| Author | Message | ||
     Buell_41 |
I've posted about this before... thought I had it fixed. Now I have the same problems again. I really need your help guys. I'm planning on opening up the bike this weekend and look around. Please, all comments and/or suggestions are coveted. Here's what I know: ('04 12S) - AFV is 115 and surges to 127 @ 3k rpm (bike on stand in neutral) - no trouble codes... active or archived - rpm's "bounce" at warm idle (900-1200) - rough idle when started after being garaged all night - runs great for the first 15 of my 25min commute to work... then starts to get rough - fire it back up to go to lunch and it misses anywhere from 3-4500rmps when going about 40mph (does not miss under hard acceleration) - replaced intake seals and verified that they are sealed - fuel pump doesn't always sound the same from day to day - fuel light comes on at 115mi and by 119mi. I can tell its looking for gas (slow/stumbling on throttle up). I fill up to exactly the same point every time and every time I have put 2.8 gallons in the tank. - 42mpg with *very* light riding... used to consistently get 47 - TPS and timing check out - replaced head temp sensor - after steady state (30 min.) ride, VSDS indicates fuel pump failure (and I'm having all these problems). Come back an hour later when bike has cooled down... pump passes. Bike runs fine for first 5 mins back home, then problems start happening. Previous posts by "maximum" indicate that his bike is having some of the same problems. Only difference is that I'm not having the "must rev. to 6000rpms to keep by from dying" problem. I have limited tools and even more limited funds. There are some things I will be checking for but I wanted to get all the input I can from this community. You know everything I do... what'd ya think? | ||
| 2004xb12r |
First question. Did you do anything (take it apart) to the bike? If yes what did you add or exchange on your bike? The fuel pump failure could be caused by a loose or High Ohms(resistance) condition, or it could be the pump is going out. When you get the bouncing idle do you get a varying voltage signal from the regulator? Electrical problems can be time consuming when trying to diagnos it. Not to depress you but it could be anything, ignition relay, loose connector to PCM, clogged pickup screen, and the list goes on. Do you have a shop manual and a DVOM? If no just bite the bullet and bring it to the dealer. If yes I'll help you as much as I can. | ||
| Bombardier |
Check the KV for fuel pump. Early models had chaffed wires inside the fuel tank/frame causing running issues. | ||
| Jos51700 |
All signs point to low fuel pressure or intermittant pump operation. Do you have a way to check fuel pressure? | ||
| Buell_41 |
Hans: Yes, the bike has been apart for the repairs listed, but other than that, the bike is completely stock. I didn't notice what the VR was doing when the rpms were bouncing... I will check this weekend. I do have a manual and a DVOM. Thanks for your willingness to help. John: I don't personally have a way to check the fuel pressure... I may know someone who could tho... I'll look into it. One more thing I didn't list. A couple cap fulls of STP octane booster does make a small improvement in running performance... rpms still bounce around when I'm at a stoplight. Injectors looked clean when I had the intake off while replacing the seals... | ||
| Moosestang |
How many miles? Have you replaced the spark plugs? If not I would go ahead the replace with NGK or better. Did you reset the TPS? You said TPS checks out, but I don't know what that means. | ||
| Twinv |
My $0.02, I remember reading that octane booster are not recommended by Buell due to potential O2 sensor damage. Also, when you mention the fact that the bike runs well under hard acceleration, I can't help thinking that the issue could be with your O2 sensor, since under hard acceleration the ECM runs in open loop (no O2 sensor feed back), the rough running when not in WOT/hard acceleration could be coming from a fouled O2 sensor since in that mode the ECM runs in close loop. What puzzles me is the fuel pump failure you get!!?? maybe two issues at once?? Anyone, please share your thought on my thinking. Cheers, | ||
| Buell_41 |
24500 miles and some change. NKG Iridiums have been in for about a year now. TPS has been reset. | ||
| Xl_cheese |
Try to clean your fuel system. Pull the injectors out from the throttle body and use ecm spy to cycle some straight injector cleaner through the tank. Cycle the fuel pump then the diagnostics tab has the option of testing the injectors. Does that make sense? | ||
