Any idea why specifically the recall was done to the PCV system? Any known issues in converting it back to original (and maybe adding a standard GM filter to the air filter housing)?

Input?

I'm tired of the gunk forming in the intake and gunking up my IAC and throttle plate...

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Patrick W. Heinske -- LZeitgeist@aol.com

"There are two types of Fiero owners - those that have gotten ripped off by Toddster, and those who will get ripped off by Toddster."

You're getting gunk blowing into the intake hose? Seems that should be flowing the other direction.

I did however make a change to mine before I pulled the engine apart. I moved the PCV valve to the front valve cover, and was going to put a breather on the rear valve cover, eliminating the connection intake hose. The stock PCV line is actually formed perfectly so you can do this. Just cut it back at the right spot and put the rubber elbow on.

[This message has been edited by Xanth (edited 04-28-2011).]

Isn't the PCV hose attached to the intake hose so that the vacuum created as the throttle opens pulls the fumes/etc. out of the forward valve cover attachment? Or am I misunderstanding the systems's construction?

I can't see the way the system is set up blowing air INTO the valve cover... seems more like it pulls the fumes into the intake for recombustion.

Its possible I have it backwards, but I thought the vacuum port under the manifold draws crankcase vapors in through the PCV valve on the rear cover, which in theory should cause a draw at the intake tube on the front cover. It connects to the intake hose so that a filtered air source is drawn into the crankcase.

The PCV valve hose is connected to the intake manifold. It runs to the PCV valve that is inserted into the rear valve cover. The intake manifold sucks in the air from the crankcase via the PCV valve/hose. The other hose from the throttle body connector to the front valve cover is supposed to feed air INTO the crankcase.

If you are getting an oil mist flowing backwards from the crankcase to the throttle body connector that means either your PCV system isn't sucking in air, or sucking it in fast enough, OR your engine is putting out so much blowby that it overflows the system and pushing the oil mist into the throttle body.

[This message has been edited by phonedawgz (edited 04-28-2011).]

Recall Date:
APR 23, 1990

Model Affected:
1988 PONTIAC FIERO

Summary:
PCV GROMMET OIL LEAKS, TRANSMISSION OIL COOLER LEAKS, PISTON CONNECTING ROD FAILURES BREAKING THROUGH ENGINE WALL CAUSING OIL SPILLAGE, FUEL RAIL LEAKS, COOLANT LEAKS, ROCKER COVER OIL LEAKS, AND MAINTENANCE OR SERVICE RELATED FACTORS, COULD CAUSE ENGINE COMPARTMENT FIRES.

Consequence:
AN ENGINE COMPARTMENT FIRE CAN SPREAD TO THE PASSENGERCOMPARTMENT AND INJURE OCCUPANTS.

Remedy:
CORRECT OR INSTALL NEW COMPONENTS TO PREVENT UNREASONABLE FIRE RISK.

Potential Units Affected:
102162

Thanks for posting the recall info, but that raises a question - if the PCV grommet was leaking oil, then why reroute the entire system? Why not just install a better grommet?

quote Originally posted by Gall757: Recall Date: APR 23, 1990 Model Affected: 1988 PONTIAC FIERO Summary: PCV GROMMET OIL LEAKS, TRANSMISSION OIL COOLER LEAKS, PISTON CONNECTING ROD FAILURES BREAKING THROUGH ENGINE WALL CAUSING OIL SPILLAGE, FUEL RAIL LEAKS, COOLANT LEAKS, ROCKER COVER OIL LEAKS, AND MAINTENANCE OR SERVICE RELATED FACTORS, COULD CAUSE ENGINE COMPARTMENT FIRES. Consequence: AN ENGINE COMPARTMENT FIRE CAN SPREAD TO THE PASSENGERCOMPARTMENT AND INJURE OCCUPANTS. Remedy: CORRECT OR INSTALL NEW COMPONENTS TO PREVENT UNREASONABLE FIRE RISK. Potential Units Affected: 102162

Anyone have a schematic of this?
The 88 V6 I have has the pcv valve in the (rear of the car facing) valvecover already.
There is a hose atached inder the drivers side of the top intake that is kind of cruddy....

