How does the Tourer's fuel pump work?

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tonythecarguy	How does the Tourer's fuel pump work?		Lead	[-]
HSATF 1st Officer Posts: 573 01/04/08 12:13 PM	Tags : None I've been thinking about the logic of the Tourer fuel pump lately. It's been a long cold winter already. It was been discussed before how the Tourer takes a lot of cranking to get running if you let it stall at the end of a tank of gas and don't switch to reserve quickly (thus keeping it running). I have found the same thing when taking it out after it sits for the winter. The bowls are dry (as with the failing to get on reserve in time) and I usually kill the battery then recharge it then finally get them to refill and the bike to start. I suspect this is due to the fuel pump. You can't just turn the gas on and have gravity fill the bowls. This leads me to thinking about the fuel pump logic. It seems to me that the pump only runs when the engine is turning over. This is not the same as most EFI systems in which the pump runs as soon as you turn on the ignition and immediately brings the system up to pressure and the engine will start immediately when the starter is engaged. I have looked over the wiring diagram and see that the pump is controlled by a relay. The control line for the relay is wired to the control line (from the electronic Ignition module) for the coils. Thus the pump runs when the coils are firing. Now where I'm unclear is does the relay pulse (and therefore the pump) with the ignition pulses. This could make sense; as RPM's increased so would fuel delivery. But could/does it work that way, or does the relay come "on", full time with just the weak, pulsing ignition signal. Such that the pump runs full tilt all the time and the pump is fairly weak and the float bowl needles being seated is enough to stop the flow even if it is on full tilt all the time. If this is the case I could remove the relay jump the right wires and run the fuel pump for say 30 seconds before re-assembly and hopefully a quick normal start. My concern would be if I jumpered the pump to run I would force to much fuel past the needles and flood the engine, wash oil off the cylinder walls etc. This would lead to hard starting at least and I gained nothing. So if you've made it this far: If no one can enlighten us on the pumps operation, does anyone have some better way of starting the bike after the long winter. Thanks Tony
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Fredrider		#1	[url]	[-]
Posts: 5937 01/04/08 12:19 PM	Tony, The T's would be quite a bit different than auto fuel pumps if it works the way you suspect it works. If you try some experiments I would really be interested how they turn out. Fred
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dukey33		#2	[url]	[-]
HSATF 1st Officer Posts: 695 01/04/08 1:03 PM	I recall some early applications of electric fuel pumps used the oil pressure sending unit as a safety cutoff to control the fuel pump. newer cars and bikes with on-board electronics use more complicated logic to determine when to run the pump. most cars will run the pump for a few seconds after keying up the power, and then look at the engine to determine if the pump should keep running. high pressure systems typical of FI setups use a pressure regulator that dumps excess back to the tank to control the fuel demand. if the Shadow uses a simple signal from the ignition control box, try putting a voltmeter to it and see what it does when you key up, crank and when the engine is running. Since the bike uses carbs, it may rely on the bowls to store fuel and not run the pump until the engine is lit. That would be fine for most circumstances but with dry bowls, obviously you have a greater challenge. Have you tried starting fluid after a long winter nap? Just spray it thru the air filter. It should make the engine at least cough and fire and few times; possibly enough to get the fuel pump going. duke loud horns save lives
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CleRider		#3	[url]	[-]
Posts: 1905 01/04/08 1:06 PM	Tony, From what you have described, I would approach the upgrade as follows: I would connect a momentary push switch parallel to the control relay. When I wanted to charge a dry system, I could reach down, push the button which would start the pump and fill the carbs. After the bike started I would rely upon the designed circuitry of the relay tied to the coil.
