surging idle problem, this is apparently not the fast idle

Lucifer Caitiff · Nov 28, 2003

go here. http://www.grenadebrothas.com/lucifer/prelude/sinvid.avi

why do you guys think its doin this? it doesnt go away, warm or cold it does it.

edit: shit....sry for the multipost. i havnt seen an actual vid tho, so i thought id post

cowsnuker · Nov 28, 2003

mine's doing the same... is urs doing anything funny while driving it?

also, i checked my map sensor and found buildup of white junk in it, check with urs please?

i talked to a friend today, he thinks it may be the o2 sensor, but im also having a problem with my driving.

Lucifer Caitiff · Nov 28, 2003

i havent done that yet. i should. its not so bad when im driving, the throttle feels a little too sensitive, and the clutch needs to be adjusted...but when its in gear it drives fine, but when i shift the rpm's jump up and it causes it to grind. when i go to neutral it jumps up then starts gettin the rev problem

Jump · Nov 28, 2003

Wow - that's exactly ............ simuliar (lol) to the problem on my friends car last weekend. I found the problem on his TB. Here's the dialog from 3gdude.

PROBLEM:

Idle bounces up and down from 800 to 1100 RPMs - can it be the Throttle Angle Sensor

SOLUTION:

Absolutely it will.....Are you having this symptom or just curious ?? The TPS volts need to be rock steady at idle or else the ECU injects extra fuel into the motor everytime the voltage goes from a lower value to a higher value. It works very much like an accerator pump on a carbed engine.....3gdude

There are many areas that cause these idel problems - does this happen rught away, of only after warm up?

While you answer that, here are several areas that forum members have found:

"From Slipslap

1st time- It was the idle engine temp sensor, your idle stays high until it's warm then it drops. If it warms up & doesn't drop, it just goes up & down that can be a cause.
2nd time- Intake gasket leaking, if it has a leak, it's getting to much air and it tries to add more fuel then it just goes up & down. To check for this, get some throttle body cleaner & spray it at the base of your intake. Spray it by each injector if you spray in an area and the engine dies or almost dies, thats where your intake leak is.
3rd time- A vacuum leak, check all your vacuum hoses if ones off or has a hole it will do that also. You can spray throttle body cleaner on them as well to check for a leak.
4th time- That idle screw can be screwed out to far. When you car idles high(like it's supposed to) then drops, but goes up and down, try screwing it in some and if it stops that surging it was out to far, causeing a similar situation like a vacuum leak, allowing to much air in.

I'd check all those things, it's probably one of those. I've had all those problems before and they are fairly simple to fix."

Have you bled the coolant system at the thermostat?

Another forum member: (didn't get the name)

"Had the same problem on my 88 automatic lude... test the TW sensor (coolant temperature sensor) to the right of the thermostat housing. Warm the car up.. remove the connector and look for 200 to 400 ohms between the terminals on the sensor itself. My sensor was bad but did not cause the check engine light to come on .. or any codes. Normaly a bad TW will show check engine and code 6.. but mine did not and it had the same symptoms yours is experiencing. There are two sensors next to each other .. its the one with the green/white and yellow/green wires."

Are you tossin any codes on the ECU?

need4speed · Nov 28, 2003

my car used to have that problem, when i had a coolant leak, and lost alot of coolant. I topped it off, and I didn't bleed off the air, so there was a pocket of air in the cooling system. Basically, the coolant tempreture sensor isn't getting any reading, which is causing the erratic idle.

so, you should try bleeding the air from the cooling system.

while the engine is cold, open the rad cap, and start the engine, and top up the radiator. crack open the bleeder screw at the thermostat housing, and watch the rad coolant level drop, as air is let out of the cooling system, and close the bleed screw as soon as you see coolant seep out the bleed screw. top up the rad, as the coolant is sucked into the engine.

as the engine becomes warmer, you will have to recap the rad, before the thermostat opens up.

3gdude · Nov 29, 2003

I wanted to participate in this discussion, but I could not get the page at the top to load. My browser is a little queer. Maybe start a new thread with all the symptoms and all the things you have tried and checked....3gdude

boon · Nov 29, 2003

i have that current problem! i know its my coolent temperature sensor (code6 ecu) its perfectly fine when its cold but right when its supposed to switch over to the slow idle it would bounce between normal idle and fast idle (1500rpm) im slow to fix cause the part costs 56 monies. another quick fix is to just unplug the sensor and put it back in, i heard sometimes theres buildup on connectors that would cause it to stop sending and make it seem like its broken.

BTW, i own lucifer in my sig. LOL but lucifer owns me cause he let me borrow 250 bucks when a fellow luder needed it, so he's super cool in my book.

