jtr book/wiring issues

[b18crx]

So, I'm in the process of doing a gen I SBC swap into my 260. I have the JTR swap kit and even the expensive book he offers. I think he needs to read it once and rework his wording/diagrams. I figured it'd be crystal clear after reading through the book, still isnt after doing that a few times. I'm no noob at wiring, tucked several cars, obd swapped several others, and have been doing car audio setups for over 10 years. But I am a noob to carb'd and sbc motors.

 

I guess I'm confused by his chrysler fuel pump switch.

 

*From what I gather the Black/yellow wire goes to the sbc starter "S" terminal, and also t's off to the "bottom" terminal (of the chrysler switch as you look at it in the book).?

*That same "bottom" terminal goes to the "+" on the fuel pump?

 

*The "top" terminal has a fresh wire that connects to the "bat" wire on the HEI distributor (which ties into the black/white wire from the ignition box)

 

I'm sure my (early) 260 has a oil pressure warning light, but the book says nothing as to where that goes.

 

 

 

This is really bugging the sh!t out of me. Thanks for any help.

Edited December 20, 2012 by b18crx

[rsicard]

b81crx:

 

The Datsun Z V-8 Conversion Manual (Seventh Edition) is somewhat misleading and inaccurate.  The wire going to the "S" terminal of the starter is a momentary +12 volts to energize the starter ONLY for the time to start the engine.  Tying the bottom of the chrysler three terminal oil pressure activated switch to the "S" terminal provides a continous +12 volts when the engine starts and has built oil pressure to close the three terminal from the top to the bottom terminals of the three terminal oil pressure activated switch providing a continous +12 volts to the fuel pump and IMPROPERLY to the starter keeping the starter engaged when the engine is already running yielding a REALLY BAD noise from the engaged electric starter.

 

The proper way to provide +12 volts to the bottom terminal of the three terminal oil pressure switch from another source ("S" terminal of electric starter) ONLY during the time to start the engine and activate the fuel pump for this short period of time, is to install a 12 volt automotive relay activated by the wire to the "S" terminal of the electric starter to supply the 2nd momentary source of +12 volts for the fuel pump ONLY during the starting period.  Once the engine is started, the relay must revert (relaxed/unenergized) to NOT supplying +12 volts to the fuel pump because the oil pressure switch should provide a circuit between the top and bottom terminals providing a continous +12 volts from the ignition HOT wire to the HEI distributor through the activated oil pressure switch to the fuel pump for the engine run mode.

[Miles]

My seventh edition of the JTR manual is confusing on some of the fuel pump wiring and has been discussed in the V8 forum.

 

My experience is with a 240Z so verify the following:

 

Green-White:  This wire is energized as the ignition key is turned toward the "start" position. Its' pupose is to provide power to the fuel pump while cranking. I also find it handy to prime the carb if the  car has been sitting for awhile. It taps into the wire that connects to the fuel pump + side of the switch.  This should be wire No. 1 on the JTR diagram.

 

Black-White without protective sleeve: Tach terminal of HEI dist.(280Z tach) OR neg terminal on a coil.

 

Black-White with protective sleeve: Bat terminal on HEI dist. Positive termanal on points type distributor. This is your "ignition" wire. You tap off of this wire to the pressure switch.

 

Black-Yellow:  Starter "S" terminal. The wiring diagram in the JTR book shows this wire connected to the oil pressure switch. Do not connect this wire to the oil pressure switch. This is confusing because  the JTR book says in section 13-2 not to connect this wire to the the wire on the oil pressure switch at runs the fuel pump (see 4th para down pg 13-2 under Fuel Pump Wiring), but shows it connected in their wiring diagram. Connect the Black-Yellow wire to the starter only. The Green-White wire runs the fuel pump while cranking.

 

In summary, there is a power (ignition) wire to the distributor which has a tap to the power side of the pressure switch to run the fuel pump. To make the fuel pump run while cranking,  there is the Green-White wire that taps into the fuel pump side of the pressure switch.

Edited December 20, 2012 by Miles

[Miles]

Also see : http://forums.hybridz.org/topic/105051-jtr-wiring-questions/?hl=pressure+switch&do=findComment&comment=982976

[rsicard]

The link http://forums.hybrid...tch#entry982976 is misleading and will cause the starter to be energized with the engine running and generate quite a NOISE. 

 

"In summary, there is a power (ignition) wire to the distributor which has a tap to the power side of the pressure switch to run the fuel pump. To make the fuel pump run while cranking,  there is the Green-White wire that taps into the fuel pump side of the pressure switch."

