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Discussion Starter #1
I have been to this site over the years but this is my 1st post.

My Canadian 2003 GSXR750 with 48,000 km's on it, stock with a Yosh TRS carbon muffler sometime (this spring I suspect) stopped revving to full rpm. It appears to run 100% but it is like the rev limiter cuts in either at 10,000 rpm or at 12,200 rpm. It seems to randomly choose 1 of these 2 rpm's to stop revving at. Otherwise it seems to run perfectly. I very rarely rev it this high so do not know how long this has been the situation. It used to rev to 14,000 cleanly.

It is stored indoors in a unheated garage. I see no damaged wires.
The crank position sensor checks out ok with an ohm meter.
The spark plugs and air filter are new.
There are no faults showing on the dash just the clear, all good readout of -C00.
I have put 5 tanks of 91 octane gas in this year.
The battery seems to be good at 13.3 volts with the ignition off. And it turns over and starts like a new bike.
The throttle valves seem to be ok and working properly including the secondaries.
The dealer suspects the ECU after discussions with them.

I am suspecting the ECU and wonder if they all are the same in that I see different part #'s for used ones listed.
Mine is a Denso 32920-35FD0 & 112100-1161.
I see them online with other #'s also like: 32920-35F30 & 112100-0561.
Are these the same, or different and will the 2nd one work properly for my bike?

Any suggestion or assistance is appreciated.

IKan, not fix my bike right now. :banghead
 

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My bike has done the exact thing it would stop revving right around 12k. I tried everything and i mean everything until i pulled the fuel pump. Pull the pump and disassemble it. Go get a couple cans of carb cleaner. Spray off the sock filter then disassemble the pump what made the difference on mine was spraying out the black plastic canister part of it. I sprayed 3 cans through it and crap was still coming out but i decided to see if it helped and my bike has never ran better. Good luck.
 

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Also check for a kinked fuel line. The one that runs from the pump to the fuel rail it has a tendency to kink. Definitely check that first.
 

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Discussion Starter #4
Well I got off my butt and did some checking of things which all seem to be good. So I think it is either a dirty fuel pump/filter maybe (see flow results below), battery or ECU.

Followed my Haynes manual and checked all that applied (such as: for volts input, volts out, volts through range of motion, Ohms resistances, resistances to ground...)

All ok:

1). Fuel pump flow rate of 1.3 litres in 30 seconds (which is supposed to indicate a good pump and filter)
2). CKP, Crank Position Sensor
3). No codes on dash -C00
4). IAP, Intake Air Pressure sensor input volts, output volts, do not have a vacuum pump for that test
5). TP, Throttle Position sensor
6). ECT, Engine coolant Temperature sensor
7). IAT, Intake air temperature sensor
8). AP, Atmospheric pressure sensor
9). TO, Tip-over sensor
10). STV, Secondary throttle valve servo,
11). STP, Secondary throttle position sensor
12). GP, Gear position
13). Fuel injectors
14). All connectors feel tight and the bike is very clean everywhere. Cannot find a dust bunny anywhere.

IKan
 

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Discussion Starter #5
So I now have the fuel filter element in my hand. The little sack and it barely has any little black specks on it. The bowl had black stuff in it equivalent to 1 or 2 shakes of black pepper from a pepper shaker. Not much in my experince.

Having trouble pulling out the fuel filter itself. If I am trying to pull out the correct thing. Not feeling confident that it is the filter itself. Dealer thought that is was not the filter. They may be correct.

I am suspecting the ECU even more. I am in the process of buying a used one which matches all my ECU`s numbers exactly. Wil take a few days to get it. Also a new battery on order (what the heck I am getting antsy to ride it).

Oh my god, I will have to ride my 2008 CBR1000RR some more. :laughingr

Note: I bought the 2003 GSXR750 brand new from the local dealer in 2007! It never saw gas until March 2007 when they did the PDI (Pre-delivery Inspection). It has 48,000 km or approx. 30,000 miles. It has been flawless until this.

Bought 2008 CBR1000RR this year with approx. 300 miles on it (550 kms). Nibbies still on original tires. I know the bike and owner since new.

IKan
 

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my 02 750 was having the same problem. I took off the fuel rail and injectors and soaked them in carb cleaner and blew them out with compressed air. bike has never ran better after.
 

