idle problem.

[johny24]

I have a strange problem when im at a stop light or leave the engine running at neutral the engine goes down below 1 rpms and turns off then kick on by itself. THis only happens when engine is idle any one knows what is happening? I changed the sparks to see if that was the case but it the problem still happens anyone ever had the same case??? help?

 

[4UH8ERS]

I have a strange problem when im at a stop light or leave the engine running at neutral the engine goes down below 1 rpms and turns off then kick on by itself. THis only happens when engine is idle any one knows what is happening? I changed the sparks to see if that was the case but it the problem still happens anyone ever had the same case??? help?

could be alot of different things? is there any other symptoms?

Could be your TPS or IAC.
If its runing rich could also be upstream o2 sensor.

 

[Dave Chan]

I have the exact same problem johny but mine doesn't do it everytime, it just does it sometimes/randomly hahaha.
It' only happens when i'm driving and i come to a stop, while i'm hitting the brakes sometimes it will want to drop near zero and then it will shoot back up to about 800rpm when my car is more slowed down. Then when i'm just sitting there it idles good 750-800rpm but it just sounds like a muscle car haha

I changed everything!! every sensor i could think of and i tried swapping injectors/harness from my old motor since it was running great, changed spark plugs, cleaned the IAC and so on...and my timing is right as well... but my vacc still reads at 10-11hg at idle..
we bought this motor off a wrecked eclipse and it came with some aftermarket parts like unorthodox underdrive pulley, headers/downpipe. Could be work done internally? i'm not sure.. could it have come with camshafts?? i never took the valve cover off yet.

My car sounds JUST like this at idle haha same loud pulsating noise like a muscle car at idle

http://youtube.com/watch?v=iy7k3adtu78
http://www.youtube.com/watch?v=e_9z726eABc
http://www.youtube.com/watch?v=OcFqWROWq6o

P.S - When i got my car e-tested they said i was running really rich and that i have an exhaust leak where the downpipe connects to the headers, near the o2 sensor

 

[Slo2gen]

Could be the speed sensor. Does it do it when you are rolling with it in neutral?

 

[4UH8ERS]

I but my vacc still reads at 10-11hg at idle..

Your vacuum is pretty low. If your engine was new it would read about 18-20 some higher mileage eclipses sit at about 16.

If you have upgraded cams/cam gears, low compression ect, then these numbers will change. (i.e. standard vacuum for JE 8.8:1 rebuild would be between 15-18)

You really shouldn't ever have 10 or 11 though.



These are a few causes or low vacuum: bad egr, vacuum leak, burnt valves, worn rings ect.

 

[Dave Chan]

While i'm rolling in neutral it doesn't do it but only when im coming to a stop/pretty much hitting the brakes then it will "sometimes" do it.

and yes on my old 420a the vaccum was at 15 but now.. hahah
i've tried checking for vaccum leaks but i'm still not 100% positive, i changed the egr valve so i'm sure that's not it.

 

[4UH8ERS]

While i'm rolling in neutral it doesn't do it but only when im coming to a stop/pretty much hitting the brakes then it will "sometimes" do it.

and yes on my old 420a the vaccum was at 15 but now.. hahah
i've tried checking for vaccum leaks but i'm still not 100% positive, i changed the egr valve so i'm sure that's not it.

Well, you need to find out your vacuum problem first. Just start from top to bottom and find it! Do a compression test to find out if its an internal problem.

 

[dr1665]

This thread needs a new exhaust gasket for starters. If you're leaking exhaust gas before the O2 sensor, it's not giving the ECU an accurate reading. Along those lines, my first stop would be to replace the coolant temp sensor under the radiator cap. That is known to result in some shit-ass idling issues.

Don't know what to tell you about cams. You'll have to yank the VC to get a look and maybe spot a stamping or something. Cams could present a vacuum reduction problem at idle.

 

[JpZero]

johny and dave, i had the same problem as well. And what was wrong with mine was that my fuel injectors where clogging and the oil seal gasket was jacked as well. Tryin cleaning your fuel injectors first before removing the gasket and see if that helps. If it dosent then try the gasket.

whats wrong with your car is that the air/fuel ratio is being tampered with thus the weird idle. It dosent do anything when your moving because the fuel is being forced through the injectors and so you really dont feel anything. But if you dont get it fixed then you will start to feel it when you drive just like i did because of the build up. Try sending it in to a shop just to get a tune up and get everything cleaned out and then see how it runs.

 

[johny24]

well guys thanks guess what i was under hood looking at everything taking apart the battery and the intake when i realized is that my air intake tube has and hole. NOT GOOD well i got it a cold air intake and my idle problem has disappeared..

 

[Locke]

well guys thanks guess what i was under hood looking at everything taking apart the battery and the intake when i realized is that my air intake tube has and hole. NOT GOOD well i got it a cold air intake and my idle problem has disappeared..

Ehhhh? I don't see how that was related to your problem.

Maybe on a 4g63. The air isn't metered until after it has passed the TB on a 2gnt. A hole in the intake tube means unfiltered air, not unmetered air, and should have no effect on the idle or drivability.