| Author | Message | ||
     Dwilson357 |
Hey Guys if you remember a year or so ago I posted about this problem, the bike had to take a back seat to buying a house and other busy life stuff. Getting back on trying to pin down why my Bike progressively loses power from the top end down once warmed up. It typically happens after about 15 minutes of riding(I usually give it 5 to warm up int he driveway) On warmer days it happens faster. First the bike starts breaking up at 5k+ when WOT. Then it works it way down to the point I cant go past 1/4 throttle and barely idle, within another minute it just wont run until it cools off. It feels like a fuel based off of how the bike will surge when it gets worse. I can hold the throttle WOT in mid RPM range and it will hit for half a moment, and then I lose it. During this stage the intake will backfire as well. Once cool and ready to start I typically reset the AFV because it will be sky high when the bike dies. It throws a code 13(rear o2 always lean) So far I have replaced -The coil wires and plugs -o2 sensor -IAT I have tried getting the bike to idle then heating up the -Cam sensor -Injectors -TPS With no results. Otehr not eworthy things - I noticed today was my TPD was at 4.4 Deg. While I was idling at 950ish. I Did a reset and now I'm at 5.3 deg. I cant imagine this being the source of the problem though. -the intake past the throttle flap(?) IS sooty and oily. The itnake is also collecting oil outside of the air filter. Does anybody have any ideas on what to to check out next? (Message edited by Dwilson357 on June 05, 2017) (Message edited by Dwilson357 on June 05, 2017) | ||
| Joe7bros |
How many miles on the bike; did you do a cold compression check and then a hot compression check after it acts up? Eliminates a strictly mechanical issue, no electronics to second guess. | ||
| Sagehawk |
you haven't mentioned the head temp sensor. If you have ecmspy, have bike at ambient temperature. Shoot fuel tank with laser thermoeter. note temp. hook up to bike and read what sensors are saying. the iat and clt should be within 4 to 6 degrees of each other as well as close to ambient fuel tank. I believe all readings should be in centigrade. also, check fuel pump and fuel rail pressure. may have a hole in fuel line if pump runs good. I've read here that a high afv happens when this goes on. That would be a internal fuel line inside tank. | ||
| Audiowize |
The issues you're having sound a lot like what my XB did when the cam sensor wiring was chafed and intermittently causing ignition problems. I'd inspect the wiring under the front pulley cover just to be certain. Spraying some propane around your throttle body might help also to be sure there aren't any leaks in there. | ||
| Ducbsa |
Five minute warm up sounds high. I just drive away after starting, but I don't hammer it right away. The 25 mph speed limit here helps that, too. It may have been needed for panheads with Linkert carbs, but our fuel injection takes care of driveability issues. | ||
| Dwilson357 |
Bike has 20k So I'll do a compression check, that's a good idea. I've checked out the wiring around the front pulley everything looks good. I've been keeping an eye on the head temp readings, they are what I would expect, but will check as you've said | ||
| Natexlh1000 |
If the AFV is sky high, It must be a fuel starvation thing. Maybe the pressure regulator in the tank has a booger in it? | ||
| Greg_e |
Fuel pump going out is my guess. | ||
| Froggy |
I've seen the fuel pump have issues keeping up causing it to run lean, which results in the AFV spiking. Might be the culprit here. | ||
| Joe7bros |
I think the joker here is his statement "It typically happens after about 15 minutes of riding(I usually give it 5 to warm up int he driveway)"; so 20 minutes after he starts the bike, it starts running poorly. Wouldn't low fuel pressure, internal fuel leak problems show up sooner? That's why I asked about a compression check when hot. (Message edited by joe7bros on June 06, 2017) | ||
| Greg_e |
It can take a little while for the pump to get warm. The cylinder compression is so much easier to check that it should be done without regard to the possible fuel pump issue. And when we say fuel pump, this also includes the input strainer and the output high pressure filter, either of which could be the problem as well. But once you have it apart, if the pump is at all suspect, then all three get done. The strainer and pressure filter are going to be around $10-$15 total so they must be replaced with a pump swap. And pump will be around $100-$150 depending on your shopping skills (1985-1986 Mustang V6 pump). Mine started to get loud, I replaced it and went on with life. I also did around $2500-$3000 worth of other engine work so the pump was a trivial expense at the time. I'd clean the fuel rail and hoses, and probably send the injectors for a service. Now all that said, with the time issue, could be you are puking oil into the intake. Maybe toss a catch can on there as see what's happening. Maybe you are getting a lot of oil after it warms up and causing run issues, but usually this would go rich not lean. (Message edited by Greg_E on June 06, 2017) | ||
| Dwilson357 |
Thanks for the input thus far guys -Bike has a catch can -I have less than 2k on the current fuel pump, did a regulator and filter screen at the time, not that rules out a bad pump. -I did pull the pump to fix a bad low fuel light over the winter(after I've been having these problems) and gave everything a once over. -Its also worth saying that the bike runs AWESOME until it starts breaking up, after 10 minutes I will stretch its legs out and it runs really well. I need to go grab my fathers compression tester, I will do fuel and cylinders cold/hot once I have it. But the way the weather is looking I'll be lucky if I get something done before the weekend. Is the pressure test in the manual adequate? | ||
| Greg_e |
Lots of oil in the intake but catch can might be a problem. | ||
| Sagehawk |
Is your catch can vented to atmosphere as well? | ||
| Dwilson357 |
It is vented to atmosphere. There doesn't seem to be a crazy amount in the catch can. | ||
| Sagehawk |
How is throttle body? Checked for broken or a breaking throttle shaft? Perhaps bushings there are giving a leak if you don't find intake seals leaking. Injector seals? Perhaps a bare wire grounding in some other system? Boy, you checking on a lot of stuff! | ||
| Dwilson357 |
So I forgot to grab the compression gauge, I jumped into testing intake leaks. Bingo! Sprayed brakleen at the intake seal and it dropped rpm front or back. So I will order A set and see how I fare. Does anybody have recommendations on what to use oem? Aftermarket? and whether or not to get new flange rings? | ||
| Greg_e |
I would suggest Hylomar on the seal faces. | ||
| Dwilson357 |
To create a flexible interface between the seal and head/throttle body? Where do you typically pick it up? | ||
| Audiowize |
The last time I got Hylomar, I had to order it off eBay. | ||
| Greg_e |
There is a company on ebay that sells it, and from what I can tell it is the same process that is specified from the UK patent owners but made over here. You can also find the Permatex made racing purple stuff, which did work and is holding my Buell together. Haven't tried the stuff from ebay yet, but I did buy what I think are two different formulations. | ||
| Sagehawk |
I've used syl glide from napa with good results. Works with a lot of other things as well. Silicone based product. Be sure and measure your spigot diameters and hold manifold in between cylinders to get a visual on fitment. Had a road king that gave me fits on sealing . Finally measured spigots and rear was egged .025". Bought a s&s for my mikuni 42 and all that crap went away. | ||
| Dwilson357 |
So what I'm looking for is an anaerob8c gasket maker correct? Amazon has several available on prime. | ||
| Dwilson357 |
Hey guys just checking in, bike is running great! New James intake seals, used anaerobic flange sealant. Thanks for the help guys! | ||
| Natexlh1000 |
Nice to hear a followup with good news  | ||
| T9r |
I had never heard of that 'anaerobic flange sealant' before.... wow that is pricy stuff. I will have to invest though after reading about what it does. |
