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Discussion Starter #1
Questions:

Is the plenum-pan gasket a doable full-weekend repair?

Does anything think I could pass CA smog inspections with a M1 2BBL intake manifold instead of the stock one?


Reason's why:

I've been having a problem with pinging under light load from 3000 rpm on up for about 6 months now. Fuel doesn't seem to have any effect, I run high octane, and it still does it... I had originally thought it was fuel-related, then was able to dismiss that.

Next I worried about the plenum-pan and it's leaking gasket, but I didn't have the excessive oil consumption, and still don't.

So I've been figuring that it was spark-plug related. It followed not too long after I put in some Autolite 5224s, and I may not have gapped them correctly (Ok, I didn't gap them at all, my bad).

However, doing a post-mudding cleaning/inspection over the weekend, I pulled the air-box off the truck to get to the K&N filter. I knew mud/water had gone up the stock tube, but from popping the latches, and peeking in, I had seen that it didn't get past the filter. After getting the filter out, it was filthy, with a good amount of mud in the cotton. That was killing my torque, and it was running WAY rich, and the exhaust was a bit smokey.

While I had the airbox off, I noticed that there seemed to be a build-up around the blades in the throttle-body. Flipped the throttle wide open, grabbed a flashlight, and the entire inside of the intake is coated in black grime. Really thick, kinda wet. Not shiny wet, but sticky. Didn't like to come off, wasn't at all powdery. I have two thoughts on the source, too much oil in the K&N filter, the PCV is stuck open, or I'm sucking oil from the pan.

BUT, other from needing to be changed, the oil-level is fine. Do I just have a minor leak then?

I've also got what sounds like a vacuum leak. When I have the climate-controls to anything other than off, I hear a sucking/whistling sound. Can't hear it with the windows open or the radio on. Seems to vary somewhat with rpm, throttle, and load. Without a vacuum gauge, I can't tell how closely it follows vacuum levels. Seems to be worse during decel, or right when I step off the throttle, and tends to come/go a little bit when driving at 2000-3000 rpm with light throttle.

I figure it's the plenum-pan leak, or another leak on the intake. This is such an idiotic setup.

I'm out of warranty. I'm loathe to take it to a dealer, I don't want to be without my truck for a few days, it makes my life miserable. And frankly, he doesn't like it when I turn him over to the stealers for a few days. Tends to get orney, and breaks extra things out of spite.

Thanks for the help,
 

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I talked to a Dodge Mechanic(a trustworth friend of the family) and he said it takes them around 3 or 4 hours to do one. And that I could probably do it in about 8 hours or so. Here is a website that shows the install procedure with some pics...
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Discussion Starter #3
I think I've seen that before.

That's the older M1, the 4bbl. Runs around $250 for the intake. They have a newer intake, P/N P5007398, that's a 2bbl intake that's completely setup for all the sensors, but is $350 or so. And also hard to order, apparently demand is more than they expected.

One problem, of course, is that I'm in California... But with all the modifications that people get away with out here, I _should_ be able to swap intake manifolds... At least if I'm passing smog with flying colors, that is...
 

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Does this new manifold you want have a CARB#? Have you tried calling a "Referee" to see what problems you may encounter? This SMOG crap, unbelievable. If the vehicle runs cleaner than what it did in stock form, then the mods should be able to remain on!. And pass the test. But because some buracrate doesn't know his ass from a hole in the ground, that just isn't the case out here in CA.
 

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Has to have the CARB #. Buddy had a custom manifold on his burban and they didn't pass him cause no smog # = not somg legal.
 

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Discussion Starter #6
I know if they go peeking, they'll figure it out, but also I'm not against doing a swap every two years to pass smog... It's not THAT much work.

I did find my vacuum leak, the gasket between the airbox and the trottle-body got f'd up when I put it on. So that's cured, and it's MUCH quieter now.

I tried to test for the plenum-pan gasket leak, but according to the test procedure, you need to block the pcv valve outlet, and the inlet from the PCV to the manifold. Well, at idle, if I block the inlet from the PCV to the manifold, it stalls instantly.

This was fully warmed and idling at 625 rpm.

If I disconnect the hose from the pcv to the manifold, and let it suck air into the manifold, then block the PCV output, I do get a bit of blow-by coming out the breather hose that comes from the passenger valve-cover to the airbox.

I'm thinking that the VERY strong suction through the hose from the PCV to the manifold may be sucking oil into the intake, especially on steep uphill grades (oil pooling at the rear of the valve-covers).

I'm going to get a vacuum/pressure gauge, and the requisite caps to properly seal things off for testing, and do the test procedure correctly to see if I can determine if I have the leak or not.

It may be the sudden drop of incoming air that is making the truck stall. Or maybe my TB is screwed up, and idle isn't open enough so that it can draw air from around the blades, so it has to pull air through the passenger-side breather, through the lifter valley, and through the PCV to get any air at all... Odd, but I don't know engine internals enough to know for sure.

So I'll get the tools (only $15 or so), and see what the results are.
 

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Hey Woody, you should be able to take the airbox and throttle body off and look down into the top of the intake and see the oil or take the airbox off and turn the baffles in the throttlebody and look down in there with a flashlight, if the plenum gasket is bad, then oil will be all over the inside of it.
 

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Discussion Starter #8
Biginuf,

With just the airbox off, you can see oily grime around the blades of the TB. But I'm going to put a vacuum gauge on it to be certain. Only costs a little bit, and doesn't take very long.
 

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before the test i would cleen the throttle body blades and bore with some carb clean and a rag. then take off the IAC motor clean that really good. it sounds like when you go to test it your IAC motor is not compasating for the loss in vaccum when you pluf the pcv vaccum from the intake. just a thought so that you have good testing grounds. let me know how it goes man if you need anymore help call me between 3:00 pm and 12:30 am i will be at work and i have books and maybe a good idea. just call me on my cell#. all my info is in the members area. good luck man
 
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