Bike won't idle correctly

[Charlesbusa]

This is the same problem as my orginal post .  I decided to update and summarize everything in the hopes that someone can help with the problem.  I'm hurting on cash, so I'm trying to do everything I can before having to take it to a shop.

The problem started on July 23rd;

1st) The bike is hard to start.  It takes 3-10seconds of holding down the start button.  In that time, the bike fires a few times but doesn't stay running.  Finally it stays running, but idling bogged down around 900-1000rpm(1500-1700 fast idle).  After 10-15seconds of running, the rpms increase to proper idling speed 1100-1200(1800-2000 fast idle).  Even after the bike is at temp., the idle doesn't jump any higher.

2nd) After riding the bike for at least 5 miles, the idle runs at 1500-1600 rpm(2200-2400 high idle).

3rd) The fuel pump makes a strange noise when you turn the key.  There is the normal high pitch, but accompanying the normal high pitch is another sound.  The fuel pump was replaced a couple months ago and only has a few hundred miles on it.

4th) One time that I have noticed, when the bike was getting hot and the fan kicked on.  The rpms dropped by 500rpm.  As soon as the fan stopped, rpms jumped back up.

5th) The bike is hard to start cold, warm and hot.  Hard to start with or without fast idle.

The bike;
2002, 42,000miles, full yoshi pipe, bmc air filter, and a pc3r.

Attempted fixes, none worked;

1)Checked charging system by putting a multimeter accross the battery at 5,000rpms per manual.  Checked OK. Also put a different battery in, idle still messed up.

2)Replaced spark plugs.

3)Removed air filter.

4)Disconnected pc3r for a week.

5)Opened gas cap while starting and while idling.

6)Checked and rechecked electrical, fuel, vacum lines.



Any other ideas?



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[Aquaman]

Charles,does the rpms drop the 500 everytime the fan kicks on?If so,this may mean that power to run the bike (ignition/spark) which needs 12 volts for electronic igniton to fire properly is being robbed.
when it dropped in rpm,did it pop out carb or exhaust?
I know you said you checked the battery,but do you have another known good one (perhaps a friends) that you can stick in there and try?

 

[Charlesbusa]

Charles,does the rpms drop the 500 everytime the fan kicks on?If so,this may mean that power to run the bike (ignition/spark) which needs 12 volts for electronic igniton to fire properly is being robbed.
when it dropped in rpm,did it pop out carb or exhaust?
I know you said you checked the battery,but do you have another known good one (perhaps a friends) that you can stick in there and try?

Its only happened once that I've noticed.

Not sure what you meant by popping out carb or exhaust.  There was no backfire if that's what you meant.

I did try another battery as well as checking the charging system.  Still has the same problem.



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[Aquaman]

Yes,I was talking about backfiring.Then,and I'm no expert,but it almost sounds like a timing issue,but it could also all go back to that fuel pump thing.
Are you sure that the other one that you got was a good one?
It seems strange that it makes that funny noise you talk about..
I hate like hell to do this to any member,but if you do still think that it is the fuel pump still,maybe you can talk to board member Andymann66.
He has a lot of used parts he sells. If he has one,see if he can 'consign' it to you to try,using my name as a guarantee that if it doesn't work,he gets it back.

I have dealt with him,and I know this man trust me fully and I would personally pay him for it if somehow you decided to dissappear off the face of the earth,which I dont ever believe would happen.

The reason I suggest this is because I know you are short on money, and you find out that this is not the problem,you dont have to eat it.
It just could be that the one you bought is 'F'd' too.

 

[Sloto200]

i wonder if it could be some strange issue with either the voltage regulator or stator...

 

[Charlesbusa]

Yes,I was talking about backfiring.Then,and I'm no expert,but it almost sounds like a timing issue,but it could also all go back to that fuel pump thing.
Are you sure that the other one that you got was a good one?
It seems strange that it makes that funny noise you talk about..
I hate like hell to do this to any member,but if you do still think that it is the fuel pump still,maybe you can talk to board member Andymann66.
He has a lot of used parts he sells. If he has one,see if he can 'consign' it to you to try,using my name as a guarantee that if it doesn't work,he gets it back.

