electronic high pitch tone when boosting st165 (halleluja)

Ok so heres the deal. Whenever I hit boost theres this high pitch tone, similar to a warning tone that start emitting somewhere in the driver side dash area. It seems to change its pitch at differing boost levels which points to it being tied into the PIM sensor off the map sensor which feeds the boost signal to the factory boost gauge via a variable 5v signal. It is not rpm or speed dependent either. purely boost depending as i can willingly change the pitch by laying off the gas pedal and on it again.

I have not yet tried disconnecting the PIM signal but may do that today before work just to double check.

At first I thought it may have been some kind of silly after market system which just alerted the driver of boost... perhaps a warning tone which was set all the way down to 0 PSI in order to prevent on of the two previous owners from going fast/speeding? lol

However last night...

... I was going over the st165 wiring diagram (for the 100th time) and I took special notice to something wired into the gauge cluster after the factory boost gauge. Its a square box with TURBO INDICATOR written on it Ive notices this before but didnt think much of it. So NOT being a newbie i searched for it "turbo indicator" and all i came up with was a post listing the differences between jdm and usdm st165 ecu's (one difference is that the JDM ecu has a turbo indicator LAMP TIL which is shown in an ecu pin out diagram to be on the pin out right next to the SPD pin out on the 24 pin plug AND this is not shown on the EWD for the usdm diagram ive been referencing).

My question is what the heck is that TURBO INDICATOR in the gauge cluster, which wired in after the boost gauge? Could this be where my high pitch variable tone is coming from?

Im hoping someone has an answer other wise i have to pull out my vac/pres pump and trick it into thinking the car is boosting as i disassemble the dash areas to track down this pesky electronic tone.

Super thanks in advance

You got a good one there ... I've never heard of that one ... no lights or tones on mine .. just the gauge ( which looks kewl , but is useless :rofl: ) let us know what ya find please ... very curious ... :smokes:

You stated that you put a boost gauge in. Do you recall hearing
A noise after you put it and got louder? For shits and giggles pull the
PIM vac and plug it and run it and see if noise is still there. Let us
know and we can only try our best good luck bro!

MD. Celica":22bgsysg said:

You stated that you put a boost gauge in.

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nope no after market boost gauge just the inaccurate factory one.

could it be the water pump for your wta ic making the sound and it seems like its in the dash? im probably way off but its just an outside thought;

UPDATE:

Well hummmmm. I disconnected the PIM signal and my factory boost gauge was not working AND I STILL GOT THE G.D. TONE argggg lol

Ok so heres the deal. the st165 has a st205 motor in it... I did all the work including the wiring. The only wires which interface with any part of the st165 off of the st205 wiring loom are the power lines feeding the key switch and the wires off the II1, II2 IJ1 plugs. These are the three plugs off the st 205/204 which DONT get plugged into the ECU or COR but are on the same end of the harness and interface with the car.

(I might also note that im pretty handy with wiring as much I hate doing it. Ive done an st205 into an st204, dealt with an 2nd gen 3s in an st165 and st204, rewire a 77 motorcycle and a 67 el camino just to name a few recent.)

The corresponding plugs or rather plug on the st165, as there is only one (two on the st185) is a 20 pin plug that interfaces with the things in the car.

These are the items which are interfaces into the st165 from the st205 harness

To ecu from gauge cluster speed sensor signal
From fuel pump relay to fuel pump
L off of the alternator
IG off of the alternator
Oil pressure switch to gauge cluster (oil pressure gauge)
ECU to warning light (CEL light)
Water temp sensor to gauge cluster (water temp gauge)
PIM to gauge cluster (boost gauge)
Ignitor to gauge cluster (tach)
brake signal to ecu
starter signal to starter relay
from the reverse light switch on the trans
to the reverse light switch on the trans

Yes i have double check all of my wiring and the car does drive properly with now CEL's

Im assuming that the electronic tone is from an after market something somewhere in the dash probably hidden really well. I had to pull and de-wire a turbo timer, after market alarm, and after market window control unit which had been installed by either of the previous two owners.

The noise is fosho coming from the dash area on the driver side. And thus must be something that interfaces with the plug... Since ive disconnected the PIM signal im thinking of trying other things which build up pressure (non rmp dependent) and feed a signal back into the car... Perhaps the oil pressure signal.

Ill get back to you folks.

So ive tried disconnecting the signal going to the tach as well as the oil pressure gauge and the tone is still there.

