LS2 Turnkey, odd behaviour at idle
08-09-2010, 02:59 AM
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LS2 Turnkey, odd behaviour at idle I have a Turnkey 510hp crate engine in my tube buggy.
It behaves like this and I think its not normal:
http://www.youtube.com/watch?v=sgezTLUNSu8
What happens on the video, is that I "simulate" an obstacle (say a hill or going over a large rock) while rock crawling by using a bit of brake and load the engine slighly.
What happens is that when I let of the gas / put the gear in neutral, the idle runs wild (up to 2500rpm sometimes) and it takes 15-25seconds for it to return to normal idle. This is very undesirable where precise control of the throttle is needed.
The basics are ok:
- the engine and the electronics are new (MEFI4 + LS2)
- fuel pressure is correct and the engine works normally at any rpm, but at idle.
- no intake leaks (tested with vacuum gauge and manual inspection). All unsused vacuum ports are closed / plugged and the vacuum is as its supposed to.
- 4-gas analyzer values are top notch, nothing there.
Turnkey could not solve the problem for me, although they did try by for example sending me a new ECU.
They told me to run it with the IAC ( idle air control valve) disconnected and it does run better so... but this cannot be right with an engine like this?
Any ideas what could be the cause of this behaviour and a possible solution for it?
Thank you for any input you might have.
It behaves like this and I think its not normal:
http://www.youtube.com/watch?v=sgezTLUNSu8
What happens on the video, is that I "simulate" an obstacle (say a hill or going over a large rock) while rock crawling by using a bit of brake and load the engine slighly.
What happens is that when I let of the gas / put the gear in neutral, the idle runs wild (up to 2500rpm sometimes) and it takes 15-25seconds for it to return to normal idle. This is very undesirable where precise control of the throttle is needed.
The basics are ok:
- the engine and the electronics are new (MEFI4 + LS2)
- fuel pressure is correct and the engine works normally at any rpm, but at idle.
- no intake leaks (tested with vacuum gauge and manual inspection). All unsused vacuum ports are closed / plugged and the vacuum is as its supposed to.
- 4-gas analyzer values are top notch, nothing there.
Turnkey could not solve the problem for me, although they did try by for example sending me a new ECU.
They told me to run it with the IAC ( idle air control valve) disconnected and it does run better so... but this cannot be right with an engine like this?
Any ideas what could be the cause of this behaviour and a possible solution for it?
Thank you for any input you might have.