I have dealt with him,and I know this man trust me fully and I would personally pay him for it if somehow you decided to dissappear off the face of the earth,which I dont ever believe would happen.

The reason I suggest this is because I know you are short on money, and you find out that this is not the problem,you dont have to eat it.
It just could be that the one you bought is 'F'd' too.

Thanks.

The strange noise makes the fuel pump suspicious, but its practically new. Unless some kinda crap in my tank has clogged this one.

I was really hoping it wouldn't be, because of the cost of fuel pumps...

I might try your cosign idea. Just trying to elminate other possibles first.

 

[Charlesbusa]

The other thing is;
When my orginal fuel pump went the bike idled normally. It just didn't deliver enough fuel under heavy load and high rpm to get the busa to redline in 3rd and above.

The new fuel pump doesn't have this problem at all. Haven't gone to a dyno(costs $$), put it pulls hard all the way to redline.

BUT, the strange noise is/was present with both fuel pumps...

 

[PACIFICBUSA]

Have you tried changing out your injectors and/or injector screens? Sounds like they could be the culprit.

If the fuel pump is working like a champ, but you still have idle problems, try checkin your fuel rail for any defects or loose connections.

There is also a possibility that your ECU may be starting to conk out.

Another possibility is that your voltage regulator may be headed to the crapper too.

Other ideas...other ideas....hmm...


Triple check those vac lines. Plug one end and put pressure through it to be sure that there are no leaks. Don't ballon the thing, but do try and put a substantial amount of pressure to be sure that there are no hairline fissures along the length of the lines.

Have you tried synching your t-bodies yet? Perhaps they are out of whack. Another area to check would be your butterflies...it's a long shot, but could there be a possibility of one of them being outta synch with rest?

Cross your fingers on this one...cause this may be the doozy:

Are your valves and valve stems still in good shape? Are they burnt? Are the tappets spaced out correctly and do the valves perhaps need to be shimmed?


Just tryin the shotgun approach here, Chuckster...I really hope we can get to the bottom of this.

TDC miscalculations/adjustment could possibly be a factor, but from the sounds of it, I don't think we need to worry about that yet.

If worse comes to worse, you have my number. Give me a call so I can listen to it to get a better idea to base my guesstimations on.

We'll get to the bottom of this...I'm sure.

 

[Charlesbusa]

Thanks Pac!!

Bunch of new ideas to try.

I'll start with the fuel injector screens, where are these. Can I take them off and clean them??

 

[Charlesbusa]

This morning when I was starting the bike it took longer than normal and,

I noticed the FI light falshing on and off.

A ha, is there an error message in the CPU now that can be pulled out??

What do you guys think??

 

[Charlesbusa]

 

[Charlesbusa]

For $33 the dealership pulled out the error code from the cpu.

Throttle position sensor out of alignment.

Man, I hope this is the end of the problems... please please let this be it...

Anyone ever mess with the throttle position sensor?? I looked at the service manual and it looks like you need a special tool to adjust it...

 

[Sloto200]

 

[Charlesbusa]

Paid $66 for the dealer to adjust the TPS(throttle position sensor).

The mechanic said the TPS was way out of adjustment.  I asked him how it would do that all of a sudden(3 weeks ago) and he guesses the springs on the throttle bodies have lost some tension.  

It does start better now. The TPS was definately the major problem.

but

it still has a 300rpm difference between hot and warm.  And it drops around 300rpm when the fan kicks on.  I'm hoping sync the throttle bodies and checking valve tappet clearances(shim if needed) might fix the rough idling... Or maybe my bike is just gett'in old...

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[Johnnycheese]

FI light should not come on if TPS is out of adjustment,( I have gone to both extremes and never had a FI light. Did the bike run good before the light?

 

[Busa Bill]

Well what did you find out . I would like to know . something sorta like that happend to me also.

 

[Charlesbusa]

Part of the fuel pump fell off inside the tank, here's the fixed thread

 

[Busa Bill]

Cool ..Glad you got it fixed bro...

peace