| Author | Message | ||
     Ratsmc |
I need some help. The Buell has been down for some time now because I am out of ideas on how to proceed with diagnosing the problem. Background: The bike ran fine for a quick hop about 5 blocks where I stopped and turned it off. On the return trip about 20 minutes later, the bike sputtered and stalled. It started up again and as I started moving did the same thing again. I was able to limp it home by throttling the crap out of it. 130hp turning itself on and off randomly is a little terrifying. Following that, I did some runs up and down the block. The bike would start and run for a bit and then when I let off the throttle for a second, it would seem to drop to one cylinder and die if I didn't hit the throttle and clutch right away. After some screwy around a bit more, the bike didn't start at all. Went through a bunch of troubleshooting which kept leading me back to fuel. In tracing the problem back from the throttlebodies, I separated the fuel line at the quick connector before the fuel rail. It was then that I noticed there was no fuel in the line. Turning the motor over didn't cause fuel to pump out of the line. At this point, I figure I have a fuel pump issue. This is supported by the fact that I don't hear the fuel pump pressurizing the fuel rail when I turn the bike on. I start tracking down fuel pumps. The stock pump assembly is almost $300 and most of it isn't failure components so I start looking for just the pump itself. I find Airtex E2337 is the same form factor and has a slightly higher LPH rating. Since I was unemployed at the time, I ordered some off-brand replacement. Installing the replacement changed nothing. This is where I am at now. It is possible that the replacement DOA but it seems unlikely. I don't have the electrical diagnostics manual so I am not sure about which relay is used by the pump. On the same note, there are no codes of any use. All the ones displayed are from when I disconnected everything to do the valves. So: *no fuel in the line *same with two fuel pumps though neither are known good *no codes I am employed again so buying parts isn't an issue though I'd rather not spend hundreds on troubleshooting. Help! Please. | ||
| Nuts4mc |
Trouble shooting over the internet isn’t easy… a) I assume you have a good battery and the battery connection are clean and tight….With a meter ( buy one at Walmart – get some alligator clips at Radio Shack) does the pump get power when you turn the key on? b) With the meter still in the circuit ….try turning the handle bars, turning the kill switch on and off, try the front brake ( switch for brake lights)and the clutch ( switch for starting/shifting)- do any of those actions affect the meter’s reading?( in a bad way)...if so there’s your starting point- if not, go to next step c) Power(electrical) to the pumps – there’s a relay in the black plastic case back by the battery – the relay is black – all the rest are white ( at least on my ’08 they are)– it’s turns things “on” when you turn the key – try replacing it – it’s a problem on HD Vrods – the relay is a headlight relay found on some cars – you may be able to “match it” at an auto parts store- did the relay replacement solve the problem? – if not, go to next step d) The ECU connector is very “dense” check all the wires going into the housing ( pull/wiggle them)that connects to the ECU..any of them loose?- reinsert them if you can and test. e) Wasn’t the ECU? – I see from your profile that the speed sensor was replaced – are the wires correctly routed? are they burnt thru due to contact with the exhaust? f) Grounds – I believe the ground circuit in the wire harness is marginal – try adding an additional ground ( 10 ga wire) from the battery to the frame ( where the rear subframe bolts to the frame) and see if that helps….I posted a mod I made awhile back to add a battery cable ( 4 ga) ground from the ground stud under the subframe directly to the starter to help in hot weather starting – do a search, try the mod, it may help Hope this helps | ||
| Ratsmc |
