PCV and vac. lines, where does it go?????

Stang_ROTY · 07-31-2001, 09:52 PM

I would like to know where all the vac. lines on my intake manifold go but I can't find a diagram anywhere. Can anyone help me?? I think I might of done some damage by sending my PCV hose into the upper intake rather than the valve covers because I found oil in the upper plenum. It wasn't brake fluid as I thought.

jimberg · 08-01-2001, 12:52 AM

The PCV line does go into the upper intake. That's even what the vacuum diagram says. Don't you have the original emissions sticker? The vacuum diagram is on there. Mine was on the cover for the coil.

With a stock intake, the PCV line would go to a T-fitting attached to the bottom side of the plenum and then the other side of the T-fitting would go to the front of the intake manifold. Essentially making the PCV connect to two places on the intake.

There were two big vacuum nipples on the front underside of the upper intake. One was for PCV and the other for the evaporative emissions canister.

On the back underside of the upper intake was a vacuum tree with one large nipple and two small nipples. The large nipple had a vacuum line connecting to the vacuum tree on the firewall (brake booster, A/C, etc).

One of the small nipples would have a vacuum line going to the FPR, and the other nipple had a vacuum line connecting it to the vacuum tree on the passenger side of the engine. That line would feed the EGR vacuum control and the thermactor vacuum controls. Lines would then come up from those vacuum controls, back to that tree and then one line going to EGR valve, and two other lines going to thermactor flow control valves.

The only other line is the one going from the throttle body to the oil filler neck.

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351W 89 Mustang GT Convertible

Stang_ROTY · 08-01-2001, 08:41 AM

Jim-

I have no stickers under the hood from thefactory. This car was a drag car. It was missing a engine, tranny, and almost EVEYTHING else when I bought it.

ok. here we go

I'm not using any smog pump or cannister purge and my PCV is letting oil into the intake manifold when I hit the gas. I thought it was brake fluid from the master cylinder but it's engine oil. Now I have another problem.

To solve it, why can't I run the PCV vac. line into the oil spout on the pass valve cover and run the TB vac. that was in the spout into the intake?? That way when it leaks, the oil doesn't go into the manifold and goes back into the engine. I'm really confused and need to get this right.

I had the PCV line going into the neck of the upper manifold (the Edelbrock RPM upper has vac. holes drilled on the neck). I still have the vac. line going from the underside of the plenum to the vac. tree, and the line going from the intake to the FPR. But I need help figuring this PCVsystem out. I'm getting confused b/c I don't have all the OE smog crap on the car.

jimberg · 08-01-2001, 09:43 AM

The valve cover is not a source of vacuum. The idea of the PCV is to suck fumes out of the block. Connecting the PCV to the valve covers would be the equivalent of just plugging the PCV hole and the valve cover hole.

Here's the official diagram for my car:

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351W 89 Mustang GT Convertible

Stang_ROTY · 08-01-2001, 11:05 AM

Jimberg-Thanks for the pic. I now understand what you are saying. Sometimes I'm a little slow :-) I called Edelbrock and they said the problem is that I didn't install this plate on the lower manifold which is supposed to deflect the oil from entering the PCV valve. In order to install this plate I need to take apart the engine and lower manifold. That reall sucks. Should I a) keep running the car with the oil seeping into the manifold or b) forget about driving the car this year and sell it or rebuild it?

jimberg · 08-01-2001, 11:54 AM

Those choices aren't that great. I can understand your frustration. Giving up is not an option, so just put that out of your head.

My biggest concern with just leaving things the way they are is that there are probably other things that just aren't right. I know that draining coolant and buying gaskets is a pain, but doing it one more time would be worth it to get everything just right.

You've really only got two issues that aren't that hard to fix. First, the oil in the intake. Since you don't have that splash guard on the intake, I can only assume that you don't have that PCV filter screen, either. It's been a while, but I think the filter rests on that plate.

The next issue is the overheating. TFS TW heads may be different than Edelbrock (did Edelbrock have anything to say about the water passage issue) heads, but I doubt it. I'm sure these heads were designed to match up with late model blocks. Drilling a 3/16" hole shouldn't be that big of a deal. Cover everything with a plastic bag and have a big magnet to catch the iron shavings. The biggest problem is that you have to pull the heads to do it. Head gaskets aren't cheap, either.

Could the previous owner have already made this modification? What all did you get when you bought the car?

You may want to take your car and get the air/fuel ratio analyzed to make sure it's not running too lean.

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351W 89 Mustang GT Convertible

jimberg · 08-01-2001, 12:06 PM

I forgot to mention the other potential problem that can cause overheating. Putting the head gasket on facing the wrong way. I suppose it's common enough a problem that they have to warn you not to do it, so I thought I would mention it.