3rdgenluder · Nov 29, 2003

wow i have never seen lucifer actuly keep up with people...you guys must have been going slow

.....j/k

Lucifer Caitiff · Nov 29, 2003

hahaha shut up! my car handles like a demon and u know that, i was keepin on that 5th gens ass thru the turns and almost made him lose it!

boon you own nothing in ur sig! haha my car handed ur ass to you up that hill

anyway, 3rdgenluder you should try comin down here tomorrow on sunday and help me with this. im gona try a few of these things out tomorrow. the idles jumping as high as 3000 rpm's tho. not just 1500. i start it up, and it stays at 3000 for a few seconds then starts jumping up and down.

the vacuum hoses look kinda worn out too, they come off way easier than they do on my blue car. Jason, you still got that vacuum box that we ganked? or did you not take it?

when i shift, it stays at 3000 rpms, i think this is contributing to the grind between gears, as well as the clutch needing to be adjusted, i think it grabs so close to the floor that when you put the clutch in, its not actually going in all the way.

3rdgenluder · Nov 30, 2003

yea man i still have the vac box..hell i still haven't installed the other stuff we ganked off that clunker....haha and you talk about owning a 5th gen...you can't keep up

you know i can smoke you like a cheap cigar

.....i also can't beleave that guy jacked you sig...i saw that the other day and said...sh!t what an imatator...oh well rember one thing...imatation is the biggest form of flatery.

Lucifer Caitiff · Nov 30, 2003

aaahahaha i rocked that guy!

i shoulda been second in line right behind schel, yeah i got a big head but i know when to bow down to skill. you got more skill than me i know that. my car still handles better though!

PrecisionX · Dec 1, 2003

My idle is surging doin the same thing I was told it is my Idle Control Valve which is $80 to replace ... I was wondering if anyone knew of a temporary fix ??

3rdgenluder · Dec 2, 2003

ok i just delt with mine....try this...new pcv valve...it's like a $3 part...after i did my timing belt i broke my valve and forgot to replace it (duhhhhhh) and when i went to work today it started doing it...ten 1/2 way thru work i relized i didn't replace it...well i just replaced it and now my idle is back to being low and the jump is gone...this fixed my prob and it's only a $3 investment..worth a try...hey lucifer you can try just pulling out you pcv from the blue car and slap it into the project car and see if it helps....worth a try..just be careful not to snap it like i did...

ps.....bow befor me lucifer!!! :twisted:
it is probuly a good thing your suspention is better then mine becouse if my suspention was upto par i would have lost you after the 2end curve

Lucifer Caitiff · Dec 2, 2003

lol i was way behind u and driving like a pussy the first time i followed u to your house because it was an unfamiliar road. lol

im gona try the pcv. also i think the coolant is very low. so...just for shits and gigles im gona run a chemical check on it once i get exhaust on there, to see if the head gaskets blown. hopefully its not, but its worth a try before i start spending money. after that, if its good, im gona flush the radiator, coolant, and refill it all. then replace the idle sensor.

im gona do this next weekend, not this weekend, with my mechanic Randy. I popped the bolts ot the flange of the exhaust off, now the hard part is gona be getting the thing off. i need to attack it with a hammer and flathead screwdriver to separate the thing...hopefully it will work

B20A5T · Dec 2, 2003

I can pretty much tell you what's going on w/o even seing the vehicle.

The PCV system is almost NEVER even thought about by anyone, and it's the reason our intake's and TB's and everything in between get gummed up. Check out what this gumming did to my Idle Air Control Valve (IAC)...

Good Voltage Waveform...
http://dustin_palmer.tripod.com/pics/electrical/IAC-good.jpg

My Bad Voltage Waveform...
http://dustin_palmer.tripod.com/pics/electrical/IAC-bad.jpg

Cleaning out the IAC and reinstalling it did help some with the idle concern, but I will need to replace it come Friday (payday). That gummy stuff gets attached to everything, and it becomes almost impossible for sufficient air flow through passage ways at times.

There are always possibilities like vac. leaks and such, but I can almost bet ya that the cause of the concern is from gummy intake ports/runners/passages. Installing a catch can should eliminate the concern from ever coming back again once trully fixed.

BTW.. you may just try adjusting the flat head screw on top of the throttle body itself. Idle should be ~750RPM's engine warm.

Dustin

Lucifer Caitiff · Dec 2, 2003

well you should look at the vid to listen to it. the idle control valve does sound like the problem here. i unplugged it and it stopped surging, it just sat at about 3500 rpm's, but it stopped surging, so thats most likely it. when i get some time ill try to take the thing off the back of the TB and clean it up

B20A5T · Dec 2, 2003

I never said the IAC was the cause of the problem of course, and what you have is a great indicator of the concern with yours.

However, they get gummed up with all that oil stuff, and this is inheritly what usually causes these items to go bad. In any case, I wish you the best!

