Frustrated!!!! Electrical, fuel ??

[mobileortho]

Can't figure out what the heck is wrong with my truck. Prior to relocating to the East Coast, I was having issues with it seeming down as though it were starving for fuel. Thought it was the TPI system and I got tired of it and switched back to a carb. Still had the same issues, switched back to the TPI and the truck sat for several months during my relocation. Recently took it out for a drive and still having the same issues. When it dies, it's as though the alternator (new) is not charging. I had the alternator tested last night and it checked out fine so I was wondering if perhaps is wired wrong. I have the main wire from the battery hooked to the stud, of the three wires from the pig tail, the red is also hooked to the stud, brown to the guage & black capped. Is this correct? Any other thoughts as to what the issue may be???

[Speedbumpauto]

A bad alternator won't make it die unless the battery is dead also. If it starts back up it's probably not the alternator, etc. You didn't say if you relocated the tank. My bet is a dirty or plugged tank if it's still the stock one, or an electrical fuel pump problem if the tank has been relocated and an electric pump added for the fuel injection. More info?

[1project2many]

There are many unknowns here. When it dies will the headlights work? Does the starter click or try to crank over? The wire colors and locations sound correct for a newer vehicle. What is your harness from? What is the alternator from? Any chance the pulley is slipping in the belt?

You can check the wiring with a test light. The stud with red wire should have power with the key off. If not then the alternator can't get electricity to the battery. If you disconnect the two wire connector the brown wire should light the test light dimly with the key on. On many GM vehicles with this wire disconnected the system will still charge but only after bringing the engine rpm up a fair amount.

[mobileortho]

I did relocate the tank to the rear, but I've ruled out the fuel system. Tha tank is clean & the frame mounted pump & the injectors are new as well as the fuel lines.

Can't really say if the headlights still work when it dies cause I never checked them. Once it quits, it won't start unless I jump it. The harness is an aftermarket setup from American Autowire & the alternator is from Orielly Auto. It has a serpentine setup and the belt is tight. The strange thing is it will sit and run @ idle for hours fine. It only dies after I try to drive it.

[meter swinger]

I have a very similar issue with a 55 D@DG€. It will idle for eternity, but will loose power and die while driving and then need to be jumped. However only after its well warmed up. And i can keep it from dying if i dont let rpms drop. It has an aftermarket harness. I am 90% sure its the PO installed harness, i just havent had time to get a meter on it.
Happy troubleshooting.
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[1project2many]

Driving does take more energy from the battery than idling. Easiest way to start is by making the tests I mentioned with a test light. If you have a voltmeter you can check voltage at the battery and at the alternator when the engine's running to see if it's charging. Best way to have least frustration is to test and isolate.

[parkwood]

Originally Posted by mobileortho

Can't figure out what the heck is wrong with my truck. Prior to relocating to the East Coast, I was having issues with it seeming down as though it were starving for fuel. Thought it was the TPI system and I got tired of it and switched back to a carb. Still had the same issues, switched back to the TPI and the truck sat for several months during my relocation. Recently took it out for a drive and still having the same issues. When it dies, it's as though the alternator (new) is not charging. I had the alternator tested last night and it checked out fine so I was wondering if perhaps is wired wrong. I have the main wire from the battery hooked to the stud, of the three wires from the pig tail, the red is also hooked to the stud, brown to the guage & black capped. Is this correct? Any other thoughts as to what the issue may be???

sounds like your truck didn't won't to move to the east coast... but really could you be having vapor lock? fuel line running close to header pipes?

[Chevette]

MAS in the TPI. When you changed back to a carb, you had a carb problem. When the MAS is faulty, the engine will act just as you have experienced. If it's not that, then maybe an inline fuel filter.

