OK, so this one should be dead simple, right? It the TPS.
Except when I checked it last year, the TPS was spot on where it should be. (Note: I will check it again as a matter of course ;) )
But I'm getting ahead of myself... Let me start at the beginning. A little background, if you will.
I got my '03 14 in November 2015. It's a standard bike apart from a set of cans (no idea what brand) with less than 20K on the clock. Cans were supplied with bungs but weren't fitted. No original pipes supplied.
I had trouble from the off. Started getting the famous ole' C28 error right up, might have been a sticky secondary TB because the more I rode the bike the less it did it, now it's pretty rare. The secondary TB shaft doesn't feel stiff when I move it manually. For now I'll discount this as a cause but it's noted here in case it becomes important later.
Another issue I had was rough running on part throttle - this is the issue I'm trying to solve:
When going from closed throttle to open, there's a big hesitation before the bike stutters and lurches forward. Sometimes it seems worse than others but it's always a pain when riding in traffic, and also when balancing a neutral throttle for tight turns. A typical scenario is I'll close the throttle on approach to a bend, feed throttle in to find a neutral balance, get nothing, nothing, nothing, reach corner, tip in and begin to turn, still nothing, then lurch-bang power comes back in and I'm suddenly racing for the hedge, so I have to control it on the rear brake and wobble around like a plum.
Sometimes in traffic it'll stall when I feed in throttle to pull away. It's like the motor just doesn't get the fuel it wants and cuts out.
When cruising along at a constant speed that needs only a tiny amount of throttle, it sometimes feels like it's about to run out of fuel.
I checked the TPS (fine) and STPS (fine) and checked the STPV moves smoothly. All fine.
Then I stumbled on a fix by refitting the baffles in the cans. The part-throttle problem went away and all was fine. Or if not fine, then, much better. Until one day last summer when I overtook a truck, the bike gave a big bang and the FI light came on. I figured it was just a C28 (didn't have a wire and spare key so couldn't find out) so I carried on and it got me home without any issues. And I discovered I'd lost a baffle!! Bolt must have come out and baffle escaped down the road :(
So this tells me it's a fuelling issue caused by the cans, and the solution would be a PC3 and a remap.
I whipped out the other baffle and, as you'd expect, the running problems continued. I booked into a local dyno place, they fitted a yoshibox to tweak the fuelling. The result? Naff all. I couldn't tell the slightest difference.
I got a new set of baffles but the problem hasn't gone away. New baffles may pass slightly more air than the old ones so it could still be a mixture problem.
It seems to me the obvious solution is to get booked into a dyno shop and have a PC3 fitted and tuned up properly for both baffle-in and baffle-out operation. However, I don't want to spend a heap-load of cash to find there's an underlying issue.
Next time I do a service (not sure when, got a 5 week old baby which is taking most of my spare time :p ) I intend to:
Check throttle cables
Check TPS and STPS settings
Replace plugs (got all new ones anyway, why not?)
Replace air filter
Check airbox and all vacuum lines for leaks
Balance TBs
Check coil pack voltage?
General visual check over anything else I can see or think of at the time
Any other things I should / could check?
Any other ideas or thoughts?
Much price difference between PC3 and PC5? Last time I looked the PC5 wasn't an option but it seems you guys have found a way. Will I save money if I go for a PC5, fit a wideband sensor and do an auto-tune? I have no idea how good auto-tunes are these days - back in my day it was dyno or blown engine time ;)
Sorry if this is a bit long but wanted to cover all bases :)
I'd check is the low pressure fuel filter in the fuel pump
especially if it sits for a while between getting used.
i had a similar problem and thats what it turned out to be.
a service (plugs,oil,oil filter and air filter )will also help as ive had plugs fail in the past(especially the iridium ones)
good luck
:cheers:
Hi Sparey, I bought my '02 14 last year (5X k Km on clock) and also had some problems what you have described. At these few months I tried several ways to improved the situation (also read the posts and try by error) and I found the result is quite happy to me. Here were what i tried:
1) change the spark plugs (the last owner used wrong type CR10EK :facepalm: :facepalm:), but changing spark plugs didn't improve much.
2) clean the throttle body thoroughly and fine tune the TPS, I do it myself and found there were quite some dirt in the "small passages" but the TPS was generally ok. It helped the throttle response better but the rpm still refuse to rev freely over 5.5K rpm (at that time I though it was a fuel pump dirty problem), the low rpm throttle stutter improved .
3) Clean the injectors as learned from YouTube, I use 12V battery and carb cleaner. I don't know did it bring any improvement but at least I do some cleaning. I think the best way is to sent them to professional shop.