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351W 89 Mustang GT Convertible

Stang_ROTY · 08-01-2001, 12:40 PM

Jimberg- I did call Edelbrock and they siad that it si not an issue with their heads. There is no drilling required. As far as the car goes. I bought it with no engine, tranny, radiator, hood, etc. The engine I'm running I pulled out of a '69 Cougar. As far as the gaskets are concerned, my engine builder is very reputable and experienced, but you never know. So what do you think will happen if I don't install that plate in the lower manifold?? I DO have that PCV screen and the vac. fitting that plugs into the PCV grommet has two openings on it. I assume I can run the vac. into both. I also called March and they said the pulley set I'm using will decrease water flow and I should get a new crank pulley to speed up the water pump. Makes sense to me. Analyzing the air/fuel ratio is also a great idea. I know the engine is running lean because I haven't put the chip in it and stock comp. runs for 19lb injectors. So what damage can I do by not putting in the plate in the lower manifold?

jimberg · 08-01-2001, 01:30 PM

I think the underdrive pulleys are beneficial so it would be better to keep the pulleys and get a higher flow water pump. In the mean time, going back to the stock pulley may work.

A MAF computer is not programmed for any specific injectors which is what makes them so great for building up the engine. The computer will add or remove fuel depending on the feedback provided by the oxygen sensors. As long as you have a properly calibrated MAF sensor to match your injectors, you should be fine.

One question about this, though. I remember you mentioning that you aren't using the stock ignition system or stock distributor. How does the computer know what RPMs your engine is running at if you don't have a TFI module and the distributor to go with it? If it doesn't know your engine RPMs, how can it look up values for proper air/fuel control? The look up tables are based on load and RPMs. Also, wouldn't the computer just stay in open loop mode if it doesn't detect a TFI module?

I don't think a little oil in the intake will hurt you much. Do you notice blue smoke or anything when you step on it? I'd inspect a spark plug every now and then and make sure that they aren't getting fouled.

I'm going to look into the drilled hole issue a little more.

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351W 89 Mustang GT Convertible

Stang_ROTY · 08-01-2001, 01:53 PM

The car did come with the stock EFI harness so I do have the TFI unit and it is plugged into the distributor. Also, I called my Edelbrock guy and he verified for me that my heads do have the passages already machined in so I do not have to remove them. He did say to check with my engine builder and make sure that the head gaskets were put on the correct way.
I guess I can keep my car now :-)
He also said (like you) that a little oil in the manifold won't hurt a thing. He just reminded me that when I take it to the track and step on it to watch the mirror for smoke. He also suggested removing the lower man. and putting the plate on OR get a baffled grommet for the PCV valve. As far as the water pump is concerned, I have a Edelbrock Victor high flow pump but if it isn't turning at the speed it was designed for (due to the pulley) than it's basically a normal flowing pump. Regarding open loop mode, won't the comp. stay in open loop without a thermostat?
And is it true that a lean running motor creates more heat??

jimberg · 08-01-2001, 02:20 PM

Quote:

Originally posted by Stang_ROTY:
The car did come with the stock EFI harness so I do have the TFI unit and it is plugged into the distributor.

Okay, I guess I remembered wrong. I thought I read that you were using a separate ignition.

Quote:

Also, I called my Edelbrock guy and he verified for me that my heads do have the passages already machined in so I do not have to remove them.

It's not the heads that need to be machined, it's the block itself.

Quote:

As far as the water pump is concerned, I have a Edelbrock Victor high flow pump but if it isn't turning at the speed it was designed for (due to the pulley) than it's basically a normal flowing pump.

A stock pump with regular pulleys should be enough to keep your engine cool, or at least out of the ranges you're hitting.

Quote:

Regarding open loop mode, won't the comp. stay in open loop without a thermostat?

No. It bases it on the temperature of the coolant provided by the ECT sensor. Your temp is rising to the range that the computer expects.

It would be cool if there was a way to hook up a little LED to indicate whether you are in closed-loop mode or not.

Any fault that would force open-loop mode should show a check engine light or at least generate and store a code.

Quote:

And is it true that a lean running motor creates more heat??

Yes. When you're at cruise the computer will try to maintain a stoichiometric ratio of 14.7:1. The heat from this isn't a problem, though, since RPMs are low enough to give the cooling system time to remove the heat.

If, however, you try to maintain a 14.7:1 ratio under load and high RPMs, the combustion chamber (and the rest of the engine) will get real hot which would prevent some of your potential air flow. We make our best power at about 13:1 or lower because the rich air/fuel mixture keeps the combustion chamber and intake temps down allowing for a denser air charge.

The only way you are running lean is if you are stuck in open loop mode. Especially at idle and normal cruise.

