Upper Intake Manifold

[DIGItonium]

Anyone notice some sort of yellow residue or build up on the side of the intake plenum? It's a bit dry and powdery. I'm just wondering if it's a sign of a leak.

Anyone ever taken one apart? If so, would it be possible to pull one apart and reseal it?

[DEpointfive0]

Build up on the inside? Or which side?
Pics?


And no, it's not possible to open it unless you have a hot knife, and best of luck getting it back together.

[DIGItonium]

It looks like the seam where the upper and lower halves meet. I see it on both sides near the throttle body.

[TopgunZ]

Wait. Am I missing something? There must be tons of people who have taken this apart. Pretty much anyone who has swapped injectors should have had to.

[DIGItonium]

Removing it from the lower intake manifold is one thing, but I'm talking about disassembling the actual plastic manifold.

I'm in the middle of troubleshooting a rough idle issue in which the car is running on 5 cylinders as of this morning. It's something never happened before, and the drive over the weekend was quite pleasant. It'll involve taking stuff apart, so I went ahead and inspected the upper intake manifold in the process. Right now I'm thinking it's a dud spark plug.

Basically I plan to use this opportunity to clean the intake system once everything removed to diagnose the issue.

[Nut_N_Much]

While you have the intake off, rent a compression check kit to see if you have a dead cylinder. I am getting a rough idle, I swapped plugs out and still getting it. I pressurized the intake and tubing and found a leak at the base of my throttle body, also found #2 cylinder is week after the compression check.

I checked my radiator fluid and it was low, but my oil isn't milky. I am praying the head gasket isn't blown. If it is it will suck to pull everything and replace it.

I do hope your diagnosis isn't as bad as mine .

[DIGItonium]

Ditto. I checked the reservoir, and the level is still the same (min) as it was months ago. I've checked the fluid a few times in the past month, and the levels didn't change. The color was good. There's no rusty color.

I'll check the dipstick this afternoon. Oil is about 800 miles old, but I'll go ahead and get it changed after diagnosing the spark. I'll have my buddy do a compression test as well.

BTW, this is something I've noticed before, but it was quite frequent and louder this morning. I can hear the exhaust sputtering and popping quite a bit. The only hard run I did over the weekend was a quick 3rd-4th pull in which the exhaust backfired in between shifts. That was pretty much it, and I've not had any issues all weekend.

[Nut_N_Much]

I am not a pro at Forced Induction but check your BOV's and see if they have moved any. They can shift or come loose, ORing can break or springs can break or were down, might be something simple that can through off one bank. Just a thought!

I got a Stillen so I'm already screwed no matter what I do

[DIGItonium]

After work I checked the coolant level, which was halfway between min and max. That level wasn't any different from months ago. Then I pulled the dipstick, and it looked good. There was a hint of fuel smell, but it was not milky either. Then I wiggled the ignition cables, and it was fine as well.

Then I plugged in the Cipher cable to get some datalogs. I cranked it and it was fine! It idled fairly smooth, and it sounded like all 6 cylinders were firing. There was still a strong fuel odor for a bit as it warmed up, but it went away afterward. All that was left was the familiar smell of the test pipes. I turned it off and cranked it again, and it was fine. I pulled up Cipher and slowly revved it a bit to 4k, and it was fine. The exhaust looked like it's steaming, but I didn't see anything out of the ordinary. Ambient temps was around 47F.

A/F Correction hovered between 93-98% as it idled. Mass A/F on both sides were very close by a tenth hovering around 0.68-0.73 (Volts?). In GM/s it's around 3.15-3.30.

Anyhow, I grabbed some MAF cleaner and sprayed the seams of the upper intake manifold, and it didn't affect anything. So perhaps it's fine, but I'll look into it again when I change the plugs and clean the intake system.

Hopefully this gets me by for now so I can deal with it after the holiday season. Thank goodness for the daily driver, which also needs attention (tires). >.< Doh!

[TopgunZ]

I had a similar issue with this in my 350 and it turned out to be a fuel issue. My pump assembly blew a ring that holds the output of the pump itself to the assembly. Was a nightmare to diagnose. Just an FYI if everything else fails.

[DIGItonium]

It caused your 350 to run on 5 cylinders and burn super rich? I bit the bullet and took the Z to work (nice day, low 60s before the cold front moves in). So far so good - smooth, and quiet. O_o Maybe it's a sign I shouldn't sell the Z (or else).