VFRBuggy Posted October 31, 2015 Share Posted October 31, 2015 OK - so first off... thank you for being here. I fix more stuff via internet forums and help from folks like you, I am expecting this forum to be just as helpful.. Now.. onto the scenario and questions. I just picked up a single seat offroad buggy that (I am told) is powered by a VFR800FI motor. based on size, I would say the 800 seems right, and based on wiring and ECU, the FI is right as well.. I cant locate a VIN to confirm year which makes hunting down the engine wiring schematic difficult to say the least. This buggy ran for years and then developed a wiring problem that the previous owner never got fixed. Via jumping wires, I can get the fuel pump to spin and the engine to turn over... I dont have power properly to this so the ECU and therefore ignition are not powered so it wont start. There is no instrument cluster, so the FI light cant tell me anything (unless maybe I can find a way to wire that up to have the indicator) My first guess is that the ignition switch isnt right (as it is all just wires and not an actual switch at this point Red/Black, Blue/Orange, Red, (and a pink one too) .. none have power. I have checked fuses and they are all good.. so I think the first thing I need is a schematic and suggestions on what would keep the ignition switch from getting power at all (if anything.. if nothing, I can trace wires or jumper it to move to next phase). TLDR/ how do I confirm year of the motor and once I have that, find an engine wiring schematic? Thanks all!!! Link to comment Share on other sites More sharing options...
Sweeper Posted October 31, 2015 Share Posted October 31, 2015 Post a pic of the motor. Lots of folks here can id a generation based on that. That would give you enough information to find what you need. Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted October 31, 2015 Member Contributer Share Posted October 31, 2015 Engine serial number will tell you the year. Ciao, Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted October 31, 2015 Member Contributer Share Posted October 31, 2015 Hope we can help. VFR's became fuel injected from 98 onwards, earlier engines are 750's and carbureted. From 86 to 01, 750 and 800's used gear driven cams, then from 02 they shifted to camchains and VTEC heads. The wiring diagrams are in the service manual, example here for the 98-01 Fi: http://www.vfrdiscussion.com/forum/index.php/files/download/171-98-01-honda-vfr-service-manual-optimized-bookmarked/ If you have a FI engine, and it has gear driven cams (either pull the cam covers off to check, or look for an absence of the cam chain tensioners on the outside) then the link above should be right. If you have cam chains, then you'll need a manual for the 02 to 13 model years. Good luck. Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 1, 2015 Author Share Posted November 1, 2015 Confirmed via the ECU part number that it looks to be a 98 model. Thanks for the link to the service manual... looking at the schematics now to see if I can figure out this problem. Is it correct to assume that I will ALWAYS have a hot wire behind the ignition switch? (looks like I do not and need to trace back from there, but wanted to confirm what I think is a safe assumption) Any link or pic that can show a clearly the cover of the fuse panel? I would like to stop guessing at each fuse slot... also, what is the funny 3 pronged fuse like thing in there and what does it do? Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted November 1, 2015 Member Contributer Share Posted November 1, 2015 Here's a link to download the wiring diagram for a 1998 model year unit. It should cover everything you're looking for. http://www.vfrdiscussion.com/forum/index.php/files/file/230-5th-gen-super-high-resolution-wiring-diagrams/ Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 1, 2015 Author Share Posted November 1, 2015 Ok guys.. thanks to you and the links.. I was able to find the main fuse that is attached to the relay mount.. it was blown.. that and a faulty run/stop switch and I am able to get it to crank from the start switch. I noticed that I dont hear the fuel pump come on when I set the ignition on.. so guessing no fuel when cranking (or ECU is still not all the way awake/faulty).. when I hot wire the pump, it still wont catch. Is there a way to test the ECU? I only have 3 relays (that I can find) left on this harness... one is the big relay that has the main fuse piggy backing on it.. Starter relay.. the other is the fuel pump relay based on the brown wires headed in to it the third *I think* is the engine stop relay... I am having a little trouble keeping polarity in my head straight as there seems to be a zillion colors used for grounds... I am guessing this is because the harness is ground triggered vs +12 triggered... Could someone just explain what voltage/continuity I should expect to see at the engine stop relay? I think I can then use that as a reference for the rest of them. I would like to be able to jump the relays to see if the relays may be bad etc as well (dont have known good spares to use as testers). The red/orange wire on the engine stop relay looks to have some damage (slightly melted)... any tips there would be appreciated also. Thanks all!!! From no power to cranking over with the switches in 24hrs.. at this rate ill be doing hot laps around the neighborhood by next weekend!! Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted November 1, 2015 Member Contributer Share Posted November 1, 2015 This help . Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 2, 2015 Author Share Posted November 2, 2015 Is that true for earlier model? Also, I seem to have a pink wire in the ignition switch that isnt in the diagrams... any help? (searching shows people have it, but not really sure what it is.. seems to have power with ign on) Should I be opening new topics for these? Link to comment Share on other sites More sharing options...
