Replaced fuel line and added electric fuel pump, now won't start.

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Bl1zzard

Bl1zzard

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I finally broke down and ordered a new fuel line because it's the only part of the fuel system that we haven't replaced. Decided to ditch the mechanical fuel pump too for an electric. Anyway, some time during the process, I unhooked a jumper wire that fed into a plug. I assumed it was something to do with bypassing the ignition lockout. It's a 1974 Dart with a 360LA. It was running fine before we swapped out the 50 year old fuel line. There is gas getting to the carb, but no spark. I have a wiring diagram, but this plug isn't on it. It has a yellow wire, yellow/black stripe and a brown wire. The plug is red. Any thoughts on where that jumper was connected? I don't want to randomly plug in the jumper and fry something in the process.

Thanks in advance.
 
Picture would be nice, but my offhand guess is it's the plug for the seatbelt interlock. Jumper wire (IIRC, it's been a while) connects the Y-Y/Bk wires.
 
The seat belt interlock will only prevent it from cranking.

Without a photo of the connector and some idea of the location, no idea

What needs to be jumpered on the seat belt interlock reset connector are the two yellowish wires, which are the "start" wire coming from the key, interrupted by the reset box if tripped, and then sent onwards to the start relay.
 
It does crank, so maybe that's not it. Here's pics.

PXL_20241120_033024218.MP.jpg


PXL_20241120_033039782.jpg


PXL_20241120_033108839.jpg
 
Bl1zzard said:
If only I knew, it got pulled out while I was working on the car. There's 3 possible combinations, which one is right and which one fries some 50 year old wire?
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Del told you right up there ^^^^
 
@Bl1zzard hope these guys get you going again. What electric pump did you go with? I'm going to have to switch over this winter.
 
That is a puzzle. The jumper should be in the yellowish wires. Someone must have bypassed it elsewhere. In other words it should not crank.

Here's how things work. You have IGN1 off the ignition switch, is the only "run" line from the key which goes into the engine bay. That powers the ignition system, the alternator field, the VR, and depending on year, other underhood loads. Electric choke if used, AC idle solenoid, etc.

THAT POWER GOES DEAD during cranking.

The ONLY power which fires the ignition system during cranking is the IGN2 normally brown, which comes off a separate contact on the ignition switch, and like start, is hot only in the start position. That wire goes only one place ---to the coil + side of the ballast resistor

A THOUGHT: Maybe someone had problems with the yellow "start" wire circuit (where the jumper is) and rewired the bypass / IGN2 circuit to fire the start relay. That wire must not be used for that as it will backfeed.

NOTE!! The diagram is not quite correct. They show the 12y and the 12BR coming off the same switch contact. This is not so. They are separate and isolated electrically

Notice that the switch connector shows them to separate terminals

74Ignition1.jpg


74ign2.jpg
 
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Bl1zzard said:
We bought the Carter P4594. The car still isn't running. It got cold here -12C and I'm getting too old to go work in the garage when it's that cold. Good luck with your swap.
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Eff that. I'd relocate. lol
 
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