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351W 89 Mustang GT Convertible

Stang_ROTY · 08-01-2001, 02:41 PM

I think I typed the wrong wording. The Edelbrock guy told me that the heads have pocket grooves manufactured in the head to prevent stem pockets from forming. I should call him back though just to verify. He said that the only cooling issue with the Edelbrock heads is gaskets being installed incorrectly. I also should call TF and ask them if any other heads would require the block to be machined.
Regarding the ECT sensor. I have mine placed in my thermostat housing, is that a problem? I think the stock 5.0 has it placed in the manifold rather than the thermo. housing? Maybe since I placed the sensor in the housing it's preventing the thermostat from opening completely which in turn restricts my water flow?
And yes, a little LCD light would be nice.

07-31-2001, 09:52 PM	#1
Stang_ROTY Registered Member Join Date: Feb 2001 Location: Berkshire County - Massachusetts Posts: 735	PCV and vac. lines, where does it go????? I would like to know where all the vac. lines on my intake manifold go but I can't find a diagram anywhere. Can anyone help me?? I think I might of done some damage by sending my PCV hose into the upper intake rather than the valve covers because I found oil in the upper plenum. It wasn't brake fluid as I thought.

08-01-2001, 12:52 AM	#2
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	The PCV line does go into the upper intake. That's even what the vacuum diagram says. Don't you have the original emissions sticker? The vacuum diagram is on there. Mine was on the cover for the coil. With a stock intake, the PCV line would go to a T-fitting attached to the bottom side of the plenum and then the other side of the T-fitting would go to the front of the intake manifold. Essentially making the PCV connect to two places on the intake. There were two big vacuum nipples on the front underside of the upper intake. One was for PCV and the other for the evaporative emissions canister. On the back underside of the upper intake was a vacuum tree with one large nipple and two small nipples. The large nipple had a vacuum line connecting to the vacuum tree on the firewall (brake booster, A/C, etc). One of the small nipples would have a vacuum line going to the FPR, and the other nipple had a vacuum line connecting it to the vacuum tree on the passenger side of the engine. That line would feed the EGR vacuum control and the thermactor vacuum controls. Lines would then come up from those vacuum controls, back to that tree and then one line going to EGR valve, and two other lines going to thermactor flow control valves. The only other line is the one going from the throttle body to the oil filler neck. ------------------ 351W 89 Mustang GT Convertible

08-01-2001, 08:41 AM	#3
Stang_ROTY Registered Member Join Date: Feb 2001 Location: Berkshire County - Massachusetts Posts: 735	Jim- I have no stickers under the hood from thefactory. This car was a drag car. It was missing a engine, tranny, and almost EVEYTHING else when I bought it. ok. here we go I'm not using any smog pump or cannister purge and my PCV is letting oil into the intake manifold when I hit the gas. I thought it was brake fluid from the master cylinder but it's engine oil. Now I have another problem. To solve it, why can't I run the PCV vac. line into the oil spout on the pass valve cover and run the TB vac. that was in the spout into the intake?? That way when it leaks, the oil doesn't go into the manifold and goes back into the engine. I'm really confused and need to get this right. I had the PCV line going into the neck of the upper manifold (the Edelbrock RPM upper has vac. holes drilled on the neck). I still have the vac. line going from the underside of the plenum to the vac. tree, and the line going from the intake to the FPR. But I need help figuring this PCVsystem out. I'm getting confused b/c I don't have all the OE smog crap on the car.

08-01-2001, 09:43 AM	#4
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	The valve cover is not a source of vacuum. The idea of the PCV is to suck fumes out of the block. Connecting the PCV to the valve covers would be the equivalent of just plugging the PCV hole and the valve cover hole. Here's the official diagram for my car: ------------------ 351W 89 Mustang GT Convertible

08-01-2001, 11:05 AM	#5
Stang_ROTY Registered Member Join Date: Feb 2001 Location: Berkshire County - Massachusetts Posts: 735	Jimberg-Thanks for the pic. I now understand what you are saying. Sometimes I'm a little slow :-) I called Edelbrock and they said the problem is that I didn't install this plate on the lower manifold which is supposed to deflect the oil from entering the PCV valve. In order to install this plate I need to take apart the engine and lower manifold. That reall sucks. Should I a) keep running the car with the oil seeping into the manifold or b) forget about driving the car this year and sell it or rebuild it?