Member Contributer MadScientist Posted November 2, 2015 Member Contributer Share Posted November 2, 2015 I didn't check the wire colors, but the safety circuit posted by Switchblade is the same for a 5th Gen. Here is a diagram I made a long time ago for someone else that was troubleshooting a fuel pump issue: Since this is a buggy, the original builder might have opted to remove the bank angle sensor(aka Engine Stop Sensor) and bypassed it improperly. Alternatively, they may have the bank angle sensor mounted at the wrong angle. But you said one other thing that I'm wondering about: "when I hot wire the pump, it still wont catch." Do you mean that the engine won't fire? Also on the same circuit connected to the bank angle sensor are the fuel injectors and ignition coils, so if there is an issue here then you still won't get fire. Trace the wire from fuse B (Black w/ pink stripe on 5th gen VFR) and see what the first thing you hit is. If it is the engine stop relay (which it should be), then you could feasibly bypass the bank angle electronics by connecting the black/pink wire to the black/white wire. I'm not sure how much of the original wiring harness is used though, and if this has already been bypassed, then it will branch to the fuel cut relay, injectors, coils, and ecu. I think this is also the sole 12V input to the ECU (Pin B8). WARNING: if you do this, the kill switch will NOT WORK. You will have to turn the engine off with the key or pull fuse B. To get a FI light, you will need to connect the Blue/White wire from pin A7 of the ECU to one contact of a light bulb and the other side of the light should go to +12V, the ECU provides ground to light up the FI light. Link to comment Share on other sites More sharing options...
Guest Posted November 2, 2015 Share Posted November 2, 2015 Can we skip all of the electrical crap for one post? Please post a picture of this buggy. This sounds interesting. I am hoping it looks really cool... Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted November 2, 2015 Member Contributer Share Posted November 2, 2015 Ok guys.. thanks to you and the links.. I was able to find the main fuse that is attached to the relay mount.. it was blown.. that and a faulty run/stop switch and I am able to get it to crank from the start switch. I noticed that I dont hear the fuel pump come on when I set the ignition on.. so guessing no fuel when cranking (or ECU is still not all the way awake/faulty).. when I hot wire the pump, it still wont catch. On my bike, with the ignition switch on, the fuel pump won't run unless then engine stop switch (on the right bar) is "on". Do you have an equivalent switch, if not maybe you need one. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted November 2, 2015 Share Posted November 2, 2015 An easy way to confirm that it is a 98/99 vfr800 engine It is fuel injected, but still has a manual choke No signs of catalytic converter or o2 sensors If it is indeed a 98/99, you struck gold, as those are the simplest, bullet proof and best fueling of the 800's. Fit a modern regulator/rectifier on it and it is bomb proof. Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 3, 2015 Author Share Posted November 3, 2015 That helps... do you have the colors for the wires coming to/from the ECU? I have made a lot of progress... I have confirmed spark (at least as far as getting a timing light to blink on a plug wire) I have confirmed injectors are cycling (using a NOID light on a pig tail) I have confirmed there is SOME fuel pressure by loosening a supply side fuel line and cycling the fuel pump manually.. I have found that if I connect a test light to the brown/black wire on the fuel cut relay, the pump runs... with the pump manually running, it still wont start... I can make it start and run using starting fluid. My thoughts are: Bad fuel (it has been sitting a while.. not sure how old the fuel is) Injectors clogged (really dont want to pull them as it is more work since there is buggy frame above the airbox) Low fuel pressure (is there a schreader valve on these things or anything? cant seem to see one) So .. three questions at the moment: 1 - colors of wires coming from the ECU in the above diagram? 2 - is there a fuel pressure test port somewhere on this thing? 3 - any ideas on why the ECU wouldnt provide ground to the brn/blk wire on the fuel cut relay? I am SOOOOO close!! Gold struck.. no O2 sensors for sure... not sure I would recognize a manual choke (maybe that is why it wont start??) where is it? I am fine fixing ford EFI all day and night in a full size car/truck.. the parts and pieces are just different enough to make me question my knowledge with this thing.. thanks again for the help guys!! ,... and it looks really cool if you like ghettofabulous!! I will take and post a pic later tonight! I do have the start/stop switch (still original from bike) with the engine start button.. it works... but the rocker switch is finicky... needs a new one (probably will just convert to regular switches) Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 3, 2015 Author Share Posted November 3, 2015 youre gonna have to wait until tomorrow for a pic.. phone is dead.. BUT ... IT RUNS!!! Sounds angry too... think I need some fresh fuel in there to help out some... and still dont know why the EEC isnt controlling the fuel pump (any tips on that would be greatly appreciated) but if I provide my own ground for the pump (runs all the time when ignition is on) it starts if I feather the gas a little!!! Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted November 3, 2015 Member Contributer Share Posted November 3, 2015 I think what we'd really like is a video! If yours was from a '98, it would have had manual starter valves - look for a lever on the (rider's) left side of the throttle body. It's cable actuated. You could probably rig something up pretty easily. If you can't figure out the fuel pump / ECU issue, you could wire in a switch to ground it manually. Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted November 3, 2015 Member Contributer Share Posted November 3, 2015 The starter valves are in a bank on the right side of the throttle bodies; 3 adjustable screws, one fixed. The cold start cable pulls on a plate that lifts all the starter valves together. The idle adjuster screw bears on the same plate. There should be 4 hoses terminating either two either side of the side of the airbox, or joining together at a 5-way joint for US models, these are used to set the starter valves with a vacuum gauge. There's no port to test fuel pressure, the manual describes using a banjo fitting in the main fuel line connected to a gauge. Great to hear of your success. Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 3, 2015 Author Share Posted November 3, 2015 Cool.. I will post pics (and a video) soon. It sounds like I have the 98 motor... and will have some fun ahead of me setting the starter valves and idle adjustment (or at this point might be worth it to just have a honda guy do a quick tune with the proper tools??) Now that it will run, I need to make it stop.. where do you guys buy parts? I need a new master cylinder for the brake before I get out there and make a video!! Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted November 3, 2015 Member Contributer Share Posted November 3, 2015 Brakes are an interesting topic. What calipers are you running with? Foot brake or hand? Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted November 3, 2015 Share Posted November 3, 2015 On the topic of why the fuel cut relay isn't getting any power, Think about everything responsible for triggering the fuel cut relay: Neutral sensor Bank angle Sensor Side stand switch Engine kill switch Ignition key Switch Clutch switch Main Fuse Fuel pump fuse ECU fuse Also there are about a million ground wires going in and out of the big blue connector, big grey connector and orange ground block connector that are responsible for all these switches and sensors that can trigger fuel cut..... Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 3, 2015 Author Share Posted November 3, 2015 Brakes are an interesting topic. What calipers are you running with? Foot brake or hand? Good question.. but thinking it is the rear brake. the cylinder is actuated by an bellcrank attached to linkage running to a foot pedal.. is rear brake only. On the topic of why the fuel cut relay isn't getting any power, Think about everything responsible for triggering the fuel cut relay: Neutral sensor Bank angle Sensor Side stand switch Engine kill switch Ignition key Switch Clutch switch Main Fuse Fuel pump fuse ECU fuse Also there are about a million ground wires going in and out of the big blue connector, big grey connector and orange ground block connector that are responsible for all these switches and sensors that can trigger fuel cut..... N sensor, side stand, engine kill, ignition, clutch, main fuse, ecu fuse .. wouldnt that keep it from cranking/sparking? bank angle, side stand, clutch are all bypassed. FP relay gets power.. isnt getting the ground to complete the circuit. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted November 3, 2015 Share Posted November 3, 2015 "Also there are about a million ground wires going in and out of the big blue connector, big grey connector and orange ground block connector that are responsible for all these switches and sensors that can trigger fuel cut....." Link to comment Share on other sites More sharing options...
Member Contributer MadScientist Posted November 3, 2015 Member Contributer Share Posted November 3, 2015 Yeah, none of that stuff is relevant anymore. If the bike is making spark, then the engine stop relay is energized. The fuel pump relay ground is provided via the Brown/Black wire on A5, check for connectivity. The ECU is provided ground via the 2 green/pink wires A9/A20. If the ECU ground connection was crap, you might see poor fuel injector performance too (ECU triggers ground to actuate the injectors). There is no port for checking fuel pressure and the regulator is non-adjustable. Link to comment Share on other sites More sharing options...
VFRBuggy Posted November 4, 2015 Author Share Posted November 4, 2015 Ok... Grounds will be checked... A5 for the FP and A9/A20 for overall ground.. bad grounds ruin more EFI than anything I have ever seen... Dumb question - is the grey plug or the black plug the one I need to look at for these wires? Which way do I orient it to start counting pins? My ford EEC has an embossed "1" over the #1 pin.. this doesnt seem to have that.. I guess I can find the Brown/Black and orient myself with that as A5 Link to comment Share on other sites More sharing options...
Member Contributer MadScientist Posted November 4, 2015 Member Contributer Share Posted November 4, 2015 Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.