"Bring engine to boil"....Wait, what!!!!

[bosljeff]

Okay, so I go to turn the key in my ignition, at 'ACC' all is good.

*Problem*
then when I get to 'ON' (just the position in ignition, car isn't actually running/on) and I hear this funky boiling/sizzling sound coming from the area around my intake.

*Symptoms*
I get the stethascope thingamajig and found the sound strongest coming from inside the Idle Speed control/servo (I've heard it called Idle Air control/servo too).

When the car is running, you can still hear it strongest there. The sound "echoes" throughout the TB and intake, but seems to be focused inside the ISC.

*Question*
What in God's name is it?

Ideas? Need more info?

Thank you.

Boz

 

[crankbender]

When you go to on the ISC moves. It may be that you have a bad ISC (do you have any idle problems?). Since it happens before the car is running that is really the only thing that can be causing sound in the intake. I Don't believe your model prims the fuel system but maybe somebody else knows for sure.

All in all if it is just noisy ISC I wouldn't worry too much it is suppose to move only once tho....shouldn't keep making noise. It it only mkes the noise for like 5 seconds after you go to on that is what it should do. It is a stepper motor so it isn't exactly quiet.

might want to tke a look at the ECU when the caps start going it will do really funky things.

 

[bosljeff]

Originally posted by crankbender
When you go to on the ISC moves. It may be that you have a bad ISC (do you have any idle problems?). Since it happens before the car is running that is really the only thing that can be causing sound in the intake. I Don't believe your model prims the fuel system but maybe somebody else knows for sure.

All in all if it is just noisy ISC I wouldn't worry too much it is suppose to move only once tho....shouldn't keep making noise. It it only mkes the noise for like 5 seconds after you go to on that is what it should do. It is a stepper motor so it isn't exactly quiet.

might want to tke a look at the ECU when the caps start going it will do really funky things.

"When you go to on the ISC moves"
Okay, I'll look and see if it is moves into position....

"(do you have any idle problems?)"
No-maybe very, very slight "stuttering" problems when accelerating or simply driving at steady rate.


"I Don't believe your model prims the fuel system but maybe somebody else knows for sure."
(Not being a smartass) I assume you meant 'trims' or is there something new for me to learn?

"shouldn't keep making noise"
It does (let it sit in ON position for 5+mins), in the on position, whether running or not. It doen't make the nose when turned to ACC. I wonder if it is stuck, so to speak, and that is why it is making the sound continually. I'll let you know when I look at it.

"It is a stepper motor so it isn't exactly quiet."
I would have notice before-it may have done it and gone away at one time, but it stays now.

"might want to tke a look at the ECU"
That's what I'm worried about.

Should I get a hold of an ohmmeter or whatever and see if the ecu is sending the right numbers to the isc?

Thanks, we'll see what others say and stuff.

Boz

 

[crankbender]

"When you go to on the ISC moves"
Okay, I'll look and see if it is moves into position....

Don't bother...just when it is making the noise unplug it and see if the noise goes away.

(Not being a smartass) I assume you meant 'trims' or is there something new for me to learn?

Older vehicles use to "prime" the fuel system. This is when the fuel pump would come on even when the car wasn't running. The DSM doesn't do this from the factory. However if somebody did a fuel pump rewire incorrectly yours might.

Should I get a hold of an ohmmeter or whatever and see if the ecu is sending the right numbers to the isc?

First just see if it is the ISC making the noise.

 

[bosljeff]

Originally posted by crankbender

1. Don't bother...just when it is making the noise unplug it and see if the noise goes away.
2. Older vehicles use to "prime" the fuel system. This is when the fuel pump would come on even when the car wasn't running. The DSM doesn't do this from the factory. However if somebody did a fuel pump rewire incorrectly yours might.
First just see if it is the ISC making the noise.

1. I'll go and unplug it right now.
2. Hmm, I just did the fuel pump rewire several days ago, and I checked, rechecked, and checked again to make sure it was done correctly.

What done incorrectly could lead to this funky sound in/at the ISC?

 

[crankbender]

you could have wired the fuel pump so that it comes on whenever the car is in the on position. This will cause fuel to flow through the rail and fpr back to the tank. It can sound like gurgling as it is liquid flowing.

 

[bosljeff]

Turned key to ON position and

Based on the pic in my Haynes manual I just unplugged the "ISC motor and position sensor electrical connectors"...well, I only unplugged the larger rectangular one that comes in horizontally, not the more vertical circular one....

and the sound stopped.

Now what does that mean?

 

[bosljeff]

Originally posted by crankbender
you could have wired the fuel pump so that it comes on whenever the car is in the on position. This will cause fuel to flow through the rail and fpr back to the tank. It can sound like gurgling as it is liquid flowing.

Well, since I added a switch in the middle of the groundwire, I can go and turn off my fuel pump, turn to ON, and see what happens.


*Edit*
Nevermind: turned car to ON, switched fuel pump off, still have the sound.:thumbdown

 

[bosljeff]

I appreciate your eyes crank (and anyone who has viewed this), but don't leave me hangin' people, tell me somethin'.

Am I asking a repetative question, is there something I may have missed in a search?

Sorry to be a burden, I just don't like unusual sounds any more than the next guy.

