spark plugs & IAC help
ok ive gotta change the spark plugs, this will be the first plug change ive done so im a lil outa my legue when it comes to good plugs
so what are the best plugs i can buy for the v6 ecotec duel fuel?
and today i thought i would give the IAC a clean as the car has been idling anywhere from 1000rpm - 1500rmp and after giving it a clean it seem's to be idling up to 1750rpm now what's the go with that?
Genuine AC Delcos are the best plug I've used on V6's. Some of the others don't seem to last very long. GMH recommended the standard 'plugs (heat range etc.) for dual fuel. That's good enough for me.
If the idle doesn't settle (relearn) you may have created a vacuum leak. Did you remove the throttle body or IAC while cleaning it (you should have)? There is an 'O' ring between the IAC and TB that probably should be replaced if the IAC is removed. Lube it with some engine oil befire installing.
are you talking about the one in the yellow there if so mine was still fine ?
okay so i got bored and started to pull everything apart and i might of found a little reason for it to idle high??? see what you think
okay not the best photo but it look's like the (betterfly i think it is called)??? isn't closing fully
i put a light under it and you can see the big gap in it
and the only thing i can think of stopping it from closing fully is this screw witch seem's to be sticking out to far what do you think?
Just wind the screw out a bit until the gap is gone,then see how she idles..Heres what the gregorys workshop manual says about checking the base idle...
"The base idle should not need to be adjusted unless the throttle body has been renewed or if the base idle adjusting screw has been disturbed from its original setting.
Prior to any adjustments,make sure that the IAC valve and the IAC ports and the throttle body itself are clean.Deposits around the throttle valve and bore will effect the base idle speed.
(1)Ensure that the throttle valve moves freely and returns to the fully closed position when released slowly.If necessary,adjust the throttle cable.
(2)Run the engine to normal operating temperature,preferably by driving the vehicle for 15 minutes.
(3)While the engine is idling,ensure that the engine cooling fan and all accessories are off and disconnect the wiring from the IAC valve at the same time the engine is switched off.
(4)Open the throttle slightly and start the engine.After the engine starts,slowly allow the throttle to close.If the engine stalls,adjust the base idle screw half a turn and start the engine again.
(5)After the engine has been idling for 2 minutes,check the base idle speed ensuring that the engine cooling fan is off.If the base idle speed is not 450-550 RPM,adjust the base idle screw to achieve a speed of 450 -550 RPM.
(6)Stop the engine and connect the IAC valve wiring connector.
(7)Start the engine and after 5 seconds check that the curb idle speed is to specifications.
The curb idle speed for a manual VSV6 is 775 +/- 50 RPM
The curb idle speed for an automatic VSV6 is 800 +/- 50 RPM in neutral,and 700 +/- 50 RPM in drive..."
Last edited by Brett_jjj; 12-04-2011 at 09:45 PM.
I thinbk that this is the key sentence:
"The base idle should not need to be adjusted unless the throttle body has been renewed or if the base idle adjusting screw has been disturbed from its original setting."
I'd look for other things first.
Yes, that's the 'O' ring.
TB gasket?
The throttle shaft loose in the TB bushes?
Thats fine if youve owned the car from new and know 100% that the throttle stop screw has never been touched,but if the car is second hand,then anything could have been done.It makes sence that someone who doesnt know a great deal about cars,might adjust the throttle stop screw if the car is idling badly from a dirty throttle body,and now the throttle body has been cleaned,its probably idling too fast...so it cant hurt to check it by following the workshop manuals instructions...Originally Posted by Cheap6
OKAY so i did number 3 all fine
then i went to number 4 and once i start the car it sit's at 2100rpm what do you think is the go there?
It should be sitting between 450-550 +/- 50 rpm ,not 2100 rpm,so Id adjust the throttle stop screw to give a rpm reading of 450-550 rpm,also take note and write down how many half turns of the throttle stop screw you needed to make to get it in the right idle speed range,and just keep it for reference if its still not right..Then once its been adjusted back to 450-550 rpm,then follow the book,and re connect the IAC and see how she idles then..Let us know how it goes..