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alepel		#4	[url]	[-]
Posts: 7898 01/04/08 1:12 PM	dukey33 wrote: Have you tried starting fluid after a long winter nap? Just spray it thru the air filter. It should make the engine at least cough and fire and few times; possibly enough to get the fuel pump going. I had not thought of this idea of spraying starting fluid into the carburetor. I know that after long idle periods the Tourer is rather stubborn to start. This sounds like a potential fix for that troublesome starting problem especially after the winter respite. Are there any negatives or downsides to this idea? alepel "Ride with the Spirit always, and in all ways"....hombldr
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tonythecarguy		#5	[url]	[-]
HSATF 1st Officer Posts: 573 01/04/08 3:37 PM	All right so it seems that I need to get the multimeter out and see what the signals look like. Which is what I figured I needed to do anyhow. But right now that will require draining the battery trying to refill the bowls so I can get some measurements. The starting fluid may be enough to increase my ignition pulse to cranking ratio and hopefully get it running before the battery is flat. My other thought is to temporally route the fuel line from the tank directly to the input lines of the crabs, open the petcock, let gravity do its thing to fill the bowls, then reassemble and hopefully start right up. I think this may be the simplest option and once I have it running I can check the power to the pump. Based on the wiring diagram I'm fairly confident that there is only power to the pump when there is an ignition signal. the question is, what does that power look like. If it is being pulsed I think I would need an oscilloscope to know. Has anyone heard of a relay used in a pulsed manner like that? Tony
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bamaTrider	5	#6	[url]	[-]
HSATF 1st Officer Posts: 3746 01/04/08 10:44 PM	When I let the bike sit for any length of time, I run the starter for about 5 seconds, then wait for 5-10 seconds. This allows the fuel pressure to build up initially, and time enough to allow the bowls to become full. I may have to do this a second time before it will start, but it seems to work. I got used to having to do this on my '85 CB650SC Nighthawk with a vacuum actuated petcock. On that bike, I eventually got smart and installed a split vacuum line that I could pull out and apply vacuum by mouth 1st before attempting to start it. It worked well that way so maybe the pulse switch would do the same. Stan Last Edited By: bamaTrider 01/14/08 11:44 PM. Edited 1 time.
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Chicago		#7	[url]	[-]
HSATF 1st Officer Posts: 1123 01/05/08 6:49 AM First Officer	alepel wrote: I had not thought of this idea of spraying starting fluid into the carburetor. I know that after long idle periods the Tourer is rather stubborn to start. This sounds like a potential fix for that troublesome starting problem especially after the winter respite. Are there any negatives or downsides to this idea? I can think of two. First, you'd have to remove the seat to get to the air cleaner and carbs, not an easy task. Second, there's all kinds of improtant wiring under the seat. What if the engine backfires and you get fire in the air box? YIKES! You meet the nicest people on a Honda (forum).
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bamaTrider		#8	[url]	[-]
HSATF 1st Officer Posts: 3746 01/05/08 10:47 PM	It's a lot easier and safer to spray some WD40 into each spark plug hole, then hand installing the plugs. The WD40 not only will ignite, it will help lubricate the cylinder walls also. About a 5 second spray in each works good. Another option is to spray it directly into each carbs forward boot. There is a vacuum port there that is used to synch the carbs. You would need to remove the screws from the sides of the boots and install a vacuum line orifice in it's place, add a short section of vacuum line to that to make it easier to access, then plug that line off with the screws that you just removed. Motion Pro should have the vacuum line orifices to fit, as well as most dealers. Stan "We are different - yet we are the same" 2004 GL1800 Goldwing (Titanium) 1999 Ace Tourer (Silver over Black)
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tonythecarguy		#9	[url]	[-]
HSATF 1st Officer Posts: 573 01/08/08 11:47 AM	thanks for the replies guys. i did think though a few more things. the relay is controlled by the ICM which grounds the coils. the coils fire when the ground is broken, so as RPM's go up the time the circuit is closed (activating the pump) is less, so my pulsing idea is junk; as rpm's goes up fuel delivery would go down. that said jumping the pump to on looks like an OK idea. the pressure should be low as the speck is .8 liters a minute for the pump. Buy chance i was looking though the hondashadow.net and found a thread on the same topic. it seems that many have already implemented clerider's idea. Tony Last Edited By: tonythecarguy 01/08/08 11:52 AM. Edited 1 time.