| Punkid8888 |
I agree with Twinv, You said in the first 15min of your commute it runs great, again you bike will be in Open loop until its at operating temperture, then it goes into closed loop and uses the O2 sensor. Maybe the sensor is good but how about the wiring | ||
| Buell_41 |
Can the sensor be replaced without dropping the engine? | ||
| Moosestang |
Can the sensor be replaced without dropping the engine? I read that it can be done by just removing the fan. I looked at it today when I changed my spark plugs and it looks easily doable going through the fan hole. You might need a special O2 sensor socket unless you can get a wrench in there. I ordered a 02 sensor with my spark plugs, just in case. I think you can pick one up anywhere though. | ||
| Iamarchangel |
Go back to the temp sensor (and here I need some tech guidance). There are two temp sensors: engine and air intake. Your figures indicate that you have some kind of readout available. I don't know what you can read but go look at the temp info. The tests may be showing input from the temp sensors but the info may be inaccurate. Check and see if the temps make sense. Here's my reasoning. The problems seem to be related primarily to cold engine and off idle. It sounds like the old fashioned choke issue, in fact, it sounds like the choke is coming on at different times. It would also use more fuel. In the ECM the choke function, whatever you want to call it, is determined by the temp sensors. They trigger the O2 sensor. As long as either sensor is sending the ECM a signal, no fault code will be generated. However, the signal may be incorrect and the ECM just follows along. So, if you can, track the temps from both sensors and see if they are realistic. | ||
| 2004xb12r |
The bike running well or OK for the first few minutes can be still an electrical issue. When temperature rises so does resistance. Buell 41 what repairs where done or listed? The O2 can be changed without rotating or dropping the engine. Remove seat, rear shock, and cooling fan. Most likely is not the O2 sensor because it would of set a code by now. Whatever you do DON'T throw parts at it until you know what's wrong. | ||
| Buell_41 |
when testing on vsds straight off a steady run, I think it read something like 330-350deg. When we tested it again an hour later I think it read just under 200deg. so yes I do think they make sense. Does anyone know what the correct fuel pressure should be? | ||
| Iamarchangel |
I'm not sure what displays are available to you. Some displays allow you to check the temp history. The numbers you have sound like the average, you need to be able to see the fluctuations. Does anybody know how he can do this? (My info is from my mechanic, he says this is a common problem/failure with nissans. You only find it by tracking each temp signal to the ECM and notice when there's a bad signal. His readouts give him the history.) | ||
| 2004xb12r |
The fuel pressure is 49-51 psi. | ||
| Buell_41 |
wow, thats higher than I thought. Ok, I drained the fuel and pulled the footpeg off and this is what I saw  I'm not sure this is where other bikes have had the chaffing issue but I'm thinking that sleeve should be covering those wires so the aren't exposed. The intake air sensor looked clean. I have all the fasteners and the fuel line out of the pump but its not coming out of the frame. Is there something I missed? | ||
| Xl_cheese |
See that threaded hole in the base plate? Put a throw away bolt in there and use some channel locks to slowly work the pump out. Wiggle it side to side by grabbing the bolt. The wire harness looks fine. The black sleeve wasn't designed to cover the wires all the way down. Use a lot of oil on the rubber orings when installing the pump as to not bugger them up. | ||
| Mikexlr650 |
how about the vent line from the tank, could be pinched? | ||
| Iamarchangel |
Why are we taking the fuel pump out? The fuel pump works, just inconsistently, so it's not likely the problem by itself. Electrical things are on/off. The fact that it is usually on indicates that it is okay. Something else is telling it to shut off. If there was a mechanical failure with the fuel pump, you'd probably see other indicators and the bike wouldn't run in a steady state or 30 minutes of great. Those sensors that control the fuel pump are most likely the problem. Somehow wrong info is getting to the pump from the ECM or the ECM is getting wrong info from the sensors. You need to spend more time there. Do you have the service manual that explains how the ECM works? | ||
| Jos51700 |
