Advice please

[nwguy]

I've posted about different aspects of the issue I'm having with my 08' xb9sx already. The back story:

It has a race exhaust, K&N air filter and ECM from IDS specific to that exhaust and air filter. Now 15k miles on it. Bought it at 10k miles and it ran perfectly then. Fuel pump fuse blew while on a trip. Replaced fuse, bike ran OK for the most part, but was hard to start sometimes (cranked but didn't fire) and would occasionally stall while idling. After getting home from the trip I replaced plugs with Iridium ones and their wires, cleaned the air filter and changed the oil. I sent the ECM back to IDS. They didn't see any error codes, but they tweaked the setting on the ECM for a slightly richer fuel/air mix. I also found that insulation on 5 or 6 wires on the ECM harness had worn from the seat rubbing on them, and copper wire strands were exposed (no doubt why the fuse blew). I cut those wires and soldered them back together with heat shrink on them to act as insulation. Someone on this forum suggested that the fuel pump might be the problem, so I bought a NOS fuel pump and installed that. TPS reset too. It ran worse after this. Felt like the fuel supply was shutting off intermittently as it bucked like a bronco. Took it to a local v-twin mechanic who had replaced the neutral position sensor for me on a previous xb9 I owned. I ordered a Buelltooth dongle and had it shipped to him. He used that with ECM Droid, and also put it on his dyno. With it running in his shop he found that it started normally, but then would stall at idle once the engine warmed up a bit. Again there were no error codes. His dyno had these air/fuel mixture readings:

14:1 when bike nearly cold (engine temp 70-80 degrees)
15:1 to 16:1 when bike got warmer and while still running
18:1 to 20:1 when warmer and when stalling

So too lean when warmed up. He thinks it's a fuel delivery issue. I asked if he thought I should try reinstalling the old fuel pump, but he thinks the next thing to do is to replace the engine temperature sensor and the air intake temperature sensor. It does start right up. We ran it to get it up on my trailer. Seems to just run badly when warmed up now. I haven't tried test riding it as we're being deluged with rain and wind with temps in the 40s here in the Northwest.

What do you think?

I found that the engine temperature sensor is available:
https://www.ironmachine.com/08-10-bu...ets-p02784a8a-

as is the special socket wrench needed to install it:
https://www.ironmachine.com/03-10-bu...cket-xbxststl-

Would you go this route? Any thoughts on where to source the air intake temperature sensor? I can't find them anywhere.

How hard is it to replace the engine temperature sensor?

[Barrett]

fuel-compression-spark-timing...and the motor will run perfectly. it has no choice. a problem with 1 or more of those requirements results in sub-standard operation. clearly, yours is fueling.
i find it odd that your stoich dramatically climbing when warm...popped 10A pump fuse...difficult warm start...and a new pump didn't resolve all this.

ETS: prior to replacement, test for both volts received and resistance. simple test procedure spelled out in SM section 4-18.
ETS R&R socket is Snap-On M3503B. perhaps borrow from local shop? advance/autozone/pepboys lend it for free.


all XB IAT sensors now NLA in dealer system. a few dealers still have a few in stock.

XB IAT SENSOR cross reference as follows: FORD F57Z-12A697-AA......MOTORCRAFT DY-735
94-99 FORD EXPLORER IAT exactly same part. Ford harness plug-end EXACTLY the same but has tiny off-set internal tang to reference the male plug end. simply snip or remove said tang with small file or similar device and plug exactly matches.
AUTOZONE house brand 2000-and up FORD MUSTANG IAT crosses over---CHECK wiring harness plug end for fitment.

[nwguy]

Thank you Barret. I found an OEM Buell IAT. Ordered both sensors and have printed out the relevant manual pages. We'll see what happens.

[d_adams]

14:1 when bike nearly cold (engine temp 70-80 degrees)
15:1 to 16:1 when bike got warmer and while still running
18:1 to 20:1 when warmer and when stalling

So too lean when warmed up.

Intake seals. Use a high quality grease to install them properly and ensure that they don't leak.

[Cooter]

14:1 when bike nearly cold (engine temp 70-80 degrees)
15:1 to 16:1 when bike got warmer and while still running
18:1 to 20:1 when warmer and when stalling

That is lean all the time, not just running. I'm with Dean about intake seals being a strong possibility. Very easy to check by spraying carb cleaner at them (and I would think your Buell guy would have already done that as the next step).
What is the AFV? That will tell you what the ECM is doing to compensate for that condition and will lead you in the right direction.
I am very concerned for you that he is recommending to start just replacing things (sensors are easy to test) without any diagnosis. That is a worrisome step in the path of lots of $$, lots of down time, and lots of frustration. His guesses will cost you.

Did you replace the OE pump or the OE pump assembly? If it's suspect, a pressure/volume test next would be the right answer. Putting the old one back in would be the wrong answer. And it's another guess that costs you

[nwguy]

That is lean all the time, not just running. I'm with Dean about intake seals being a strong possibility. Very easy to check by spraying carb cleaner at them (and I would think your Buell guy would have already done that as the next step).
What is the AFV? That will tell you what the ECM is doing to compensate for that condition and will lead you in the right direction.
I am very concerned for you that he is recommending to start just replacing things (sensors are easy to test) without any diagnosis. That is a worrisome step in the path of lots of $$, lots of down time, and lots of frustration. His guesses will cost you.

