wheres the idle ajustment

[PaRaDoX]

this may sound silly, but where is the idle ajustment on the vn 3.8L v6???

my idle is far too low and the engine keeps cutting out when shifting gears, (auto, park > drive, park > reverse)

cheers

[vt1538]

There is no idle adjustment as such.The idle is controlled by the ECM through the IAC valve.

[pro_gmh]

I thought there woulda been somthin on the cable like the VL's or a screw on the ecu also like the VL's

[HDT_aero]

lol no adjustment my ass

theres a stopper screw on the back of the throttle body.

to set your base idle you unplug the IAC valve connection and put the car in diag mode (short the black and white wires on the empty plug near the computer)

start the car up and adjust the idle screw so your base idle is where you want it.

then plug the IAC back in and reset the comp and start it up and rev it stedily above 2500rpm for 20 seconds

and thats how you set your base idle..... pfft no adjustment :rolf:

[samuels]

lol no adjustment my ass

theres a stopper screw on the back of the throttle body.

to set your base idle you unplug the IAC valve connection and put the car in diag mode (short the black and white wires on the empty plug near the computer)

start the car up and adjust the idle screw so your base idle is where you want it.

then plug the IAC back in and reset the comp and start it up and rev it stedily above 2500rpm for 20 seconds

and thats how you set your base idle..... pfft no adjustment :rolf:

as you said BASE idle...thats not your actual idle adjustment.the ECU adjusts idle according to conditions,just as it alters timing if detonation is occurring(detected)the ECU retards the timing to about 8 degrees.same as if the coolant sensor picks something unusual up,the idle is adjusted accordingly.

[vt1538]

By no adjusment as such I meant that the throttle stop is factory set & should not be adjusted.The operation of the IAC valve & condition of the throttle body should be checked first. Any dirt & crap in the throttle body or IAC valve can play havoc with the cars ability to idle. Increasing the airflow by adjusting the throttle stop can just cover a symptom & not fix the cause of the problem.

[HDT_aero]

as you said BASE idle...thats not your actual idle adjustment.the ECU adjusts idle according to conditions,just as it alters timing if detonation is occurring(detected)the ECU retards the timing to about 8 degrees.same as if the coolant sensor picks something unusual up,the idle is adjusted accordingly.

and what did you think he ment??

[HDT_aero]

By no adjusment as such I meant that the throttle stop is factory set & should not be adjusted.The operation of the IAC valve & condition of the throttle body should be checked first. Any dirt & crap in the throttle body or IAC valve can play havoc with the cars ability to idle. Increasing the airflow by adjusting the throttle stop can just cover a symptom & not fix the cause of the problem.

when i cleaned my TB and IAC i still had to readjust the base idle to get it right

[samuels]

and what did you think he ment??

there is a differnce between base and actual
base is a starting point,not actual...as you know auto's idle higher than manuals,the computer picks up on the base setting,just for argument sake....base setting is 700-800rpm,and your auto motor is running perfectly (remember i said arguments sake )the actual idle for the auto is around the 900-950 actual
actual,in carby model cars is what is manualy set by adjusting screw

[samuels]

when i cleaned my TB and IAC i still had to readjust the base idle to get it right

you shouldn't of had to....

[HDT_aero]

you shouldn't of had to....

it was idling too high for my liking i have it set at around 800rpm when it was about 1k (manual BTW)

[samuels]

it was idling too high for my liking i have it set at around 800rpm when it was about 1k (manual BTW)

don't you find that even a tad too high...i prefer to see manuals at 600-700 rpm,thats what mines running at,and i didn't have to adjust anything.

[HDT_aero]

i have it sitting on the line just below 1k (i think its around 750) i got a calais cluster so you should have the same dash and know where i mean.

i find any lower and it feels a bit low when changing gears (normal style driving) ..... like it feels like it will almost miss a beat (but doesnt) if yuo know what i mean... when i adjusted it i simply lowered it just above stall but so it wasnt "hunting"

[samuels]

i have it sitting on the line just below 1k (i think its around 750) i got a calais cluster so you should have the same dash and know where i mean.

i find any lower and it feels a bit low when changing gears (normal style driving) ..... like it feels like it will almost miss a beat (but doesnt) if yuo know what i mean... when i adjusted it i simply lowered it just above stall but so it wasnt "hunting"

no fair enough we all have our preferences,if thats what makes your car comfortable to drive.
have you hooked into your ECU to see why it has that missing feeling?

