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I think its the CPS again?

S

SINCITY192

NAXJA Forum User
Location
Bronx, NY
88 xj 4.0 L 6cyl auto trans I have been getting the shut off while driving here and there and I figured its the CPS going again cuz after a unplug or two of the sensor connector it would start right back up... but today after taking the kids to school. It shut off on me. I unplug it and plug it back but it wouldnt start up... starting fluid gets it to start but it cuts right back off.... I think its the sensor? what do u guys think?
 
the sensor controls spark. if your getting spark its not the sensor. and you are getting spark if starting fluid will get it to start. the cps unplug and plug back in was just coincidence, and you are not getting fuel is what is sounds like
 
ok so ill run down the street and throw the pressure gauge on it and see what pressure i get problem is i drained the battery tryna figure the problem out so will i be able to get a reading without being able to start it or with no battery power i think its sout of pointless to get a jump if i cant start it?
 
you'll need battery power to run the fuel pump-- either get the battery charged, or have another vehicle and jumper cables attached when you're checking the pressure. Just be careful that you don't create any sparks during the procedure, as you are playing with gas.
 
are the battery cables in good condition? terminals cleaned/well connected?
 
i tested the the pressure on it but like i said the battery is dead from trying to start it up......
good citizen gave me a jump so i can see if i was gettin pressure....
the gauge didnt budge at all last time i used it.. it worked fine....
so i assuming im not getting fuel pressure I rolled under the car with the meter and tested the connector there was a pink purple like color and black... i put negative on the black and probed both the other lines looking for voltage and i didnt get any with the key in the on position shouldn't i be getting voltage there?
I lost on what it could be Im thinking pump but since money is tight I would like to be sure before i replace something please guys help...
 
Fuel pressure won't rule out anything if your not getting voltage.
Jumping could help temporarily or not at all.
start from your battery and go from there.
 
SINCITY192 said:
...with the key in the on position shouldn't i be getting voltage there?...
Click to expand...

unless you turned the key on and managed to dive under there and check the meter in under 3 seconds, you won't have power to the pump. It only primes for about 3 seconds in the "run" position. You'll need someone cranking the engine to check for sure-- and you'll need a fully charged battery for that. First step= charge the battery.
 
Check and clean the three grounds under the hood. Grounds are very important on Renix Jeeps. You have a dipstick ground, a ground at the left rear of the head and the firewall ground. Ensure all are clean and tight. It may also be a bad B+ Latch Relay or the Ballast Resistor. Do you have a Renix Fuel Injection manual? You can find it online. I have one that I may be able to post. The B+ Latch Relay starts the 3 second fuel pump priming prior to start. Once started, the latch relay sends voltage through the ballast resistor to the fuel pump until the engine reaches operating temperature. You can bypass the ballast resistor but it will make the fuel pump noisy and may shorten it's life. I recommend reading the Renix manual. Have you been able to check the fuel pressure yet?
 
Shorty said:
unless you turned the key on and managed to dive under there and check the meter in under 3 seconds, you won't have power to the pump.
Click to expand...

Sounds like a new game for naxja events.
 
Unless you have someone that's going to sit with you and leave jumpers hooked up I'd pull the battery and take it to a parts store to get recharged. You need to check for voltage at the pump while the engine is cranking. You should be able to hear the pump running anyway during prime.. Prob won't hear it when starting because the engines too loud

But it sounds like your pumps probably dead if you got zero pressure during engine crank.. I'd go back and recheck voltage while cranking and during prime.
 
BigSky89XJ said:
Check and clean the three grounds under the hood. Grounds are very important on Renix Jeeps. You have a dipstick ground, a ground at the left rear of the head and the firewall ground. Ensure all are clean and tight. It may also be a bad B+ Latch Relay or the Ballast Resistor. Do you have a Renix Fuel Injection manual? You can find it online. I have one that I may be able to post. The B+ Latch Relay starts the 3 second fuel pump priming prior to start. Once started, the latch relay sends voltage through the ballast resistor to the fuel pump until the engine reaches operating temperature. You can bypass the ballast resistor but it will make the fuel pump noisy and may shorten it's life. I recommend reading the Renix manual. Have you been able to check the fuel pressure yet?
Click to expand...


I thank you for the input you and everyone else.... so far I understand the part about not being able to get the voltage from the fuel pump..... I dont have a resistor though I took that out about 1 1/2 back after changing pumps and havin problems... kept gettin bad resistors and the noise didn't bother me cause i like knowing the pump was working.
I will print the the injection manual now I have it saved to my PC. also I will clean mentioned grounds & make sure they are good and tight.
still cant check the pressure because i have no charger for the battery I know I should have been got one by now.... jumping didnt seem to help with checking the pressure so I'll have to check the grounds and the switch relays and get back to you.
thanks again
 
ok well when i went to get the battery i realized i do have a charger i just need to charge the battery in my house with 110v plug attach to the charger.... so its charging now... but when i went to get it i ask a guy for a jump so i could check for voltage at the fuel pump connector... i stuck the probes into the connector still connected and the guy cranked it for me and I got voltage.... so does this eliminate anything? I will clean the grounds and swap the relays so I can be ready when the battery is charged unfortunately i work tomorrow this was my day off so ill have to finish whatever it is before I need to go to work.... is there anything else any one wants me to check while the battery charges?
 
That may or may not eliminate your batt cables/grounds. Just clean them for good measure.
when was the last time you changed your fuelfilter? test pressure at the fuel rails
 
you "got voltage" - how much? That's like saying "you have miles per hour" because you're driving. How many matters a lot, it can make the difference between not going anywhere or getting a speeding ticket...
 
kastein said:
you "got voltage" - how much? That's like saying "you have miles per hour" because you're driving. How many matters a lot, it can make the difference between not going anywhere or getting a speeding ticket...
Click to expand...

sorry took so long to respond computers going a little slow today but I got a 19. something voltage as it was cranking and it fell down slowly cant tell where it stop at cause once he stop cranking so did the voltage!
 
OK i charged my battery and checked the voltage on it 12.81 and I installed it back in the jeep... I attached the guage and nothing Im not getting a reading at all i wouldn't see why my guage could stop working outta the blue so im assuming no pressure pumps no good right? well I told my girl to put the key in the on postion so i could listen for priming of the pump.... and with she did i heard a shhhhhhhh sound coming from the pump for a couple of seconds... is this priming? and does that mean the pump is good?
 
SINCITY192 said:
sorry took so long to respond computers going a little slow today but I got a 19. something voltage as it was cranking and it fell down slowly cant tell where it stop at cause once he stop cranking so did the voltage!
Click to expand...


19V would be bad.

you're looking for full battery/charging system voltage (roughly 11.5V-12.5V during cranking and 13.0V-14.5V if it starts)

did you check for fuel pressure while it was cranking?
 
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