this may be of benefit to others...

I installed a Hughes Plenum kit sometime ago- like maybe a couple months.. I also did several upgrades at the same time.. THAT, was interesting enough- and some of you may recall that episode.. it's here..

As it turns out, I wasn't done with plenums yet...

I ordered and installed a FM 52mm TB- and while doing so took a peek down into the intake- only to see oil in the corner.. "You've gotta be kidding me!" I screamed, and my truck answered "Well, no shizen buddy" (My truck wishes it was German sometimes).. I figured, in my angst during the previous episode that I had seriously goofed up a simple job.. (again)..

Whatever.. I'm done with floggin' plenums.. I ordered an F1 AirGap from Hughes, and used a 'gift' as a returned item to knock the price down.. She sure is pretty..



I intended on installing this weekend.. And, then, I made a little discovery after browsing the site here, and the PCV all of the sudden came into question..

The part I'm not sharing- My fuel mileage has hit the skids of late.. I went from 12mpg average to right at ten.. I figured this was the fault of a leaking plenum (again).. and wrote it off.. The F1 will end that.. forever.. but, I popped the hood for another reason all together while the truck was running (check AT fluid), and heard a whistle.. DO WHA??

The PCV valve, which is new from the plenum repair is an after market variety- and it wasn't a happy part from the onset I've figured.. But there is more.. The intake end of the hose was split the length of the nipple- big time loss of vacuum.. Not enough to cause the engine to idle terribly, but enough to matter..

I fixed that today, and I topped off the tank (and while doing so the math indicated 10.3mpg).. I replaced the aftermarket PCV with one from a dealer, and used new tubing. This next part is surprising:

I ran the truck for 80 miles today going here and there in basically city driving.. Then went and re-topped the tank.. Floggin 14.3mpg.. 14.3.. A floggin' $5 PCV, and $3 worth of tubing has been costing me serious $$ over the last 1k miles or so.. But, not only that.. The truck is a ton more responsive without that vacuum leak and I can feel the engine settling in at a steady 45-60mph, instead of that slight bog I know is costing fuel.. Damn it Jim..

I've built the truck for bottom end and economy (if I keep my foot out of it) and I've been pretty disappointed in it.. That said- I don't expect 15mpg city, 20mpg highway from it w/ 35" rubber and 4.56:1 gears either.. But I didn't expect 10mgp overall either..

Can a floggin' PCV dump a tablespoons worth of oil in an intake? I thought it was mostly vapor and such.. Is that possible?

I'm pretty sure I can pinpoint the time when the hose failed, (and that pretty much stopped the PCV from dumping oil in the intake as it was), but wouldn't (shouldn't) it have been more noticeable than just a slight roughness to the idle? I mean, that's a pretty good size vacuum leak, no?

 

A stuck PCV will throw an amazing amount of oil at the intake manifold. That's one of the reasons I make it a point to always mention that five dollar part that causes bigger headaches than the price tag might lead you to expect from it.

Bummer!

 

you suck ! ! let us know the results , i been thinking of getting it too. just cant see myself lying down 2300 dollars for gears right now ,but maybe and airgap

 

an aftermarket pcv valve will leak oil into intake making it look like plenum is blown.....only way to go for pcv is the dealer....

 

I'll buy your air gap so you don't have to go through the trouble of tearing it all apart again

 

It wasn't the "Stupid plenum..." thread that brought the PCV valve into question was it? After I took my kegger off I noticed that the oil was coming from the nipple that the PCV valves hose is connected to.
https://dodgeforum.com/forum/2nd-gen...id-plenum.html
I still have the junky aftermarket PCV valve on mine and I'm going to get one from the dealer here in a little bit while I take it for a test drive to see how it likes not dumping exhaust through that crack in the header.

Even if it was in fact the PCV valve spitting oil into your intake, just be happy that your anger over the suspected plenum repair failing lead to a nice upgrade to the intake manifold.

I was having trouble getting the cross over fuel line that connects the fuel rails to seal up when I installed the airgap. cmckenna told me about a certain type of fuel line that I should use and since I couldn't find it locally he ended up finding some and sending it to me.
Regular rubber fuel lines from the parts store won't work on the fuel rail because they're not made for 49psi constant pressure and they'll break down on the inside over time.
cmckenna had a plugged injector or two from the rubber fuel line that he used breaking down.
This is the line he sent me http://www.goodyearep.com/ProductsDetail.aspx?id=5144
It has teflon inside and rubber outside and I believe I still have a piece of it that is long enough to reach between the rails if you can't find it locally.
You have to use fuel injection clamps on it and not regular screw clamps.
In case you're wondering, the rails are moved closer together with the airgap so you do have to replace that fuel line.

 

My truck was going thru three quarts of oil a WEEK. (less than 150 miles driven per week) I thought that it was due to the blown plenum..... Did the plenum fix. Drove it for a week, and was STILL down two quarts of oil. (with the same average distance driven.) Checked the aftermarket PCV valve. Rattles nicely. Checked the rubber hose, full of oil...... Drove to the dealer, got a pcv valve from them. Oil consumption just went to zero.

The aftermarket PCV valves are not QCed as well as the units the dealer gets. They do not have consistent flow rates. Too high of a flow rate will suck oil vapor right out of the valve cover, and deposit it in your intake manifold. This has been a problem since the little fellers became so popular with our government regulators.... On some of the GM vehicles, the aftermarket units were so bad, they would cause the computer to set a code..... Change the PCV valve, problem goes away.

 

I didn't know this- this is good info for sure... Thanks for the heads up! If I can't find any, I may be giving you a holler..

 

That, and air filters. I can't understand people who balk at changing their air filters and other inexpensive items. They then scream when the vehicle has to be repaired to the tune of a few hundred dollars.

 

Don't even get me started! Oops, too late.

I had a neighbor who was almost constantly working on his '69 Plymouth and most of it was because he'd neglected to do preventive maintenance over the years. One day I watched the fool remove the air cleaner from the running engine, and when the idle jumped up a couple hundred RPM he exclaimed "Wow!", then "Look at how filthy this thing is! I guess I should change it more than once every seven years!" -- right before rapping it against the bottom of the breather. Which of course sent what looked like a gray baby blanket right down the carb throat.

I helped him rebuild the heads the following weekend.