Stuck at 30psi

[kmorgan23]

If the voltage and the grounds check out, it might be an amperage issue. Think of volts as “pressure” to the line and amperage as the amount of “flow”. If the wires can’t provide the right amount of flow, the pump isn’t going to turn enough to provide enough fuel pressure.

The amp rating on the fuse would tell you how many amps should be at the pump.

A poor connection or a damaged wire can cause an amperage issue.

Ok so I'll hook some jumper wires direct to the battery, per JerryC, and see if that resolves the issue. Can that direct connection remain? Or replace old wiring instead?

 

[sgtsandman]

Ok so I'll hook some jumper wires direct to the battery, per JerryC, and see if that resolves the issue. Can that direct connection remain? Or replace old wiring instead?

If it’s a wiring issue, I would replace the wiring. You don’t want an unprotected circuit running things. You shouldn’t have to replace the entire wire or wires. Just find the spot causing the issue and repair the wire.

Also, bad grounds can do weird things. It doesn’t even have to be one directly connected to the thing causing issue. Just something in common with that panel, component, or frame part.

 

[lil_Blue_Ford]

^^^ this. Grounds can be a huge, huge problem. I forgot about this and I really should know better. My choptop had weird things going on at one point. Was chasing my tail it seemed for awhile. Then one day I happened to flex the negative battery cable and it was quiet at the time and I heard this nasty crunchy sound when I flexed it. Scratched my head, pulled my knife and skinned a little insulation off and found the main ground had corroded to junk INSIDE the insulation. Wire looked fine from the outside, but was junk inside. Now I pay close attention to that on my trucks and if I’m suspicious or if it’s something like I have the motor out, I’ll replace the battery cables. I took to building my own with welding cable and generous use of dielectric grease or sometimes NoAlox (electricians use it when connecting aluminum wire to prevent corrosion). I’ll even go so far as to replace the little 8 or 10 gauge body ground wire with a bit of 4 gauge welding cable.

 

[kmorgan23]

^^^ this. Grounds can be a huge, huge problem. I forgot about this and I really should know better. My choptop had weird things going on at one point. Was chasing my tail it seemed for awhile. Then one day I happened to flex the negative battery cable and it was quiet at the time and I heard this nasty crunchy sound when I flexed it. Scratched my head, pulled my knife and skinned a little insulation off and found the main ground had corroded to junk INSIDE the insulation. Wire looked fine from the outside, but was junk inside. Now I pay close attention to that on my trucks and if I’m suspicious or if it’s something like I have the motor out, I’ll replace the battery cables. I took to building my own with welding cable and generous use of dielectric grease or sometimes NoAlox (electricians use it when connecting aluminum wire to prevent corrosion). I’ll even go so far as to replace the little 8 or 10 gauge body ground wire with a bit of 4 gauge welding cable.

So funny enough, when I received the truck, there was this mess of 5 14 gauge grounding wires (4 black with green stripe plus 1 black grounded to battery) all mixed and twisted together with electrical tape. And I know through experience that if they disconnect, the truck stalls. I increased wire size to all and reattached with proper connections instead of tape just now.

Also, another fun find just now: I did NOT seat injector 3 properly. Will report back tomorrow. I swear I'm not this incompetent

 

[sgtsandman]

Things happen. We all miss stuff. Especially when we have been at it for hours and are real tired.

 

[kmorgan23]

Things happen. We all miss stuff. Especially when we have been at it for hours and are real tired.

So had some time tonight to work on it. Reseated and quadruple checked seating, checked plug gaps. Also, found and OLD, before-my-time o ring in the fuel rail.. wtf. Still nothing. Went for a 10 minute test drive, no improvement. Got home and did a full check of the engine and drivetrain. No gas leaking, no smoking, no vacuum leaks; however, the linkage between my brand new catalytic converters was RED HOT. I'm going to do some research into that. Any thoughts? That could be why I stalled a few times yesterday?

 

[sgtsandman]

Just spit balling here but I think your low fuel pressure is causing a lean condition, which is causing the cats to get overly hot and thus the exhaust behind it.

 

[kmorgan23]

I just did a bunch of "research" into it. Red hot is indicative of excessive fuel getting into the cat, accompanied with low power, unresponsiveness, etc.. multiple routes to causes from there: low compression/damaged valves (I have refurb headers, new valve springs/stems, new pistons and rings, so I can hopefully eliminate that), bad fuel pump or filter (we've exhausted that option), or misfire from bad ignition coil/plugs/wires. I am going to explore this option tomorrow. I put in an upgraded MSD coil last year long before the rebuild this last March.. may possibly not be the best fit for a 2.9l. I'm test that out tomorrow. These symptoms have existed and persisted before and after the rebuild, so we'll see.

 

[sgtsandman]

I’ve seen mixed reviews on MSD products. Some great. Some bad. With how people are these days, that may mean nothing. But something to keep in mind. I’m sure the MSD products of today are bot the same as yesterday. But that doesn’t address your issue and isn’t related as far as I know.

You may be right on the fuel being rich instead of lean. If that is the case, I wonder if there is an issue with the injectors or the command system telling the injectors to spray and how much?

One of those could be answer to your fuel pressure issue as well. And you are getting into a realm where I have more theory than practical knowledge. So, any help I provide is going to be of diminishing return.

 

[Roert42]

Have we discussed the possibility of issues with the O2 sensors?

Bad O2 sensors or wiring, ect. Would cause low power, poor running, and excessive fuel usage.

 

[lil_Blue_Ford]

I can’t help but wonder if perhaps the computer is wonky. Maybe pop it open and see if the capacitors exploded? Or if you know someone with a known good one swap it out and see if it runs better?

 

[kmorgan23]

Have we discussed the possibility of issues with the O2 sensors?

Bad O2 sensors or wiring, ect. Would cause low power, poor running, and excessive fuel usage.

It's crossed my mind, I replaced it about a year ago. I'll take it out and give it a look. Might be shot by this point since the cat was running so hot.

 

[kmorgan23]

I can’t help but wonder if perhaps the computer is wonky. Maybe pop it open and see if the capacitors exploded? Or if you know someone with a known good one swap it out and see if it runs better?

The computer is under passenger dash, correct? Willing to give it a look

 

[kmorgan23]

I’ve seen mixed reviews on MSD products. Some great. Some bad. With how people are these days, that may mean nothing. But something to keep in mind. I’m sure the MSD products of today are bot the same as yesterday. But that doesn’t address your issue and isn’t related as far as I know.

You may be right on the fuel being rich instead of lean. If that is the case, I wonder if there is an issue with the injectors or the command system telling the injectors to spray and how much?

One of those could be answer to your fuel pressure issue as well. And you are getting into a realm where I have more theory and practical knowledge. So, any help I provide is going to be of diminishing return.

I think it is running rich because my fuel economy sucks.. I think somewhere around 10-12mpg. Per Roert42, I'm going to take a look at the ECU today.

 

[lil_Blue_Ford]

The computer is under passenger dash, correct? Willing to give it a look

Passenger floor, the kick panel under the dash by the door