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2005 Ram 4.7L major misfire but Goodyear's computer says no problem

@“Honda Blackbird”

Back in the 90s I read an article in a magazine . . . seems they were testing plastic engine oil pans

Plastic timing case covers and plastic valve covers seem to already be pretty common

I just remembered something from pretty far back . . . I remember on some cars, when you wanted to replace a leaking headgasket, and the car had a plastic intake manifold, if you weren’t extremely careful when removing hoses from that manifold, it would break

The plastic would become somewhat brittle. The best way to prevent this was to very carefully cut off the hose, versus trying to remove and reuse it. Using those hose pick tools sometimes worked, but even if you worked that hose pick all the way around and the hose spun freely, when it came time to pull it off, sometimes the plastic hose pipe would break off of the manifold, as well

I’ve seen many guys over the years light a cigarette, inhale a lung full and then blow smoke into vacuum hoses and pipes, in hopes of finding a leaking vacuum door lock actuator, leaking hvac vacuum diaphragm, leaking intake gasket, etc. It often worked, but they were usually tired by the time they found the leak.

Back in the days when car electronics were still rather primitive, and scan tools weren’t so good, either, I saw guys spray carb cleaner at suspected vacuum leak sites, hoping the idle would change. It sometimes worked. But the results were also subject to interpretation. One guy would swear on his mother’s life that the idle went up 50rpm, while the other guy would swear that the idle didn’t change at all

HA…yes…Ive seen the same cigarette smoking guys do that too! Also the spray trick does work if you pay attention AND the leak is substantial enough. The idle will go down when using an oil spray and is usually accompanied by smoke out the tail pipe…which is another reason I use oil based sprays…not sure what happens when using carb cleaner since it burns. The vacume leak almost always produces a higher idle… As in the Air Idle Control Valve scenario but who knows what the engine does with a flammable mix going into the leak…lol

I imagine all plastics get “Cooked” over time…you would think they would use a plastic that is more…well…Plastic in nature…and would want to bend or flex after being heated. But maybe the long term testing is being conducted in the field to save on R & D ? LOL Dunno… When I try to get hoses off…I use my Snap On hose pick tool…pry under on section…spray Blaster onto the lifted part of the hose…and then wiggle the pick around the nipple to spread the Blaster a bit… they pop off like magic. But not when any component is brittle…when that is the case…something breaks and repairs expand as they contract.

Man Im telling you…they are going to try and Foist the most plastic upon us that they can… Iron used to be the industry’s plastic…look where we have gotten ourselves today…

There is still more than one method for everything I suppose. Always will be as long as people are doing the work.

Blackbird

@“Honda Blackbird”

A few years ago I was working on a truck with a P0171 . . . straight 4 with a plastic intake manifold

it had an electronic throttle, and the idle was absolutely perfect. smooth as a baby’s bottom.

My colleagues swore on their mom’s life there’s no way the engine has an intake leak

I had already ruled out fuel and ignition problems

I hooked up the smoke machine and quickly saw the intake manifold itself was leaking. At a seam, from where the two halves were pressed together. But the manifold did not look damaged or distorted in any way

Until you saw the smoke, you would have thought the manifold was just fine

My colleagues saw this and couldn’t wrap their heads around the fact that the engine was running so smoothly.

Rather than try some hokey repair involving glue and/or rtv, I replaced the intake manifold. I hooked up my scanner and initially did NOT clear the dtc. I let it up warm up, and the fuel trims remained at 0. After driving the truck, letting everything get warmed up, I checked again. It was still at 0, and that’s when I cleared the dtc and declared the repair a success

I’m not sure why the intake leaked at the seams, but who really cares? That truck has returned for several regularly scheduled services since then, and that code has never returned.

Maybe some smart guy will decide to use plastic steering knuckles or brake rotors :fearful:

A lot of cars had separate intake manifolds and valley covers. Made it a lot easier to change the manifolds.

WOW… Why did you suspect a leak… Oh the code… duh. Yeah I think wherever the main seam is…on the plastic stuff… that is where problems arise. I had to replace the Plastic/Metal conglomeration of an intake on my girls 96’ Mustang GT because it was slowly leaking coolant out the top …Apparently they are known for this and it can also fail in a way so as to suck in coolant into the cylinder…so away it went. I did this what 1.5yrs ago now? Working fine with new and updated style intake…I forget if the NEW one had the metal incorporated in it and the old one was all plastic… Yes I think thats how it went…the old was entirely plastic and the new used Aluminum for the coolant run…and plastic for the rest. Cost was $177 for new updated intake.

I dunno… more and more plastic keeps showing up on cars. When you open the hood on many if not most cars…you are usually greeted with a few square acres of the stuff. Some of todays engines are ugly to be quite honest. I like the days when mfg’s were proud of their valve covers and displayed them proudly… That went out in the late 90’s I think. Oh well…Im sure more plastic is on the way.

Blackbird