Advice on 1996 LX450 (1 Viewer)

[RaleighCJ]

Thanks for advice in advance.

1996 LX450 with 280k miles. Runs and drives fine. Standard oil leak on the front.

I am third owner.

I have the standard EGR codes throwing a CEL. I am cleaning the intake, EGR, etc and replacing all the tubing. Pulling the top portion of the intake off this afternoon and the intake is covered in black carbon. Is this somewhat normal?

How should I attack cleaning the lower portion of the intake? Need to remove it to clean or is there another way to clean it.

Finally, if the intake is this covered, should I be concerned about the condition of the head and valves?

Again thanks for the honest feedback.

Edit for grammar and spelling

 

[Tools R Us]

... Runs and drives fine. ....

What problem are you attempting to solve? It looks dirty, motors do that, a perfect cleaning job is likely to net somewhere around zero percent change, power improvement.

 

[RaleighCJ]

What problem are you attempting to solve? It looks dirty, motors do that, a perfect cleaning job is likely to net somewhere around zero percent change, power improvement.

To pass inspection, the vehicle cannot have any error codes/CEL. It currently is throwing P0401/P0402. Wondering if I am OCDing or should I go further in.

 

[shocktower]

To pass inspection, the vehicle cannot have any error codes/CEL. It currently is throwing P0401/P0402. Wondering if I am OCDing or should I go further in.

Clean it and get a new EGRif you have not already, and check your O2 sensors

 

[Pin_Head]

It is pretty typical of high mileage engines. If you clean it out, it will come back. It is time for a rebuild.

 

[madisonr34]

Amsoil power foam!

 

[rolliges]

Clean, replace ALL EGR/VSV system, after inspection put in a catch can on the PCV hose.

 

[Ocho77]

Probably head gasket failure...

 

[Malleus]

What problem are you attempting to solve? It looks dirty, motors do that, a perfect cleaning job is likely to net somewhere around zero percent change, power improvement.

Yeah, but it'll make you feel better after you've spent all that time doing it

Seriously, it's normal. It will come back, in about 100k miles. EGR codes are a PITA. Sometimes you can follow the FSM and get rid of them, sometimes they defy logic. Follow the FSM guidance and do the easy, inexpensive stuff first.

 

[RaleighCJ]

The EGR passage where the throttle body attaches at the upper portion of the plenum was completely blocked with carbon. Used a pick and throttle body cleaner to remove it. Going to go ahead and clean up the remainder of the plenum since I already have it apart.

 

[RaleighCJ]

p0401 part numbers

 

[LINUS]

Pulling the lower intake means fully unplugging the wire harness for you guys.
Might as well go full HG at that point.

Or chop the lower intake flange like I did. -That's still my personal best mod.

I hotsie'd my intakes & brake/carb cleaned the throttlebody when I did my HG.

 

[DSRTRDR]

take some time to search for the resistor mod

 

[jpoole]

Beyond all of the other cleaning/etc you are doing, while you've got the throttle body off be sure to check/clear the vacuum ports. Port R and E are related to p0401 if clogged. If the vacuum modulator diaphragm has failed and was putting carbon into your vacuum system there's a good chance that carbon has been sucked/lodged in one/both of these vac. ports on the TB.

 

[RaleighCJ]

Cleaned the plenum, throttle body, related ports and metal hoses. Replaced the VSV and with new OEM. Replace all the rubber hoses.

Drove it about 30 miles on Saturday, then on the way to work this morning, CEL. Going to check the code, the recheck everything again and and test the EGR again and may pull the trigger on a new EGR vavle.

 

[roadstr6]

Resistor Mod X2. Bye Bye CEL.

 

[RaleighCJ]

Whoops...P0401....these two could have something to do with it.