Dustin

Lucifer Caitiff · Dec 2, 2003

but nonetheless i SHOULD try to clean the sensor

lol

PrecisionX · Dec 2, 2003

I concur

PrecisionX · Dec 2, 2003

It is also makin this really loud swooshing sound like air sucking in really loud. I think its coming from the intake manifold cant be sure.... does this help any

PrecisionX · Dec 2, 2003

Oh and I just took my IACV apart and cleaned it really well.. Although I could not get the bottom peice of and one of the screws stripped .. !!!! just my luck oh well.... I put it all back together but it made no difference car idle still bounces up and down between 1000rpms and 3000rpms!!! ARGH sounds horrible

3rdgenluder · Dec 3, 2003

try just unpluging it and see if it smooths out..even though it might still idle high...that is how we found it on lucifer's car...just unplug it and see what it does....when adjusting the idle you are suposed to unplug this sensor anyways (acording to my chiltions book)...now i thik i need to adjust mine up a little becouse it is idleing below 750...damn it makes me nervouse when i pull upto a light but i will get used to it...i just need to makesure it is the normal for my car with the changes made...

Lucifer Caitiff · Dec 3, 2003

well, i think its because the cars low on coolant. i tookthe valve off and cleaned it today, you should see the q-tips after i cleaned out the piping on the bottom of the valve...damn.

maybe when i flush the system it will stop.

Lude019 · Dec 3, 2003

Lucifer Caitiff said:
well, i think its because the cars low on coolant. i tookthe valve off and cleaned it today, you should see the q-tips after i cleaned out the piping on the bottom of the valve...damn.

maybe when i flush the system it will stop.

I had the same problem. I found out mine was a blown piston. :?

B20A5T · Dec 3, 2003

Your concern, Lude019 would cause a dead cyl. as we call them in the auto world. Nice way to test for a dead cyl on a diesel... spit on the exhaust manifold ports.

How does this work? The one that doesn't smell/hiss is USUALLY the one that's coldest due to being connected to the bad cyl. You could also "unload" a dead cyl for trial/error by pulling the spark plug wire while the engine is running and listen for the engine to stay running the same. When the sound changes due to pulling the wire, you know that THAT cyl is still fully operational... if any of this makes since.

Anyhow, I'm glad you took the initiative to clean out your IAC!!! Regardless of fixing the concern or not, you took initiative! Not only this, but you OBVIOUSLY didn't hurt anything as you cleaned it out and you still have an idle concern. The IAC (valve or motor, whatever, we call them I'AC's) is of course connected to the front of the intake manifold and on top just above the fuel rail. You should try screwing in the screw on the fast idle valve... Flat Head, located on top of the Throttle Body. If that's screwed in all the way and your still having surging... you could either have a bad fast idle valve, still have a bad IAC (even though it's clean now, the motor can go bad due to the gunk build up inside causing it not to work properly over time), or even have a NICE vac. leak.

I want to say, the system should hold about 17" - 21" psi at idle on a vac. gauge. It IS possible that you have a compression issue... most don't care to think about it but it's true. Like Lude019 said, you may try a compression test. Try my spit test above even. Doesn't matter. Not sure how you drive your car or anything that you have done to it as far as mods go, but you could have something as well like a bent valve. Who knows. Not USUALLY going to be a compression problem, but if you have a bouncing vac. needle, I'd almost bet it is.

Anyhow, hope some of this helps as well.

Dustin

notAcarGUY · Dec 3, 2003

need4speed said:
my car used to have that problem, when i had a coolant leak, and lost alot of coolant. I topped it off, and I didn't bleed off the air, so there was a pocket of air in the cooling system. Basically, the coolant tempreture sensor isn't getting any reading, which is causing the erratic idle.

so, you should try bleeding the air from the cooling system.

while the engine is cold, open the rad cap, and start the engine, and top up the radiator. crack open the bleeder screw at the thermostat housing, and watch the rad coolant level drop, as air is let out of the cooling system, and close the bleed screw as soon as you see coolant seep out the bleed screw. top up the rad, as the coolant is sucked into the engine.

as the engine becomes warmer, you will have to recap the rad, before the thermostat opens up.

i bought my 90 si from a dude that broke an axle....my boi and i just fixed it but before that it had been sitting for a year...so all the fluid were drained out... but yeah it was the coolant thing... after we put that in the idle stopped jumping... i wasnt able to wacth ur video but im assuming that u mite have the same problem... another thing check the main hose that runs from the engine to the radiator when is starts idle jumping the hose should start expanding/balloning out, at least mine did. u mite wanna change that hose cuz if ur shit was doing that hella much liek mine was the hose may have leaks or just be strecthed out and getting out and nasty anyways thats wut i think...

surging idle problem, this is apparently not the fast idle

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