fuel delivery

P

polermo

Registered
i have a 94 mark with 195000mi received code 4 low speed fuel pump and open circuit between pcm and battery. replaced fuel pump had the same prob. tested psi at rail no leaks and operates at proper psi. help anybody
 
Before you go out testing all your wiring system I would do yourself one favor, and that is to go to one of the large retailers (AZ or AA) and have them drag out their battery and alternator system checker. It is not uncommon for our cars to start poping off all kinds of codes when the system is getting ready to crash because of a bad battery/alternator. From there you will then have to find where the ground fault is.
 
just put a new battery in 2mos not sure about the state of charge. i had distribution box off everything looked pretty good will check again to be sure. thx alot
 
I had the same code along with O2 sensors going bad. After replacing the O2s, the codes were gone. Go to Autozone or Advance Auto Parts - get the codes pulled for free, and then start from there. Let us know what you find out.
Good luck,

Mike
 
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changed 02 sensors looked like the fix. replaced them on sunday have put about 200 mi on since with no problems. thanks alot for the help
 
Drivers side on my 94 was tough. it was hard to reach the plug put it all together by touch. passenger side piece of cake u can reach everything.
i had to use the socket cause the o2 sensor is right up against the cat on passenger side. i used the ntk o2, got it from summit. car is really running better than it has in a long time.
 
Thanks

Thanks

This thread is exactly what I need. I am getting the same fuel pump code, also getting codes for "o2 sensor always lean" AND "o2 sensor always rich". Now to look for the thread on replacing the O2 sensors...

-D
 
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