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Old 11-27-2012, 08:05 AM   #1
Louis
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Low fuel pressure?

I switched from a PCIII to a SEPST. I have a Twinscan.

Loaded a supposedly suitable map from off here. It ran lean. Upped the fuel. I keep upping the fuel, it keeps running lean at the top end.

Due to bad weather it has sat for ages. Now tested the latest revisions, running leaner than ever despite the fuelling having been upped.

Bike also stalls at idle when it has been thrashed. Does not do so when ridden normally. Starts idling again if you keep it alive for maybe ten to twenty seconds. This behaviour has become progressively worse.

I don't think it can deliver the fuel it is being asked for.

Sound likely? Any other guesses?

Getting the fuel pressure checked in rural Portugal will be a hassle. In fact anything, especially getting spares, is a hassle out here, so I really have to call it right first go.
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Old 11-27-2012, 09:19 AM   #2
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Either load a different map or restrict the air intake (via filter or putting the top back on). Restricting the air in should richen the mix but it may not run as hard to redline. Another option would be to put the PCIII back on. Maybe the SEPST is just bad???
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Old 11-27-2012, 11:36 AM   #3
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Restricting the air intake is an interesting bodge but doesn't solve the problem! The SEPST is just an interface, either it works or it doesn't.

I make the choices:

Air leak, intake side.
Low fuel pressure.
Faulty Twinscan (bike FEELS fine, apart from the idle glitch) combined with duff IAC.
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Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



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Old 11-27-2012, 12:52 PM   #4
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no codes?
You have hit the the basic where to start problems,
to check the twin scan, isn't it enough to pull one run on a dyno and pay 20 bucks to check the AF ratio?
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Old 11-27-2012, 01:03 PM   #5
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no codes?
You have hit the the basic where to start problems,
to check the twin scan, isn't it enough to pull one run on a dyno and pay 20 bucks to check the AF ratio?
Love to, but it is donkey carts and beat up old trucks here, dynos don't exist!

One thing I can do is check the free air reading on the Twinscans sensors. But it is both pots, and it seems odd they are both playing up...

No codes - apart from the idle glitch all seems well.

Static battery voltage is poor, but the v-gauge reports a steady 13+ V in use, so I don't suspect grounds.
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Old 11-27-2012, 01:20 PM   #6
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look at your plugs, they usually are a tell tail sign,
might be clogged injectors, fuel filter, you seem to be good doityourself kinda person, so start with the fuel pressure, and go from there,
dont know how many kilometers you have logged, but, i would be worried more about the stalling,
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Old 11-27-2012, 01:37 PM   #7
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Your first post stated that the problems are happening now that you changed to a SEPST. That is why I recommended putting the PCIII back on and see if you still have similiar problems (I'm assuming it ran correctly with the PCIII). Also, it may run correctly with the air restriction (easy to try) then you can assume it's your A/F mix and probably not a bad injector or air leak. Running throttle body cleaner through my IAC while the engine was running helped settle my idle a bit.
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Old 11-27-2012, 01:40 PM   #8
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Originally Posted by santeg View Post
look at your plugs, they usually are a tell tail sign,
might be clogged injectors, fuel filter, you seem to be good doityourself kinda person, so start with the fuel pressure, and go from there,
dont know how many kilometers you have logged, but, i would be worried more about the stalling,
About 30,000 miles.

What do you mean by worry about the stalling? If you mean in riding terms, no issue, I've spent years riding ;airy race bikes with no idle :-) It's a worrying symptom, not a problem in itself.
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Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



2007 VRSC-AW (Fun).
2007 KTM 990 Adventure (Off Road and Touring).
2006 Triumph Daytona T955i (Evil).
2009 Fatboy (Heavily Tarted Up Show Pony).
2011 Bonneville (On long term loan).
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Old 11-27-2012, 01:42 PM   #9
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Originally Posted by pgilliam1 View Post
Your first post stated that the problems are happening now that you changed to a SEPST. That is why I recommended putting the PCIII back on and see if you still have similiar problems (I'm assuming it ran correctly with the PCIII). Also, it may run correctly with the air restriction (easy to try) then you can assume it's your A/F mix and probably not a bad injector or air leak. Running throttle body cleaner through my IAC while the engine was running helped settle my idle a bit.
Ah, that's the wonder of the SEPST - you can't actually put it back to stock, Harley don't publish the damn map, and you can't store it at the start. Harley have to do it...

However, I'm now starting over with a close-to-base map to see if that stops the stalling...
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http://www.thegentlemansnapper.co.uk

Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



2007 VRSC-AW (Fun).
2007 KTM 990 Adventure (Off Road and Touring).
2006 Triumph Daytona T955i (Evil).
2009 Fatboy (Heavily Tarted Up Show Pony).
2011 Bonneville (On long term loan).
1978 Triumph Bonneville Based Racer (Needs A Rebuild)
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Old 11-27-2012, 04:52 PM   #10
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Louis, excuse me needing a translator but by SEPST are you referring to a Screaming Eagle Race Tuner? If so, my recollection is the software has stock maps already loaded, along with a bunch of maps for different mods. I assume you have the CD and pigtail you have to buy separately. If nothing else, try a map for a stock engine with a K&N air filter. I know that map is in there, and it's a pretty good running map on a stock engine with stock exhaust. It cleans up all of the cold drivability problems of the stock map.
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Old 11-27-2012, 06:35 PM   #11
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Louis, excuse me needing a translator but by SEPST are you referring to a Screaming Eagle Race Tuner? If so, my recollection is the software has stock maps already loaded, along with a bunch of maps for different mods. I assume you have the CD and pigtail you have to buy separately. If nothing else, try a map for a stock engine with a K&N air filter. I know that map is in there, and it's a pretty good running map on a stock engine with stock exhaust. It cleans up all of the cold drivability problems of the stock map.
SERT was written outside Harley by the guys who now do the Mastertune, apparently it is fine.. Harley fired them and wrote the later SEPST in house (as I understand it). The SEPST is junk - truly dire. But all it does is allow you to modify the tables, so no big deal - it works, it is just horrid to use. However one nasty is you cannot read maps OFF. Dim-witted copyright protection.

