Ignition Problem?

No more reports until after WeSTOC. But PJ, the dyno owner consulted with his FI engineer friend and he has also suggested O2 sensors. I'll fiddle with it more when I get back.


-Jeff
 
wjbertrand said:
No more reports until after WeSTOC. But PJ, the dyno owner consulted with his FI engineer friend and he has also suggested O2 sensors. I'll fiddle with it more when I get back.


-Jeff
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Interesting, for your sake I hope they're right and this gets resolved finally.
 
dwalby said:
Interesting, for your sake I hope they're right and this gets resolved finally.
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My plan is to disconnect the O2 sensors and re-set the computer by disconnecting the battery. I've heard conflicting information that the computer will run on a default map when the sensors are disconnected and on the other hand I've also heard it will just use the latest data from when the O2 sensors were last connected. I think I'll disconnect the battery before I leave for WeSTOC and let it sit that way while I'm gone.
 
wjbertrand said:
My plan is to disconnect the O2 sensors and re-set the computer by disconnecting the battery. I've heard conflicting information that the computer will run on a default map when the sensors are disconnected and on the other hand I've also heard it will just use the latest data from when the O2 sensors were last connected. I think I'll disconnect the battery before I leave for WeSTOC and let it sit that way while I'm gone.
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That's what I thought too, that the vehicle will still run with the O2 sensor completely failed, but perhaps in a sub-optimum mode. If you were getting a minor stumble that could easily explain it, but the major misfire you're getting seems more extreme than what you'd expect the O2 sensors to have as a control range, but who knows? I e-mailed a friend who designed, built, and installed a couple of custom FI systems many years ago, to see if he has any empirical data to throw into the mix.
 
Sounds like it may be the crank sensor. Check the electrical connections first. Then, maybe swap your crank sensor with a friends to see if that makes the difference.

The CKP sensor is in the front of the engine next to the two holes used when turning the crank to perform a valve clearance check.
 
Doug,

O2 sensors have limited authority over mixture and in my opinion, a properly designed system which this probably is, is designed to run with it misbehaving without misfires etc. Just won’t pass smog etc.
If it were mine and I was told that, I would try the bike with the O2 function open (disconnected) and then shorted but be careful not to short the heater input if it has one.

Btw, cars are designed to have a “limp home mode” which will get you home if even a very important sensor like mass air flow or even MAP croaks…..it may not have much power and the check engine light will be in your face but it won’t miss and will run easily well enough to not strand you. An O2 is a very minor sensor by comparison.

The FI systems which I designed (actually ECU’s) for my entertainment over the years don’t even use O2 sensors although I could have easily added it. They used the main sensor MAP or Mass Air Flow to provide quantity or air information for the computer.
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Here is my friend's reply to the e-mail. It confirms what I thought I had heard over the years but wasn't sure. Also, here is a second reply he sent a minute later.

Oh, if I was not clear, the mechanic does not know what he is talking about.
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to frame his comments a bit, he is an Analog Hardware Design Engineer, formally trained, with 25+ years of experience. For entertainment he built his own FI systems for a '71 Vette and a '70 El Camino from parts he scrounged from junkyards, and ECU systems he designed and programmed himself. The El Camino was his daily driver for many years, the quality of his systems were well proven.
 
Thanks Doug, sigh, :( this O2 idea sounds like it's just going to be another dead end.

Thanks for the input RCS, I've already replaced the crank position sensor. It was a used one, but what are the chances of getting two bad ones that malfunction exactly the same way? Further, I can't recall a single post where one has failed. I've stripped the entire harness and and inspected the connector. Nothing looks amiss.


-Jeff
 
I don't know that I'd give up on the O2 sensor entirely, but I'd view it with a suspicious eye. To be honest I was going to say that a few posts ago, but wasn't sure enough to come out and say it at the time. Any chance you could swap those out with someone else's bike? That would be worth a try to at least cross those off the list without spending a few hundred $$$ on new ones.

Have you looked into the fuel pressure regulator? If that were failing that could cause temporary fuel starvation, which would be consistent with your symptoms and affect all cylinders, which is consistent with the extreme power loss you are seeing. Seems like a diaphragm based part might be susceptible to failure, and its a $40 part, and I think there's only one of them.
 
Here are a couple of additional thoughts.

