fuel issues

[Tomcomox]

Good day Ladies and Gents,

1984 Gl1200 Aspencade, 93 ,200 kms, new to me August 2021, turned over wouldn't start.

I'm not going to bore you with ALL the work I've done thus far, thanks to this forum and others like it but I'm moving along...except.

I'm not getting the bike to start when it's all hooked up. It starts and runs when I bypass pump ie: jerry can to carbs direct, bike starts,runs nicely, even synchronized the carbs this way. When I hook everything back up the bike won't start ? Have fuel coming out of pump, so from tank - line - filter - pump is good, disconnected fuel line at # 3 carb, fuel came out. What I'm I missing ....?

Carbs rebuilt, tank, petcock, sender cleaned, all new fuel lines, filter, relay, fuel pump. I know enough to be dangerous when it comes to mechanics, joined the Canadian Air Force in 1979 AirFrame Tech ( helo mechanic ) 5 yrs, have owned 2 motorsailers up to 40 ft and had numerous boats and bikes, so I like to wrench abit.

Any advice / guidance would be greatly appreciated. Thanks.

Tom

[joecoolsuncle]

fuel pumps are cheap. its old. you probably need one,

[Tomcomox]

Done as noted in last paragraph. Thanks for the quick response.

Tom

[joecoolsuncle]

Done as noted in last paragraph. Thanks for the quick response.

Tom

sorry i missed that. im guessing here, but with the fuek pump connected, it must be flooding with fuel? test fuel pressure and float height.

[Tomcomox]

Will do.... but it starts and runs when a jerry can/fuel is attached ...?

Tom

[WingAdmin]

There's a specific test in the service manual to determine if your fuel pump is flowing sufficient fuel:

GL1200 Fuel Pump Test

[Tomcomox]

Did that test on old and new pump, it was all good, I now have a spare pump.

Thanks,

Tom

[joecoolsuncle]

how long after connecting gravity feed tank does it take to get engine running?

[Tomcomox]

Instantly. after carbs were put back on, turned over wouldn't start, went the jerry can route started right away. ( happy dance ). Ran it for 30 mins, smoke cleared. was running a little off but I expected that, played with carbs a little settled down. Put everything back together , pump,relay, went to start to sync. carbs next day, same thing, bypassed fuel system again and was able to synchronize the carbs, idles 950 - 1000 rpms.

I'm trying to figure out if there is some collation between , fuel shut off relay (new), coil/CDI, fuel pump (new) wiring that i'm missing or if it has some sort of bad wiring somewhere. When she runs she purrs like a kitten, just a little perplexed with this problem.....

Thanx....

Tom

[joecoolsuncle]

but you said fuel comes out fuel hose when connected to pump. i mentioned pressure test from pump.............. im lost.

[Rambozo]

Even with no fuel pump it should run for a bit on what is in the carbs. So, I would also be inclined the think the fuel pressure could be too high and it is flooding.

[Tomcomox]

I will be doing a pump pressure test tmr. Will post results / info .

I did the GL1200 Fuel Pump Pressure test ,5 sec / beaker as per WingAdmin info. That was good.

I'm also working on a 40 ft motorsailer so if I don't get to any of these responses quickly please don't take it personally, I'm just busy elsewhere.

Between bike, boat, an ongoing divorce and with ALL the snow and rain we've been getting I'm just trying to keep my head above water...with a smile.

Thanks to all for your inputs, keep em coming, there's a light at the end somewhere.

Cheers,
Tom

[Rednaxs60]

Not much on carb issues, but isn't the fuel pump required when the fuel gets low in the tank. As long as the fuel tank is full there is enough head pressure to operate the engine.

When you tested the fuel pump - on or off the engine? Power source from the bike or other? Fuel will flow through the fuel pump when the engine is not operating, but there may be no power to the pump with the key "ON".

As Rambozo mentions, there should be enough fuel in the carbs to start the engine without the fuel pump coming on. Try filling the fuel tank, bypass the fuel pump and the engine should start. This will isolate the problem to the fuel pump and/or the electrical to the pump.

Is there a blockage in the fuel tank itself? Could be some crap in the bottom that when the fuel pump comes on, it is drawn into the fuel piping and blocks fuel from coming out.

has to be in the fuel delivery system.

Good luck.

[Tomcomox]

Good day all,

Sorry for the delay, boat issues,that took 3 days.....

Just want to make a slight correction on my 12 Jan 22 post. I mentioned the CDI, thats wrong I meant to say ICU, which i believe is part of the fuel relay,coils, fuel pump system. I think my problem lies somewhere within here, I just don't know enough of the system to diagnose it. Working on it.

Have my exhaust system off at the moment so i wont be starting the bike until parts come in, but i did a pressure test on fuel pump and had 4 psi just by cranking. Not sure if bike needs to be running to get a proper reading.

Will update ASAP.

Cheers ,Tom

[Tomcomox]

Hello all,

Could someone shed some light for my 1984 GL1200 A . What is the difference and jobs of the Igniter CDI unit ignition and the ICU ignition control unit. Or are these one of the same thing ...? Would these both have any connection to my fuel pump issues ?

