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87 700 fuel pump relay intermittent failure?


THRASHED

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Is it possible for the relay to work intermittently, or does it just fail?  Bike died last week obvious fuel delivery issue.  Without reading into this, I didn't do any flow tests or test the relay.  I just bought a fuel pump.  Installed it, it ran fine, but only lasted 19 miles on my morning 42 mile commute.  Figured then (after reading some stuff last night) that it might be the relay.  Only problem is after jumping the relay, it seems to be working whether jumped or not (jumped, constant power, not jumped, only runs with engine running).  I then tried the old fuel pump and it flows perfectly (inlet to pump, outlet to glass beaker).  Both pumps seem to be working so I can only assume that the relay is not working all of the time. Per the title: is that possible?

 

Thanks,

 

Scott

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the relay just turns on the power to the pump when the bike is on.. .so yes it could have been bad or just stuck one day..

the pump itself has very little pressure and simply stop pumping with resistance..

 you need to check the points under the black cap and make sure they are flat. you can lightly file them. or place fine sand paper in between and put it out.. 

 

the weird thing about these pumps.. they are set up sideways.. and with time they develop leaks.. which flow into the "top" aka electrical side of the pump and SHORT IT OUT......makes it stop pumping.. 

until the gas evaporates then it starts up again..

now the fun part..depending on other conditions the pump can catch fire! :blink:

happened twice to me and a few other people..

i now mount mine vertically..when not by passing it all together..

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I ordered a new relay yesterday. Given that both pumps pump well, I can only assume that the relay is the issue.  Time will tell. 

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jUst bypass and forget about the relay already.................😱

 

one wire fixes it.

 

NOTE: suggested for testing purposes only.

 

proper fix is the  parallel switch installed  to have both modes for  safety and convenience.  😊

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A little more help, please.  l just installed the new relay (not discounting bypassing it but I had already ordered the new relay) and the bike made it 1/2 mile before cutting out.  I unplugged the fuel pump, plugged it back in and it worked.  This is the new fuel pump. It is one of the aftermarket ones from ebay.  I suppose that could be the issue, but I haven't re-wired the old one yet to check it out but as I said above, it does seem to work fine.

 

I have seen some posts that say both the green wire and the black/white-stripe wire are supposed to have current. This seems odd to me because the pump is not grounded, is that correct? I currently only have power to the black/white-stripe wire when the bike is either cranking or running.

 

Thanks again. 

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Alright, the struggle continues.  First off, the colors of the wires in the previous post are incorrect.  Those are the colors on the newer pump.. The stock wire colors are Green and Black with a Dark Blue stripe.  

 

Now to continue.  Figuring that maybe I was dealing with different issues, I rewired the original pump (passed pump test fine) and took it for a spin.  It did fine around the long block so I took a quick speed run down the freeway.  As soon as I got off the freeway, the bike died.  I pulled the side cover, unplugged the pump, plugged it back in and made it home.  I started thinking that maybe there is a short somewhere, or a loose wire. The other day I noticed the wires coming from the stator were a little dark.  I decided to start there.  The pics are what the plug and wires look like.  Though the bike definitely feels like it is starving for fuel, I assume that the stator is what is sending the signal to the relay to power the pump.  I replaced the RR last year with a Ricky Stator model.  Is it possible that the stator is putting too much power out, or more likely that there is a short?  I assume that replacing it will fix the issue either way but would like to hear from someone with more experience with this.  I just checked, Ricky Stator does not list one for my bike.   I emailed them to check on availability or possibly re-wiring it.  Any suggestions on where to pick one up?

 

Thanks. 

 

 

 

Stater plug 1.jpeg

Stater plug 2.jpeg

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That could be a photo of any model VFR! What you are seeing is the result of water/dirt getting into that plug, causing corrosion, which increases the resistance, which causes heat, and et voila! (as they say in France), burning/melting. When this gets really bad, the conductors will touch and as they say in Ghostbusters, you don't want to cross the streams. That connector would quite likely reduce the voltage getting to the RR and hence the battery, not increase it. As that connector looks pretty bad, I'd suggest you chop it right out and splice in and hard-solder the wires with suitable heat-shrink to keep them water tight afterwards (I did that myself on my 1999). How is the charging voltage at the battery looking while running? 

 

The fuel pump relay would be energised by the ECU using a grounding signal, which is a separate system to the alternator and charging system, so I doubt they are rleated. However if the connector above is corroded, I would suspect some other connectors will be as well, and corroded connectors can cause intermittent faults. Maybe it is time to systematically go through all the connectors and give them a clean-up?

 

Regarding the wire pump colours, green is always a ground on Honda harnesses, and you should have a steady 12v on the black/blue wheevern the relay is energised. The relay would be energised only when the yellow/green wire is grounded through the ECU I think, and there would be a steady 12v on the black wire to the relay at all times the ignition is on. You can rule out a relay issue by bypassing the relay so the pump is always running, as suggested by Squirrelman above. 

 

 

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Thanks Terry.   I'll consider splicing the wires, on the charging system, but I may try to find a plug first. It's a long shot, but worth a try.  I agree that there's a chance of other corrosion in the system, that's why I started with the first one I saw.  Hopefully I'll see something else that makes sense because the current issue is really starting to dive me nuts. 