Facts as presented:

1. ST1300 has 148,000 miles
2. Engine dead issue is within a rpm range - 4,000 to 4,500. This coincidentally is the highway cruising rpm range for the ST1300

My approach would be to look for a dead spot in engine sensors that are rpm related. The reasoning is that the dead spot may be the result of high usage of the sensor at the particular voltage output when the engine is at highway cruising rpms.

a. Crank sensor - ruled out because already changed.
b. Throttle position sensor - seems next most likely
c. Cam position sensor - seems third most likely

Now, I have spent a little time reading through the service manual trying to locate these sensors and I have not been able to yet. I am fairly sure the ST1300 has them because you can purchase them on ebay for the ST1300

http://www.ebay.com/itm/HONDA-ST130...sor-/221852218627?hash=item33a76c3503&vxp=mtr

http://www.ebay.com/itm/2005-Honda-ST1300-ST-1300-Camshaft-Position-Sensor-OEM-/400904477098
 
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dwalby said:
I don't know that I'd give up on the O2 sensor entirely, but I'd view it with a suspicious eye. To be honest I was going to say that a few posts ago, but wasn't sure enough to come out and say it at the time. Any chance you could swap those out with someone else's bike? That would be worth a try to at least cross those off the list without spending a few hundred $$$ on new ones.

Have you looked into the fuel pressure regulator? If that were failing that could cause temporary fuel starvation, which would be consistent with your symptoms and affect all cylinders, which is consistent with the extreme power loss you are seeing. Seems like a diaphragm based part might be susceptible to failure, and its a $40 part, and I think there's only one of them.
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Have tried a new FPR, was replaced along with the fuel pump and fuel filter.

RCS said:
Here are a couple of additional thoughts.

Facts as presented:

1. ST1300 has 148,000 miles
2. Engine dead issue is within a rpm range - 4,000 to 4,500. This coincidentally is the highway cruising rpm range for the ST1300

My approach would be to look for a dead spot in engine sensors that are rpm related. The reasoning is that the dead spot may be the result of high usage of the sensor at the particular voltage output when the engine is at highway cruising rpms.

a. Crank sensor - ruled out because already changed.
b. Throttle position sensor - seems next most likely
c. Cam position sensor - seems third most likely

Now, I have spent a little time reading through the service manual trying to locate these sensors and I have not been able to yet. I am fairly sure the ST1300 has them because you can purchase them on ebay for the ST1300

http://www.ebay.com/itm/HONDA-ST130...sor-/221852218627?hash=item33a76c3503&vxp=mtr

http://www.ebay.com/itm/2005-Honda-ST1300-ST-1300-Camshaft-Position-Sensor-OEM-/400904477098
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TPS & cam position sensors have both been replaced with no change in the behavior at all. The TPS is brand new.
 
Could this be something as simple as an air leak in the intake system somewhere? Throttle body butterfly shaft. idle circuit etc. that is causing a lean condition miss?
 
bdalameda said:
Could this be something as simple as an air leak in the intake system somewhere? Throttle body butterfly shaft. idle circuit etc. that is causing a lean condition miss?
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I certainly think that's possible, damned if I can find a leak anywhere though...
 
You can always try taking some wd40 or carb cleaner and with the engine running spray around all manifold connection points, hoses and throttle body and if the engine begins running rough due to pulling in the chemical you can trace the location of the leak. I have done this before with hard to find vacuum leaks.
 
Nearly three months and 21 pages, and no solution yet? Time to either live with it, take it to the dealer, or sell it because you guys are just grasping at straws now.
 
Mandrake said:
Nearly three months and 21 pages, and no solution yet? Time to either live with it, take it to the dealer, or sell it because you guys are just grasping at straws now.
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Grasping at straws? Perhaps. However, can you name me one Honda dealer that you think is capable of solving this problem??? Sadly I can't. :shrug2:
 
I can't because I do all my own work and don't deal with dealers (see what I did there?), but it's clear that nobody here is going to solve it over the internet either. Myself included. Admittedly, I haven't read through all 21 pages of "try this; nope didn't work; now try this; it's still doing it; well, what about this; ect..." but this exemplifies the futility of online diagnosis. I am assuming that after three months, all viable potential causes have been checked and have come up as non- solutions, so at this point, it's safe to say that something this complex and specific is either a figment of the owners imagination, or something that cannot be diagnosed without experiencing it first hand. Time to admit defeat and pick one of the three aforementioned options.
 
Mandrake said:
but this exemplifies the futility of online diagnosis. ..... Time to admit defeat and pick one of the three aforementioned options.
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The point of this forum is to exchange ideas and socialize a bit in the process. Sometimes problems get solved, sometimes they don't. The information exchange in the middle is often valuable to various people for a variety of reasons.
 
Mandrake said:
... this exemplifies the futility of online diagnosis.
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I've done remote support for several products, and it's not futile. It just has to be done deliberately, with a good understanding of what you're working with and the ability to ask the right questions. The process isn't any different than when you're there.

I am assuming that after three months, all viable potential causes have been checked and have come up as non- solutions...
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That a big assumption. We've got a pretty good track record of diagnosing problems. This one happens to be a tougher nut than usual and is well beyond what's in the service manual, which is where a dealer would punt. I've put forth a few things to look at that require additional test equipment that's not available, so those avenues haven't been explored.

I don't know Jeff personally, but I do know what he does for a living. I have my doubts he'd be long in his industry if he were prone to figments.

--Mark
 
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