TOPIC:

You should be able to put 12 volts D.C. to the pump at the connector. The Orange/Black will be plus (+) and the other Black/Yellow wire will be ground (-).

These pumps need gas as a lubricant, so don't run it for extended time dry.

This is for future fuel-pump checkers.

HERE IS THE FUEL PUMP, PUT BELOW THE LEVEL OF THE GASOLINE TANK TO IMPROVE FLOW -- I had to suck on the pump-side of the clear tubing to draw fuel out of the gas can, just like you might siphon gas out of a car -- once the gas progressed the entire length of the clear tubing I connected it to the bike's fuel filter, which I had previously removed and kept hooked up to the fuel pump:



HERE THE INPUT TO THE PUMP HAD ALREADY BEEN CONNECTED TO THE OUTPUT SIDE OF THE FUEL FILTER prior to my siphoning the gas out of the tank to get it started. Note that the output side of the fuel pump has a long black tube draining into a clear plastic (old peanut butter) container. And note that I have hooked up my '+' and '-' power leads to the pump, from my power supply:


I fired up the power supply and set it at 12vdc:



Fuel exiting out the output side of the pump:



HERE IS THE IMPORTANT BIT to my fuel-pump "bench test" procedure above:

1) when I initially siphoned gas out of the gas can and hooked up gas to the input side of the pump, I did NOT put a rubber fuel hose on the output nipple

2) I turned the power supply on and held the pump in my hand to see if it came on -- it did in fact start humming very softly and vibrating. ALSO: the input side of the pump absolutely has suction on it -- I visibly watched gas flow through the clear tube and the filter after the pump started up.

3) I shut off the power supply and put the pump down.

4) I turned the power supply back -- several seconds went by -- NO GAS ON THE OUTPUT! "Ahh, sh!t, bad pump, just as I suspected."

5) After several seconds though there was a minor explosion of gas everywhere from the output nipple and I immediately shut the power supply off. I hooked up a drain hose to the pump's output nipple and within a few seconds the clear plastic peanut butter contained was 1/2 full.

PUMP OKAY (maybe).

Put the pump back on the bike and she started right up.

BOTTOM LINE OF 'BONE DRY FUEL PUMP PRIMING' STORY -- if your fuel pump is bone dry, as in -- you turned it upside down and let the input side drain out, then you turned the pump upside down the OTHER direction and let the output side of the pump completely drain -- your bike's starter motor may not be sufficient to re-fill the dry pump if you put the fuel pump back on the bike in a 'bone-dry' condition.

I say this because I originally put the 'bone dry' fuel pump on my bike, and then cranked on the starter for a total of 20 to 30 seconds, with breaks in between to let the starter cool, and the bike would not start, and no gas was coming out of the pump's output hose (I pulled the pump's output hose off the injectors and cranked the bike's starter, no gas came out). Then when I then removed the pump to check it, the pump had no gas at all dripping from the output side -- after a lot of cranking on the starter motor.

'Your mileage may vary,' not sure how my experience above will transfer to other bikes.


THE BUMMER is that I took the bike for a spin and it has the same symptoms: okay over 3000rpm, engine dies when you let off the throttle.

I am moving on to checking the fuel system relay, the fuel pressure using a gauge, and disassemble the injectors to check for clogs.

Because all four cylinders are shutting down, I suspect at this point it's the relay, the fuel pressure, or the controller.

I don't think it's a main power issue (as in loose connection on the ignition switch) because if I open the throttle the bike wakes right back up, also the lights never go out when the motor dies.

I have got to ask, when you replaced the Throttle switch, did you follow the adjustment procedure? It needs the contact switch closed at Idle. If not closing it may not want to Idle, it may surge etc.
The pump is at least flowing and only a pressure test will determine its capabilities.
If the relay, pump, or injectors were failing when it shuts down below 3K RPM, why would you be able to get it to stay running above?
Anyway keep on playing with it, you'll figure it out.

Motor Head wrote:

I have got to ask, when you replaced the Throttle switch, did you follow the adjustment procedure? It needs the contact switch closed at Idle. If not closing it may not want to Idle, it may surge etc.
The pump is at least flowing and only a pressure test will determine its capabilities.
If the relay, pump, or injectors were failing when it shuts down below 3K RPM, why would you be able to get it to stay running above?
Anyway keep on playing with it, you'll figure it out.

The manual said 'line the engraved grooves on either side of the throttle switch with the grooves on the mounting plate' which I did. Keep in mind too that when I initially installed the new switch, I went out on that sunny day and drove around for 45 minutes and no hiccups. Maybe it's loose, maybe the switch internals have 'settled' after being on the bike and running and being twisted around by the throttle opening/closing, maybe the switches now having had voltage through them, it needs a new adjustment, ie. "the throttle position switch has been broken in and needs an adjustment" like re-torquing the heads after a break-in.

I will go check that throttle position switch right now.

I would use the OHM meter I saw you had out. Here is another good article on the procedure and discussion on everything works together.
www.firstfives.org/faq/throttle/throttle.html
Here is one from the Datsun Z car site, that's the switch you bought.
www.zcarcreations.com/howto/tpsadjust.htm

Motor Head wrote:

I would use the OHM meter I saw you had out. Here is another good article on the procedure and discussion on everything works together.
www.firstfives.org/faq/throttle/throttle.html
Here is one from the Datsun Z car site, that's the switch you bought.
www.zcarcreations.com/howto/tpsadjust.htm

I checked the new throttle switch behavior against what my Clymer manual requires for my Z1 Classic and it is operating correctly.


On goes the search.