 

I just thought of another thing.  Is it possible that the shorting wires could give the same indication of the engine starving for fuel?  I know it's a long shot, but I thought I'd ask.  

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I bought myself a 1990 ST1100 that had been parked up for 10 years and didn't run, as a do-up project; the bike had been parked up covered but outdoors with no thought to storage prep, so the fuel system was predictably clogged, and I was pretty sure I had a fuelling problem even after a new fuel pump and cleaning the carbs six (yes six) times). Turned out that I had a corroded red connector where power was fed to/from the right switchpod and ended up at the ECU, which lead to lower voltage and weak sparks, so the bike just wouldn't rev out over 4000rpm. Cleaning that connector fixed the problem right up, hence my suggestion to you to do the same. 

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I pulled the plug farther apart tonight. Not only is the plug completely melted, but the wires on the RR side are very stiff.  I can't imagine things got so hot that the wires melted because I think the sleeve would have completely melted first.  It actually looks like there may be some corrosion.  I did not cut/strip them yet because I wanted to make sure I could find a new plug set.  I ordered the new set today.  Tomorrow I'll replace the parts and see what happens.  Another rider here pointed me to a thread about adding a thicker wire for the RR ground. I think I may do that at the same time.  

Still not sure how this all plays into the starved-for-fuel feeling unless I have that completely wrong.  It seems that if it was the stator only causing this that the bike would still run fine off of the battery. When it dies, there is still plenty of juice to crank the bike for a long time.  

 

I hate electrical issues. 

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Yes the bike will run fine without a functioning alternator/RR so long as the battery is well charged. 

 

If you've not already done so, I'd suggest you hook up a voltmeter so you can see what is happening to the battery voltage when the engine is running, whether the voltage is stable or too high/low. It should be around  13.5 - 14.5V if the RR and alternator are doing their things. 

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That's the next step as soon as I get the plug. I figure as bad as the old plug is, it won't give me accurate information right now.  

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I'm still researching while I wait for my electrical plug to get here.  I have read several articles about stators but still can't find an answer to one question:  if there is a bad ground from the stator, or if the green wire (ground?) on the RR is bad, will that affect the ignition and/or fuel relay?

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15 hours ago, THRASHED said:

I'm still researching while I wait for my electrical plug to get here.  I have read several articles about stators but still can't find an answer to one question:  if there is a bad ground from the stator, or if the green wire (ground?) on the RR is bad, will that affect the ignition and/or fuel relay?

 

no, and the stator has no ground.  i'm thinkin you struck out too many times and may need a Honda dealer to finally sort out your problems.

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  • 2 weeks later...

So, it seems (tentatively) that I have corrected the issue.  My new plug arrived last week so after a cooler weekend in the mountains, I arrived home yesterday and swapped out the fried plug.  Now that I have clean terminals, I checked the Ohms on the stator.  All combinations across the wires showed .4 which seems to be within the suggested limits. 

  The connections on the plugs seem very tight and after a few trips around the block and a speed run down the freeway, all seemed good. When I got home I pulled the left cover and checked the wires. They were warm/hot, but not insulation-melting hot.  Also, the plug seemed no warmer than anything else.  The bike got me to work this morning just fine.  I'll keep monitoring the new plug but hopefully that was the issue.

 

Now, another question: I already dropped in a Ricky Stator Mofset RR.  Does anyone know if they make a stator, and if so, are the wires any heavier gauge than the stock wires?

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  • 2 weeks later...

Well Squirrelman, you win!!  The bike ran great for 4 1/2 days last week then stranded me again on my way home.  I stopped by my local dealer over the weekend. Unfortunately, the young guy there admitted he has no idea how to troubleshoot the bike...however...he gave me a name of another guy at another dealership that has been around for a long time.  I called and will be dropping the bike off on Friday.  I hate spending the money, but if he can find a definitive answer to my issue it will be worth it. 

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You know, I haven't checked the stator (ohms) since I swapped the plug.  One of the issues I'm having is finding out if the stator supplies spark to the plugs (as I understand some of them do) or if it just provides a charge for the battery.  The battery is still charging fine so it can't be completely fried (if it's possible for it to be partially fried).  The issue for me has finally come down to: I have no confidence that the bike is reliable.  I love riding it, but as a primary commuter bike I need that reliability.  It may be the stator, but there may be something else.  Hopefully, I can find out everything that is wrong.  

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  • 3 weeks later...

  I managed to find  a mechanic that is old enough to have worked on these bikes.  I can't say enough good things about Martin at Mid Cities Motorsports (Honda) in Paramount, CA.  He did some troubleshooting and wired up some tell-tale lights and only charged me 1/2 hour.  When the lights weren't conclusive, I trailered the bike back over there.  He came out and we talked for a few minutes (he seems very work-oriented and doesn't seem to like small talk at all, which I'm fine with).  He basically said it's down to either the fuel pump, the fuel-pump relay, or the ECU.  He told me where to move the tell-tale lights and I was off without this costing me any more money.

