Weird "sucking-sound" after cam swap

[BlackZJ]

Hi all

I installed a ZZP GT1 cam and now there is a weird "sucking-sound" out of the intake at idle, when the engine is cold. After warmup this sound almost disappears.
I thought the AFR could be to rich, so the IAC needs to open much more as usual which could cause this sound. But after tuning the MAF and VE Tables, the sound didn't change.

Apart from that, the engine runs and idles fine.

Does someone have the same problem or an idea what I could try to solve this problem?

Thanks,
Mat

[LETZRIDE]

Re: Weird "sucking-sound" after cam swap

sounds to me like the engine is just taking more air now because the valves are open a little longer/higher...maybe a video would help a little more? Is the car running roughly? Do you have a vaccuum leak?

[ssms5411]

Re: Weird "sucking-sound" after cam swap

sounds to me like the engine is just taking more air now because the valves are open a little longer/higher...maybe a video would help a little more? Is the car running roughly? Do you have a vaccuum leak?

x2...

[BlackZJ]

Re: Weird "sucking-sound" after cam swap

sounds to me like the engine is just taking more air now because the valves are open a little longer/higher...

Maybe.. But why would it get quieter when the engine warms up?

maybe a video would help a little more?

I'll see if I can make one.

Is the car running roughly? Do you have a vaccuum leak?

The car runs absolutely fine. At idle (engine cold), it just sounds like something is wrong. OR maybe I'm just paranoid. ;)

[LETZRIDE]

Re: Weird "sucking-sound" after cam swap

Maybe.. But why would it get quieter when the engine warms up?

IAC usually holds the throttle open when warming the car up...if you look at your rpms when it is cold they are generally higher.

Even look at hp tuners under idle control...colder the temperature the higher the idle is set.

Mine is set around 1100 when it is ECT is below a certain point, then as it warms up it will slowly decrease to 800-900

[BlackZJ]

Re: Weird "sucking-sound" after cam swap

IAC usually holds the throttle open when warming the car up...if you look at your rpms when it is cold they are generally higher.

Even look at hp tuners under idle control...colder the temperature the higher the idle is set.

Mine is set around 1100 when it is ECT is below a certain point, then as it warms up it will slowly decrease to 800-900

Yes I know and I already lowered the rpms because they seemed quite high.
I will try to set Idle to 800-900 rpm via the scanner so I can hear if this changes something. But I think it must be something different. To me it just sounds like it would get to much fuel and the PCM opens throttle more to compensate. I devinitively need to weld on a bung to the exhaust so I can hook up my Wideband!

[LETZRIDE]

Re: Weird "sucking-sound" after cam swap

wideband is good for tuning, get a video and it will help us...but I think your probably over thinking things a bit...sounds like its just the throttle cracked open more to warm the car up...which is normal...but like I said, get the video and we'll tell you for sure.

[BlackZJ]

Re: Weird "sucking-sound" after cam swap

but I think your probably over thinking things a bit...

That's quite possible. I'm a perfectionist... and therefore a bit paranoid sometimes. ;)

[BlackZJ]

Re: Weird "sucking-sound" after cam swap

Here's the video:
http://www.youtube.com/watch?v=4j0E0Fk2avw

[bwkmaro]

Re: Weird "sucking-sound" after cam swap

oh god junk that intake and get a reaL LID LOL sounds like air getting caught up in therenada to worry about imo

[pace2006]

Re: Weird "sucking-sound" after cam swap

You should look into getting this. http://www.fullthrottlev6.com/forums...FS-Whisper-lid

[LETZRIDE]

Re: Weird "sucking-sound" after cam swap

Ya, I wouldnt be too worried about that sound...although that does sound much odder then I am used to...if the car is running ok, I wouldnt worry too much...even if you change the idle, I dont believe that is going to change the noise much....just tell people you got a big blower on there lol...

[BlackZJ]

Re: Weird "sucking-sound" after cam swap

Yeah, a very big blower! :D

Well, it sounds much louder in the video than in reality. I will try if some changes in the tune help a bit.

[bwkmaro]

Re: Weird "sucking-sound" after cam swap

have u tried unhooking the intake on there to see if it goes away? i bet it would

[BlackZJ]

Re: Weird "sucking-sound" after cam swap

have u tried unhooking the intake on there to see if it goes away? i bet it would

Yes, I have. And it just gets louder. My first thought was that a cam bearing could be bad. But as far as I know these bearings would make a ticking or a whining sound, right?