Jeep Cherokee Talk banner
1 - 12 of 12 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
Going to try again. I just replaced the fuel pump in my Cherokee. It starts up fine and idols pretty good after a bit. If I try to accelerate it will spit, sputter, backfire and not accelerate. I have checked all vacuum lines, all good. Has new cap, rotor, plugs. If I unplug the crank position sensor, dies or no start. Unplug MAP sensor, ugly. Unplug the cam position sensor, no change. I have done the test the Hayne's has. I used a digital Volt meter on AC and got 0 volts. Should it be on AC?? Are these symptoms conducive to a bad cam position sensor. I really don't want to spend the $$$ just replacing sensors. Any and all help is greatly appreciated!!!
 

·
Marshmallow
Joined
·
3,780 Posts
Look at the TPS and check the fuel pressure at the rail in the engine compartment, should measure around 41-46 psi. I would also think about giving the throttle body a good cleaning.
 

·
Registered
Joined
·
52 Posts
Do cruisers ground refreshing then check out his renix tips. I would guess its your fuel pump and test it like already stated.
 

·
Registered
Joined
·
36 Posts
Same issues with my '92. Cleaned TB and replaced the TPS and cleaned the IAC. runs great now.:thumbsup:
 

·
Registered
Joined
·
7 Posts
Same issue with my 97 take ECM out take the three screws on the top and replace with shorter screws then after you put ECM back on use 3 large zip ties and zip tie the plugs into the ECM very tightly make sure you unplug battery first
 

·
Registered
Joined
·
700 Posts
Same issue with my 97 take ECM out take the three screws on the top and replace with shorter screws then after you put ECM back on use 3 large zip ties and zip tie the plugs into the ECM very tightly make sure you unplug battery first
The op has a renix system. His ecm is under dash behind stereo.
Still sounds fuel pressure related.
 

·
Registered
Joined
·
9,244 Posts
:agree:


Most likely fuel delivery issues...

As mentioned, test fuel pressure during prime, running at idle, AND for about 20min after you remove the ignition key.

As suggested, a throttle body cleaning is also a good idea. An entire can of Berryman's B-12 shot down 'er throat at high rpms should do the trick.

Also, you might try hardwiring your balast resistor to see if it makes your fuel pump run any smoother.
Not sure what the resistance is "supposed" to be on the Renix?



Just some thoughts
;)
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #9 ·
I tried the shooting ether in while running and no difference. Thinking a timing problem. Any thoughts on that??? Thanks all for some checks. Have done everything suggested........
 

·
Registered
Joined
·
1,151 Posts
The only thought I have on timing is that the 4.0 engines don't really lose their timing. The only maintenance items that I can think of that could throw off timing is replacing the entire distributor and getting the timing belt wrong.

If you just did cap, plugs and rotor, you may want to confirm that your wires are plugged in the correct spots and that they are firmly seated. If you got your wires crossed, that will jack things up.
 

·
Registered
Joined
·
5 Posts
Going to try again. I just replaced the fuel pump in my Cherokee. It starts up fine and idols pretty good after a bit. If I try to accelerate it will spit, sputter, backfire and not accelerate. I have checked all vacuum lines, all good. Has new cap, rotor, plugs. If I unplug the crank position sensor, dies or no start. Unplug MAP sensor, ugly. Unplug the cam position sensor, no change. I have done the test the Hayne's has. I used a digital Volt meter on AC and got 0 volts. Should it be on AC?? Are these symptoms conducive to a bad cam position sensor. I really don't want to spend the $$$ just replacing sensors. Any and all help is greatly appreciated!!!
Fuel filter??
 
1 - 12 of 12 Posts
Top