Just below the map sensor there is another sensor that is cylinder in shape an about 5 inches long and it plugs into another connector that has vaccum lines. The cylinder has two wires that run into the side of it and on the other end it has what appears to be another vacuum line. Can anyone tell me where that line attaches to. I have replaced about every sensor on the engine, yet the service engine light comes on after driving for about 30 minutes, (shut engine off and restart and service engine light is off). Plugged the line in question and drove for over thirty minutes without service engine light coming on (not sure if this is the cause, but have spent well over $900 in service (Pontiac Dealership doesn't wish to service car, have been using Toyota dealership great people, however they have not worked on Fiero's; in our area no one wishes to work on Fieros) trying to have the light fixed, have decided to try my hand if anyone can help) after driving car for well over an hour light failed to come on during driving speed, however did come on a couple of times at red light then would go out after starting to drive again. It would really be nice to have a sketch or picture of where this vacuum line goes, have the feeling that all vacuum lines should be correctly attached to proper place. Have always like the look of the Fiero, this is my toy, new leather seats, all gauges work, new transmission, many many new parts engine runs great, (idles high for about 2 minutes before dropping even if warm). I have been looking at turbos and a way to increase horsepower greatly, even considering Northstar or 3.4 twin turbo, but would prefer the 2.8 with about 300 + horsepower if possible.

If its towards the front a little on the pass-side ---its your egr solenoid, the forward vacum your talking about , attaches to a metal line underneath the the pass-side glass--there is a little & big metal tube that run the whole firewall, if you run your hand strait forward, to where the deck-lid hinge is , then look right below that , you`ll see the opening to plug the line into. Also you should be getting a code 32. BTW Welcome to the Forum ...

Code 32
EGR Vacuum Control
Code 32 is by far the most commonly encountered trouble code. The most common cause for this trouble code is a leak in the EGR vacuum lines. This code is often disregarded since a malfunctioning EGR system seldomly has any effect on the car's driveability, and only on the engine's emissions. It's also tremendously difficult to diagnose the problem. If your car passes emission tests and is otherwise running ok, it's often not worth the trouble trying to find the problem.

here the trouble code page link:

https://www.fiero.nl/cgi-bin/main.cgi?ECMCodes

quote Originally posted by 3800superfast: If its towards the front a little on the pass-side ---its your egr solenoid, the forward vacum your talking about , attaches to a metal line underneath the the pass-side glass--there is a little & big metal tube that run the whole firewall, if you run your hand strait forward, to where the deck-lid hinge is , then look right below that , you`ll see the opening to plug the line into. Also you should be getting a code 32. BTW Welcome to the Forum ... Code 32 EGR Vacuum Control Code 32 is by far the most commonly encountered trouble code. The most common cause for this trouble code is a leak in the EGR vacuum lines. This code is often disregarded since a malfunctioning EGR system seldomly has any effect on the car's driveability, and only on the engine's emissions. It's also tremendously difficult to diagnose the problem. If your car passes emission tests and is otherwise running ok, it's often not worth the trouble trying to find the problem. here the trouble code page link: https://www.fiero.nl/cgi-bin/main.cgi?ECMCodes

What he said
Mine is disconnected and I have yet to see an error code. I was told most people don't bother wth that hose so I haven't either yet.

Ð

Thanks a million. Hope that I may be of service in some way to this forum, will be visiting often.

The rubber hose that connects to the metal line on the firewall is just a fresh air supply from the base of the air cleaner, it has no vacuum and won't cause or create a Code 32 unless the line is crimped shut (highly unlikely to happen). Its main purpose is to give a source of air to break the vacuum to the EGR valve that doesn't come from right above a hot catalytic converter and dirty swirling air in the engine compartment.

JazzMan

quote Originally posted by JazzMan: Its main purpose is to give a source of air to break the vacuum to the EGR valve that doesn't come from right above a hot catalytic converter and dirty swirling air in the engine compartment.

On an S-10 (or similar), they have a nice simple setup - but just a little cube of foam (a filter) with a hole in it to cover up the port!

Oh, and since nobody has seemingly posted this for some time....

Had no problems for two days with the line plugged that went to solenoid, purchased some vacuum line 2' and found the tube to the left and underneath the hinge, plugged everything in being sure that was my problem. Go to get the better-half and in about five minutes their it is again that "service engine soon" light and it seems to stay on. Again plug the line out of the solenoid and drive for 20 or 30 minutes, no problem with the service engine soon light. Anyone have any suggestions.....I know I am not as smart as the engineers at GM, they must have designed those lines for a worthwhile purpose.

The Code 32 is designed to activate when there's no vacuum at the outlet port of the vacuum solenoid when there should be. If the vent line that runs to the firewall is plugged then there will always be vacuum at the port, that shouldn't set a 32. I think it's just coincidence, the EGR system is only active when part throttle cruise exists above a certain RPM and below a certain TPS value. If you're getting a new 32 then you need to find out why the switch isn't reporting vacuum to the ECM.

Also, a scenario is that you've got a stale 32 and the light coming on is for a transient problem that isn't setting a code.

