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Won't start....... Ahhhh....... GL1500, it is fixed now. Bad Transistor in ECU

11K views 45 replies 13 participants last post by  DaveO430 
#1 · (Edited)
I removed the air cleaner assembly from my GW 1500 SE and, although it started briefly whilst removed, it cut out and now won't restart.

Plenty of fuel in tank and battery fully charged but won't have it.

It seems as though fuel is not getting to carbs. Have removed fuel lines and sucked through and they seam fine?

Am I missing something??
 
#5 ·
Right. Have removed and reassembled the air cleaner unit, checked all connections are good, but it wouldn't start.

Decided to try running a jumper wire from the positive terminal of the battery to the fuel pump and it started. It will continue to run when removing the jumper wire, but when I try to accelerate, it hesitates and cuts out again. The only way to restart it is to use the jumper wire again.

Weird !!!
 
#7 · (Edited)
If you're referring to the Petcock Assembly, I bypassed that first and it didn't make any difference.

I have had it running with it bypassed, and fitted 'in line' with the same results.

Just found this underneath the bike. Does anyone know what it is, what is does and where it goes? Must have come off when removing air cleaner assembly earlier?
 

Attachments

#9 ·
The fuel pump gets power directly from the ECU so no fuse or relay involved that would not also keep the engine from running. Check for power on the blk/blu wire in and out of the inline capacitor on top of the tank.
 
#10 · (Edited)
I have run some basic checks and can confirm there isn't any power (either when running or on start up) at the BLK/BLU wire to fuel pump. Also, there isn't an in-line capacitor fitted to my machine as far as I can see.

Seems to be a common problem with these machines?

Could the ECU be toast ?
 
#11 ·
I removed the air cleaner assembly from my GW 1500 SE and, although it started briefly whilst removed, it cut out and now won't restart.

Plenty of fuel in tank and battery fully charged but won't have it.

It seems as though fuel is not getting to carbs. Have removed fuel lines and sucked through and they seam fine?

Am I missing something??
Did it start and run before you started down this path outlined in this thread?
 
#14 ·
I bet you have a low voltage problem at the pump. I would start the bike with the jumper wire and with the bike running check voltage at the pump. If it's less than 10 or 11 volts that is the issue. Check again for a poor connection etc. and check at the ECU for voltage in the same configuration. If it's good at the ECU but not at the pump you know it is a connection issue.
 
#18 ·
As mentioned but no reply that I see(may have missed when scrolling through?). Have you checked all fuses?
Can't remember right off if there are any connectors that the airbox may hit or have to unplug.
There is a ground that goes under the radio. Not sure if that is just for radio or not? There are several connectors on left side when you remove the left fairing?
I don't have wiring diagram in front of me to see what may cause the fuel pump not to work.
 
#19 ·
Take the fuel petcock off the gas tank and see if fuel flows freely.\
Not sure on Goldwings but on all my past bikes fuel pours out when pet **** removed as yu would expect on a Goldwing.

Not much info in manual regarding fuel tank, just removal or pinched breather at te gas cap.

GL
Rick
 
#20 ·
Just an update.

Firstly, to answer a few questions. There isn't any fuses or relays controlling the fuel pump on later 1500 models. Have by-passed the Petcock valve and fuel flows freely, either when sucked or using the jumper wire

Secondly, have started the bike using the jumper wire, removed it, then tested the voltage of the BLU/BLK wire at the ECU = Zero volts. Took readings at various points along this wire and nothing.

Re-connected the jumper wire and got battery voltage at the ECU. This, in my opinion, indicates the fault is within the ECU module?

Have ordered a replacement transistor and will install this and see what happens. Have nothing to loose at this stage so may as well give it a go!
 
#21 ·
Chris,
Don't tie in to the ECU too early. The ECU needs to know the engine is running or it will turn off the fuel pump. That is a safety feature in the event of an accident so the pump does not continue to pump fuel in case of a fire. So it needs an engine running signal. I noticed the cruise takes a similar signal off the number 6 coil. The ECU has two choices. The tach signal or the #6 coil signal.
I'm just trying to tie both of your problems together if it is possible. What if there was an issue with the #6 signal and you moved something etc. and now have the signal at the cruise but not at the ECU? I wish I knew for sure where the ECU got the engine running signal from. Can anyone say for sure? Is it the #6 coil. (It's at the ECU) Is it the tach signal? (It's also at the ECU) Chris I think you get my drift. Before you dig in to the ECU be sure the ECU has an engine running signal. Without that the ECU says "Engine not running , I won't turn on the pump." I think the reason the bike continuous to run after you take the jumper off is either it siphons or gravity feeds the carbs slowly. Especially if the tank has lots of gas in it.

Edit: Did a little more investigating. If you turn the key ON, the pump should run for a second or two. OFF, then back ON the pump should run for a second or two. OFF..then ON and the pump should run for a second or two. Does it do this? All above is correct but this feature makes sure the bike has fuel to start only.
 
#24 ·
snip...
Edit: Did a little more investigating. If you turn the key ON, the pump should run for a second or two. OFF, then back ON the pump should run for a second or two. OFF..then ON and the pump should run for a second or two. Does it do this? All above is correct but this feature makes sure the bike has fuel to start only.

Redwing, I'm pretty sure the fuel pumps after the 88-89 do not run for a couple of seconds after key-on. Then after those years were modified to have a vacuum petcock, that feature was deleted. It is of no use with a vacuum operated petcock in the gas line.
 
#22 ·
Thanks for the information and the comments are duly noted.

The fuel pump doesn't prime (run for a couple of seconds) when switching on the ignition or when repeating this routine, this is why I suspected the wiring in the first instance, and now the ECU itself.