[HDT_aero]

theres no errors i just rekon it was cause i had the idle too low and when i was changing gears i wasnt using the accelerator causing the car to almost stall and jump start (if you get me) but just enough idle was retained for it not to stall and jump start....

as soon as i uped it that little bit it was fine

[PaRaDoX]

lol ok ok, so can anyone provide me with pics?? so i just cross the black / white wires near the ecu to put it in diag mode then ajust the idle? what if i dont put the car in diag mode??? which ones the IAC vavle connector, when im doin round 2000 revs i get a funny sound like somethings rattling round on the air intake.. any suggestions?

[samuels]

lol ok ok, so can anyone provide me with pics?? so i just cross the black / white wires near the ecu to put it in diag mode then ajust the idle? what if i dont put the car in diag mode??? which ones the IAC vavle connector, when im doin round 2000 revs i get a funny sound like somethings rattling round on the air intake.. any suggestions?

manual or auto?does the rattle go out past 2000?
from past experiences....if it's auto.....flex plate,guts slog out or fractures around bolt holes,another possible one, harmonic balancer,if manual....loose flywheel bolts.....balance shaft bearings...if your not a mechanic and decide to take it to one,i guarantee they will say balance shaft bearings.
easy way of finding out,get a long screw driver,a length of garden hose....better still a stethascope,put her up on ramps,listen around the front of auto, if it's flex plate you'll here some weird noises at idle at front of tranny(front edge of tranny..lower half closest to sump)

[Emackulation]

Man, myne idles fine like when I start her up, but when slowing down to lights it surges and when i stop it idles about 400ish. I needa beef my idle up a bit there, its getting a bit hairy. Ive also cleaned my TB by hand and taken out the IAC.

[samuels]

Man, myne idles fine like when I start her up, but when slowing down to lights it surges and when i stop it idles about 400ish. I needa beef my idle up a bit there, its getting a bit hairy. Ive also cleaned my TB by hand and taken out the IAC.

have you checked the adjustment of the IAC? measure the distance between the tip of the pintle and the flange mounting face..it should be 28mm or less. you then have to remove ENG.COMP fusible link from fusible link housing for 10 secs and replace the fusible link,then start and increase engine speed to 3000for 10 secs allowing IAC to reset,you only have to do this if you had to adjust the distance on the IAC.

[Emackulation]

Where is this fusable link located? cuz I just discon the battery, but that looses my stezza settings. Isnt the pintle inside the TB casing, how can u measure how far it is from the flange?

[PaRaDoX]

ok ok, its auto and no it dosnt keep going past 2000, and weird today it dosnt make the noise at all... its only occasionally it does how much is that to get fixed?

[vn4play]

i have been told by a mechanic that a common symptom for vn- vp is valves wearing and alowing gas through. he said it will make a knock noise just above idle almost like a missing type noise. also it is common for the noise to come and go. He said put a piece of paper over the exhaust at idle and if the paper gets sucked back to the muffler at any point its the valves. anyone heard of this, and could this be the noise that 1337 paradox is talking about

jimbo

[samuels]

i have been told by a mechanic that a common symptom for vn- vp is valves wearing and alowing gas through. he said it will make a knock noise just above idle almost like a missing type noise. also it is common for the noise to come and go. He said put a piece of paper over the exhaust at idle and if the paper gets sucked back to the muffler at any point its the valves. anyone heard of this, and could this be the noise that 1337 paradox is talking about

jimbo

yes thats the oldest trick in the mechanics book,although i use a rag,and if it gets sucked in your looking at burnt valves or valves not seating..... it's a short cut rather than compression testing.

[samuels]

ok ok, its auto and no it dosnt keep going past 2000, and weird today it dosnt make the noise at all... its only occasionally it does how much is that to get fixed?

if your not mechanically minded,and it does turn out to be a flex plate,your looking at $400.0 +
a lot of mechanics will tell you that it's balance shaft bearings,guaranteed,it's because they don't seem to have the knowledge these days of what noises are what.....

[samuels]

Where is this fusable link located? cuz I just discon the battery, but that looses my stezza settings. Isnt the pintle inside the TB casing, how can u measure how far it is from the flange?

just take engine fuse out,not the one with the 10 mm bolt going thru the wire from battery.although it doesn't matter which one you take out
they are in the fusible link block,the one below the big fuse block with the fuel pump relays,etc,etc under bonnet)
as for measuring the IAC it has to be out of the throttle body to do this procedure....if it needs adjusting you just push it back in towards the casing with a slight side to side movement until the desired length is reached