New on here, no clue how to make a post.

that being said, my 2012 express (6.0 vortex)
is making a clicking/ ticking sound. I have low manifold pressure (2 psi under normal load on freeway for intake manifold pressure, map sensor is at 13psi same application)

 

definitely don't hijack other people's unrelated posts about Suburbans.

It's not complicated. You just open the van section and click the "New Thread" button.

I'll peel off your question and move it for you this time.

 

I'm confused. The MAP sensor measures intake manifold pressure. It literally stands for Manifold Absolute Pressure.
So where are you seeing the 2psi?
2PSI is normal for idle or coasting. 13 PSI is high load. What is the MAP reading at idle, and with the engine off key on?

Ticking would be unrelated though. Maybe you're talking about low oil pressure?

 

The g series vans have 2 separate sensors…

one is the intake manifold pressure sensor and one is the manifold absolute pressure sensor

i forget to be completely honest but one is based off of engine vacuum and the other is based off of actual pressure.

anyway at idle the intake manifold pressure is around 8.9psi and the map is at 5psi

on the freeway, at 70mph (1700rpm) I am around 13pdi for the MAP sensor and 2psi for the intake manifold pressure.

a little bit of a stumble at idle and negative fuel trim by like 2-3%

also have a ticking that gets pretty rapid around the 1600rpm and sounds like a rattlesnake… changes with engine speed etc… but I think it is injectors because the 2012 vans just have a strainer in the fuel pump and don’t have any inline filter. Just did intake manifold gaskets and I have typical carbon buildup on my head ports… spray pattern looks pretty small and like it’s not spraying in a very good pattern. My idle fuel pulse is around 1.5 milliseconds.


anyway hope that helps, it’s the l96 6.0 vortec from what I understand and it has around 110,000 miles

 

Sorry. Not the best with forums. I will not do it again 👍

 

No, they don't. The engine doesn't need two sensors measuring the same thing.
There hasn't been a g-series van since the 90's

You are probably misunderstanding your diagnostic tool.
The pressure outside (atmospheric) is roughly 15 PSI. If the pressure in the manifold is 13 PSI, that's a difference of -2 PSI. Which is the same as saying 2 PSI of vacuum
I think your tool is simply doing the conversion for you and showing it as a value. It is not a real sensor. Your engine only has one manifold pressure sensory. The MAP sensor.
Anyway, your manifold pressure is normal.

fuel trim is fine.
Do you basic engine checks. air filter, spark plugs, check for vacuum leaks, etc.

L96 is a flex fuel engine. Make sure alcohol content is showing correctly.

all cars today do

 

For a ticking sound fuel system might be the last place I would check. A stethoscope could help narrow down the location if you have one. I'd check the accessories first. Does pulling the belt make it go away? If it isn't the accessories, I'd look for an exhaust leak second. Do you have any broken exhaust manifold bolts?

 

sorry... let me clarify some stuff. was very tired after a long day of work yesterday...

2012 Chevy Express 3500 LT, 6.0 flex

-I live in kentucky. Baro is reading around 14.3 psi

-Manifold absolute pressure is at 5psi at idle, 13psi on the freeway.
-A separate sensor shows up on the scan tool and is labeled as "intake manifold pressure sensor" and is showing up as a different sensor from the map, you are probably correct that it is just the scan computer calculating different intake sensor readings and calculating a value.

-Fuel trim was -10 the other day which was a bit concerning to me. Recently it has been a little bit lower, but on some drives it will still be -10... upstream o2 sensors are fluctuating as they should and the downstream sensors for both banks remain at a consistent 700mA and will sometimes dip down

-as for alcohol content, it fluctuates from 0-5% depending on where I fill up, I personally never run e85, just 87.


As for the fuel filter do you mean all cars have an inline filter or all cars just use the fuel pump strainer? From what I understand Chevy quit using them on the express vans and just used the pump strainer. Strainers seem to be way less precise with filtering than an actual filter, thus leading to my concern about my injectors ticking way louder than they should. I am probably going to run some lucas fuel system cleaner for a week or 2 and see if that will help at all. It has gotten louder over time but isnt easily heard unless you are underneath the vehicle or right next to the wheel well.

brand new air filter, spark plugs and wires, did a vacuum leak test with a smoke tester and did not see any leaks. changed the oil yesterday and didnt see any flaking of any kind which is obviously a plus lol

 

I had the drive/ serpentine belt off to do intake manifold gaskets a month ago and spun every pulley except for the crank pulley/ harmonic balancer and they all spun freely and did not have any sound or rattling. It really sounds like injectors. Fuel trim fluctuates from -3 to -10%. Also I have replaced many exhaust manifolds from the studs/ bolts breaking off and have heard that type of tick, it really doesnt sound like an exhaust tick to me... I have meticulously kept up with oil changes (like 3-5,000 mile intervals) otherwise I would suspect a possible lifter issue. It is not an afm motor and isnt throwing any codes. A little bit stumped but will probably run some fuel system cleaner to at least break down/ push any debris to the front of the fuel system so that if I replace the injectors they wont just immediately get clogged again.

 

This is what she sounds like... its kinda faint but you can heard the ticking