08-01-2001, 11:54 AM	#6
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Those choices aren't that great. I can understand your frustration. Giving up is not an option, so just put that out of your head. My biggest concern with just leaving things the way they are is that there are probably other things that just aren't right. I know that draining coolant and buying gaskets is a pain, but doing it one more time would be worth it to get everything just right. You've really only got two issues that aren't that hard to fix. First, the oil in the intake. Since you don't have that splash guard on the intake, I can only assume that you don't have that PCV filter screen, either. It's been a while, but I think the filter rests on that plate. The next issue is the overheating. TFS TW heads may be different than Edelbrock (did Edelbrock have anything to say about the water passage issue) heads, but I doubt it. I'm sure these heads were designed to match up with late model blocks. Drilling a 3/16" hole shouldn't be that big of a deal. Cover everything with a plastic bag and have a big magnet to catch the iron shavings. The biggest problem is that you have to pull the heads to do it. Head gaskets aren't cheap, either. Could the previous owner have already made this modification? What all did you get when you bought the car? You may want to take your car and get the air/fuel ratio analyzed to make sure it's not running too lean. ------------------ 351W 89 Mustang GT Convertible

08-01-2001, 12:06 PM	#7
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I forgot to mention the other potential problem that can cause overheating. Putting the head gasket on facing the wrong way. I suppose it's common enough a problem that they have to warn you not to do it, so I thought I would mention it. ------------------ 351W 89 Mustang GT Convertible

08-01-2001, 12:40 PM	#8
Stang_ROTY Registered Member Join Date: Feb 2001 Location: Berkshire County - Massachusetts Posts: 735	Jimberg- I did call Edelbrock and they siad that it si not an issue with their heads. There is no drilling required. As far as the car goes. I bought it with no engine, tranny, radiator, hood, etc. The engine I'm running I pulled out of a '69 Cougar. As far as the gaskets are concerned, my engine builder is very reputable and experienced, but you never know. So what do you think will happen if I don't install that plate in the lower manifold?? I DO have that PCV screen and the vac. fitting that plugs into the PCV grommet has two openings on it. I assume I can run the vac. into both. I also called March and they said the pulley set I'm using will decrease water flow and I should get a new crank pulley to speed up the water pump. Makes sense to me. Analyzing the air/fuel ratio is also a great idea. I know the engine is running lean because I haven't put the chip in it and stock comp. runs for 19lb injectors. So what damage can I do by not putting in the plate in the lower manifold?

08-01-2001, 01:30 PM	#9
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I think the underdrive pulleys are beneficial so it would be better to keep the pulleys and get a higher flow water pump. In the mean time, going back to the stock pulley may work. A MAF computer is not programmed for any specific injectors which is what makes them so great for building up the engine. The computer will add or remove fuel depending on the feedback provided by the oxygen sensors. As long as you have a properly calibrated MAF sensor to match your injectors, you should be fine. One question about this, though. I remember you mentioning that you aren't using the stock ignition system or stock distributor. How does the computer know what RPMs your engine is running at if you don't have a TFI module and the distributor to go with it? If it doesn't know your engine RPMs, how can it look up values for proper air/fuel control? The look up tables are based on load and RPMs. Also, wouldn't the computer just stay in open loop mode if it doesn't detect a TFI module? I don't think a little oil in the intake will hurt you much. Do you notice blue smoke or anything when you step on it? I'd inspect a spark plug every now and then and make sure that they aren't getting fouled. I'm going to look into the drilled hole issue a little more. ------------------ 351W 89 Mustang GT Convertible

08-01-2001, 01:53 PM	#10
Stang_ROTY Registered Member Join Date: Feb 2001 Location: Berkshire County - Massachusetts Posts: 735	The car did come with the stock EFI harness so I do have the TFI unit and it is plugged into the distributor. Also, I called my Edelbrock guy and he verified for me that my heads do have the passages already machined in so I do not have to remove them. He did say to check with my engine builder and make sure that the head gaskets were put on the correct way. I guess I can keep my car now :-) He also said (like you) that a little oil in the manifold won't hurt a thing. He just reminded me that when I take it to the track and step on it to watch the mirror for smoke. He also suggested removing the lower man. and putting the plate on OR get a baffled grommet for the PCV valve. As far as the water pump is concerned, I have a Edelbrock Victor high flow pump but if it isn't turning at the speed it was designed for (due to the pulley) than it's basically a normal flowing pump. Regarding open loop mode, won't the comp. stay in open loop without a thermostat? And is it true that a lean running motor creates more heat??

08-01-2001, 02:41 PM	#12
Stang_ROTY Registered Member Join Date: Feb 2001 Location: Berkshire County - Massachusetts Posts: 735	I think I typed the wrong wording. The Edelbrock guy told me that the heads have pocket grooves manufactured in the head to prevent stem pockets from forming. I should call him back though just to verify. He said that the only cooling issue with the Edelbrock heads is gaskets being installed incorrectly. I also should call TF and ask them if any other heads would require the block to be machined. Regarding the ECT sensor. I have mine placed in my thermostat housing, is that a problem? I think the stock 5.0 has it placed in the manifold rather than the thermo. housing? Maybe since I placed the sensor in the housing it's preventing the thermostat from opening completely which in turn restricts my water flow? And yes, a little LCD light would be nice.