So now the problem is i have to look for it while accelerating fast cus thats the only time the tone goes off. Im going to see if i can find the number of the guy i bought it from who use to rally cross it and see if he knows what it is.

So i pulled the gauge cluster totally out and the tone was still there.

Not sure what it is now... its hard to tell what part of the driver side area its coming from but im beginning to think that it might have something to do with the door chime/key still in the ignition chime.

This is a stretch but i might try to disconnect the integration relay 1 as i think thats where the door chime thing is. ill have to see tmw.

update:

pulled the intergration relay box #1... door chime stopped but the tone did not.

I have no idea where this tone is coming from or how/what signal its reading, although it seems connected to the boost pressure, of which ive already disconnected the PIM signal into the car/cluster.

the problem is it only comes on when im driving and its too high pitched and hard to tell where its coming from.

AHHHH lol i hope i figure this out soon

Anyone have any ideas

This has me very puzzled ... keep us posted

Woooo so pretty much disconnected every plug off of junction box 1 except for the fuel pump wire (L-B) and the lines to and from the key switch... and the tone is still there.

Short of taking the dash off ive taken everything else off and still cant see any type of aftermarket box or what have you.

another friend and car guy, who also use to be a toyota tech not to long ago as well as being a 1st 5th and 6th gen celica guy (engine swaps and other thing) also took a look under the dash and poked around. He is just as puzzled as i am.

The tone acts as tho its boost related but from what i can see, did with the swap theres no way for a boost signal either electrical or pressure/vac wise that should be entering the car other then the PIM signal from the 205 harness, of which ive already disconnected.

On top of all of this the tone must be after market as there isnt anything other then the door chime which would make a tone. Right?

Thats the only thing I'm aware of ( door chime ) I'm shocked that no 205 owners have chimed in here. I mean if this was a 205 thing I'm sure someone would know of it , and If I remember you did a 205 swap in a 4th gen before so I'm sure you would have run into something there ... didnt find anything on a google search of this either .... :shrug:

88gt4DE":1zgw7ksn said:

Thats the only thing I'm aware of ( door chime ) I'm shocked that no 205 owners have chimed in here. I mean if this was a 205 thing I'm sure someone would know of it , and If I remember you did a 205 swap in a 4th gen before so I'm sure you would have run into something there ... didnt find anything on a google search of this either .... :shrug:

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yeah didnt find anything on the google search. and yup im doubting this is a 205 thing since i already disconnected all the 205 stuff that goes back into the car except for the power lines to the key and the fuel pump.

EVEN MORE WEIRD is this.......

.... So evidently, when the tone is on and being annoying (seems to be when i am boosting) IF i step on the brake to activate the brake switch (this is done with my left foot as my rt foot is still on the gas creating boost), THE TONE CEASES its annoying rant. when i let off the brake it continues and thus in stead of the tone being constant i can momentarily turn it off.

so this made me again bust out the st165 EWD to see what that brake switch interfaces with and they are the following

Cruise control computer
Light failure sensor
Brake lights

After seeing this i thought perhaps the Cruise control computer was the one causing the problem (its on rt side of car which is not where the tone seems to be permeating from) . So i went about wiring the brake signal in and out of the cruise control computer in a fashion which would have tricked the computer into thinking the brake switch was active without actually activating the brake lights. It was a long shot and yielded no results.... the annoying tone still comes on and is capable of being silenced by making the brake switch becomes closed i.e. stepping on the brake.

So this tells me that whatever it is, is tapped in passed the CC computer.

Oh and i might also note that i have taken all of the panels/covers below the top dash off now including the center counsel and glove box and have yet to see any after market unit or areas of wiring that look to be worked on/not factory.

:shrug:

Brake booster leaking? and whistling? its tucked behind dash??

MrDB":ozhdryel said:

Brake booster leaking? and whistling? its tucked behind dash??

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Hmmm .. good thought .. wouldnt have gone away with his wiring bypassing though ... keep at it man !!!

MrDB":25nczo3b said:

Brake booster leaking? and whistling? its tucked behind dash??

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yeah i thought about that too but the tone sounds too electronic... however i might just give that a try. At this point , with the interior half apart im running out of options and things to check.

OOOOOOOOMMMMMMMMMMMMGGGGGGGGGGGGG :shock:

It seams as though that was the problem. Tried it this morning, with half the interior apart and the tone didnt even make a sound.

well no shit .... good job man 8)

looks like its a fault check valve for the brake booster.