07 Busa With Rough Idle And Hanging Revs

[Shaun Ketterman]

Have you done a throttle body sync yet,,,

Yessir, I've done 3 so far. The problem I've had with the TB sync is the idle is pretty rough, and the gauges on my CarbTune Pro 4 are *sorta* all over the place, making it difficult to even them out. I can sync up TB's 1 and 2 so that the levels are very close together, and after a few seconds, with the idle all funky, the levels separate again. Same thing with 3 and 4. It's like I can line them up, but only temporarily, as they just seem to alter themselves after a few seconds.

After removing the air box, I do reconnect the green connector on the left side of the box, as well as the (I think) black connector on the back of the airbox that is screwed on. I leave the two vacuum hoses near the back right side of the box unconnected, as well as the smaller hose on the bottom of the airbox.

I tested all the vacuum hoses for leaks by spraying TB cleaner on the connection points and listening for changes in the idle. Didn't notice anything at all, and I've confirmed that they are all connected up properly.

 

[David Offor]

Are you blocking off the vacuum pipe from the VTV on the left throttle body (no. 1) take off point, when connecting your gauge?
Have you made sure that you don't have leaks on your actual vacuum gauges?
Fuel coming out of cap under load, could point to a blockage in the tank.
Hesitation under load/high rpm points to coils or lack of fuel, when the bike demands fuel the most.
Has the cam timing been checked or tensioner changed, slack/loose timing chain? It would be a good idea, just to start your diagnosis from the basics.

View attachment 1570201

 

[GIXERHP]

While doing the sync, you need to use the second vacuum from 1 and 4 cylinders for the map sensor! That you help stabilize the bad idle

 

[David Offor]

Hi gixerhp.
What do you mean about the "second vacuum from 1 and 4"?
I've always put the gauges on by blanking the VTV hose and using the 4 throttle body take off points, for the vacuum gauges, leaving the single '4 into 1' vacuum hose on the MAP sensor.
I got my new timing chain today, so I hope it's going to solve my own running problems, I've run outa things to try lol.

 

[Shaun Ketterman]

Are you blocking off the vacuum pipe from the VTV on the left throttle body (no. 1) take off point, when connecting your gauge?

I don't think so. TB's 1 and 4 each have 2 nipples. I use the right/inside nipple on TB # 1 for the sync. The left one goes beside the TB/fuel rail against the fairing and toward the back of the bike, plugs into a sensor under the tank. I also use the right/outside nipple on TB # 4. The inside one is attached to another sensor behind under the tank.

Has the cam timing been checked or tensioner changed, slack/loose timing chain? It would be a good idea, just to start your diagnosis from the basics.

Not since I've owned it, but I can add that to my list of chores.

While doing the sync, you need to use the second vacuum from 1 and 4 cylinders for the map sensor! That you help stabilize the bad idle

I think I know what you mean. [See my reply a few lines up to Daved] The 2nd nipples on TB's 1 and 4, on my bike, are already connected to sensors that are under the tank. Should I disconnect these 2 lines and use a 'T' connector to run them together and then to the MAP? Or is it okay to leave them as they are?

 

[David Offor]

I know that the gen 1s went up to 07, so I'm guessing we have the same set up, mine is a 2000, this is how I connect up my gauges, I leave the airbox connected to the side of the bike for the atmosphere sensor and vacuum connections (loose in the photo).
I stand corrected, if I'm syncing mine wrong .
Do you still have the exhaust gas paired contraption attached?
P.s excuse the state of my bike, I'm in the process of fitting a new timing chain.

 

[Shaun Ketterman]

I know that the gen 1s went up to 07, so I'm guessing we have the same set up, mine is a 2000, this is how I connect up my gauges, I leave the airbox connected to the side of the bike for the atmosphere sensor and vacuum connections (loose in the photo).
I stand corrected, if I'm syncing mine wrong .
Do you still have the exhaust gas paired contraption attached?
P.s excuse the state of my bike, I'm in the process of fitting a new timing chain.

Ah! So here we see it now! Your bike and mine are different! You have TWO nipples on EACH throttle Body, where I have two nipple on ONLY Throttle Bodies 1 and 4! My bike IS an 07, so it looks like there were some changes. With any luck, someone with some photos of another 07 could chime in and validate that mine is factory.