[This message has been edited by 2.5 (edited 04-28-2011).]

In theory, oil should not travel up and into the intake, but in practice it does... especially during WOT and as the engine racks up miles and starts to experience blow by. The original routing to the tube on the firewall placed the tube at the low point in the system and probably allowed oil to accumulate in this low point. Then if the hose ever cracked (or melted) it would dump the accumulated oil onto the exhaust.

That's my theory...

This is from page 4-7 Chilton Fiero repair book. Is this incorrect, or as it should be? I have never owned a 2.8, but am in the process of installing a 3.4 into my 88 Coupe.

-Joe

[This message has been edited by josef644 (edited 04-28-2011).]

That picture is of the pre recall setup. I like fieroguru's theory on why it was changed, that whole tube could fill with oil over time.

quote Originally posted by fieroguru: The original routing to the tube on the firewall placed the tube at the low point in the system and probably allowed oil to accumulate in this low point. Then if the hose ever cracked (or melted) it would dump the accumulated oil onto the exhaust.

That is correct, but it's even worse. Any oil lost would drip directly onto the catalytic converter, which is the worst possible place since it runs considerably hotter than the rest of the exhaust system.

quote Originally posted by fieroguru: In theory, oil should not travel up and into the intake, but in practice it does... especially during WOT and as the engine racks up miles and starts to experience blow by. The original routing to the tube on the firewall placed the tube at the low point in the system and probably allowed oil to accumulate in this low point. Then if the hose ever cracked (or melted) it would dump the accumulated oil onto the exhaust. That's my theory...

The solution is to install custom piping with a oil catch can. This has been done on hotrods and race cars for thousands of years, The romans first used it on the 427 hemi's they used to race in chariots.

http://www.eliteengineeringusa.com/Catch_Can.html

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quote Originally posted by fieroguru: In theory, oil should not travel up and into the intake, but in practice it does... especially during WOT and as the engine racks up miles and starts to experience blow by. The original routing to the tube on the firewall placed the tube at the low point in the system and probably allowed oil to accumulate in this low point. Then if the hose ever cracked (or melted) it would dump the accumulated oil onto the exhaust. That's my theory...

Ah, you may be onto something there... hmmmmm.

Edit: whoops, missed the following replies as well...

I'm wondering if I just installed an appropriate rubber hose from the valve cover, mounted higher than the original one on the firewall, to the original port on the air filter housing, incorporating one of the older-fashioned in-housing filter assemblies inside with the air filter (tight fit, I'm sure, would probably take some finagling, but you follow my logic)... I already have a pre-'88 V6 intake hose without the PCV connection point.

[This message has been edited by LZeitgeist (edited 04-28-2011).]

quote Originally posted by LZeitgeist: Ah, you may be onto something there... hmmmmm. Edit: whoops, missed the following replies as well... I'm wondering if I just installed an appropriate rubber hose from the valve cover, mounted higher than the original one on the firewall, to the original port on the air filter housing, incorporating one of the older-fashioned in-housing filter assemblies inside with the air filter (tight fit, I'm sure, would probably take some finagling, but you follow my logic)... I already have a pre-'88 V6 intake hose without the PCV connection point.

I wouldn't suggest using hose, but you could probably make/bend an aluminum or steel hard line from the valve cover to the air filter housing. Just make sure the entire line travels uphill to allow any oil that gets in there to drain back into the valve cover.

quote Originally posted by fieroguru: I wouldn't suggest using hose, but you could probably make/bend an aluminum or steel hard line from the valve cover to the air filter housing. Just make sure the entire line travels uphill to allow any oil that gets in there to drain back into the valve cover.

True... I'd have to incorporate enough hose at either end, though, to allow for engine movement, but that might be a step in the right direction.