4) I changed motor oil. It helped better low rpm response and smoothness a bit.
5) Most Important: I changed the old battery. The bike came with a YUASA YTX9BS which was not for the 14 :thumbs_down: :thumbs_down: I found this problem lastly :doh:(It should be YTX14BS but at last I chosen TTZ14S). This helped a lot, the rpm could rev freely now and can feel the fuel supply was stable to the bike. I thought the old battery was not providing enough power for the fuel pump or other electric related devices.
6) I also changed the ignition coil (I bought a 2007 used set). This also helped to restored the power of the bike, the acceleration became more stable and strong.
so now the bike now becoming fine to me. I don't know if this can help or not but hope can provide some information for your reference.
(sorry my eng is not so good, the verbal expression was limited :whatever:)
Hope your bike can get well soon !
Thanks - some very useful info there :)
The bike did have a duff battery when it arrived but I fitted a new one of (hopefully) the correct type and it holds a charge well between use. I try to use the bike often, at least a couple of times every week, depending on what work I'm doing, it's got a lot of use recently as I've been doings lots of journeys into the city and, if I'm honest, it feels like the problem has got worse.
I think I'll have to be patient and strip it down during lunchbreaks. Since the wife will be using the car for the next few months that means I'll be stuck with the gas-guzzling van for my commutes :facepalm:
Will let y'all know what I find when I get busy with the spanners.
Any findings on this matter Alex? Mine has similar issues... When accelerating she hesitates quite alot. This happens from idle up to 2500 rpm, after that hesitation is gone and i have hold on tight. Happens on every gear, on all throttle positions and every day all day. TPS is ok, teabag cleaned, throttle cables checked. Could this be battery related? Voltage reading with power off 12,7 V and power on around 12,4 V.
Also while engine braking she starts to stutter after revs falls under that magical 2500 rpm. Related to above symptom or normal behaviour, please advice?
Fyi mine has yoshi cams and full Akra system...
Quote from: DTTW on Tuesday, 13 June 2017, 03:13 AM
Any findings on this matter Alex? Mine has similar issues... When accelerating she hesitates quite alot. This happens from idle up to 2500 rpm, after that hesitation is gone and i have hold on tight. Happens on every gear, on all throttle positions and every day all day. TPS is ok, teabag cleaned, throttle cables checked. Could this be battery related? Voltage reading with power off 12,7 V and power on around 12,4 V.
Also while engine braking she starts to stutter after revs falls under that magical 2500 rpm. Related to above symptom or normal behaviour, please advice?
Fyi mine has yoshi cams and full Akra system...
- can your problem be cam related? ( and.. has your bike seen some Dyno time to set it up ? )
i once fitted lumpier cams in a carbureted bike. It wouldn't idle below 1.750 rpm due to the higher lift cams.
I raised the idle speed and it was good.
Actually it might be that.. When looking the dyno chart it seems that she's running little on the rich side but AFR is still above 12. Could it be then that? I remember the guy at the dyno shop saying the low RPM's were quite difficult to get right because of the more steep cams.
Oh I got a new air filter as well. I'll check the plugs tonight... I got this feeling that it is not tune related stuff but you guys probably know better. Dyno chart attached as i don't master inserting pics on the post yet. :embarassed:
:onya:
Nice graph... thin lines "as found" thick lines "as left" values.
I used this for a guidance / for better understanding ( recently after fitting a Power Commander 5 with a Autotune )
http://www.afrplus.com/AFRplus-unit-functionality.asp (http://www.afrplus.com/AFRplus-unit-functionality.asp)
i have copied some relevant info :computer_type:i modified it slightly for clarification :
RECOMMENDED AFR VALUES
IDLE / LIGHT CRUISE: 13.5 AFR
When you start your vehicle we refer to this as being in IDLE condition. When you shift into gear and drive at a low mph we refer to this as being a LIGHT CRUISE. With 14.7 being the industry standard stoich AFR value, we typically like to see these conditions run slightly richer. We suggest to tune by leaving the vehicle at an idle, but hold the throttle slightly open to a constant rpm. Adjusting the fuel will affect the sound of the engine. We are looking to adjust the fuel to get the smoothest engine operation.
CRUISING: 13.5 to 14 AFR
Most of the time you are driving your vehicle you will be within our CRUISE zone. This condition is the most wide open for customer preference based on two factors. If you prefer better GAS MILEAGE then run a leaner mixture.
14 AFR (on-road bikes)
Most stock to slightly modified engines will run just fine at an AFR of 15:1 and yield better MPG. If you prefer better PERFORMANCE then we suggest to run an AFR of 14:1 or even richer to around 13.5:1.