OK, that is at the switch it self, and not at the computer connector?
As you saw with some of your injector connectors, is your pins loose at the switch. You could back probe at the computer connector, and wiggle at the switch, testing. This would be good on basically every circuit.

from the looks of your pump it a high pressure system. 45-60 psi i piss harder than that out put. #1 buy a book! onyour bike. need to know pressure.buy a pressure guage 0-100 brass tee it into your system. system must have load to fault.when it act up check pressure. pinch return hose should be max. out put should be over 100 psi. if the pump you have you need to hold it in a bucket, to keep it for sprayin your leg.

I went back and re-checked the air flow sensor and the air temp sensor -- those are on the metal cannister just behind the carb's 4-into-1 black plastic collector box -- this is the 'Air Flow Sensor' part of the fuel injection system that I'm re-checking.

- the temperature sensor was supposed to read 2100 to 2900 ohms if it's 72 degrees, but when I measured it, the outside temp was about 62 degrees and it read about 2900 ohms. So the air temp sensor part of the Air Flow Sensor box looks to be reading in spec.

- I checked the ohms as I moved the flap that's spring loaded and is found inside the Air Flow Sensor box.
So this might be something: the ohms really jumped around as I moved the air flap, as opposed to a smooth increase of ohms when I move the flap one way, then a smooth decrease in ohms when the flap moves the other way. I used my analog (dial-gauge, old style) ohmmeter because it tends to be really good for showing changes.

Now, the ohms reading for the airflow-detection flap inside the Air Flow Sensor box is never supposed to go to infinite ohms, and never supposed to go to zero ohms, the test procedure just says 'as you move the flap, the ohms should change, but never go to zero or infinite.' The procedure didn't even say 'range between X and Y ohms', only that the reading should change as I move the flap.

Well, my ohmmeter's needle was REAL jumpy. And sometimes sticking at one particular value, as if the wiper blade that sweeps across the variable resistor is sticking.

Makes me think the variable resistor inside the Air Flow Sensor box is dirty. If the air flow is not accurately fed back to the computer, I wonder if that would cause the 'not running well under 3000rpm' and anything above that runs great? It seems like with the throttle open wide, the flap in the Air Sensor is wide open and maybe in that condition the variable resistor is cleaner and gives a good signal.

This box has NEVER been apart, it still has factory seals on it -- any suggestions on how to clean that variable resistor inside this box?

I'm thinking maybe the computer's freaking out about the air flow.

I didn't get to checking fuel pressure yet. I did get a good ride out of the bike today, no hiccups.

Friggin gremlins. It's like having a friendly dog then it walks up and bites you for no reason.

As to 'get a manual' I have one, it's a Clymer manual and it is great coverage for this bike (although it left out clogged fuel pumps).

This could still be a simple wire issue. The wiring harness for the computer, unfortunately, flexs and bends through 90 degrees every time you open the seat because the computer is inside the rear of the seat pan. Just think, since 1980, how many times has the seat been lifted up on this bike, that's the # of times the computer wiring harness flexed 90 degrees 'seat open,' then 90 degrees back down, 'seat closed.'


Kaw should not have put the computer wiring harness this way -- wiring harnesses that bend through 90 degrees as the seat is open and closed, it's just asking for trouble. If Kaw had put the computer in the tail piece then the fuel injection's wiring harness would have never needed to move.

For all I know, there is an intermittent open wire in the bundle of wires that rise from the battery area up into the rear of the seat pan. And today, the reason I got a good ride out of the bike may be due to the fact I had the seat up to remove and test the airflow switch.

If I exhaust all other possibilities, the Clymer manual has a procedure for yanking the FI wiring harness and thoroughly testing it. I feel I'm headed in that direction.

P.S. at $85/hour for shop time, we're at, say, $4000 of shop time. (can you say 'lien sale'). Good thing (?) I'm doing all the work myself. Real (?) good thing (?).

Have a look here:


the fact that you had it out running again, with no "Hick-up's" makes me think you have a connection or wire problem. Moving the connectors, and wiring, and suddenly its OK again?
I think I posted a great way to check wires, but I'll add it here again.
1 Test light, Isolate circuit to be tested, un-plug each end, loop the test light into the circuit to be checked with batt power and ground. Now the light should be nice and bright, start wiggling the harness and give it a decent pull. If it blinks dims or goes out then try to duplicate until short to ground/ broken wire/ or other problem is found. You could do it with the Idle switch circuit, or the fuel pump circuit, or any others you suspect.

Go to Radio Shack and get a can of "De-Oxit" contact cleaner/preservative. It's what I use on my bike,home entertainment center cables and cordless phone charging cradles.

www.deoxit.com is their website.

I'd spray the variable resistor and related conectors.

Motor Head wrote:

Have a look here:

the fact that you had it out running again, with no "Hick-up's" makes me think you have a connection or wire problem. Moving the connectors, and wiring, and suddenly its OK again?
I think I posted a great way to check wires, but I'll add it here again.
1 Test light, Isolate circuit to be tested, un-plug each end, loop the test light into the circuit to be checked with batt power and ground. Now the light should be nice and bright, start wiggling the harness and give it a decent pull. If it blinks dims or goes out then try to duplicate until short to ground/ broken wire/ or other problem is found. You could do it with the Idle switch circuit, or the fuel pump circuit, or any others you suspect.

While you were writing that above, I edited my post with thoughts on the computer wiring harness being opened/closed through 90 degrees every time in the past 31 years the seat on this bike was open and closed. And maybe the reason I had a good ride today was -- I opened the seat to remove and test the airflow sensor. Go back and read my edit about the wiring harness testing if you want.