Alternator question., Not Charging. Options

[Gatornapper]

What is this jumper in the lower left corner of my relay board?

(IMG:http://www.914world.com/bbs2/uploads_offsite/i890.photobucket.com-21449-1568122651.1.jpg)

[ClayPerrine]

What is this jumper in the lower left corner of my relay board?

(IMG:http://www.914world.com/bbs2/uploads_offsite/i890.photobucket.com-21449-1568122651.1.jpg)

That would jump the starter circuit to the fuel pump relay output. It doesn't make sense to be there.

Maybe you have a relay board issue? Did you try another one?

[Gatornapper]

Spoke -

Do not know where/what this is - car is carbureted:


2) Remove the power to the FI ECU (if you have FI). If you have carbs, remove the ground jumper from the FI connector on the relay board. This jumper powers the fuel pump. We want the fuel pump off.

[Gatornapper]

Clay -

Another relay board is being loaned to me and should be here tomorrow.

Should I remove this jumper? No idea why it is there, relay board looks original to car.....

If I remove it, will fuel pump relay still be energized by ignition key ON?

Thanks,

GN

That would jump the starter circuit to the fuel pump relay output. It doesn't make sense to be there.

Maybe you have a relay board issue? Did you try another one?

[Spoke]

Spoke -

Do not know where/what this is - car is carbureted:


2) Remove the power to the FI ECU (if you have FI). If you have carbs, remove the ground jumper from the FI connector on the relay board. This jumper powers the fuel pump. We want the fuel pump off.

The way that jumper is installed, the FP will not run while you crank the engine. When you release the starter, the FP relay is energized through the starter and runs normally.

The front left pin should be connected to ground. This happens in your car when you release the starter.

[ClayPerrine]

Clay -

Another relay board is being loaned to me and should be here tomorrow.

Should I remove this jumper? No idea why it is there, relay board looks original to car.....

If I remove it, will fuel pump relay still be energized by ignition key ON?

Thanks,

GN

That would jump the starter circuit to the fuel pump relay output. It doesn't make sense to be there.

Maybe you have a relay board issue? Did you try another one?

That jumper hooks the yellow wire for the starter to the output side of the fuel pump relay. It would not power the fuel pump when the car is running.

Like I said, it doesn't make any sense to be there. Without something to energize the ECU relay, the fuel pump relay won't turn on.

It is possible that someone moved the pins around in the harness connectors to the relay board. I would take a long wire, and hook it to the rearmost pin on the relay board where the jumper is. Then touch the other end to the positive battery post. The engine should crank if everything is wired correctly.

[Spoke]

Ok, will do today.

One additional bit of info: GEN light is OUT when engine is idling.....only comes on with rpm increase, more rpm = brighter GEN light. Bat to chassis when light is OUT is about 12.2 on a fully-charged 12.6 v resting battery.

GN

That the GEN light goes out means the D+ voltage is equal to or near the Bat voltage. In the test that I detailed with the alternator yesterday, the GEN light was out on my car with the alternator unplugged from the relay board even though the VR was in the circuit.

In the run that you describe above, does the GEN light come on with key ON and engine not running?

In the run you describe, with more RPM the GEN light is brighter. It would be interesting to know what the battery voltage is as well as the D+ voltage. They are different but not sure which one is greater than the other.

[Spoke]

Clay -

Another relay board is being loaned to me and should be here tomorrow.

Should I remove this jumper? No idea why it is there, relay board looks original to car.....

If I remove it, will fuel pump relay still be energized by ignition key ON?

Thanks,

GN

That would jump the starter circuit to the fuel pump relay output. It doesn't make sense to be there.

Maybe you have a relay board issue? Did you try another one?

That jumper hooks the yellow wire for the starter to the output side of the fuel pump relay. It would not power the fuel pump when the car is running.

Like I said, it doesn't make any sense to be there. Without something to energize the ECU relay, the fuel pump relay won't turn on.

It is possible that someone moved the pins around in the harness connectors to the relay board. I would take a long wire, and hook it to the rearmost pin on the relay board where the jumper is. Then touch the other end to the positive battery post. The engine should crank if everything is wired correctly.

The jump powers the FP relay any time the key is in the ON position. In the start position, the FP will not run.

[ClayPerrine]

The jump powers the FP relay any time the key is in the ON position. In the start position, the FP will not run.

Per the wiring diagram and lots of years of experience, it won't work that way. If it does, then something has been altered in the wiring or the relay board.

[Spoke]

The jump powers the FP relay any time the key is in the ON position. In the start position, the FP will not run.

Per the wiring diagram and lots of years of experience, it won't work that way. If it does, then something has been altered in the wiring or the relay board.

Yeah that jumper connection threw me for a loop too. I didn't think it work work and maybe something was re-wired from the OEM wiring.

However looking at the wire diagram below shows the path to ground for the fuel pump relay coil going through the starter bendix. When the starter is energized the FP turns off. When the key is ON, the FP will run. Not ideal but still operational. It would be best to remove that connection and just ground pin III of the FI connector.

[lierofox]

The jump powers the FP relay any time the key is in the ON position. In the start position, the FP will not run.

Per the wiring diagram and lots of years of experience, it won't work that way. If it does, then something has been altered in the wiring or the relay board.

From the relay board wiring diagram I have, it looks like Spoke's right.
Terminal III (top left) goes to the ground terminal on the fuel pump relay, the positive terminal of that relay is fed by the Power Supply relay.