13.5 AFR (off-road vehicles)
Most stock to slightly modified engines will run just fine at an AFR of 14.5:1 and yield better MPG. If you prefer better PERFORMANCE then we suggest to run an AFR of 13.5:1 or even richer to around 13:1.
FULL THROTTLE / HIGH RPMS: 12.5 AFR
Driving full out within a gear will bring you into our FULL THROTTLE zone. This condition is where the peak horsepower value is obtained. The Acceleration zone below may throw in a quick adjustment of fuel, but usually only engages for a couple of seconds. When maintaining a full throttle condition you will want to run a richer AFR to get the best performance. Best performance for most vehicles is in the 12.5:1 to 13:1 AFR range. Going too rich will have the opposite affect and decrease your performance.
ACCELERATION: 12 AFR
Getting up to cruising speed or getting ready to pass someone, you usually are looking for the performance to get up and go. We refer to any fast turn of the throttle as our ACCELERATION zone.
and...
Rich Conditions - Common Side Affects
Engine Flooding
Decel Pop / Backfiring
Lethargic Throttle Response
Excess Carbon Build-up (sooty pipes)
Fuel Smell from the Exhaust
- see anything familiar ?
i *think* your problem may be a tune problem which can be fixed with a re think of the tune.
I am pretty sure someone with a similar setup will show you his findings.
You haven't got the dreaded green pins in your plugs have you? Or a pinched wire in and around the clutch slave area?. Might be worth a couple of hours checking the electrics .
Can you open the green pins issue a bit please, never heard of those?
Might check the clutch slave area tomorrow. What exactly I am looking for in there?
check all the electrical connectors as when they corrode the pins/terminals inside go green thats what what your looking for .
once clean use silicone grease to seal them .
:cheers:
Quote from: DTTW on Wednesday, 14 June 2017, 05:29 AM
Can you open the green pins issue a bit please, never heard of those?
Might check the clutch slave area tomorrow. What exactly I am looking for in there?
The mentioned green pins are corroded connection pins.. to be found in your connector blocks and even in your spark plug leads.
The twisted/ pinched wire in the clutch slave area are the ones around your front sprocket.
The black plastic cover can catch them or the wire guide clips are to tight.. etc
OK, so been a long time since my last update, basically been way too busy to do any work on the bike. Joys of having a new baby to look after and a house to put back together :D
Anyhoo, I've basically been through everything I can think of, ending with balancing the throttle bodies at the weekend and re-setting the TPS to 1100 on the dot (according to my unit, anyway). The result was a bike that popped and misfired so bad it was like riding a bucking bronco. Now, to be fair, I only rode it around the block - it seemed to improve a bit after the first part of the block so maybe the motor had cooled off - I'll give it a longer ride out this week if I have time. However, if it still ain't fixed, I'm pretty much ready to put it in a workshop and have someone else look at it because it's taking too much of my precious time, and it'll probably be Christmas before I do anything more on it.
I supposed I could still check more of the wiring harness to make sure nothing is corroded (I have the intermittent STPS error but the STPV isn't jammed so that's probably a wiring fault somewhere). I could take off the TBs and give them a good clean. I could whip out the fuel pump and clean the teabag.
But I'm still not sure it isn't just a mixture issue caused by the aftermarket cans.
I'll recap from the beginning: the bike had this issue when I got it, and it was running aftermarket cans. I stuck in the baffles and the problem went away. 8 months later one of the baffles came out during a ride and the problem reappeared. I couldn't get identical replacement baffles so I bought some of a similar size, but this time the problem didn't go away - I assume the new baffles don't add quite so much backpressure as the old ones (they have lil holes in them that the old ones don't have). I sent the bike to a local dyno centre and they did a "Yoshi tune" - they showed me a slight improvement in fuelling and power output but they said they couldn't really get it right without fitting a PC.
I've just about got the budget for a PC, but my next question is do I fit a PCIII and pay for dyno time, or do I fit a PCV and auto tune and let it sort itself out? I'm not really sure what's going to work out cheaper and I don't want to throw any more money at it than I have to.
:)
Tea Bag! - All your symptoms I had on my '03
Quote from: Globalrider on Wednesday, 28 June 2017, 02:07 AM
Tea Bag! - All your symptoms I had on my '03
OK - I'll teabag it at the weekend :salute:
Quote from: Alex Sparey on Wednesday, 28 June 2017, 07:48 PM
Quote from: Globalrider on Wednesday, 28 June 2017, 02:07 AM
Tea Bag! - All your symptoms I had on my '03
OK - I'll teabag it at the weekend :salute:
http://gsx1400owners.org/forum/index.php?topic=430.0
Sorry for replying to old topic, but this is to update the situation what I had earlier. You can read the symptoms from my previous post in this topic.