[mknittle]

Originally Posted by meter swinger

I have a very similar issue with a 55 D@DG€. It will idle for eternity, but will loose power and die while driving and then need to be jumped. However only after its well warmed up. And i can keep it from dying if i dont let rpms drop. It has an aftermarket harness. I am 90% sure its the PO installed harness, i just havent had time to get a meter on it.
Happy troubleshooting.
Posted via Mobile Device
Posted via Mobile Device

This may sound dumb but i once had a fuel filter do somthing like that. i figure when the truck would die the particals in the filter would settle allowing enough fuel through to start the cycle over again

[_Ogre]

check your fuel pressure at WOT.
sounds like your starving for fuel.

i had a similar problem with truk
found out that the fuel pressure was dropping to 10 psi at WOT
i had a hole in the fuel line in the tank.
truk had all new tank, pump and lines

[meter swinger]

I once had a problem with "boiling fuel" or "vapor lock" on my 59 when I changed carbs. a spacer (phenolic resin or some sort) between the carb and intake fixed that. Also as parkwood suggested if the line is to close to a direct heat source that could be an issue, it is summer time, the last time you had this issue was it the same time of year? reason i say this it gets well over 100 deg where I live right now and problems will suirface that could be previously hidden.
I had a fuel problem with my Travelall that I narrowed down by running clean fuel out of and empty beer bottle ( i know, i know, i'm a whitetrash hillbilly) and bypassing the tank and filter with fuel hose to the pump to see if it was the pump or filter.
if its the MAS as chevette suggested do you have any way to trouble shoot it? what would be sign of it malfunctioning? maybe unplug it and see what it does?
or could it be the IAC?
I stole the following from another site.
"To test the IAC, remove the IAC from it's home in the throttle body, connect it and lay it somewhere easy to see. Put a paperclip between contacts A&B in your diagnostic port (same thing for checking engine codes). Turn the car to run (but don't start it) and see if the pintle moves out. Don't let it move out too far, or the pintle will shoot out of the IAC then you will have to replace it. If it moves out steadily, then it's working, which means go buy a MAF. "

[paintman]

is your fuel filter directional that is to say..... is it possible you have the fuel filter plumbed backwards and the element is collapsing under load? Just throwin it out there.

[Russell Ashley]

"Once it quits, it won't start unless I jump it."

So you are saying that the battery is dead when it quits, am I reading this right? If so you definitely have a electrical issue somewhere in the charging circuit. I think I would get a volt guage and wire it either temporarily or permantly so you can observe what is going on with the battery. For testing purposed I would wire it directly to the battery.

[1project2many]

Exactly. Since it only acts up after he drives for a while, duplicating the problem would mean driving away from home and tools. Better to start by making sure the alternator connections are correct while it's still home in the driveway.

[mobileortho]

Got a chance to briefly look at it. I started with the alternator, someone suggested that it was wired wrong. It has three wires coming from the pigtail, red-jumped to the stud, brown-ignition/volt guage, & black which I assumed was ground, but someone told me that should be connected to the stud as well. Tried that hoping that would work but it still didn't so back to the drawing board. Going to get a voltmeter as many has suggested to check things out.

A guy at the parts store also suggested I was testing it the wrong way. My father taught me years ago to disconnect the battery cable while the engine was running to test the alternator, if it still runs it's good but this guy says that was true for older carbed motors but since I'm running TPI, it doesn't work because disconnecting the cable doesn't provide enough juice for the computer. Anybody else heard of this?

[mobileortho]

Originally Posted by 1project2many

You can check the wiring with a test light. The stud with red wire should have power with the key off......

Hmmmm, maybe onto something.......no power.

[1project2many]

When you converted the harness, did you remove all the old wiring under the hood? Including everything for the old voltage regulator? Is the alternator wiring connected to the original wiring under the dash? And finally, do you have the original gauges with the ammeter showing charge current or have you replaced them?

[mobileortho]

Think I found my problem!! The alternator wire had shorted out at the starter. A quick splice and power's restored. Hope to road test this later in the week.

[OrrieG]

Seems like it is always something basic and easy.