Here is how my vacuum lines look normally:

Then, in order to perform a Throttle body sync, I disconnect w/x/y/z, while keeping connections A and B as they are, as shown here:

Finally, here is a photo of my gauge connected:

The back of the airbox has TWO rubber hoses (one on the rear-right corner, and another about 6 towards the center). I disconnect BOTH of these when performing a sync. There is also a 3rd hose, very skinny, runs under the airbox and connects to a circular fitting. This one I leave disconnected as well.

There are also two connectors - one is green in color, it attaches on the left side of the airbox and is screwed in, the other has a phillips-head screw that connects it to the back of the airbox itself (Connects to vacuum line C/D in my 3rd photo above). I disconnect both of these in order to remove the airbox, then I sit the airbox on a chair next to the bike and RECONNECT both connectors.

While doing the sync, you need to use the second vacuum from 1 and 4 cylinders for the map sensor! That you help stabilize the bad idle

Now, it seems that GIXERHP, in post #23, was suggesting that I take connection A and B in my photos, and connect them together, along with hose C/D to the maf/map (presumably with a "T" connector), but I would *really* like them to clarify this!!

I hope this all makes sense! You guys are the best!


Shaun

 

[David Offor]

Ok, now the confusion is clear.
On my bike and I presume yours, it's important that the IAPS (map) is connected to all 4 cylinders for syncing.
Leaving the airbox on a chair connected is fine.
I imagine that no. 4 hose that you are leaving connected, is to the VTV (if so, I remove it and shove something in the hose) the vacuum on no. 1 is a mystery to me, I'm afraid but I'd do the same with this one too, remove and blank but it's important to know what sensor it goes too.
This is how I'd connect up your bike to the gauges, given the information you've supplied and how I understand your setup but you should never presume about this type of procedure, maybe gixerhp will be able to shed some more light on it.

 

[RansomT]

If it was my bike, I wouldn't do anything until the valve clearances were checked.

 

[sixpack577]

If it was my bike, I wouldn't do anything until the valve clearances were checked.

A Busa with 100k+ miles on it has a 99% chance of all the valves still being in spec.
And even if they were out, you wouldn't notice it, before or after a shim change.
It wouldn't cause the problems they are having.

 

[Shaun Ketterman]

Ok, now the confusion is clear.
On my bike and I presume yours, it's important that the IAPS (map) is connected to all 4 cylinders for syncing

I don't know how I can get all 4 cylinders connected to both the gauge and the IAPS. I have a bunch of T fittings, maybe I can rig something up....but:

I imagine that no. 4 hose that you are leaving connected, is to the VTV (if so, I remove it and shove something in the hose) the vacuum on no. 1 is a mystery to me, I'm afraid but I'd do the same with this one too, remove and blank but it's important to know what sensor it goes too.

Just want to clarify here - should I utilize those secondary fittings on cylinders 1 and 4 to connect to the IAPS, or should I just disconnect the lines from them and plug them up?

This is how I'd connect up your bike to the gauges, given the information you've supplied and how I understand your setup but you should never presume about this type of procedure, maybe gixerhp will be able to shed some more light on it.

Yeah I see what you mean here, but again, getting all 4 cylinders on the IAPS could be a pain. I think what GIXER was saying previously was to utilize cylinders 1 and 4 secondary fittings, connect them with a "T", and run that to the IAPS. I'm going to give this a try when I get home today, see if that calms the idle down. If it is still really rough, I'll see what I can do to get all 4 on the IAPS along with the gauge.

FWIW, I've read a ton of threads on this (both here and on various other forums) with contrasting views on whether or not out-of-spec valves will effect a proper TB sync. Obviously I don't know either way, but I am going to have my valves checked/adjusted as needed (mostly for peace of mind at this point).

New fuel pump, injector rebuild kits (and hopefully the motion pro injector cleaner tool) will all be here by Friday, so pulling the tank and getting all this stuff torn apart, cleaned, replaced, etc will be my weekend project. I might just need a miracle to get it done properly ;-)

Shaun

 

[David Offor]

That's very true, mine had been terribly abused, from provirus owner, first oil change, oil came out like thick black tar, never seen anything like it, with 40k miles but valve clearances were still within tolerance.

