intake plenum

[Mickey Bitsko]

Hey guys, I know my intake plenum 4.0 OHV is warped or just old [165k] and causing performance problems . So, before I waste a bunch of time replacing the gasket and or the plenum, are there better than oem plenums out there that I would get better fuel mileage or performance?

 

[adsm08]

How do you know it is causing your problems?

 

[Mickey Bitsko]

How do you know it is causing your problems?

Ironic..I just got off your thread about looking for a replacement intake on one of your rigs.... well it's throwing [if I remember..171] which i believe is lean or vacuum leak, anyhoo, the mechanic says its possible the plenum is leaking.

 

[adsm08]

P0171 is bank 1 lean, but that by itself does not mean the intake manifold is bad. Also, your mechanic said it's "possible" the manifold is leaking.

It's also possible that the injectors on that side of the engine aren't supplying enough fuel, it's possible there is a vacuum line broken, it is possible the MAF sensor is dirty, it's possible the gasket has failed and not the manifold itself.

In fact, I have never seen a warped intake manifold cause your concern, especially a plastic one.


In short, the only thing you actually know is that you have a lean condition on the passenger side of the engine. It is not time to start replacing parts yet, it is time for more diagnosis.

 

[Mickey Bitsko]

P0171 is bank 1 lean, but that by itself does not mean the intake manifold is bad. Also, your mechanic said it's "possible" the manifold is leaking.

It's also possible that the injectors on that side of the engine aren't supplying enough fuel, it's possible there is a vacuum line broken, it is possible the MAF sensor is dirty, it's possible the gasket has failed and not the manifold itself.

In fact, I have never seen a warped intake manifold cause your concern, especially a plastic one.


In short, the only thing you actually know is that you have a lean condition on the passenger side of the engine. It is not time to start replacing parts yet, it is time for more diagnosis.

I'm on your side.. I'm not in a hurry... This is why I ask questions, still runs like a brass balled cat and mileage is hangin in there. Ok, now I have a couple places to check first and we'll go from there..thanks adsm08

 

[adsm08]

No problem.

Grab some carb cleaner or brake cleaner and spray around, listen for changes in the idle.

Also check the PCV hose for damage. They can break down and tear after a number of years.

 

[Mickey Bitsko]

No problem.

Grab some carb cleaner or brake cleaner and spray around, listen for changes in the idle.

Also check the PCV hose for damage. They can break down and tear after a number of years.

Will do..thanks , we'll stay in touch..

 

[Mickey Bitsko]

No problem.

Grab some carb cleaner or brake cleaner and spray around, listen for changes in the idle.

Also check the PCV hose for damage. They can break down and tear after a number of years.

Ok.. PVC valve is clean and operating properly, all the vac hoses I can see still look good and are still pliable , took the MAF housing apart but did not remove the MAF sensor [need a T-20 Torx, and MAF Cleaner , tomorrow].

Question: downstream from the MAF sensor in the intake tube/pipe there's another electric fitting that is connected to some kinda sensor or something that is pushed into the intake pipe, my Haynes manual does not show what it is. Any idea?

 

[adsm08]

More than likely it's an air temp sensor.

I don't have one handy here in my bedroom to look at, but an IAT is the only thing that makes sense from your description.

 

[Mickey Bitsko]

More than likely it's an air temp sensor.

I don't have one handy here in my bedroom to look at, but an IAT is the only thing that makes sense from your description.

Thanks... Found it in Haynes , not much info, how would you know if they're working correctly, Haynes has nothing on maintenance or when to replace, could this sensor thro a code?

 

[Mickey Bitsko]

Cleaned MAF and IAT, noticed the air filter housing not clamped down tight, we'll see what happens... thanks again adsm08