"The fuel pump works, just inconsistently, so it's not likely the problem by itself" This is an assumption. Assumptions are not good, when trouble shooting. | ||
| Iamarchangel |
Don't want to get into a nasty here but I'm seeing the opposite. I'm agreeing with you on the assumption part, here's my thought process. The fact is that the OP said the bike runs well for a long period at times. For the reasons above, I'm going to assume that the mechanical aspect of the pump is fine and that its incoming info is messed up. There's enough info in the OP to suggest that the electronics are not communicating very well to each other. The ECM uses six sensors to give info to the fuel pump. The symptom given strike me as the engine "choking", that the fuel enrichment circuit is kicking in. The fuel enrichment is primarily dependent on the temp signals, which in turn direct the O2 sensor. The engine temp has already been changed, so I'm leaning to the intake air temp sensor as the problem, The manual indicates that IAT sensor indicators are very similar to the symptoms described. If the temp sensors check out, then I'd go to the O2 sensor. Remember, as long as the ECM is getting a temp reading, it won't send out a code. Here's a distracting thought. OP seems to ride it to extreme low fuel every day. What does that info do to the ECM's learning habits? | ||
| Buell_41 |
Wouldn't shorting to surrounding wires (chaffing) or grounding to the frame cause the electronics to not communicate very well to each other? A tale-tale sign that its going to act up is when I go to lunch, I can start it up, let it idle while I put my gear on and then do long revs. held at 2k for a couple of seconds. As (not when but AS) it comes back to idle, it "pops" or afterfires. I don't know how much "cooling" there is with incoming atomized fuel but if the IAT is bad and is telling the ECM that there's hot air coming in, then Iamarchangel might have a vaild point. Also explains the low mpg's. | ||
| Iamarchangel |
A bad ground on any wire, in any circuit, will also interfere with the ECM but that is so hard to look for. Better to go after more obvious but, by all means, look for bad grounds. For some bad grounds, the engine light does a steady rapid flashing, but not all bad grounds generate this. I would think the popping you're describing is normal, if it's the sound I enjoy with this motor. | ||
| Buell_41 |
945pm still no luck in getting the pump out. I tried the channel lock method... didn't budge. Tried hammering, a flat blade screwdriver betweeen the pump and the frame but quickly stopped when thought I'd better not beat on the gas tank. The service manual says there's a tool to remove it. Seems to be simple enough as a piece of flat bar with the middle cut out of it. Maybe I can work something up unless there's another way to do it driveway mechanic style. | ||
| Smoke |
use a slide hammer to pull that pump. reinstall the bolt in the hole and use a slide hammer with a claw attachment on the end. should come right out. don't try to pry it out or hammer a wedge between pump and frame. good luck. tim | ||
| Buell_41 |
I used a slide hammer like tim said and it worked. Tried pulling it out but the swingarm got in the way even when disconnected from the shock. I gave it a little tug... heard something snap... pump came out and so did a piece of the fitting where it pulls the fuel in. No chaffed wires so thats good. However this tea bag looking thing is coming apart. Anyone know what it does? Does it look normal? Maybe causing my problems? I have no clue how I'm gonna get the pump (a different one obviously) back in the frame with the swingarm there... see picts below.  (above) the setup  (above) rear shock disconnected  (above) pump almost out  (above) pump removed  (above) teabag thing. You can see where some of it has come off  (above) no wires looked chaffed  (above) that round black plastic piece is supposed to be on the fitting of the intake nozzle but broke off during removal. What next?... after getting a replacement pump of course. O2? What do you think about the condition of that teabag thing? | ||
| Iamarchangel |
What next?... after getting a replacement pump of course. O2? What do you think about the condition of that teabag thing? I think there's a lesson here. Wishing you the best of luck. | ||
| Buell_41 |
I'm not sure I know what you mean... seems like I verified that the ECM and the pump are "talking" to each other and thus eliminated one possibility. How else could I have checked the condition of the wires?Also, there may be a problem with that screen... any comments about that? |