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Discussion Starter #7
Since there was nothing on the inside of the fuel filter sack I am assuming that nothing got past the sack, and therefore, nothing should be inside the filter. I back washed the filter with a bit of carb cleaner and nothing but clean carb cleaner came out.

$75 for a filter kit and the dealer did not have any!

So new battery on Monday. If that fails then I replace the ECU.

Will let ya know how I make out.

I love riding the GSXR. :twitch Rode it once for approx. 900 miles (1,440 kms) none stop other than for gas and 45 minutes for dinner. 500 km (300 miles) trips are the norm for this bike. It just fits me. However, the seat does get a tad uncomfortable after 3 - 4 tanks of gas non-stop riding. One time I thought a red hot pocker in the eye would be more comfortable. So I stopped. For 20 minutes then carried on.

IKan
 

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Discussion Starter #8 (Edited)
New battery was not the answer.
The starter does spin faster now.

12,000 max.
Tried 1st 4 gears. Never tried it in 5th or 6th.

IKan
 

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Nazi Lustful Faggot - hot for Hermann Göring & Cai
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How did you check gear position sensor? Is clutch switch working properly?
 

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Discussion Starter #10
How did you check gear position sensor? Is clutch switch working properly?


The clutch switch will not cause the engine to stop revving every time at, or near, the same rpm as I understand it. Typically it either works or does not. If it was loose then it would cause problems erratically (at different rpm's or when going over a bump for example).

I rode the bike approximately 300 km's (180 miles) today and it seemed to work perfectly except it will not go above 12,000 (give or take a few rpm)


The steps I followed to check the gear position sensor:

- The GP sensor is located on the left-hand side of the engine behind the water pump.
- I traced the wire to the connector. ( I also had the gas tank off at the time which allowed for better viewing and more light to shine into the area)
- Turned ignition on (do not start engine)
- Inserted positive probe of voltmeter into the back of the connector's pink wire (I used a sewing pin and then used a adapter on the end of the probe to hook or hold onto the pin because the meter's probe is too large in diameter)
- connected negative voltmeter probe to a ground on the bike (I just touched a bolt head of a bolt that is screwed into the frame that was handy to access)
- read voltmeter as each gear is selected (I set the negative probe down and selected another gear with my hand, note that sometimes I had to just nudge (rock) the rear wheel to help the gear change, then put the negative probe back onto the ground and read volts)
- OK is if above 0.6 volts in each gear
- if the output volts is not as specified then either the pink wire to the GP switch or the switch is bad
- if a problem is still suspected and the output voltage is ok then check the wiring from the sensor to the ECM, and check the ECM terminals

My reading (volts) per gear where:
1st: 2.01 volts
2nd: 2.44
3rd: 3.17
4rth: 3.83
5th: 4.52
6th: 4.84
Neutral: 5.16 volts

IKan
 

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Mesonychoteuthis hamitoni
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The GPS defines each gear by a different resistance, so really it would be better to measure the resistance for each gear rather than the voltage. You also don't need the bike on to test it then. ;)
 

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Discussion Starter #12
The GPS defines each gear by a different resistance, so really it would be better to measure the resistance for each gear rather than the voltage. You also don't need the bike on to test it then.



I see your point.
I am thinking that since the voltages are changing and are changing in the correct direction that that is an indication that the resistors are ok, as they are usually ok or broke electrically.

I suppose I could simply disconnect the GPS connector and then put the ohm meter across the the 2 terminal and change the gears and read each one. With the ignition switched off. Better yet with the negative battery terminal disconnected so as to eliminate any potential electrical damage via any stupid slips on my part.:lol

I was following the instructions in a Haynes sevice and repair manual.
Have not had to think about this stuff for a long time.

I appreciate all the feedback and help from everyone.

Had it out yesterday. No chicken lines on that back tire. It has always handled great and been rock solid once I learned to set the suspension sag and then fine tune the compression and rebound. All on sport touring tires.

As I say, "I paid for the whole tire so I might as well use it all once in a while." Just be smooth!:thumbup

IKan
 

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Discussion Starter #13
Well I bought an ECU and then that night Canada Post went on strike!:cursing :sad
So I do not have it yet.


Went on a trip to Pennsylvania with the GSXR750 this past weekend (3 day trip) and put on 1,000 miles (1,600 km's). Probably never revved it over 7,500 during the trip. Bike worked flawless but when I returned I revved it up and it still will not rev beyond approx. 12,000 (maybe it was 11,500, 11,600... as the tach readout depends on how fast I am accelerating).