The problem for me was as simple as having the fuel tank overflow hose clogged by the cap that should be on the hose coming from air filter. Switched the cap to that and now it runs MUCH better. Anyhow as there has been probably issue with the engine being tuned with this set up it needs to go back to Dyno. There is still light hesitation, but most of it is gone.
Not sure how the above has happened but when removing the cap there was plenty of rusty water coming from the overflow hose, not good. Anyhow something to check on your bikes as well.
It's amazing how a small thing can cause so much bother glad it's sorted now.
:cheers:
I had a similar issue and it was the after market air filter not giving the bike enough air , changed it and it was 100 % again :onya:
Thanks shanered6, I also have an aftermarket filter. I think the diameter of the inlet on the aftermarket one is less than the original part. Will change that to original.
Quote from: DTTW on Saturday, 18 August 2018, 07:58 PMSorry for replying to old topic, but this is to update the situation what I had earlier. You can read the symptoms from my previous post in this topic.
The problem for me was as simple as having the fuel tank overflow hose clogged by the cap that should be on the hose coming from air filter. Switched the cap to that and now it runs MUCH better. Anyhow as there has been probably issue with the engine being tuned with this set up it needs to go back to Dyno. There is still light hesitation, but most of it is gone.
Not sure how the above has happened but when removing the cap there was plenty of rusty water coming from the overflow hose, not good. Anyhow something to check on your bikes as well.
Hi DDTW,
I've had minor stuttering when accelerating from low speed it's intermittent and bike bikes runs sweet apart from that. I've balanced the TBs, set both TPSs as suggested, I did clean the fuel filter and I have finally taken the plunge and done the external fuel filter mod. This improved the power and general running of my which is stock, but I still get these little stutters at times when accelerating. I'm curious what you did with th breather hose as I'm running out of ideas. Doesn't the breather hose just hang loose in the bike? Mine always has, in fact I've never seen the far end! Only had the bike a short time and I didn't consider that a breather hose could cause such issues, makes sense I suppose or the fuel tank might implode! Where did you connect your breathe too?
Thanks
Also, have a search on here. The TPS and STPS can wear out. The track inside the sensor can corroded, causing spurious signals to the ECU. I've changed both STPS and TPS, plus done all of the above, and all my hesitation and stutter has gone.
Eric, i agree👍If mine ever gives those sort of probs, basic checks first but TPS must wear out, that contact moves up & down every throttle movement, would cover a bit of distance over a few years.Not real cheap but if it works, its good value👍
+1 on the TPS/STPS wear out.
Quote from: Bradders on Friday, 06 September 2024, 03:24 AMI'm curious what you did with th breather hose as I'm running out of ideas. Doesn't the breather hose just hang loose in the bike? Mine always has, in fact I've never seen the far end! Only had the bike a short time and I didn't consider that a breather hose could cause such issues, makes sense I suppose or the fuel tank might implode! Where did you connect your breathe too?
It's a common misunderstanding to think that this is a breather hose. It is just a Water Drain Hose. In my case more a spilled fuel hose (when I spill while topping of at the station). The tank breathing works through the tank lid.
The one end of the hose connects to the tank. The other end hangs loose.See the drawings for the routing (from page 8-26 workshop manual)
WaterDrain1.png
WaterDrain2.png
Quote from: Andre on Friday, 06 September 2024, 04:24 PM+1 on the TPS/STPS wear out.
Quote from: Bradders on Friday, 06 September 2024, 03:24 AMI'm curious what you did with th breather hose as I'm running out of ideas. Doesn't the breather hose just hang loose in the bike? Mine always has, in fact I've never seen the far end! Only had the bike a short time and I didn't consider that a breather hose could cause such issues, makes sense I suppose or the fuel tank might implode! Where did you connect your breathe too?
It's a common misunderstanding to think that this is a breather hose. It is just a Water Drain Hose. In my case more a spilled fuel hose (when I spill while topping of at the station). The tank breathing works through the tank lid.
The one end of the hose connects to the tank. The other end hangs loose.See the drawings for the routing (from page 8-26 workshop manual)
WaterDrain1.png
WaterDrain2.png
Brilliant, thanks guys, I'll take a look at this, I'm fairly certain my drain isn't wheee it supposed to be. I was thinking last night to retry the TPS/STPS again.