Did you replace the OE pump or the OE pump assembly? If it's suspect, a pressure/volume test next would be the right answer. Putting the old one back in would be the wrong answer. And it's another guess that costs you

I did check the intake seals by spraying carb cleaner around them while the bike was running. There was no change, so I think they're OK. I replaced the fuel pump assembly. See pic of the old one below.

[Cooter]

Ok well thats 2 major reasons why it would be lean at least checked and passed for now.

Time to dig a little deeper.
Whats the AFV? You can read it on ECMDroid. The Air Fuel Value is a global modifier to the fuel map.
100 is average and +/- 10 is well within acceptable adjustment range to compensate for elevation, temp, etc.

If you AFV is well beyond that range you need to find out why.
If you find that value way low (70-85 range) the ECM is pulling fuel away from the bike because it thinks its rich. Possible causes could be an old/lazy O2 sensor, sticky injectors things like that.
If you find the value is 110-125 the ECM is adding 10-25% more fuel and is still too lean, look for more intake air leaks, clogged injectors etc.

As a cheap easy check, pull off your air filter and make sure the airhorn gasket below it, is sandwiched properly on the lower airbox plate. Check the manual for pics. Buellmods.com

[nwguy]

First let me say how fortunate I feel to have you guys help like you are. Thank you. I used my Buelltooth dongle and ECMDroid for the first time today while watching this video:
https://www.youtube.com/watch?v=8-x2FOol12k

See screen shots below. Here is perhaps the most pertinent info I found:

AFV (rear): 99.7%
AFV (front): 100%

Current errors: No errors
Stored errors: 15 | Air temperature too high/short to ground

I ran some active tests (coils, fuel pump injectors, fan, exhaust valve and active intake). The only errors/warnings that appeared were with the Exhaust valve: "Request not acknowledged by ECM (error code 21). I'm guessing that's because I have a race exhaust.

I cleared the stored errors, ran the bike again and checked for any new errors. There were none. Wondering if the bike got hot when my mechanic had it on his dyno, even though his has a big fan mounted there.

The bike started right up both times and it idled about as smoothly as an XB can while running the Log Recorder in MSL format. Not sure how to access the resultant log.

Re: the airbox Cooter: My mechanic took the airbox off. Not sure how much he dismantled it. Last time I did I made sure the airhorn gasket was installed correctly. So if he dismantled it at least he saw the right way to reinstall it.

Screenshots from ECM Droid:

bt1.png

bt2.png

As an aside, I asked Tim at IDS (mfgr of my ECM) if cutting then splicing and soldering the damaged ECM harness wires back together could change the resistance in the wires to adversely affect the signals from the temperature sensors. He said, "Not likely if you did a good job of splicing", which I think I did. I also checked the wiring diagram in the SM and verified that the wires for the air intake and engine temperature sensors were not any of the ones that were damaged/repaired. He also said:

"It is odd that the bike leans out as it warms up. This to me points to a possible issue with the O2 sensor or grounding. The bike should idle at 14.5:1 a minute or so after engine start; this is closed loop fuel control based on feedback from the O2 sensor, and it should idle near 14.5:1 regardless of what the temperature sensors are doing. I would try loosening and retightening the bolts holding the rear subframe to the main frame. Corrosion at these bolts can cause the ECM ground to be at a different potential than the engine and O2 sensor, effectively skewing the O2 reading. Also check the main ground strap above the rear cylinder; make sure it is clean and tight."

I did loosen and retighten the rear subframe bolts, and previously I detached, cleaned and reattached the main ground strap. It is pissing rain right now, otherwise I'd try test riding my bike. Supposed to be better tomorrow.

Thanks again.

[Barrett]

our pleasure, sir. XB's have a series of bundled grounds at the head-stock area....the braided dog-bone brace...the dedicated ECM harness ground/grounds....and the dedicated grounds attached to the left rear frame rail along with the negative battery cable. one or more faulty/questionable grounds will often times result in one or more stored historical fault codes and in particular....random various codes for dedicated sensors related to the EFI system.
check your ECM ground which is black coded and i THINK...wire #11 in schematic.....and also consider running a supplemental ground from the rear-most coil attachment bracket cap head bolt, to the rear frame rail where the negative battery cable attaches. often times improves overall performance....removes low-speed jitters....steadies charging system output...and resolves false sensor trouble codes.

[Cooter]

The rear AFV looks fine to me unless he re-set it and it hasn't learned yet. (you won't have a front reading on your bike. It will just stay at 100.

The air temp sensor code could modify the fuel map a little. I'd look into "live data" on ECM Droid while it's running and see what that sensor is reading to see if that circuit or sensor needs repair.

HOPEFULLY your mechanic didn't remove the airbox and then run it on the dyno. Those AFR readings would absolutely be skewed if he didn't run it completely assembled.

Yes grounds can be a big issue. Take Barretts excellent advise to heart. A good check is to use the OHM scale on a DVOM to check for continuity between the battery negative post and the ECM ground inputs.

To see the logs from the recorder you need to use a program like MegaLog Viewer and a tuning program like TunerPro or ECMSpy. ECMDroid isn't really meant for that.