Thanks for the reply. Work schedule just got a little crazy (of course) so I won't be able to replace the relay until Saturday. A question on that: is anything else attached to that relay? I'm definitely getting power at the connector to the pump though I don't remember the voltage (checked it wen this all started). The connector is after the relay so that should rule out the simple fix. I might just replace it anyway though. I'll check the ECU but may not be able to get to that until Saturday as well. Thanks for taking the time to check my profile. The wires to the VSS were okay when I pulled the frame off to do the valves but it is worth checking their condition as I don't remember how I dealt with them in the frame removal (though I was pretty careful about wiring). Adding additional grounding is easy enough to make it worth doing even if I haven't found any issues when checking them with a meter. I'll report back as I go through your recommendations. Again, I appreciate the help. I really hate electrical troubleshooting. | ||
| Kevmean |
Doesn't the fuel pump switch on and off via it's earth and not it's power supply? so to check pump when you have 12volts going to it give it an earth and see if it runs. | ||
| Nuts4mc |
it's been my experience with industrial robots/tools that are controlled by a CPU/ECU that the supplied voltage to the CPU ( in my experience 3VDC) cannot vary at all +/- 0.1 VDC will cause a CPU to "reset" and start it's "boot" process all over - I'm no EE - but too often I'm called to the floor to start troubleshooting and a unrelated event ( compressor powers up/a bank of lights get turned-on/off, TIG welders start doing their thing) cause havic! a) check the connections to the ECU b) check that Speed sensor c) check the handlebar switches and connection d) check the instrument panel connections ( it talks back and forth to the ECU) e) check the grounds - good luck | ||
| Rodrob |
The fuel pump turns on when the ECU pulls the negative side to ground. A brown/yellow wire from the fuel pump comes to mind but I am not positive so check. If you take that wire to ground, the pump will turn on. Keep in mind that this will bypass all the pressure safety checks that the ECU does, so the pump will keep pumping even though the fuel line might not be connected, so be careful (I use a switch wired like this to be able to empty the fuel tank at the track). If you do this and the bike runs fine, then it is not the pump. Could be a bad fuel pressure switch, or bad ground or? | ||
| Tepiddeath |
I had similar issues from the fuel pump on my previous 1125r. There are some plastic clips that have a tendency to become brittle and break off, there is no rebuild kit, but the entire assembly is reasonably priced. Changed out fuel pump, bike ran awesome! | ||
| Ratsmc |
$270 doesn't seem that reasonable to me. However, I replaced the pump unit itself within the assembly and everything else within it seemed to be fine. Rodrob, I'm not completely sure how to accomplish running the negative side to ground given the type of connector. Just to make sure I understand, connecting the other three wires within the connector normally but jumping the fourth from the fuel pump side to ground should cause the pump to come on. Correct? Another thought: if the fuel pressure sensor were faulty and telling the ECU that there was enough pressure in the fuel rail, the fuel pump would not come on, correct? If there was such a failure, what would the fuel pressure sensor voltage read on in Diag mode? | ||
| S21125r |
Rats - There is a 15A fuse on the power side, but you said you had power at the connector (O/GY) so I'll assume that is good. The ground (BK) for the pump appears to be on the same circuit at the key relay, ignition relay, starter solenoid, Voltage regulator, Right Rear turn signal, tail/stop lamp and license plate lamp. Should be able to check continuity between any of those points and the fuel pump ground. A third wire (BN/Y) goes to the ECU (splits in two actually) and ends up at pin 27 and 28 on the Black ECU connector. There appears to be an intermediate connector between the ECU and the fuel pump connector so check that for tightness. I would a run a continuity check from Pin 27 and 28 on the connector all the way back to the fuel pump connector. The forth wire (Y/R) goes to the instrument cluster so I assume that is for the fuel level sender and can be disregarded. Here's a section from the electric manual that should be relevant. "The duty cycle of the fuel pump is controlled by the ECM which supplies a pulse-width modulated ground to the fuel pump. Voltage for the fuel pump is supplied from the fuel pump fuse through the key switch relay. The ECM can command a fuel pressure range from 58-75psi depend on demand of the engine. The ECM provides 5 volts to the sensor which varies the signal voltage back to the ECM based on fuel rail pressure (low pressure = low voltage signal)." So based on what Rob said and what I see in the manual, I would say pull the BN/Y down to ground with a jumper and see if the pump kicks on. If it doesn't, and you already checked the ground continuity, then I would suspect the pump itself. Hope this helps | ||