I have already striped down the ECU and removed what I believe to be the faulty transistor. It didn't cost much from Ebay, so if it doesn't work, no problem. On the other hand this could be the answer to the issue!
 
#23 ·
The 88-89 bikes had the fuel pump relay which cycled the pump on with key on. 90-up bikes the pump is powered only with engine cranking or running.
 
#34 ·
Pretty sure it's the pulse generator signal that operates the fuel pump output. That is the only input signal that tells the ECU the engine is turning. If it had a fuel pump relay the ignition pulse to the coils output would operate it.
 
#35 · (Edited)
An update for all who have similar problems.

Replaced transistor, as per attachment, and the 'old girl' fired up and ran at first attempt.

For the little time involved in stripping the ECU down, and the relatively low cost of the replacement part, well worth the effort!

Got part through Ebay at the following link: http://www.ebay.co.uk/itm/160937383031?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT, but I'm sure there are similar places to obtain the part in the US?

Thanks to all who gave me some useful advice.
 

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#39 ·
Chris,

Thank you so very much for coming back and reporting EXACTLY what fixed your bike.
So many folks just get it fixed, and disappear from the forum.

Now, we have a documented reference for folks who also have severe non-starting issues to look into.
You got a goldstar and a bookmark >:)



An update for all who have similar problems.

Replaced transistor, as per attachment, and the 'old girl' fired up and ran at first attempt.

For the little time involved in stripping the ECU down, and the relatively low cost of the replacement part, well worth the effort!

Got part through Ebay at the following link: http://www.ebay.co.uk/itm/160937383031?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT, but I'm sure there are similar places to obtain the part in the US?

Thanks to all who gave me some useful advice.
 
#37 ·
Simple things changed over the years so not every 1500 works like every other 1500.

My 88 1500 the pump will run just flipping the key on and off and not cranking or anything. Also with engine off I can fill the carb bowls just flipping on off the key. 88 does have a vacuum petcock also I'm pretty sure.
I did this to fill the carbs for push starting after I let the 88 sit a long time after that deer hit it.
However, I can also just turn on the key and use reverse without the engine running on the 88. My newer 1500's like 95 and 99 reverse will not work unless engine is running. Sometimes it's simple changes like that which can make things confusing.

I'm sure somehow Honda decided it safer for reverse to NOT work if engine not running, I consider it rather dumb and a problem at times, also unsafe!
What if 1000lb bike dies and it needs to be rolled backwards up a little hill to get out of a road??? One thing to not have a reverse at all on a bike, but if it does have reverse then it should work!

Sure was nice with 88 to be able to back up a hill a little then roll to start it (since my idler gear was busted and had to always roll start).
With 95 and 99 it's a pain that if they sit a long time and hard to start I just have to keep cranking on them till they do start or battery goes dead. I have to back up a hill in my drive to get out but then I can roll a long long ways down hill to roll start if I wanted/needed, but of course cannot do that since the engine has to be running to back up!

Again it's nice the 88 reverse works without engine running. She been sitting well over a year and I'm sure will be hard to start! SO I can roll her down a little hill at the shop and if she don't start then just back up the hill a bit and try again. If I get the battery a bit low just swap batteries and charge up the low battery while using the other full charged battery.
 
#46 ·
Chromo, it would be a simple thing to make reverse work without the engine running in your later 1500s. Just disconnect the oil pressure switch input to the reverse control unit. Also a push button switch could be added to run the pump to prime the carbs.
 
#38 ·
This is some good to have information on the ECU repair. Looks pretty simple to fix if that is your problem.
Thanks for posting that info.
 
#40 ·
Rick

Glad you are skilled enough to accomplish what you did with the replacement of the transistor. By far I believe you are one of the few that had gumption to try this fix.

I have read the posts and wires to the fuel pump go hot for a second while turning the key to run. Never heard or felt my pump run at all. I have an open circuit at the fuel pump wires. I tried running straight from the battery to the plug of the motor and nothing. Should of jumped around spinning madly. So unless I get something said in reply to surprise me regarding the fuel pump motor, I know I need a new fuel pump.

Fussed with the tank itself inside and managed to get a better flow the petcock hole in the tank. Trying the vinegar effect to clean the inside out the best I can.

I did get it running for a minute on full choke with air pressure at the sending unit location. I had to use starter fluid but it did run like that couple times. Have not been able to start it up again.

Rick
 
#41 ·
You never, ever, try to test a fuel pump that is NOT immersed in gasoline.

if you do, it will burn up almost immediately.

the gasoline is what keeps the motor cool.

the proper test is to put a length of hose on the pump's output and then have a jar/can raised up about 2 feet higher than the pump.

the pump should fill that can in short order.... a #303 can, not a gallon container. about a pint
 
#42 ·
To AZGL1800 Moderator/ 1985 fuel pump ?

O K Moderator.

I comprehend your instructions and will be doing exactly as instructed in the near future.
As of right now I know the fuel pump motor has no continuity. This check was done prior to running 12vdc directly to the female electrical plug originating at the fuel pump motor.

So would it be safe to say the motor was bad before I jumped the 12vdc to the fuel pump motor?

Thanks Rick
 
#43 ·
I have never tried to measure the resistance of a good fuel pump, but it is a DC motor and it stands to reason that "should have some continuity"...

how much? I don't know.

the only thing I cared about was that it hums and fuel spurts out :)
 
#44 ·
I believe the GL1200 fuel pumps are pulse/diaphragm so if there's pressure in the outlet line there's no continuity, when the pressure drops on the outlet line it pulses until the pressure comes up to specification then stops.
 
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