 

Latest update.  The bike died again and though it was a possibility, it was not the kill switch.  It is definitely a fuel delivery issue.  The bike starts to stutter out, then dies just about the time I make it to the breakdown lane.  I am going to move the lights so that one is on the fuel pump hot lead and the other is on the fuel-pump relay hot lead.  Assuming the issue continues, I will be able to see if it is the fuel pump (1-year old OEM pump), the fuel pump relay (brand new), or the ECU.  Martin suggested I super clean the ECU plugs because it looks like there may be a little corrosion in there.

 

  If it ends up being the ECU, I'm not sure what I will do.   From what I've seen, it's impossible to find a new module and there is no definitive way to verify that a used one is any better than what I have now.  

 

I'ts been so hot, I haven't been out to the garage since last week.  I'll see if I can get to the wiring this weekend.

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If you saw this post before I deleted it, that's fine.  Just wanted to update the latest. I have found the failure of the fuel delivery issue and I think I know what caused the failure, but I would like some input.  I am attaching four pictures. The first two are from the OEM pump I installed last year, the second two are from the new, aftermarket pump I recently installed.

On another thread, I read a comment about the fuel pump maybe not being bad, but having bad contacts.  For grins, I first verified that the fuel pump(s) had power and would not run.  Then, using 400 grit sandpaper, I cleaned the contacts. Even though the ones from the OEM pump are obviously damaged, and the new pump is, well, new, this did the trick on both pumps and they both pump now.  

On to the cause. My thought is that the fuel pump electrical plug is loose enough (it is definitely loose) to cause arcing.  This arcing could somehow either send more voltage to, or ground out, the fuel pump contacts.  

How does that sound?

 

Thanks,

 

Scott

Old FP Contact 1.jpeg

Old FP Contact 2.jpeg

New FP Contact 1.jpeg

New FP Contact 2.jpeg

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Arcing is part of the design...

 

 

with the pump powered, it moves the internal piston to suck fuel. As it rises, the contacts touch, causing a short. This then lets the internal piston drop. Only to be powered again and short etc etc.

 

So the points wear out over time. Replacement/repair kits are available. 

here my story

 

 

What can be done (I did) is solder a diode in place to minimize arcing. (i did not cover the diode in goo)  I have a few diodes left in the shed somewhere

 (

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I get the idea of how the pump functions.   The question is: Can arcing across the plug cause issues with the contacts?  Replacing contacts won't solve the problem I have.  The new pump has new contacts and it started working fine as soon as I sanded them.  Even the older pump, with the messed up contacts started working when I sanded the contacts. 

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  • 3 months later...

Here's the latest, and final solution to my issues. Ultimately, it came down to two issues, hopefully these finds will help someone else.

First off, the plug for the fuel pump was not connecting well. The female end of the bladed connector was too loose, this caused poor connectivity and explains why sometimes when the bike died I could unplug the pump and plug it back in to get it running. The solution was to replace both ends of the plug. I went with a new-style weather-proof plug and thought I had it licked. This led me to the second issue.

After replaced the plug, I decided to give myself some more access to troubleshooting if the bike died on the road. I removed the retaining screw on for the end cap on the fuel pump. This allows the cap to be popped off to examine the electrical end of the pump without needing tools. This worked out well. As we all know, with an intermittent problem, the bike has to be ridden to see if the issue is still there. I decided on a 25 mile trip to a shop down the freeway would work. I made it there but the bike felt odd. I made it almost home when the pump died again. Luckily, I was able to pop off the end cap. I checked it and found that the contacts would open, but not close. It's hard to explain all of my troubleshooting, but basically the issue was that the contacts were too far apart (you can actually see this in the pictures in my original post). I used a coin to bend the bottom bumper holder up a bit to close the gap and 2000+ miles later it seems like that was the final fix.

I know this is long-winded, but hopefully it can help someone else. I'll add a few words below as an aid for people searching this topic:

Chinese fuel pump
fuel pump contacts
fuel pump
electrical

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You seem to have narrowed the problem down to the pump and its wiring pretty quickly, but if the RC24 is like the RC36, you can actually run the bike without using the pump at all.  "Gravity feed" worked fine on my bike, and I was able to do it with (fairly) basic tools--got me home when I was stranded on an Autobahn one day.  (I usually carry a bit more than the stock tool kit when I travel, so I think I had a Leatherman and some electrical tools, but the latter were only used to troubleshoot before I decided to try gravity feed.)

 

Also, if your pump is like the Mitsubishi one used on dozens of Hondas, there's a Dutch guy who can be found on ADV who makes a nice optical points conversion kit for the OEM pump.  I fitted one to my FP.

 

Ciao,

 

JZH

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  • 4 weeks later...

I've heard mixed opinions on the gravity feed.  I've heard it can be done, but not on the 700-750cc bikes.  I guess I could have tried it, I just didn't consider bringing a shunt piece with me.  Might be worth tinkering in the garage in case I lose the pump in the future.  Not sure what Optical points are, but as a member of ADV, I'm there all of the time.  I'll check into the details.  Thanks for the heads up. 

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