I'll throw away my carefully crafted map and start with the closest Harley provide to my bike.

However, I'm pretty it isn't the map. I don't have any drivability problems except stalling when the bike is brought to a halt after a prolonged burst of WOT. But each time I use it, the Twinscan reports it leaner.

So either the Twinscan is lying, the bike is not running lean (feels fine) and the stalling is another issue (dirty IAC would be tops), or else there is an air leak making it run lean, or the pump can't keep the pressure up. Or (and this is the point of the thread) something else I have not thought of, which is...?

My current plan:

Throw the map away and start from scratch (nuisance).
Phone round every garage in the Algarve to find a pressure gauge to check the fuel pump (big nuisance).
Strip the bike down and check everything (huge nuisance, because I have a load of mods to do and I want the bike mapped first, because I want to fit the Twinscan to another bike).
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http://www.thegentlemansnapper.co.uk

Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



2007 VRSC-AW (Fun).
2007 KTM 990 Adventure (Off Road and Touring).
2006 Triumph Daytona T955i (Evil).
2009 Fatboy (Heavily Tarted Up Show Pony).
2011 Bonneville (On long term loan).
1978 Triumph Bonneville Based Racer (Needs A Rebuild)
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Old 11-27-2012, 07:55 PM   #12
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Louis,
Try spraying some carb clean in the center of the TB where the IAC is located. Let it sit over night.

This will work its way and clean it up.

The bike might stall a couple times but should clear up.

Put a map in the tuner that is close to stock. Put the PC back on and test it. See if the bike runs normal. Keep in mind the PC is a piggy back system and ou know this. See how the bike runs.

This will tell you if it is the map in the tuner.

I'll bet the map got corupted on the download.

AFR could be from a bad sensor?

Try it again.

Good Luck
Rod
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Old 11-28-2012, 11:29 AM   #13
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Louis,
Try spraying some carb clean in the center of the TB where the IAC is located. Let it sit over night.

This will work its way and clean it up.

The bike might stall a couple times but should clear up.

Put a map in the tuner that is close to stock. Put the PC back on and test it. See if the bike runs normal. Keep in mind the PC is a piggy back system and ou know this. See how the bike runs.

This will tell you if it is the map in the tuner.

I'll bet the map got corupted on the download.

AFR could be from a bad sensor?

Try it again.

Good Luck
Rod
First I changed to a stock(ish) map and fuelled it up based on experience. On the downside, this made no difference - still joke lean readings despite running fine, still stalling. On the upside, it produced similar results to the map I'd been working on, which is good, because the more I fiddled with that map the more I realised the base of it was plain wrong, so actually I'm happy to have started again.

Then I did what I have been trying to AVOID doing, and went into the airbox cover. I didn't want to do this because I have a load of fancy unrelated test kit for another project taped and zip tied in there and getting it out in one piece and back in again took hours - grrrr.

However, I think I found the problem - the WEGO III power connector had come loose, and the box was not getting enough power to work properly even with the engine running. Aha!

So we have two problems - stalling and false AFR readings. The AFR readings I hope I have fixed by re-soldering the power feed. I've soaked the IAC in carb cleaner, we'll see if that fixes the stall.

While I was at it I planned to recalibrate the oxygen sensors, but they have seized solid in the threads. There's a lesson - last time I put them in, I planned to remove them almost immediately, so I didn't bother with antiseize. Then I found they would feed the V-Gauge and left them in. Dim. Always consider how you will get something back out, just in case.
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http://www.thegentlemansnapper.co.uk

Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



2007 VRSC-AW (Fun).
2007 KTM 990 Adventure (Off Road and Touring).
2006 Triumph Daytona T955i (Evil).
2009 Fatboy (Heavily Tarted Up Show Pony).
2011 Bonneville (On long term loan).
1978 Triumph Bonneville Based Racer (Needs A Rebuild)
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Old 11-29-2012, 09:33 AM   #14
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...I planned to recalibrate the oxygen sensors, but they have seized solid in the threads. ...
Try heating the bungs with a propane torch.
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Old 11-29-2012, 11:53 AM   #15
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Try heating the bungs with a propane torch.
Tried that. Considered removing pipe to get at them properly and use serious force, but fortunately I checked them against my old (well sorted) map before I started all this, and rear read distinctly lean and the front a fraction so, so I am linking adjustments from the base map and ignoring the rear. Map seems to be coming together fine.

Spraying the IAC seems to have helped the stalling but not eliminated it. Is that plausible? Seems to be screwing in and out OK anyway.
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Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



2007 VRSC-AW (Fun).
2007 KTM 990 Adventure (Off Road and Touring).
2006 Triumph Daytona T955i (Evil).
2009 Fatboy (Heavily Tarted Up Show Pony).
2011 Bonneville (On long term loan).
1978 Triumph Bonneville Based Racer (Needs A Rebuild)
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