| Rodrob |
Yes, just tap into the Brn/yellow wire near the pump, and ground it. The pump will turn on if it is seeing V+. If it does not turn on, then check fuse and connections as above. Without the ECU controlling the duty cycle, the pump will always provide max pressure and will not shut off. Don't let it run under pressure like this for very long as it might overheat the pump. | ||
| Ratsmc |
Thanks S21125r and Rodrob. I'll be digging in to it again in the morning. That gives me the info I need to understand the whole system. Fuel pressure sensor just arrived so, even through I now know what to look for on the voltage of that, replacing it is easy enough and eliminates that as a concern. One question: the fuel line quick-connector doesn't have any sort of fuel cut-off, correct? I mean, if the fuel pump is getting the appropriate signal and voltage, it should turn on and fuel should be flowing out of the line when it is disconnected. | ||
| Ratsmc |
Anyone know what the fuel pressure should read in Diagnostic mode with the bike off? | ||
| Rodrob |
One question: the fuel line quick-connector doesn't have any sort of fuel cut-off, correct? I mean, if the fuel pump is getting the appropriate signal and voltage, it should turn on and fuel should be flowing out of the line when it is disconnected. I believe there is a safety cutoff built into the connector. | ||
| Zac4mac |
Books are at work, but IIRC it's around 400kPa running and 500kPa key-on, motor off. I'll get the exact numbers in an hour or so. Z | ||
| Ratsmc |
Even though this forum archives threads so no one will see this without searching, I figured I should update it with what I found. After replacing the fuel pump itself (not the whole assembly, I still had no fuel. Checked the continuity and everything looked good. The only thing left in the system was the ECM. After talking to a friend who is a Harley mechanic at the local dealer, he mentioned that they had a Buell in the shop with the same symptoms and it turned out to be the ECM. Since I have the Barkers exhaust and wanted the EBR ECM anyway, I ordered one. Installed the ECM and still nothing. t this point, I am out of ideas. Then a friend asked me if I was having problems with the fuse popping. I said no, why? His answer: "because you are missing the fuel pump fuse". Doh! Stepping back through my troubleshooting steps, I realized I'd forgotten to plug it back in during the continuity checks. So, the root cause was a bad ECM which was the last think I expected it to be. If I hadn't been planning to get the race ECM, I would have been pretty irritated but, it worked out just fine. BTW, the race ECM is awesome. The smoothness of the power and the linear powerband are the best I've ever felt. But most of all I am happiest about the reduced engine-braking and the smooth off/on throttle. Before, coming out of tight corners the suddenness with which the power came off made me really tense. Now, I am comfortable being able to control how much power I am putting down and getting out of corners a lot faster as a result. | ||
| Manirai530 |
Oh man, I had the same issue and traced it down to the socket where the fuel pump connects to the main harness. The 4-pin socket used by Buell (I blame Harley) at that place is GARBAGE! After swearing and yelling one day when I was stuck on the side of a road, I popped off the seat, checked fuses/relays (obviously nothing), then shook around some of the wiring and as soon as I wiggled the flat 4-pin connector for the fuel pump I heard it go off. I opened it up and bent the pins a bit, plugged back in and good to go...for a while. Later I have replaced it with a 'Deutsch DT 4 Pin Connector Kit' and solved this issue once and for all. And cost only $10. http://www.ebay.com/itm/221246505113?item=22124650 5113&pt=Race_Car_Parts&cmd=ViewItem&hash=item33835 1c099&vxp=mtr This solution has solved my hot start / no start / embarrassing stalling at red lights / headache issue altogether, and finally I feel some love for my 1125R  | ||
| Billardhockey |
Does anyone have the part number or equivalent for Buell 2008 1125r in line fuel filter that is in the pump? Thank you. |
