TOPIC:

Lets see, first make 100% sure the fuel petcock is in the correct position for how much fuel you have. I remember your petcock and the pickup tube. Then be 100% the pump "Runs", then maybe take the output line, where it goes to the fuel rail/ metal tube at injectors off and stick the hose in a can or good container. You could Jump the fuel pump to get it to spin. Did that pump have two different wire terminals so the + & - could not be confused? Being DC if backwards the pump will be in reverse, and not pump fuel out the outlet fitting.

Motor Head wrote:

Lets see, first make 100% sure the fuel petcock is in the correct position for how much fuel you have. I remember your petcock and the pickup tube. Then be 100% the pump "Runs", then maybe take the output line, where it goes to the fuel rail/ metal tube at injectors off and stick the hose in a can or good container. You could Jump the fuel pump to get it to spin. Did that pump have two different wire terminals so the + & - could not be confused? Being DC if backwards the pump will be in reverse, and not pump fuel out the outlet fitting.

I was hoping someone would have said something like 'when a fuel pump is 100% empty, you have to prime the pump and here's how."

I guess my fuel pump is no good then. It is not putting out any fuel on the output. I put my finger over the output hole and don't even feel air pressure.

I didn't remove the wires from the pump -- it has a white molex connector that you unplug to disconnect it, which is what I did. The pigtail of 2 wires stays with the pump.

I had the pump removed and outside the bike and spark plug wires off, the petcock was on 'Reserve' and there's plenty of gas in the tank. I saw the fuel come from the tank into the new fuel filter I installed, which is a see-through filter. So I think the input of the pump is pulling in fuel.

But NOTHING on the output.

So I have a bike with an irreplaceable fuel pump.


I am about ready to give up on this one. Too many bad fuel system parts and none available anymore without minor miracles. The main reason I like working on old bikes is they're not cars, the old air-cooled 2- and 4-strokes without water cooling, without computers and fuel systems, are relatively easy to work on. This bike is like a car. I will never buy a fuel injected bike again unless it's brand new and under warranty.

Let this be a lesson to others who use the forum, this old fucker aint worth it. I am going to teach myself a good lesson and push on with this p.o.s. then give it to Goodwill.

Sorry to about the extended problems.
I didn't think the wires were swapped but just threw it out there as a possibility. Those should be basically self priming, with it mounted lower than the tank.
Did you see where I posted that the older Nissan had the 90 degree intake fitting? Also you could re-plumb for a straight pump, there are universal ones for like $50. I think I saw some of those Nissan ones for $125 up to $$50 or something. I'd go universal and redo the inlet plumbing.
Seems kinda strange that NO fuel would come out? I could see low pressure/ low volume or not spinning at all.

Here is an example on Fleebay.
cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll...sspagename=DCP:RV:GI

These are set up for a Banjo fitting on the outlet, but could be plumbed quite easily and will Work fine. $50 all up.

Or something straight with a 3/8 hose barb on each end, alot of them will have a 12mm inlet fitting.
cgi.ebay.com/ebaymotors/FUEL-PUMP-OEM-RE...&hash=item336480fbdf

Yep, I searched online when this came up today, I found nothing to indicate anything other than a bad pump.

I will try a couple other things tomorrow, but in my heart I have already removed all the fuel injection garbage from this otherwise fine bike and smashed it all into relatively flat pieces of metal and some indiscernible chunks of plastic and torn rubber.

I revived a Honda cb900c that had been sitting about 12 years simply by changing the oil and filter, flushing the gas tank and charging the battery. My cb900 sits next to my p.o.s. z1 classic. The Honda had 12-years-sitting carbs, and the guy didn't use fuel stabilizer, and the cb900 runs like a champ.

I don't see a good future in fixing the fuel pump only to find maybe the injectors are screwed, or the computer goes south, whatever. I'm not even sure I want to mess with trying to put carbs on the bike, at this point I'm tired of it.

It's clear why Kaw gave up on fuel injection after this one year -- the parts quality of the licensed-from-Bosch fuel system pieces simply does NOT match the otherwise very reliable pieces in the Z1 family. If Kawi had designed this stuff in Japan instead of simply copying auto-based fuel injection crap, I bet they would not have dropped fuel injection after only 1 year.

I would not be at all surprised if the gpz1100 and the other later bikes that have F.I. were in fact designed by Japan.

It sort of sound like not only have you figured it out already, but that you are tired of messing with it. Maybe a day Of is in order and see if the bike will be kinder when you return. The old bike sat a long time and probably likes being treated to some new parts. Then it will run great and should be pretty reliable.
Its a sad fact that leaving things sit with this shitty Gas we have these days, can ruin a fuel system. The amount of in tank pumps we replaced when the Oxygen MTBE gas was being mandated, what a joke!!!

Possible fuel tank venting issue causing fuel starvation.

Would open the fuel tank cap, open petcock, and repeat efforts.

Good Fortune!

Patton wrote:

Possible fuel tank venting issue causing fuel starvation.

Would open the fuel tank cap, open petcock, and repeat efforts.

Good Fortune!

Very good point, last week I disassembled the few parts from the gas cap, really easy to do on this gas cap, made sure the vent was okay.

Then yesterday I had the gas cap unlocked and open the whole time I was messing with the pump. I was hoping to find something simple. Maybe the pump's power relay is bad or the pump really does need to be primed.

Today I'm gonna go to Harbor Freight and buy a variable power supply (if HF even sells those) so I can 'bench test' the pump. I will put a long hose on the fuel pump's input nipple, then drop the other open end of that hose into a can of gasoline.

This will allow me to power the pump with 12volts and not have to stress-out the bike's starter, which I've read you never want to crank-and-crank away on a starter.