Thanks again everyone.

Boz

 

[crankbender]

If disconnecting the ISC made the noise go away then it is the ISC....

 

[bosljeff]

*Warning: some horribly childish drawings and poorly worded questions!!*

Is the ISC the coiled thing (circular electrical plug on top) on the side of the TB (Red circle) the motor?

or is it the electrical "thing" just below the coil thing that the rectangular plug goes into from the side (blue circle) Position sensor/electrical connector?

Thanks.

 

[bosljeff]

....then the question I'll have to ask:

where to get, what to expect to pay, and any other stuff a newbie may have to know....?

Before I hassle you crank, or anyone else, is there a vfaq on this, or is this not so common?

Thanks!!!

 

[dsmturboawd]

thats the isc in your drawing. take a ohm meter to your isc to see if its bad first.

 

[bosljeff]

Originally posted by dsmturboawd
thats the isc in your drawing. take a ohm meter to your isc to see if its bad first.

So I do the check in my Haynes? Should I also check the Throttle Position Sensor, or would I only do that if I replace the ISC?

Haynes' steps:
1. Check system. Check for voltage signal from ECU.
Should read battery voltage on one terminal while others read less than battery voltage.
2. Remove motor clean IAC (what is that?).
3. Check resistance of ISC motor
Terminal 2 and 1 or 3 28-33 ohms.
4. Check resistance between terminal 5 and either 4 or 6 28-33 ohms.
5. 6v battery to ISC motor.

Right, wrong, indifferent?

 

[crankbender]

The tps is not powered...IE it can't make noise unless you are moving it.

Just do this. Pull the ISC (IAC is the same thing just different name) and hold it in your hand then have a friend turn the car on...what does it do?

 

[bosljeff]

Originally posted by crankbender
The tps is not powered...IE it can't make noise unless you are moving it.

Just do this. Pull the ISC (IAC is the same thing just different name) and hold it in your hand then have a friend turn the car on...what does it do?

Will do...but,
1. Sorry, but what do you mean pull? Physically pull, pull as in take apart....? Starting to feel stupid.

2. Just pull the gold spring thing out, or do I actually have to take something apart?

3. Have them turn it simply to ON position is enough right? Not necessarily get the car running, right?


Again, thank you very much. I appreciate it.

Boz

 

[bosljeff]

I finally found some pictures to help educate me....

http://dmtalon.v8eaters.com/ISC.html

 

[crankbender]

when i say pull i mean take it off the throttle body....if you disassemble it i would expect it to do nothing when your friend turns the key....

Yes just to on don't start the car...that is when it was making noise correct?

I just noticed that in another post you said it was crackling at the plug....what do you mean. you may just have a corroded plug.

You gotta say these things man we arn't there...

 

[bosljeff]

Originally posted by crankbender
I just noticed that in another post you said it was crackling at the plug....what do you mean. you may just have a corroded plug.

You gotta say these things man we arn't there...

My apologies-I hate it when people expect you all to diagnose from afar.

Like I said in my first post on this thread there is a funky boiling/sizzling sound. It could be called crackling. God this is sounding like a Meineke commercial.

So, no idle problems. I don't seem to have any other symptoms others have posted when their ISC stuff is busted. I have some minute stuttering problems when driving but that shouldn't be ISC related.

I'll be damned, it may be corrosion. I'll do what you told me and what the above link says. Either way, whatever the sound, it does stop when I disconnect the plug...fwiw.

The sound comes from the thing in the circle and disappears when I unplug the rectangle plug also in the circle.

 

[bosljeff]

.

 

[crankbender]

Just take off the few fastners holding it on and see if it is moving/trying to move when it makes that sound. You may have a coil going out on the isc because of a short or corrosion on the plug... you will know more when you pull it and have somebody cycle the key for you.

Hell you could even have a leaf that got in there and the isc is crunching it ...wouldn't be the weirdist thing i have found.

 

[joeym4130]

My old bad ISC crackled when it was dead. I suspect the same thing. When the key is turned to on, is supposed to move once, and then again when turned to off. it supposed to do this and takes only a second so you turn the key on and hear a quick ''bzzzzzzzt''

But when it goes bad, i pulled the motor out and turned the key to on, and from in the cabin you can hear a buzzing/crackling/gurgling sound (however to describe it ) and then i went around to look at it and it just twitched back and fourth not making any progress, thats how i knew it was bad. It tested like 100 ohms at 2 of the terminals when they should all be in 28-33

 

[bosljeff]

Thanks Crank and Joey, I'll take a look and see what's going on.....

oh wait!!!!! It is snowing!!!!

Well, I'll get to it asap.

btw-thanks for the comment about your weather crank! It made me feel all warm and fuzzy.

 

[bosljeff]

Well, we tested it and if I remember right it tested at 29 ohms +/-. Took it apart and hooked it up and sure enough it didn't go in or out it just really tried.

The sound was the part trying to move in or out and rotate. Since it rotates as it goes in or out when it can't go in or out it just sits there vibrating-thus the funky noise.

What doesn't make sense is that I don't have any symptoms. So I guess I'll quit bitching and get ready to order a new TB and/or ISC depending on what's out there for when it does finally crap out.