 

[David Offor]

I don't know how I can get all 4 cylinders connected to both the gauge and the IAPS. I have a bunch of T fittings, maybe I can rig something up....but:



Just want to clarify here - should I utilize those secondary fittings on cylinders 1 and 4 to connect to the IAPS, or should I just disconnect the lines from them and plug them up?



Yeah I see what you mean here, but again, getting all 4 cylinders on the IAPS could be a pain. I think what GIXER was saying previously was to utilize cylinders 1 and 4 secondary fittings, connect them with a "T", and run that to the IAPS. I'm going to give this a try when I get home today, see if that calms the idle down. If it is still really rough, I'll see what I can do to get all 4 on the IAPS along with the gauge.

FWIW, I've read a ton of threads on this (both here and on various other forums) with contrasting views on whether or not out-of-spec valves will effect a proper TB sync. Obviously I don't know either way, but I am going to have my valves checked/adjusted as needed (mostly for peace of mind at this point).

New fuel pump, injector rebuild kits (and hopefully the motion pro injector cleaner tool) will all be here by Friday, so pulling the tank and getting all this stuff torn apart, cleaned, replaced, etc will be my weekend project. I might just need a miracle to get it done properly ;-)

Shaun

See if you can test your pump pressure and injectors, before pulling your bike pump assembly and stripping, if your pump pressure is good, during priming, cranking and engine running, Then don't fit the new pump yet, avoid unnesassary work, a valve clearance check is fiddly but once the cam cover is off, it's ok, removing the plugs will make it easier to turn the engine over, to get the cams in the right position.
You need all cylinders linked to the IAPS, to send the correct vacuum readings to the ECU, if they are not all connected the ECU will read incorrect information.
From what I understand from your set up, you will need 2 T pieces (for 2 and 3), use 1 of the nipples on 1 and 4 for the vacuum gauges and the other nipple (s) for the pipe to the IAPS.
Once you get your head around it, it will all make sense but remember to blank off and vacuums that are left disconnected.

 

[Shaun Ketterman]

You need all cylinders linked to the IAPS, to send the correct vacuum readings to the ECU...

Ran a sync using this setup, idle was still choppy (it was low, like 1k RPM. I had to open the fast idle up a bit, but I got them all a lot closer. (Video will be up later).

So now? Idle is horrible! The bike sounds like a harley almost, mixed with a helicopter. The whole bike seems to shake, and it seems as if the gauge is showing the wrong RPM. It shows it idling around 1200 but sounds and feels like it's at 800.

Incidentally, throttle response seems to have improved dramatically.

What is up with this bike? Ill he double checking all my connections but Im confident they are correct. I may go back and try gixerhp's recommendation, see what difference that makes.

 

[David Offor]

Are all cylinders firing? Pull the coil plugs off one at a time and see if the engine speed/sound changes.
Are you getting any puffs, back out of the throttle bodies?
Did you run a fuel pressure/injector test?
It really does sound like a fuel issue to me but I'd never presume.
We have a slightly different set up, so maybe I'm not the best one to go by.
It will be interesting to see and listen to a good video upload, I've found the only way I can upload, is to save it on YouTube, then copy and paste the YouTube link in the message window on your thread.

 

[Shaun Ketterman]

A Busa with 100k+ miles on it has a 99% chance of all the valves still being in spec.
And even if they were out, you wouldn't notice it, before or after a shim change.
It wouldn't cause the problems they are having.

Hey six, thanks for chiming in. Going to have the valves checked tomorrow, and adjusted as needed. Really it's for peace of mind. This bike, I believe, was abused in a previous life, so I'm just assuming it needs everything looked at.

See if you can test your pump pressure and injectors, before pulling your bike pump assembly and stripping, if your pump pressure is good, during priming, cranking and engine running, Then don't fit the new pump yet, avoid unnesassary work...

Sound advice! I fully intend to test the pump prior to doing anything, I just need to figure out what tool I need. Suggestions?

Are all cylinders firing? Pull the coil plugs off one at a time and see if the engine speed/sound changes.
Are you getting any puffs, back out of the throttle bodies?
Did you run a fuel pressure/injector test?
It really does sound like a fuel issue to me but I'd never presume.
We have a slightly different set up, so maybe I'm not the best one to go by.
It will be interesting to see and listen to a good video upload, I've found the only way I can upload, is to save it on YouTube, then copy and paste the YouTube link in the message window on your thread.