 

With this summary, the fuel pump will be provided with +12 volts ONLY when the oil pressure has built up to close the oil pressure switch to provide +12 volts to the fuel pump terminal of the oil pressure switch, not during the starting stage when oil pressure has NOT built up enough to close the oil pressure switch.  This is why I advocated the relay actuated by the wire going to the "S" terminal of the starter.

[Miles]

Per JTR pg 13-2:

 

"If you are using the HEI  distributor, the easiest way to wire the fuel pump for cranking conditions is to connect the Green-White (240Z) or black-blue (260Z/280z) wire to the fuel pump wiring."

 

Both of my 72 240Z SBC cars are wired as stated above, without relays,  and the fuel pump turns on just before the start position on the ignition switch and the fuel pump runs during cranking.  The pump turns on just before the switch reaches the start position. On cold mornings, or after the car sitting a for a long spell,  I use this feature to fill the carb bowels before cranking the engine.

 

The exception for b18crx,  is that per JTR instead of using the Green-White (240Z) wire you use the Black-Blue wire (260Z/280Z).

 

To b18crx,  I suggest that you look over pg.13-2 in the JTR manual again and hook up a volt meter to the Black-Blue wire to verify that it energizes when the ignition switch is turned to start.  If JTR is correct, you should see the Black-Blue wire energize just before the key is turned  to the start position and stay energized while cranking.

 

Again, b18crx, you should verify,  using a volt meter,  the function of each wire  as stated in the JTR manual as you turn the ignition switch through each position.

 

Trust, but verify.

 

Good Luck

Edited December 21, 2012 by Miles

[saxfiend1967]

I would like to share this. I hooked the chrysler relay to bat on dist. The reason is if I lose pil pressure I get instant engine shut off. The problem with fuel pump is yoi could run a min. Or more off carb bowls. Just my .02

[b18crx]

Per JTR pg 13-2:

 

"If you are using the HEI  distributor, the easiest way to wire the fuel pump for cranking conditions is to connect the Green-White (240Z) or black-blue (260Z/280z) wire to the fuel pump wiring."

 

 

 

The exception for b18crx,  is that per JTR instead of using the Green-White (240Z) wire you use the Black-Blue wire (260Z/280Z).

 

 

It's been hectic during this Holiday season. And you guys have been helpful, this book REALLY needs regone though and colors/diagrams triple checked. HAHA.

 

1.   So from what I gather from these posts is that I use the BLACK/BLUE wire instead of the GREEN/WHITE and that will connect to the "bottom" terminal of the fuel pump switch ALONG with another wire to run back to the positive of my fuel pump? Once this is figured out I will add in a relay to make sure my fuel pump gets full voltage.

 

2.   The oil pressure warning light "side" of the fuel pump switch does NOT get used for anything?

 

3.   Also since I have a 260 (or anything besides a 240) I DO NOT use the BLACK/WHITE (without protective sleeve) to the TACH wire. This is only for the 240's correct? Instead I use the BLUE wire from my ignition box to the TACH on my HEI disty.

 

I don't know why I'm so confused with this. Like I said I've done several wiring jobs (obd0 to obd1 swaps, wiring in extra injectors, numerous electronic boost controllers among other things). I feel better since my first post, just a few more things to clarify. Thanks guys!

[Miles]

The best way to approaoch this is to make a sketch of how the oil pressure switch is wired. Name and color code each wire.  If you are going to use a fuel pump relay add that to your sketch. Use a Painless Fuel Pump Relay kit.

 

Have you tested the Black-Blue and Green-White wires with a volt meter? As you turn the ignition switch how does each wire behave?

 

Fuel Pump Relay: run the output of the oil pressure switch to the trigger wire of a Painless Fuel Pump Relay. The painless kit comes with long wires so you can run the trigger wire to the oil pressure switch. Look at a schematic for a 260Z as there may be an unused Green wire Datsun installed to run an electric fuel pump.  The Green wire is taped up near the fuel level sensor. Inside, you can find it behind the passenger side kick panel.  It continues to some point near the fuse box. If it is there you can connect it to the output side of the Painless relay and to your electric fuel pump. 

[rsicard]

Just remember, DO NOT connect the oil pressure switch wire to the fuel pump relay with the starter solenoid +12 volt momentary actuate/start wire.  If the two are connected the starter will be continually engaged when the engine has started, actuated the oil pressure switch.

[b18crx]

This project has been going slow, just had a little girl almost two months ago. Anyways, they engine bay is almost finished being shaved and i've been staring at a few of these wires hanging out. I just wanted to make sure that I DO need to keep these two items.

 

 

Thanks!

[b18crx]

anyone? haha