Rough idle after LIM gasket repair

[Glaze]

Here we go again
VY V6 2004

I replaced the LIM gaskets and water pump. After starting car it idles really rough as if it’s missing or vac leak. During the LIM gasket repair I removed the alternator and found the worst wiring job that goes to the alternator plug/reg. I cut and soldered similar gauged wires but unsure if there’s a specific gauge needed as I needed a quick fix since car initially didn’t start since those wires were broken. There was also a high pitch hissing sound as if there’s excess current draw from a PowerPoint when I connected the negative terminal - since repairing the wiring that high pitch noise is gone and it starts but now it idles rough and can hear the high pitch noise while it idles.

Battery V when off is 12.6V
Idling V is about 14.4V
Checked alternator V when off it’s about 12.2V

Check engine also comes on after a while and it stalled once while driving, any ideas? I’ve attached a video and you can hear the high pitch nosie

Thanks

 

[ephect]

It's a vac leak that's causing the high pitch sound. Check if the gasket between your top half and bottom manifold is seated properly. If metal I bet a tab has been squashed not sealing properly.

The rough idle could be water in the cylinders but with a vac leak as well its hard to tell.

 

[Glaze]

I replaced that gasket between the plenum and the lower manifold with a crappy paper one no idea why they sent that I thought it was a stiff cardboard type. The original one was a metal with those tabs. Since that gasket was really delicate it ended up tearing in few places but I didn’t do anything about it thought it would still seal properly. I can’t find any vac leaks I made sure everything was in and even sprayed soapy water but nothing. Maybe it’s that gasket then?

 

[Glaze]

It's a vac leak that's causing the high pitch sound. Check if the gasket between your top half and bottom manifold is seated properly. If metal I bet a tab has been squashed not sealing properly.

The rough idle could be water in the cylinders but with a vac leak as well its hard to tell.

Another weird thing is that noise came when I put the negative terminal on battery before I repaired the wiring on the alternator. Once I repaired it, it went away when engine off but when engine on that similar noise. Not sure if alternator is cooked but the voltage readings are fine

 

[ephect]

Unsure on the alt. That previous wiring was dodgy as. Check voltage output on the main B terminal and the other 2 wires you've repaired.

Some do squeal, but honestly cannot remember the fix if it's a replacement, earth or something else.

 

[krusing]

Hmm,
Vac leak possible,
Did you put the EGR PCV valve back together correctly ?
and didn’t leave out or lose any parts from it ?

Correction : PCV Valve

 

[Glaze]

Hmm,
Vac leak possible,
Did you put the EGR valve back together correctly ?
and didn’t lose any parts from it ?

Does the EGR pipe have a spring in it? That’s the only piece left over from the entire job

 

[Glaze]

Took the top plenum cover off and found watery substance sitting at the back? I flogged WD-40 and soapy water around the engine bay so definitely a vaccum leak since it’s sucking in the liquids. The gasket between plenum and lower manifold is a bit out of alignment and was torn in few places so suspecting that gasket is introducing unwanted air and since it can’t hold a steady idle and idling under 1000 but above 850 there’s a lot of extra air bypassing the MAF and IAC

 

[Glaze]

Anyone know where this spring would go?

 

[Lex]

Took the top plenum cover off and found watery substance sitting at the back? I flogged WD-40 and soapy water around the engine bay so definitely a vaccum leak since it’s sucking in the liquids. The gasket between plenum and lower manifold is a bit out of alignment and was torn in few places so suspecting that gasket is introducing unwanted air and since it can’t hold a steady idle and idling under 1000 but above 850 there’s a lot of extra air bypassing the MAF and IAC

I think @krusing means the pvc valve?

I did the lim gaskets last year, the kit l got was from repco. The gasket between the lim & plenum was paper, very thin cardboard. Like yours it tore.
I took the old steel one & used a very thin rtv gasket on either side of the metal gasket.

Then took the lim back off. Had some used mace metal lim gaskets, so cleaned them back up, & replaced the crap repco ones.

I'm assuming you used the orange end seals for the ends of the lim?
While doing the end seals did you put a dollop rtv sealant on the corners?

I used a thin rtv sealant over all the surfaces orange seals.

Lastly did you connect the small hose from under the throttle body?