So before I even did anything else, my first task was to resync the TB's with the method suggested by GIXERHP, and this actually brought the bike back to normal. So what I guess we need to begin circulating through the Org is that 1st gen Busa's can come with 1 of 2 variations of TBs, and the type you have determines the correct way to sync them up. So for my setup, I disconnected the VTV from cylinder 4, as well as the unknown line from cylinder 1, connected them together with a T fitting, and ran the 3rd connection on that T to the MAF/MAP/IAPS (this thing, BTW, is officially known as a "boost sensor").

When I began syncing using GIXERHP's method, my throttle bodies were WAY off. Horribly off, which explains why the bike had such a horrible idle...so we know for certain that connecting all cylinders to the MAF/Boost Sensor with my setup is not correct. Once I leveled them all out, my idle did the same, I didn't have to adjust anything except the TB's themselves. Idle is still funky though, but the power delivery, particularly in the low end, feels a lot smoother now (as does shifting, strangely enough).

To answer your other Qs:

-I will pull the coils tomorrow evening, as I do still want to test this.
-There were no puffs or anything coming out of the throttle bodies
-Fuel pressure test - no, but I need to, just need to know what tool to use?
-Injector test - no, but I have a motion pro tool on the way to do just that

So as I sit now, the bike is idling funky still, but it's back to 'normal', or how it was when I bought it, which is much better than how it was earlier today. Power delivery has smoothed out a bit in the low end, still getting power loss/bucking in higher RPMs. Valve check and adjustment is happening tomorrow morning (by a Suzuki authorized dealer, $430.00 for a full adjustment, less if adjustment not needed).

This weekend I hope to have all the stuff needed to clean and rebuild the injectors, test them, test the compression, test the pump at prime/start/idle, and replace the pump if necessary. Fun times!

Shaun

 

[David Offor]

It sounds like you are making progress and learning a lot about your bike, I'm sorry that the things you could try yourself, haven't avoided a dealer visit, I posted a link on a method to test your pump pressure and check your injector spray/squirt, on page 1 of this thread.
Hope you get some success soon

 

[Shaun Ketterman]

It sounds like you are making progress and learning a lot about your bike, I'm sorry that the things you could try yourself, haven't avoided a dealer visit, I posted a link on a method to test your pump pressure and check your injector spray/squirt, on page 1 of this thread.
Hope you get some success soon

Thanks for all the input David. BTW - what size fitting / adapter do you use for the compression test? I see test kits with various adapters (10mm, 12m, 14mm, etc). Wanna make sure I get the correct size the first time. All the videos Ive seen so far show how to properly test, but neglect to speak about proper tools

 

[David Offor]

Hi Shaun.
The adapted for the plug hole is 10mm, we made our own one, hence the 9.79mm reading (it's possible the actual size is 3/8 imperial but I'm not 100% sure), if you do make one, make sure it's not longer than 15mm (don't want a piston clouting it).
Clamp the clutch leaver in with a cable tie and wedge the throttle wide open, also, disconnect the fuel pump (stops fuel pumping while cranking), remove all plugs (less drain on the battery and will give a reliable reading), I crank for about 5-6 revolutions, to get the highest figure.
Another thing, depending on the Union/plug hole adapted, make sure that you don't screw it in the plug hole too tight because sometimes it can catch/go tight and your hose will turn on the adapted, making it a pain in the neck to remove (I speak from experience lol).
I make up all my own testing tools from bits and pieces but they are reliable.
The pressure gauge and unions in the photo are easy to adapt to do different tests, at the moment, it's set for a 'leak down test', hence the plug adapted and airline blower.

 

[GIXERHP]

I know that the gen 1s went up to 07, so I'm guessing we have the same set up, mine is a 2000, this is how I connect up my gauges, I leave the airbox connected to the side of the bike for the atmosphere sensor and vacuum connections (loose in the photo).
I stand corrected, if I'm syncing mine wrong .
Do you still have the exhaust gas paired contraption attached?
P.s excuse the state of my bike, I'm in the process of fitting a new timing chain.

View attachment 1570211

The newer bikes only have dual nipples on cylinders 1 and 4