i was playing around with it to day i didn't really take any notice how many times i was turning i pretty much did the hole screw in and out and it didnt make any difference one the 2100rpm (with the plug out)
but i have this photo to have a look and guess about were the screw should be b4 i touched it this is really annoying me now i can't work out how to stop it from idling so high
If its not dropping the revs down when the throttle valve is closed, then the throttle stop adjustment its not gonna be the problem.Maybe theres a vacuum leak somewhere,that would be my guess.It could be the brake booster leaking vacuum,hows the brakes lately?It could be any of the various vac lines around the engine,and theres a vacuum reserve tank under the passenger side front guard..It looks like a black plastic ball,it should have a vacuum hose connected to it,sometimes this can come off...The heater can also cause vacuum leaks as its vacuum controlled.Then lastly theres the engines manifold gaskets,you can spray wd 40 around the gasket joints on the manifold whilst its running and get someone to lool for smoke at the exhaust,if it smokes when you spray a certain area of the inlet manifold joins,youve found the vacuum leak...
well i just did the code check and from what i could tell it went 12 / 35 / 57 beside's 12 what do the other to mean ?
The code 35 = "Idle speed error-IAC unable to control idle speed",and the code 57 is the "injector voltage monitor (voltage variation on ECU terminal B12)".Id clear these codes by disconnecting the negative battery termial for 5 minutes,then recheck them to make sure they have cleared,and then drive the car for a good half hour or so,and then recheck the error codes again.If they do return,for code 57, check all the major wiring and connectors in the engine bay,especially check the ECU wiring connectors and DFI module wiring connector,and also check the battery terminals ands the earth points where the negative battery lead connects to the engine and body...for code 35,Id try another IAC valve ,and see how it goes,you may have to reset the base idle if it wont idle or idles too fast now the throttle stop has been moved.If theres no difference with a different IAC valve fitted,then its most likely a vacuum leak somewhere.
well i was going threw other thread's and someone said with 57 that it will be there because my car is also on gas
if i get some time 2morrow i will go over everything
The idea behind disconnecting the plug to the IAC as you switch the engine off is to "catch" the valve in the fully closed position; it is wound all the way in as a reset then back to a start/idle position on each shut down. Sometimes it can be tricky to disconnect the plug with the valve in the closed position rather than elsewhere.
An alternative is to create a vacuum leak sufficient to cause the IAC valve to close as the PCM attempts to lower the idle speed. Pulling the hose to the brake booster then disconnecting the IAC plug should do it.
2100 rpm sounds a bit high though so, yes, vacuum leak somewhere.
okay after trying all that you guy's have said to do === nothing
i went all over i couldn't find any leaks BUT i could here air getting sucked somewhere at the front of the motor i don't no if it's the gas mixer ?
and i reset the computer and after taking it for a drive it is now coming up with code 76 i give up with this car
The manual says code 76 is air/fuel ratio,(variation between left and right banks).It goes on to say that this can be caused by dodgey 02 sensors,blocked injectors,faulty spark plugs,or leaking inlet or exhaust manifolds on one side of the engine.Mate it might be easier to get a gas certified mechanic to give it the once over,a lot of people seem to have lots of problems with gas converted cars.Id never own one..
most likely the spark plugs that's why i was asking on this thread but once again because i mainly use it on gas and because gas doesn't go threw the fuel injectors would that cause some of the codes to show?
buy the way you have been a great help thanks
You should run it for 15 minutes once a week on petrol,98 octane stuff,just to keep the petrol system in good working order.I bought brand new"cheap brand" injectors about 2 months ago,and so far theyve been excellent.They were $170, and the local EFI places around here wanted $150 to clean and reco my old injectors.Heres a link if you wanna check em out.
HOLDEN COMMODORE NEW FUEL INJECTORS VN VP VR VS VT VX + | eBay
when i get some money i might have to get some new spark plugs and lead's and new fuel injectors
i try and start the car on petrol all the time if i remember but the reason i don't drive much on petrol is because it idle's higher then the gas does
i might look at getting rid of it soon and upgrade
If the car itself is fine,then Id just look at removing the gas setup if its keeps causing trouble for ya...
Okay it seem after all the work i have done on it has helped a little bit when i start the car it idle's just under 1000rmp but after driving it it still goes up to 1500-1700rmp
after taking the air box lid off today it seem's to be to much air going it to the motor from there because you can hold your hand over it and the idle drop's down heap almost stalling it so i think it has something to do with the throttle body so i might try and get another one soon
Have u checked the small hose to the tb underneath, its a small one but its easy to slip out/off?
okay after changing the inlet manifold gasket and all the little gasket's in between and getting another throttle body off another VS the idle has gone down to 750rpm so im happy now
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