Roads #44 and 666 where great. Make sure you have a full tank of fuel for 666 as it is almost 100 miler long through the forest. Both have more than enough curves, twisties, blind turns, undulations, rollies, steep hills... next to no traffic on Saturday and minimul shoulders.:biggrin


Ride on

IKan
 

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Discussion Starter #14
If ECU doesn't fix it then I guess I will remove & clean the fuel injectors, like POCAr did.

IKan
 

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Hey, have you found the problem to this as I'm having the same problem with my K5 600 and it'd be good to see what you've found?
 

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Smashin
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bump

I was kind of interested to see what this prob was???

Did you finally get your ECU in the mail and took care of the problem and that's why we haven't heard from ya? You been out rubber to the road, too busy for gixxer.com?!?! haha j/k but I would like to know what this was??
 

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Nazi Lustful Faggot - hot for Hermann Göring & Cai
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The clutch switch will not cause the engine to stop revving every time at, or near, the same rpm as I understand it. Typically it either works or does not.
Shorted clutch switch makes ECU switch to another map with lower redline.
 

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Discussion Starter #19 (Edited)
I appologize for not being here for a while as I got frustrated and just decided to ride the 2003 GSXR750 until it broke. Well it never broke (stopped). 15,000 kms later!!!

No I have not fixed the problem! GRRR.

Last year I installed:
- new battery
- used ECU
- new spark plugs
- new air filter
= Not fixed.

Tested with an ohmmeter and voltmeter all the sensors and switches per a Haynes repair manual.
No fault codes have ever appeared.


This past month:

Installed a new:
- main throttle position switch
- new fuel pump/filter/regulator assembly.

The local dealer is stumped also. Dealer checked the fuel pressure prior to me replacing the pump assembly. They said the pressure was 38 psi and should be 43 psi.. However, they said their guage was not calibrated and could be off a bit.

The dealer checked some peak voltages. Said the crank position sensor was ok. They suggested I inspect it for metal accumlation as it is a magnet basically and runs in the motor's oil. I am in the process of putting it back together after removing the CKP, crank position sensor. It had some black sludge on it and some fine metal filings which is supposed to be normal for a bike with 61,000 kms (approx. 36,600 miles).

However, I never checked the CKP air gap before I removed it. The manuals I have read all say to just install it. The dealer does not know what the air gap should be as they mostly work on cruisers and say that most sportbikes they know are written off my 16,000 kms (10,000 miles). There is some play in the mouting plate of the CKP so the CKP could be mounted so it touched the gear wheel or have a gap greater tha 0.040". I guess I will set it at around 0.016" - 0.020" !?!?! I read all kinds of air gaps online for different kinds of motors (bikes and cars).

The fuel system is spotless clean and always has been. The bike is spotless clean. Everyone always says so.

I removed the fuel injectors the other day. They look good and open and close ok with 12 volts. The fine copper coloured screening in the intake side of each injector looked clean when I used a magnifying glass and a flashlight. I checked all the fuel lines. No leaks and not a dust bunny to be found.

Trying Seafoam fuel cleaner. Lots of it in tank!!! to see if it will clean the injectors if they are varnished but I do not think that is the problem.

Presently, in any gear when riding or in neutral on or off the side stand, it seems to rev and operate normally until about 9,800 rpm to 10,200 rpm. Then it almost stops revving higher. It sputters but does not make any unusual noises. It is like it is running out of fuel!! So the dealer thinks and I tend to agree.

If I hold the throttle open it will chug up to about 11,000 rpm max after a few seconds but never any higher. It will run like a clock at say 9,500 rpm all day long. I would never know there was a problem if I never revved it up.

I have noticed no change in fuel mileage. I have done some 700+ km day trips.

I am lost with this problem and it is starting to cost money trying new parts. It all started when I started it after a few months sitting in the garage after a winter (2 winters ago).

This is like a soft cutting out, not like a dedicated precise rev limiter kicking in. I know what that feels and acts like from when the bike worked properly the 1st few years and from how my '08 CBR1000RR rev limits.
 

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Discussion Starter #20
I recently was at a local authorized Power Commander dyno shop in town and he said that a dealer from another city had phoned him because they had a 2004 GSXR that would not rev over 11,000 and could not determine the cause.

This is appearing to be a some what common problem of GSXR's!?!?!
 
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