IAPS woefully overpriced???

[OB_Dennis D.]

{{{NOTE: My original post was unreadable.}}}

I phoned a few Suzuki Dealers for a price check on the IAPS . . . $225 - $241!!! Wow, Numbnuts was right. Unbelieveable. Is this part made out of gold???

I previously posted a request for info on the IAPS, but did not receive a reply from any other members. I will ask once again.

What is the spec for this sensor's output range in terms of an electrical signal to the ECM. I did a crude test of my IAPS the other day with engine running. At idle (1150 rpm) output is 2.45V. At fast idle
(~2500 rpm) measurement increased to 2.60V,
only 150mv difference. Is this normal?

I know the sensor is working as pulling the vacuum hose off caused the engine to stall
or run EXTREMELY rough at higher rpm. Once replaced, engine again runs "normal", off idle stumble notwithstanding.

Factory set TPS too high, so I adjusted it
back to recommended setting. Didn't really help get rid of the stumble . . . maybe a little better, but generally still evident.

Did I hear right? Numbnuts, who apparently had the same stumble in a Y2k Busa, said
plugging the PAIR line solved the problem.

comments, opinions, recommendations anyone?

 

[OB_Dennis D.]

Please post any and all suggestions. I am still stumped about the stumble. It does not seem to be spark or fuel related, but I'm not sure what is the cause. I think it affects a lot of bikes out there, but a lot of other owners are playing down the problem or just haven't noticed it.

Sonic, I will adjust (tighten) the chain today as per your sugestion. When I checked your engine at a fast idle last weekend at Alice's, I could immediately tell your '00 stumbles too, right around the same range as mine, 1500 to 2000 rpm. Since your bike is bone stock, and manufacture date only one month apart from mine (3/00 vs. 2/00), I am still suspicious that something the factory did (or didn't do) is causing the stumble.

Numbnuts, I recently re-gapped all my plugs to 0.030". I will take your advice & try 0.031" and make sure they are torqued down nice and tight. I still don't understand what you mean by "APS"? Is there another pressure sensor (as in ABSOLUTE outside air pressure)? Where is it located?

My personal feeling is that the stumble may be something vacuum control related and/or the ecm just not calibrated precisely right (by the factory and a PC-II may not help).

Appreciate the feedback and will spend some more time this weekend tinkering.

[This message has been edited by Dennis D. (edited 19 August 2000).]

[This message has been edited by Dennis D. (edited 19 August 2000).]

[This message has been edited by Dennis D. (edited 19 August 2000).]

 

[OB_NumbNuts]

you dont have a manual do you??

APS is Air pressure sensor. screwed to left hand side, inside of frame. NOT te one with the mitsibishi logo on, the one SCREWED to the frame. On the underside of that is a sensing tube (very similar to IAPS on back of air box) I attached a long tube to this. Started engine and sucked and blew a fair few times.....Engine runs smoother, engine runs rougher, engine runs smoother..etc.

THis obviously is a base line reference for the IAPS to calibrate by. change this and it alters everything, especially fueling. So I presumed either my IAPS or APS was a little blocked. Changing plug gap and retorquing made a world of difference for me.

Nuts

 

[OB_NumbNuts]

Dennis

take spark plugs out, regap to 31 thou inch and retorque.

I'll get you the IAPS spec later, but manual is in the workshop and I just got up!!!

Pluging PAIR line didn't change the idling.....Just wanted to try it. Have reverted back to open now.

I have TPS set at 1.2V at idle (spot on the 1krpm mark on the dial) have you blown and sucked on the tube for the APS ?? (you need a long tube!!) Try it with engine running.....weird eh??

will post them specs later

Nuts

 

[OB_bruce]

Pluging or removing PAIR will I am afraid make no differance all this will do is stop popping on the overrun with a full exhaust or end cans.

 

[OB_Sonic Boom]

Hi Dennis. The only thing that has worked for me, or made it bearable, is adjusting the drive chain just a tad tighter than recommended, and doing so fairly often to minimize the slop.