MY OBJECTIVE: kind of twofold. First, I want to power the pump without that relay -- I want to bypass the relay on the bike that sends 12volt to the pump. By hooking the pump up to a power supply, I can guarantee the pump is getting juice without a possible bad relay interfering.


Second, I want to have the pump running long enough to *really* find out if a totally emptied pump does in fact need to turn quite a bit before it will put gas out of the output, in other words does a 100% bone-dry fuel pump need to be 'primed.'

Reason for the second 'priming' test I want to do is I searched the web and found lots of car guys, when they install a new fuel pump that is totally empty, they will hook the new pump up but leave the output hose disconnected from the carbs and put a rag on the fuel pump's output hose.

Then they spray 'starter fluid' into the carbs and turn on the engine. The engine runs for a few seconds on the starter fluid and dies. Then they repeat with the starter fluid 1 or 2 more times. By then the rag on the new fuel pump's output should start showing signs of gas coming through the pump's output hose. The stuff I read from car guys installing a completely dry, new fuel pump says that having the car's motor actually running for a decent amount of time is better using the car's starter to crank the new fuel pump to fill it.

I've had some cooling off time to think about it and there is nothing I have done to that fuel pump to explain why it suddenly would fail. I have a suspicion that allowing the pump to completely empty of gas has returned the pump to the state of being nearly dry like a new pump, and maybe the damn things when dry need to be primed like the car guys do.

I have two questions:

1) Is the fuel pump on these fuel injected bikes supposed to come on when you turn the ignition to 'on'? Or does that relay only turn the fuel pump on when the engine turns over via the starter turning?

2) This is an electrical pump, when I buy the power supply today, will I need 12 volts DC, or AC, to power my fuel pump?

I could be wrong, but thinking the fuel pump does not "pull" gasoline into the entry side, but that gasoline gravity feeds from the tank to the pump entry.

Because of the gravity feed, the fuel pump should be positioned below the gasoline supply during testing.

Would be tempted to use a bulb syringe to inject Seafoam into the fuel pump and fill it at both ends, and allow it to soak for awhile before draining and rinsing with gasoline.
Perhaps there's some sort of check ball or check valve inside the pump that's clogged.

Then repeat with gasoline. See whether low pressure input of gasoline into the fuel pump's entry port will allow gasoline to discharge from the exit port.

When these bikes arrived new at the dealerships, there was no gasoline in them. After initially servicing the bike, surely the dealer simply added gasoline to the fuel tank and started the engine without having to contend with some mystical fuel pump priming operation.

Good Fortune!

Am thinking the fuel pump is powered by 12 VDC.

"Quote"
Today I'm gonna go to Harbor Freight and buy a variable power supply (if HF even sells those) so I can 'bench test' the pump. I will put a long hose on the fuel pump's input nipple, then drop the other open end of that hose into a can of gasoline.
> Why don't you use the battery from the bike to power it?
But do buy the fuel pump pressure test kit.

"Quote"
1) Is the fuel pump on these fuel injected bikes supposed to come on when you turn the ignition to 'on'? Or does that relay only turn the fuel pump on when the engine turns over via the starter turning?
>Since I don't have the manual for your year I will have to guess, it should be like this, pump should run briefly when key is first turned on to pressurize the system. Then once engine rotation is seen the pump will again run, and should stay running until engine stops spinning from not starting or key off/ kill switch being applied. If you put a test light across the two leads going to the pump, you will see when and under what the pump receives voltage.

"Quote"
2) This is an electrical pump, when I buy the power supply today, will I need 12 volts DC, or AC, to power my fuel pump?
> All electrical on your bike is DC, but while the pump is 12v, the injectors have a block of 4 resistors which lower the voltage down to about 9v. A small 9v battery can be used here for a bench test.

As far as the pump failing, I started thinking that possibly with the restriction on the inlet filter maybe "starving" the old pump caused a pump rotor & gear failure.
Good luck and keep everyone up dated on what you find.

Can the fuel pump be heard running?

Patton wrote:

Can the fuel pump be heard running?

Yep that is a question I wanted to answer also. In my research I have found a mention of the following, I've done a lot of reading about FI for both cars and bikes i the past 24 hours so I'm not sure if this was in a car thread or a bike thread, pretty sure it was a bike thread somewhere though:

"Turn on the ignition and before pressing the starter, the relay opens and powers the fuel pump to 'On' and you should hear the pump running. Then turn on the starter and the pump will stop running in 2-3 seconds if the oil light does not go out -- the fuel pump shuts off if the engine is not running"

I'm paraphrasing from my memory but the idea was, the controller shuts off the fuel pump when the engine is not running. It only fires the fuel pump at the very beginning when you turn the ignition 'On', my thinking is that would be a 'Ready to go' mode, to have fuel ready so when the driver cranks the starter the engine will fire. After a brief interval, the fuel pump shuts down if the engine isn't running.

I just bought a variable power supply, about $200 at Fry's Electronics here in Silicon Valley. Tools are cool. When your divorced the wife wont b!tch at you for buying the stuff you need. (And the girlfriend, she aint got no leverage in these situations.)

So I will bench test this sucker and find out how she goes and will try the Seafoam depending on how things progress.

When I had no gas output yesterday I thought "that clogged input burned up the pump" but then I thought about all the miles I put on the bike in the past 4 weeks.

For example, after I fixed the throttle position sensor switch, I took her out for a 45 minute drive. She ran PERFECT and strong. The clog in the input of the pump is intermittently 'loose' then 'tight' but damned if I know how that happens.

Even if the pump checks out today, the relay or the controller or the injectors or.......could be messed up. I have my 'student' hat on for this one.