It's been a while since I've been on the site, but I had taken a break from fixing my truck. I would start it and move it around the yard, just to run it and to keep from one continuous dead spot in my lawn.

So one day I go out to move it, like I usually do, and it won't start. It turns over, but no starting. If I spray starting fluid in the throttle body it starts up. So I pulled codes and got a code 95 "Fuel pump secondary circuit failure". So I spent hours searching the forum for answers. Based on what I'd found, I changed the negative battery terminal (which had a corroded clamp down end on it) with a solid, molded terminal connector. Checked all my grounds, everything is good. I replaced the fuel pump relay and the pcm relay.

I have 2 fuel tanks and neither pump is running. I find it odd that both pumps would go out at the exact same time. So I checked voltages at the inertia switch, fuel switch, and at the pumps. When I turn the key on, it goes to 12 volts for a second, then drops back to around 6.6 volts. I jumped pins 2 and 6 on the eec test connector, and get 12 volts all the time at the pumps.

Thinking offhandedly that my computer died, I took my older computer that was in the truck when it had a 5.0 in it. I'd read on here several times that the 5.8 would run on the 5.0 computer, but run poorly. At this point I figured poorly is better than not at all.

Well, I get the same exact same problem with the 5.0 computer, except no code 95. Still no fuel pressure, no pumps running.

What should I look at next? Changing both pumps? Changing one pump at a time? Changing the computer? I'm lost on this issue and not sure what to do next. Any suggestions?

Thanks.

 

Have you checked out the emergency trip, or tried resetting it

 

Yes I checked that, the inertia switch. I'm getting voltage passed it to the tank switch, and to the pumps themselves. The voltage at the pumps is 6.6~ volts after the first second of key on.

 

That has 3 pumps if I am correct. Not just the two intank.

 

A '93 should have 3-digit codes, and only 2 fuel pumps--one in each tank. The voltages you were getting at the fuel pumps suggest that they were cycling on for a second or two when the ignition was turned, which is proper operation.

Pull the codes again with 3 digits in mind and get back to us.

Jason

 

And have you looked at the relay...12v at the pump and no run, sounds like its bad, their bad? not real likely

 

the '93 is an OBD-I, not II, so has the 2 digit codes. There is no 3rd pump on the rail, this has the 2 high pressure pumps in the tanks.

 

I see you have the two pump system, one in each tank in 1993.
When you have 12 Volts at the pumps with 2-6 jumped and the key on do the pumps run then?
If not what is your fuel gauges doing?

Sounds like you may have lost the ground on the drivers side radiator support.

 

You should put a fuel pressure gauge on the rail, or depress the valve after a couple of key cycles to see if you have any pressure at all.

 

I replaced both the fuel pump relay and the pcm relay. The gauges never worked properly since I've had the truck.

When I jump the 2-6 jumpers, I got 12 volts, but no run. I removed the ground screw on the DS radiator support, cleaned everything up, reassembled it, and coated it with battery terminal protector. I get good ground back to the battery from there. I have 3 ohms to ground at the pump, so that should be fine. I'm starting to think that I got the perfect storm and both pumps went out from sitting...

 

A 1993 with a AOD would have 2 digit codes but a lot of 1993 with OBD-I have 3 digit codes but most that do also have the E4OD or 4R70W transmissions in them.

 

Yes it does sounds like two bad pumps.

 

That's what I was afraid of. They're not cheap either. I'm going to order 1 and try it. I found on ebay, just the pump, for less than $40. Gonna try that and see if it solves the problem.

Thanks for all the quick responses. If any other thoughts come up, please post.

Thanks