Here's a generic description of how the PCV system works.


I don't have any Fiero-specific pics, but the idea is the same. Clean air from the air filter (the metal pipe just before the throttle body) goes into the engine at the valve cover. Air with blow by and crankcase gases comes out the other valve cover, goes through the PCV valve and into the intake to be burned. On the Fiero V6, the line from the PCV valve goes under the upper intake plenum. I'm not sure where it enters the intake stream, but the metal pipe near the throttle body is the air supply going into the valve cover, not being sucked out of the engine and into the throttle body.

The first step is making sure you have a properly operating PCV system. If the PCV gromets or hoses are leaking, you aren't getting the proper airflow. Also, your PCV valve needs to be in good order. It's a cheap part and should be replaced every year, or sooner if it's suspect. If the PCV valve isn't sealing properly, airflow can go backwards through the system and you might get engine gases at the throttle body.

If you're still having problems, which isn't uncommon in high mileage engines, put a catch can in line between the PCV valve and the intake manifold. You don't need one on the pipe from the air intake to the valve cover. Putting one there won't hurt, but it won't help either.

A new PCV valve is $2.49 from AutoZone.
A PCV valve cover grommet is $1.99.

Awesome info!

It does indeed sound like I've been thinking the whole airflow in reverse.

Thanks very much, John...

quote Originally posted by LZeitgeist: Awesome info! It does indeed sound like I've been thinking the whole airflow in reverse. Thanks very much, John...

If you let the PCV valve get gunked up enough and/or you have enough of a wore out engine you can get enough blow by to reverse the airflow.

quote Originally posted by Jefrysuko: If you let the PCV valve get gunked up enough and/or you have enough of a wore out engine you can get enough blow by to reverse the airflow.

That may have been exactly what was happening before the EGR (and other) work was done. I'll check out my PCV valve and probably replace it since it's only a couple of bucks...

Also, if anyone is having problems with their PCV system, don't just block it off, fix it. As posted above it's cheap as chips and without it the blow by gases (which contain water vapor) will mix with your oil.

worse than that the system will build pressure and eminently blow every seal and gasket on the engine. making hundreds of major oil leaks
you would be driving down the road and less than 20 miles your engine would run out of oil!

quote Originally posted by timgray: The solution is to install custom piping with a oil catch can. This has been done on hotrods and race cars for thousands of years, The romans first used it on the 427 hemi's they used to race in chariots. http://www.eliteengineeringusa.com/Catch_Can.html

I tought that was Gengis Khan the first to use a Khan ( can ) LOL
427 Hemi ??

[This message has been edited by Robert 2 (edited 07-24-2011).]

I always thought that the PCV recall was done because, as the engine moved back and forth under accel/decel, it would cause the tube (and the grommet) to flex.
This would eventually cause the grommet to wear, and cause an oil leak (right above the catalytic converter, as mentioned.)
The solid tube to the intake duct eliminated any flex, and still allowed (in theory) filtered air to be fed to the engine.

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Raydar
88 4.9 Formula IMSA Fastback

Read Nealz Nuze! Praise the Lowered!

Do the 88s still have the pre-recall tubing mounted on the firewall? I thought that the newer rerouted system was incorporated into the original build of the 88.

I have a Formula with the tube still there. The recall wasn't official until 1990, but I think GM switched construction much earlier. My car was built in December of '87, and It looks like the metal tube was never used, but I can't be sure.

PCV rework was done in fire recall.
Most of recall doc's here... http://www.fieronews.net/fusion/downloads.php

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[This message has been edited by theogre (edited 07-24-2011).]

Since this found its way back to the top, I'll update it to say that since the shop that did my EGR and exhaust work cleaned out associated ports and passages, my throttle plate has not been getting gunked up (knock on wood) so I'm figuring that 20 years of baked-in goo had probably reversed the airflow and caused the initial problems I was seeking to cure.