Terminal II and IV (bottom 2) goes directly to the yellow starter wire.

With that configuration, yeah, the only way the relay would find ground is through the starter solenoid when it's NOT energized.

[ClayPerrine]

The jump powers the FP relay any time the key is in the ON position. In the start position, the FP will not run.

Per the wiring diagram and lots of years of experience, it won't work that way. If it does, then something has been altered in the wiring or the relay board.

From the relay board wiring diagram I have, it looks like Spoke's right.
Terminal III (top left) goes to the ground terminal on the fuel pump relay, the positive terminal of that relay is fed by the Power Supply relay.

Terminal II and IV (bottom 2) goes directly to the yellow starter wire.

With that configuration, yeah, the only way the relay would find ground is through the starter solenoid when it's NOT energized.

That is not a good way to do it. Very Redneck.

[Gatornapper]

NEVER have any problem starting this engine - is the easiest starting engine of any machine/vehicle I've ever owned - it always starts on the firing of the very first piston - or so it seems.

It does sometimes die after starting tho, and I have to switch the key back to "Off" to engage the starter a 2nd time.

Hard for me to believe the fuel pump isn't pumping when I crank this engine because while it idles terribly, it starts every time. It's never been a problem. Never.

The way that jumper is installed, the FP will not run while you crank the engine. When you release the starter, the FP relay is energized through the starter and runs normally.

The front left pin should be connected to ground. This happens in your car when you release the starter.

[Gatornapper]

The GEN light is on bright when ignition is ON, engine NOT running - as it should be.

Funny that while I rev the engine up and down, the GEN light goes from Dim/off at idle to bright a 2,000 rpm - while the battery voltage remains fairly constant at 12.2 +/-.

I have not checked the D+ voltage in this scenario - will tomorrow.

Thanks,

GN

Ok, will do today.

One additional bit of info: GEN light is OUT when engine is idling.....only comes on with rpm increase, more rpm = brighter GEN light. Bat to chassis when light is OUT is about 12.2 on a fully-charged 12.6 v resting battery.

GN

That the GEN light goes out means the D+ voltage is equal to or near the Bat voltage. In the test that I detailed with the alternator yesterday, the GEN light was out on my car with the alternator unplugged from the relay board even though the VR was in the circuit.

In the run that you describe above, does the GEN light come on with key ON and engine not running?

In the run you describe, with more RPM the GEN light is brighter. It would be interesting to know what the battery voltage is as well as the D+ voltage. They are different but not sure which one is greater than the other.

[VaccaRabite]

Memories guys? Jerry & Zack - Long ago I jumped D+ & DF and did get full 17v at the battery and reported on that numerous times to support my view that the alternator is fine. Even ran the test multiple times.

Also put 12+v to DF as the Pelican article suggests to check all the other diodes, and it too produced a full 14.1 v at the battery, showing all the other alternator diodes are good.

I don't usually remember what I had for lunch, let alone what happened 100 posts ago. (IMG:style_emoticons/default/smoke.gif)

Electrical problems suck! When I was banging my head against the wall over my alternator problems I wanted to just beam Jerry over to my garage. the theory goes over my head really quick.

Zach

[euro911]

I was told to install that jumper for the fuel pump by a few highly respected/knowledgeable on this board ... (for a carbureted motor) (IMG:style_emoticons/default/confused24.gif)

[Gatornapper]

Clay -

Just to make sure I don't short something out, you mean Pin III, correct?

Think I'll fuse the jumper from 12+ just to be safe.

From all you all are saying, this jumper doesn't make any sense. I get that.

But I can almost certainly assure you that the FP is running while I crank the engine. If it didn't, it seems to me I'd have a lot of dry cranking from time to time.

While this engine has poor compression and doesn't idle, it's the best starting engine I've ever seen. It seems like 1 revolution and she's running - every time.

GN

I would take a long wire, and hook it to the rearmost pin on the relay board where the jumper is. Then touch the other end to the positive battery post. The engine should crank if everything is wired correctly.

[Gatornapper]

Mark -

The first comforting thing I've heard about that jumper - as the Porsche dealer did the carb conversion, the jumper definitely doesn't look like a shade-tree mechanic one, but a very professional one. Note the extra insulation from the terminals back an inch or so....almost like it's a factory jumper....or commercial one.

Some modification would be necessary for fuel pump energizing when eliminating the ECU - as it controlled the fuel pump. So this totally makes sense......

GN

I was told to install that jumper for the fuel pump by a few highly respected/knowledgeable on this board ... (for a carbureted motor) (IMG:style_emoticons/default/confused24.gif)

[Spoke]

I was told to install that jumper for the fuel pump by a few highly respected/knowledgeable on this board ... (for a carbureted motor) (IMG:style_emoticons/default/confused24.gif)

This connection has been socialized many times and succinctly documented by SirAndy in this thread:

How To > HOW TO: run the fuel pump for carb conversions, the easy solution!

The fuel pump relay coil is grounded as shown by SirAndy in this picture. What was done on Gatornapper's car is quite unique and not ideal but does work. On his list of things to do on his 914 is correcting this connection. (IMG:style_emoticons/default/beerchug.gif)

[Spoke]

I don't usually remember what I had for lunch, let alone what happened 100 posts ago. (IMG:style_emoticons/default/smoke.gif)
Zach

I concur. (IMG:style_emoticons/default/smoke.gif) Although not yet legally in PA... (IMG:style_emoticons/default/WTF.gif) (IMG:style_emoticons/default/headbang.gif)