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Fuel pump pcm issue

9

98stocker

NAXJA Forum User
Location
Newbury Park, Ventura County, CA
Since my original thread had a bunch of irrelevant stuff in it here goes. I have no fuel to my 97. Hard wire pump and it runs fine. The relay does not turn on. The pcm is supposed to provide a ground path via the brown wire to turn on the relay, but this is not happening. The relay is verified good. Any ideas on where to go from here? I am pulling my hair out and about to go buy something else.

Thanks for the help.:cheers:
mark
 
Check and see if you are missing other things from your Computer. I fried mine two weeks after I had been in water. I had rigged things to run the first was the fuel pump, until I had no spark; then I was sure what the problem was since I had a spare coil. I pulled the computer to take it to carquest and once it turned sideways I saw the nasty rust brown(should have been grey from glacial silt) water pour out.
 
The computer seemed to be working aside from the fuel pump control. But I hard wired the pump this morning and let it run for a couple minutes, and it started running rough after a minute and then I shut it down. Now I got a code 0135 O2 sensor heated circuit. I am guessing at this point that the computer is not working and once it warmed up enough to go into closed loop, it screwed up. I dunno. Any ideas, or am I buying another computer...

Thanks,

Mark

Also, anybody have a shop in oakhurst, coarsegold, fresno they recommend.
 
98stocker said:
The computer seemed to be working aside from the fuel pump control. But I hard wired the pump this morning and let it run for a couple minutes, and it started running rough after a minute and then I shut it down. Now I got a code 0135 O2 sensor heated circuit. I am guessing at this point that the computer is not working and once it warmed up enough to go into closed loop, it screwed up. I dunno. Any ideas, or am I buying another computer...

Thanks,

Mark

Also, anybody have a shop in oakhurst, coarsegold, fresno they recommend.
Click to expand...

I'd check the 5 volt sensor supply circuit. Many of the sensors in the earlier models (before 97) share a common 5 volt supply circuit and when one sensor shorts (either fully or partially) the 5 volt circuit can cascade on you and cause many sensors to give faulty values, the CPS being one of the more important. I imagine your 98 is basically much the same setup.
 
Okay, when I unplugged the connector and tested the A17 plug side I get 7.8 volts, and 6.9 volts at the b31 plug side. These at both called 5v supply.

If you get tired of steering me through this, just let me know. I am sure a hundred mechanics in my area would love to take my money...

Mark
 
Not sure on this system but sometimes voltage readings can be thrown off by unloading them. Any body?
 
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