After dead battery, no start?

[Biff]

This is a good one. I left the lights on, came back a couple hours later to a dead battery. Tried to jump it, engine cranks like always but would not start.Came back the next day with a good battery, installed it, still no start.
Fuel pump not working. Ended up putting temp hotwire back to fuel pump, started right up. After searching posts i really think it is the Fuel Pump Switch in the VAF. I will look at that tomorrow.
I find it strange the car would not start after killing the battery. Headscratchers I guess.

Any one know if you can change the switch in the VAF? Repair?
Thank you

[Grey Vw]

Did you check your fuses?

[Pu241]

^^^
10x check center fuse/fusible link under-hood behind battery!

[Biff]

Yes fuses checked, I have been down that road before.
I find it strange that I have hot wired the fuel pump and away it goes.
Took the fuel pump relay apart and contacts working fine, nothing burnt or strange.
Really wonder about the VAF Switch?

[doylerl]

Isn't there an inertia switch in the back that cuts power to the fuel pump? Easy to reset. Do a search on it.

[JohnGunn]

Really wonder about the VAF Switch?

Assuming yours is an unaltered, fuel injected engine, you can stop worrying about the VAF switch. Until the engine starts, the fuel pump relay is controlled by power supplied through the ignition switch in the "start" position.

According to my 1990 Festiva electrical manual the path of that circuit includes the following components:

1. Battery.
2. Main fusible link.
3. Ignition switch.
4. Clutch interlock switch.
5. Fuel pump relay.
6. Ground.

You have established that the fuel pump is failing due to a lack of power.

The 12 volts supplied to the relay is the same as the 12 volts that activates the starter solenoid, so the output of the clutch switch must be correct. That leaves only the fuel pump relay.

In your situation I would do the following:

With the clutch pedal depressed and the ignition switch in the start position, use a volt/ohm meter to check for 12 volts at the disconnected fuel pump relay connector (black/red wire : 12 volts, black wire : ground). If these values check out suspect the relay.

With the relay connected, check for 12 volts on the green/yellow wire of the fuel pump relay which carries power back to the fuel pump (again, with the clutch depressed and the ignition in start position).

Your hot wire test of the fuel pump proves that the inertia switch is closed and not triggered.

Please let us know the solution when you find it.

John Gunn
Coronado, CA

[Team Lightning]

Biff, when you jumpered the fuel pump and it started, where did you get the power to run the pump? Did you run a wire from the battery, fuse block, inertia switch?
If you went from the battery or fuse block, check the inertia switch on the left (drivers) side under the speaker grill just inside the hatch. It's a switch with a red button on it. Push down on the button, if it's popped up it will disconnect the fuel pump from the electrical power.

[walth]

no one has mentioned the coil line from the disty cap to the coil. make sure that is on and all your lines are tight. they fall off pretty easily. especially if you took out the battery. but not saying you knocked it off just by looking at it.

biff, take the handle of a screwdriver and whack the inertia switch to pop it and then press it back down. repeat a few times to make sure the contacts are good too?

very interesting situation. sorry for your luck. hope you find it soon. you could also check the voltage you are getting when you turn the key to the start position at the 4 wire white connector to the fuel pump at the trap door. should be at least 10 volts but supposed to be 12.

[Biff]

Got it running, Suspect ground connection on fender by the relays. There is a ground termination of about five black wires and it seemed rusty under the bolt to fender. Sanded fender, bolt head, tightened up bolt with copper antisieze. Also retightend the wire on the fusible link block.
These two things were done and away it went.
Thank you all for the ideas.

[walth]

sweet! I hate having a downed festy...

[Basement_Modder]

I'd see if replacing the relay fixes it. I know this one seems to work, but you have no idea how many times I've been working on a computer or something and one component that "seemed" to work ended up being the problem. If all else fails, you can just return the relay to the store.

Edit-sorry for bump, didn't realize it was page 2...

Edit 2-darn, he fixed it. I just was responding to the first post. Now I feel stupid.