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tonythecarguy		#10	[url]	[-]
HSATF 1st Officer Posts: 573 01/14/08 10:43 AM	I had a chance to start up the T this Saturday. I decided to try out running the pump for a few seconds before attempting to start it. So I jumpered the wires as descried for the pump volume test in the shop manual, and turned on the key. The pump sprang to life. With in a few seconds I turned off the key reinstalled the really and had the T started in 4 cranks. The last two cranks ran for a few seconds the quit. This is great compared to what I usually have to go thru. My battery was still amply charged and I could go for a ride instead of wasting an unusually warm day while I recharge my battery. A few comments on the pump: with it on and the engine off it is plainly audible. It sounds like a reciprocating pump, that is it goes click, click, click. Also after running it for a few seconds the clicking started to slow down. I took this to mean that the bowls where filled and the needles had shut off the fuel flow. This was my cue to shut it back off. Tony Last Edited By: tonythecarguy 01/14/08 10:45 AM. Edited 1 time.
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alepel		#11	[url]	[-]
Posts: 7898 01/14/08 12:29 PM	tonythecarguy wrote: So I jumpered the wires as descried for the pump volume test in the shop manual, and turned on the key. The pump sprang to life. Tony.....I've been following this thread with quite a bit of interest. I have had the same problems or concerns as you have about the long crank time when my Tourer sits idle for extended periods of time. I too have spent a good riding afternoon recharging a battery. So please for those of us ignorant souls who do not know what you did when you "jumped the wires described in the pump volume test in the shop manual", could you explain this in a little more detail? I for one would appreciate you explaining exactly how you did this. Thanks in advance. alepel "Ride with the Spirit always, and in all ways"....hombldr
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tonythecarguy		#12	[url]	[-]
HSATF 1st Officer Posts: 573 01/14/08 2:36 PM	Alepel, Ok you asked for it. There are tree wires that lead to the fuel pump relay. Black, black with blue stripe and blue with yellow stripe. the black is the hot line coming from the fuse. the black with blue stripe heads off to the positive terminal of the pump; the pump is then grounded. and the blue with yellow stripe connects back to the coil and is grounded buy the ICM. 1. Remove the relay from its rubber holder 2. Unplug the relay, set it aside. We are working on the white connector still connected to the bike. 3. Place something conductive into plug to short the black wire to the black with blue stripe. This provides full battery voltage to the pump. The manual showed what looked like a short piece of wire stuck in the back (wire side) of the connector. I used a small u shaped spade connector. I bent each leg 90 degrees so they where parallel, to mimic the pins on the relay. errr i guess they where parallel to begin with too, click on this... of course the real one looked more mangled from the pliers but you get the idea. then stuck it in the front of the connector just like they where the pins on the relay. This worked great but I suspect a paper clip would have too. 4. making sure my jumper didn't ground out on the frame I turned the key on for a few seconds. Then off. Tony Last Edited By: tonythecarguy 01/14/08 4:38 PM. Edited 3 times.
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alepel		#13	[url]	[-]
Posts: 7898 01/15/08 7:38 AM	Tony....thank you for the great description. You did a great job of describing the process. I have one question....where is the relay and fuel pump? How hard is it to get to them? How much dis-assembly do I have to go through to get to them? alepel "Ride with the Spirit always, and in all ways"....hombldr
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tonythecarguy		#14	[url]	[-]
HSATF 1st Officer Posts: 573 01/15/08 10:13 AM	The relay is right under the seat. standing on the clutch side of the bike, looking down into the area under the seat; the relay is in the lower right corner. it's bracket is bolted to the rear cross member near the rear fender. it is held in a rubber band about 1" wide. it is roughly 1"x1"x1.5". it is very easy to get to all you remove is the seat. the pump is quite inaccessible under the air box but you will not need to get to it. I can't find a concise picture of where it is at on the on-line fiche. the relay and braket are in the wire harnes page and the lug it bolts to is on the frame page and not really visible at that. I'll try to remember to take a picture at home tonight. Tony
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alepel		#15	[url]	[-]
Posts: 7898 01/15/08 11:14 AM	Tony....well that is good news that the relay is under the seat. If your going to take a picture that will be so much the better. Thanks Tony, your being quite helpful. alepel "Ride with the Spirit always, and in all ways"....hombldr
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How does the Tourer's fuel pump work?

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