Fuel Pump failure

Hi, hope someone can help out on this one. I am no mechanic but I do know that the mechanics haven't solved the problem! I am pretty desparate now.

I have had my 1999 Honda VFR 800 FI for around 9 years. In Sept 2022 the engine cut out whilst on the motorway. I was able to restart by turning it off and on again. Happened several times and I took it to a local mechanic, ordered a replacement throttle body (fuel injector unit etc) and then all was good for a short while. A repeat happened, I was unable to get it to restart. Trip to another local garage, said it was a kickstand switch which they disabled. Hadn't travelled more than 1.5 miles and it cut again and wouldn't restart. This time the garage said it needed a new petrol pump which they installed. All good for around a month or so and I am now back to where I started.

The bike cut out, wouldn't restart. Turning the ignition on I can't hear the fuel pump prime. Then, when left for a day or two, it will prime when turned on, engine starts but then dies. Fuel pump will not prime on the next attempt. When left for a day or two, same story. Occasionally it will keep going for a while but when throttle opened a little and clutch engaged it dies and the fuel pump won't restart.

Can any kind soul shed some light on this please - I am at my wits end.

Thank you!

 

Those people aren't mechanics...

 

Tell me about it...

 

Sounds like a ground issue to me. Somebody will likely be by to get you started in the right direction. If you don't have a Multi-Meter, get one now if you're interested in figuring this out on your own.

 

Check all your connectors for corrosion, could be a bad ground with corroded connection as well. Low voltage systems are notorious for high resistance connections caused by corrosion.

 

Hi Charlie.
Sad to hear of your bike issues but more so of the way the mechanics have let you down.
- Firstly you want to make sure that SideStand switch is fixed and working properly. Appart from the saftey aspect, if the switch is bypassed (shorted to always UP position) you will not be able to see any active Fi Fault codes should you have any. The Sidestand needs to be in the Down position before the ECM will display any Fault Codes.

- The two most common issues that effect the EFI system on a 5th gen VFR is melted or high resistance wiring and connections of Main Fuse B 30amp located near your starter relay, and the common Ground Block, an Orange junction block of many grounds that join up, this block is embedded into the wire harness just above your chain guard. You need to do a good inspection of these. Poor ground connections within the Orange Block can cause a multitude of issues including Fuel Pump issues.
- You may need to do some voltage measurements around the ESR (Engine Stop Relay) and the FCR (Fuel Cut Relay) to establish what might be missing as well as establishing the Fuel Pump green ground wire is in fact properly Grounded.
- Do you have the Service Manual or wiring diagram for your bike?
- The charging system wiring connections can also be an issue, the three yellow stator wire connector to the R/R and the R/R output connector can both suffer from bad and burnt connections.
- Do you have a Healthy Battery? If you can get it started you need to measure your charging voltage at the battery.

 

Thank you so much, I really appreciate your kind words and the detailed information with photos and diagrams - I have found another mechanic who seems to be more passionate about the bike and getting to the bottom of it. At least I know what they should be doing rather than just replacing parts in the hope it will resolve the issue. I will pass all this on and will let you know how we get on.

Thanks again to you and felllow respondees for the kind and warm reponse to my first post.

 

Update....we're back on the road!

I found a genuine mechanic (Adrian) at last. I'd post his details but is that allowed on the forum?

Adrian removed the rear fairing and we found that moving the wiring loom where the earths were made diodes click like crazy. He said that it's the whole system not initialising and not the fuel pump failing. Using all of your tips, pointers, advice and the wiring diagram he worked his way through the sections, the ground block, wiring loom, making a repair along the way but issue still unresolved. Working back up, by isolating movement in some of the loom we found that the wires in/out of the ECU seem to be causing the 'clicks'. Removing the ECU (located at the rear of the bike) he noticed that the foam beneath it was very damp, he dried it out, removed the wiring from the ECU, checked the connectors and then all was good. He was unable to replicate the issues not matter how hard he tried. So, it seems that there was moisture in the ECU that was shorting the connections. ECU was placed in a plastic bag with the connector section cut away, refitted and the seat cowel fitted (for the first time in 9 years!) and all seems to be running perfectly. Adrian changed the fuel cut off relay as well.

Altogether, it seems that moisture was the cuplrit but time will tell.

Thank you all, the pointers and wiring diagram was especially helpful!