the pump to see if it works. There are 4 wires coming from the fuel pump setup. Thank you for the help.
 

dmk

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#2
When you are checking for power at the relay, do you have a constant power and a switched power? Have you started with the basics and checked all the fuses?
 
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#3
have you taken into acct- the fuelpump will only be hot (12v) for @5seconds when key moved to RUN or start? unless PCM receives a CKP referance signal

have you checked at the fuel pump for 12v?

was the ECM programed when replaced....please say you have old one still
no SES or security (SKIM) lights are on? It does Self test???

I will pull up somee wiring diagrams if you answer questions
 
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#4
Re: 1996 Jeep Cherokee no power to fuel pump, continue the ideas!!

Well, when my mechanic, who hate electrical by the way, ran power to the pump from the battery, the pump worked. First, what do you mean by switched power? Is it power when the key is switched on I assume?
Second, No we have not taken into account that there is only 5 second of power, but I have a new Crank Positioning Sensor (CKP) that would send a signal. And the ECM was out of a used 1996 Jeep Cherokee with a 4. 0 lt engine with auto tranny. It was tested and warrantied. I don't know what you mean by SES or security (SKIM) lights?
I hope this helps and tomorrow if it is not raining, I will check the power at the pump again.

Another question is: does the Jeep Cherokee have a reset button as Fords do that you reset it after an accident? By the way, the Jeep that I am fixing has not been in an accident for over a year, but it was in a front end accident prior to me buying it and I had to replace grill/radiator,bumper, etc. . .

Thanks to all who read and helped.
 
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#5
Re: 1996 Jeep Cherokee no power to fuel pump-me again

The Chilton's Manual says if I use a DRB II Scan Tool, it can activate the fuel pump. Does anybody know what a DRB I scan tool is besides a OBD II tool? And who makes it?

Sparkknock
 
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#6
Re: Sorry about this.

In the second sentence I meant DRB II scan tool as I stated in the first sentence.

Sorry,

Sparkknock
 
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#7
OK
SES: also called CHECK ENGINE or SERVICE Eng Soon.... jeep uses a little  ENGINE icon on dash.....Is it on? does it come on when key moved to run?

OBD II: is the ON BOARD DIAGNOSTICS.... II denotes second generation. The vehicles computer diagnostics system

DRB I or II- DEALER READOUT BOX ... the name of JEEPS scan or computer interface tool Ist or 2nd generation a hi end aftermarket scanner will surfice...as long as BI Directional..
   An expensive tool for a DIYer


SKIM - Security Key Immobilizer Module.. A  vehicle anti theft,  jeep uses a KEY icon to illuminate if a problem.... Do you see it during start?


No inertia switch

I will look and see if I can get the FP relay pin out.

Let us know about the SES and SKIM lights

check fuse #20
At the relay you can use a FUSED jumper to energize the Dark Green with a TAN or White tracer ....this would energize pump
wire may be Dark Green with Red tracer at pump connection
 
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#9
Re: 1996 Jeep Cherokee no power to fuel pump- replay

The check engine light comes on when the key is turned on, but not on otherwise. I tried to start it and it won't, then I put my cheap OBD II on it and it said, "No Codes!"

My Jeep does not have a SKIM light.

I will check fuse #20, but my Chilton says I don't have a #20, but I will look tomorrow at my fuse box. (?)

Also, I will jump the pump with a fused wire to see if I get pressure to the fuel rail and to make sure it is running. If it is running and I don't get pressure to the rail, I will check the fuel filter for a plug, but I changed it only 6 months ago and only drove about 10,000 miles. Maybe I am only getting the 5 seconds of run time and the filter is plugged. (?)

Check stuff out tomorrow.

Thanks,

Sparkknock
 

hector85

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#10
check your fuses if the fuel pump fuse is blown and keeps blowing every time you put the key forward check your O2 sensors on a chrysler vehicle i had same problem ended up being an O2 sensor shorting on frame blowing fuel pump fuse
 
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#11
Re: IT IS FIXED

I would like to thank everyone who has posted a reply. I was finally able to get to the Jeep today, and was check power to the pump and happened to slide by the fuel filter and saw that the pump was still un-plugged from before the crank sensor was put in. I plug it in and it started (image that). So I replaced the ECM that I just bought with the original and it still started. Thanks to my mechanic, I now have an extra ECM for my 1996 Jeep Cherokee Sport with a 4. 0 liter engine with automatic transmission. So, I have one to get rid of through ebay or something. Sorry, I can't sell it on this site.

But again, thank you all for all your ideas and help. If it wasn't for you people, I would not have crawled under the back of it and seen that my mechanic left it un-plugged. By the way, I chewed him out today and I think he is going to change a CV axle for me in my VW Jetta.
 

dmk

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#12
I'm glad you problem is fixed---
But remember...we all make mistakes and that is how we get better. You have said that your mechanic is not into electrical so maybe you should leave that work to someone else. :)
 
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#13
Re: Back to the problem again 1996 Jeep no fuel pressure

Well, it ran for 4 different time but now it is dead again with no fuel pressure. I am going to check out what everyone wrote and go from there. . I will post again later.
 
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#14
I guess you need to take your jeep to a specialist to let him fix or troubleshot the thing inside of your jeep, and there is a jeep cherokee site. You may check out some available models and parts. Of course the fuel efficiency of the new Jeep Grand Cherokee, just check it out...


_________________
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#15
Sounds to me like you have a bad fuel pump. Try having someone start the vehicle while hitting the fuel tank with a hammer or mallet. If it starts your pump is bad. Before getting under any vehicle make sure the park brake is on and the wheels are chocked or the drive wheels are off the ground. Safety first. HTH Greasemonkey :)