figure this one out

[speadfreak]

messing around with a completely stock speed density mustang today. It was idling at like 1500 RPM with throttle body all the way closed and IAC disconnected. The IAC is working properly. I found a vaccum hose that had come off. As soon as the vaccum hose was put back on the idle came down to 800 but the car starts to miss very bad and blows blue smoke out the tailpipes. Also, when engine is running there is an extreme amount of crank case vaccum. If you loosen the oil fill cap it hisses loudly. I thought it had intake gaskets leaking so I replaced them.....same problem. If you unhood a hose and create a vaccum leak....the idle goes back up to 1500 and you can't get the car to smoke even if you beat on it. Only thing i can think is that the rings are shot and with a vaccum leak it doesnt have enought vaccum to pull oil past the rings. When the vaccum leak is sealed there might be enough to let the oil travel past the rings, but I am not real convinced on my theory. Anybody else have an idea?

 

[Daggar]

Check the PCV valve/system the EGR and the solenoids on the pass side (don't remember what they were called). Start disconnecting and capping vac lines one by one until you notice a change (hopefully for the better). Verify that the MAP sensor is in good working order or swap it with a known good one. If the fuel regulator is stock, check to ensure that the diaphram doesn't have a hole in it.

That's all I got for now.

 

[speadfreak]

For some reason I think this is a pcv/vaccum related problem. When the car is idling high, if I pinch the vac line running to the map sensor it insantly idles down and starts smoking. I'm not looking at it right now but I believe the vac lines on intake are as follows
One small one coming from vaccum block on passenger side to upper intake

One small one that goes from upper intake to FPR

One big from upper to brake booster

One big one from upper to vaccum tree on firewall

One medium one the goes from upper to MAP sensor

there is also a small one that goes from the vac block on pass. side to the EGR, and a medium size one that goes from the front of the upper (underneith) to some little solinoid looking thing over on the passenger side.

Does this sound right?

 

[Daggar]

The lines you listed appear to be correct. I'd be more concerned with 20 year old vac line that may be leaking or 20 year old vac solenoids that may be stuck.

 

[speadfreak]

The lines you listed appear to be correct. I'd be more concerned with 20 year old vac line that may be leaking or 20 year old vac solenoids that may be stuck.

They all look pretty good to me except for the one that runs from under the upper and goes to the canister on the pass. side. Even so, I tried capping that one off and got no change. And there is still that little issue of massive amount of blue smoke coming out the back It pretty much boils down to this....if I somehow purposely cause a vaccum leak, the car runs good except for the high idle. If I seal all vaccum leaks, it is sucking oil from somewhere, burning it, and blowing out the tailpipes.

 

[speadfreak]

This motor is actually in my notch right now. I had no plans on using this motor at all. I have a carbed windsor sitting on the stand ready to go in, but I have yet to buy a flywheel, fuel system plumbing, and various other small details need to complete the swap. I just thought since the weather was getting nice I would roll around with the stock motor for a little while until I was ready for the swap. I never really drove this car much, thought the idle problem was something stupid and didnt worry about it much since the motor would be ditched anyway. Now I'm just aggrevated that I can't figure this out. I wanted to sell the complete 5.0 with wiring harness and computer, but I don't want to sell somebody a possibly roached out motor.

 

[Daggar]

have you opened the TB to see if there's any oil lying in the spacer or anything?

 

[speadfreak]

yes, there is oil at the bottom of the TB, but I have no possible explination of how it got there, because the tube that goes from the valve cover to the TB is gone and both the V cover and T body have been capped off.
LOL....see what I mean?

 

[speadfreak]

I know that the 93GT that I had a few years back didn't have anykind of a vaccum line going to the MAP sensor, and two of my friend's cars are the same way. They all seem to run fine. Actually my 93 was going 12.60s on about a mid 13s combo.....so it ran better than "fine". I know it's a manifold absolute pressure sensor, but I don't really understang what it does. I don't understand why manifold pressure needs to be monitored if a mass air meter is used.......sorry to veer off topic here.

 

[1988WHTGT]

When my car was sucking in a lot at the oil cap I had a blown lower intake gasket

 

[Daggar]

When my car was sucking in a lot at the oil cap I had a blown lower intake gasket

...and you can really only get oil in that area from three places. The PCV, the oil filler vent line, or the gasket that 1988 suggests.

 

[speadfreak]

what about the baffle thing on the bottom of the lower intake that sits in the lifter valley? What does that do? It seems like it is sucking oil up through that somehow. The tube that runs from the valve cover to the TB has been removed and capped off. I have also tried pulling the PCV valve out.....all that happens is the checkball closes in the valve and I get the same thing.

 

[Daggar]

Have you tried venting that valve cover? The one where you capped the tube, I mean.

This might be a silly question but, are you by chance running a high volume oil pump?

I think that the part you asked about above is the splash guard. It's supposed to help prevent the very symptoms that you describe.

My thought at the moment is that maybe the oil in the lifter valley is not draining as fast as it's getting in there and that the oil is going up through teh PCV to your upper intake.

I guess I'm not quite ready to toss in the towel and say that's it blow by.

 

[Daggar]

One other question:

Beneath the PCV and rubber grommet, do you still have the mesh screen in there?

 

[speadfreak]

I can unscrew the oil fill cap and it would probably stay there all day because there is so much crankcase vaccum. I don't know exactly what is inside the motor. It seems bone stock. My car is a 90 and the motor is a speed density setup, so I have no idea where it came from or mileage or anything. I just got off the phone with a friend, he looked at his vaccum lines and all mine are hooked up correctly.

 

[mattmcdan]

not trying to hijack, but I am rebuilding now w/ a HV oil pump, and have that screen in the lower, are you suggesting to take it out?

 

[speadfreak]

I'm not sure if the mesh screen is in there, but I can pull the PCV out altogether and it is still sucking oil from somewhere. If I wasn't 110% positive that the intake gaskets were sealing I would pull it apart and do it again. I put new gaskets on it and even used a light film of silicone around the intake ports on both sides of the gaskets.........didn't help

I'm thinking about pulling the upper back off and capping off all the vaccum fittings except for the EGR and FPR, just to see what happens.......or is that a bad idea?

 

[Daggar]

Ok... this may sound like I'm grasping at straws (largely because I am) but your description of the vacuum coming from the oil filler neck makes be think that maybe the TPS is bad. The butterfly valve is not opening enough to properly sustain idle and it's sucking air from where it can.

This still doesn't explain the oil in the TB (unless oil is being sucked through the PCV hose) but....

when you jog the throttle... does it sound at all like air is being forcibly sucked past the throttle body blade?

 

[mattmcdan]

This may be way off but a bad master cylinder can leak brake fluid in the power booster, and your power brake vaccum hose can suck fluid in your intake causing smoke or wetness.

 

[mattmcdan]

Also dagger, do you reccomend removing that mesh screen for HV oil pump