Cheers,

Tom

[joecoolsuncle]

you have already stated the fuel pump runs, it pumps (flows) the correct amount of fuel, and now state tho pressure is 4 psi, which indicates the pump is working correctly.
you have also stated the motorcycle starts and runs great while gravity feeding fuel directly from a container. this would be at zero pressure above atmosphere.
the only difference is the fuel pressure, which should be perfect for a pump fed fuel supply to most carburetor engines.

next step is to check for float valves not sealing well, or they are set too high, or floats that are too heavy, or float valve leaking around the base gasket or cracked carb bodies (not likely).

you should stay away from thoughts of anything electrical!

[Tomcomox]

Thanks for the reply, food for thought.

Still waiting for parts ,mounting tires and installing rear tire today and other stuff.

Fuel issue is on the back burner for now, plan on troubleshooting it a bit further as I go.

Cheers,

Tom

[Claude]

Hi, I would agree with joecoolsuncle comment “next step is to check for float valves not sealing well, or they are set too high, or floats that are too heavy, or float valve leaking around the base gasket or cracked carb bodies (not likely).”
I would like to add to his comment, when you installed the float did you slide the small tab located in the center of the float it into gap of the little hooks on you float valve. If not your float will be pushing against that float valve hook which will keep your fuel port constantly close thus no fuel in the cab bowl. Remember there is qty 4 carbs and each will have to be check.

Hope this will help.

Good luck with your problem.

[Tomcomox]

Good day all,

Sorry for not getting back to this post, other projects on the go ( boat) and awaiting motorcycle parts. Have carburetors off as we speak , removed coils/wires checking them out and probably replacing very sloppy ignition will update ASAP. Thanks for the float suggestion(s) and I'll update as I go.

Thanks for the inputs....

Cheers,

Tom

[joecoolsuncle]

I would like to add to his comment, when you installed the float did you slide the small tab located in the center of the float it into gap of the little hooks on you float valve. If not your float will be pushing against that float valve hook which will keep your fuel port constantly close thus no fuel in the cab bowl. Remember there is qty 4 carbs and each will have to be check.

Hope this will help.

Good luck with your problem.

that would also be true when running off the gravity (atmosperic pressure) feed from the hanging container. he said it ran great in that situation, only when adding pressure from the pump did he experience his problem.

[Claude]

Joecoolsuncle stated “that would also be true when running off the gravity (atmosperic pressure) feed from the hanging container. he said it ran great in that situation, only when adding pressure from the pump did he experience his problem.”
You are right I missed part where he mentions gravity feeding.
To Tomcomox, this may sound stupid, but I have one question, when you did the fuel pump flow/pressure test, did you used the Maintenance manual instruction as follow: Disconnect the fuel pump relay from the coupler. Short the white and black wire terminals at the fuel pump relay coupler with a jumper wire.” This will bring the 12 volts directly to your pump to check the pump itself. But this test will bypass the fuel pump relay and ICU (Ignition Control Unit) that is part of your fuel delivery. To me your problem seem to be in the ICU

Please let me know there is a cumbersome way to check if the ICU does provide the voltage to energize the fuel pump relay which once energize will provide the voltage to the pump.

[Claude]

Ref to my last post I made a small mistake I stated “To me your problem seems to be in the ICU” correction, the problem does not seem to be in your ICU but rather the wiring from the ICU to the fuel pump relay the same wire also goes to your Ignition coil for #3 and 4 sparks. If the ICU was bad the bike would not start or run at all. Now the ICU provide a ground/low, not a voltage to the relay using Blu/Yellow wire from the ICU.

But first respond to my post asking how you did the fuel pump test, this will determine if I my troubleshooting is on the right path or we look somewhere else.

Hope this help a bit.

[Tomcomox]

This is what I did on both pumps, both will do again once carbs back on to give numbers. Also put pressure gauge on outlet of fuel pump ,4 psi, only cranking, not running ..?

Turn the ignition switch off. Disconnect the fuel pump relay from the coupler.
Short the white and black wire terminals at the fuel pump relay coupler with a jumper wire.
Disconnect the fuel pump outlet line at the 3-way
joint and hold a graduated beaker under the tube. Turn the ignition switch on and let fuel flow into the beaker for 5 seconds, then turn the ignition switch off. Multiply the amount in the beaker by 12 to determine the fuel pump flow capacity per minute.
FUEL PUMP FLOW CAPACITY:
500 cml (16.9 US OZ, 17.6 Imp ezl/minute minimum.... if i remember correctly I was slightly higher 600-650 ...?

Tom

[Claude]

Hi Tomcomox, good for your next step when permitted, redo the fuel pump test but this time leave everything connected to the bike as it should be. Turn on the ignition switch you should have NO fuel flow (not to worry, it should be like that), now push “start button” to crank the engine for a little while about 10 to 12 sec, do not crank the engine beyond that time it is hard on the starter, it will heat-up. While the engine is being crank, in normal situation there should be a fuel flow, but I am expecting that you most likely find that your pump has no flow, it is not running.

Let me know the result.

[Claude]

Hi again, been into the wine too much. I reviewed my last post and realized that yes we know it would not work it is the problem.
So, before you go any further, you could do a very quick check that will eliminate the wiring.
Hope you have a multimeter you will need it for this test.
Check with a multimeter for continuity between the ICU “Ignition Control Unit” connector with 4 wires, from the Blue/Yellow wire and the fuel pump relay connector (side that the relay pins go into) to Blue/Yellow wire, and you should have 0 ohm (continuity). If you do not read 0 ohm, this wire is broken and that is the problem.