JazzMan

I'm not sure I understand. With the line connected to the tube at the firewall that runs over to the air inlet (air filter) I get the code 32 (service engine soon), if I disconnect the line at the firewall and plug the end that runs to the solenoid then I don't get the code. It is my understanding that that line is for the EGR solenoid to get fresh air rather than hot air and has no vacuum. I must be getting vacuum when the line is plugged, no code 32, but losing it when not. Would it be wise to purchase a new EGR solenoid for I only get the code when the solenoid has access to air.
Engine runs strong, starts well, passed emission testing, it even runs as strong pulling the air. I know this is not an easy problem for I've taken it to ASE-certified mechanic and taken it back four times with an additional bill each time. The only sensor that is not new is the one that comes out of the air inlet where the air filter is. Plus I have done better on this forum than with the dealership, we have at least gotten the "service engine soon" light to stay out, even though it is not as designed by the factory. I read somewhere in the forum that this is the most difficult code to trace and fix, maybe I'm very hard headed, but I believe it can't be that complicated, I just don't understand it being from the old muscle car days, a number of years have passed since my hot rod days, two baby girls, school, college, son-in-laws, and grandkids. Now I have a toy.....maybe to remeber those days gone by, I am determined to resolve this problem.

If you want to get rid of that check engine light code 32, then do this and you have my guarantee that it will not hurt anything and the light will be gone . The problem is that your egr solenoid is shot. very common. Take the two small black wires going to the egr switch and tie together. these two wire will pull out as they have spade connectors. What this does is make up the switch and fool the ecm that the egr solenoid is getting vacuum. I know there may be some that say don't do this, but trust me it is OK
Don

Buddycraigg has an indepth explanation of the EGR system on the Fiero V6, it's actually very, very simple in design. Here's his link: https://www.fiero.nl/forum/Forum2/HTML/045528.html

Basically the solenoid opens and closes repeatedly, and the amount of open time to closed time is used to vary the amount of time the EGR is open as a function of engine RPMs and throttle position. To check that the solenoid is working there's a vacuum switch on the port that goes from the solenoid to the EGR valve, it's normally open until it sees vacuum, then it closes. If the ECM doesn't see it close when it thinks it should be, a Code 32 gets set.

When the solenoid needs to release vacuum in order to close the EGR valve it opens the EGR vacuum line to air, that air comes from the back of the solenoid through a built in filter, that hose that connects to the back of the solenoid brings fresh, relatively cooler air from the base of the air cleaner housing.

When you cap off the back of the solenoid you're preventing the solenoid from releasing vacuum, that would likely keep the vacuum switch tripped. My guess is that there's a leak inside the solenoid somewhere that is preventing vacuum from building inside the solenoid control port that goes to the valve, the leak is slow enough to cause low vacuum under part time activation.

JazzMan

Spent most of the day trying to purchase new EGR solenoid. Napa, Auto zone, Advance and others do not have and unavailable, went to GM (Pontiac Dealer) part discontinue, however was given a phone number and part number. One left in the entire country. Ordered part will let you know if this solves the problem.

I would also like to say thanks to everyone that has provided feed back. I do plan to do an engine conversion and I'm thinking I will go with the Northstar, however I'm going to keep this engine and transmission for future Fiero, this is my third Fiero and the nicest to date. Everything will be in better than excellent shape after the above problem and I get the minor door rattles out (I've found that to be a real task trial and error). Would appreciate suggestions on that as well.
Factory radio/tape/equalizer plays great, however sometimes loses reception, smack side of radio dash and comes back, have re-soldered things that appeared to be cold solder joints, but problem presists. Problem never occurs with tape.

Again, thanks to everyone, my email address is listed and for those that have any question please feel free to contact me. I also, have a web address http://www.designoutput.com

I just had to ask this, but are you sure it is a 32 code? you did pull the codes first.. cause if it didn;t pop codes with it disconnected it shouldn;t with it connected.
just for ref if you;ve never done it, behind the cig lighter plate is the aldl connector. looking into it, short the a-b pins, (top 2 on left looking into the connector). turn key to on, buit not started, will flash ses light in a 1-2 1-2 1-2, then flash any codes 3x each, then end with a 1-2 3x. i
if you didn;t pull the codes, do that first and be sure you are looking at the right broken part.....

EGR "Service Engine" light problem solved. A very special thanks to Jazzman for the indepth link of buddycraig. It has to be the very best indebt and so clear cut explanation of the system with set by step photos. Vacuum lines all tested good on my 1987 Fiero GT as well as the EGR solenoid coil, however the 19 year old foam under the sensor was gone over the tiny hole, so I cut a piece with a razor blade to size then not having any I thought was thin enough I sliced the piece I had in half. I would have never believed this could have been the problem until reading the EGR SYSTEM is a controled vacuum leak at Buddycraig's link. Everyone must be saying who would go to so much trouble to fix something that didn't affect the performance or anything else. I just wanted it right. I once hand rewind a clock coil for a 78 Chevy just because I wanted that factory clock that I couldn't buy, and yes it took more than one try.

Thanks guys you are the greatest!

ButchM, Glad to hear all is in order now, wanted to toss in --if your ecm codes on you , and you fix a problem in the future---to purge the ecm from old codes, you can , disconnect the battery, unplug that little fuse looking thing (with no fuse in it) back by your battery, or take out the ecm fuse in the fuse box. On those type of radios---I have 2 of them---banging the side works best ...lol.. seriously I have sent one of them out for service a couple of times--only to use the old stand by---bang it on the side.

pisst, my last name has two Gs in it.

glad you got it fixed. but i dont think it's finished yet.

[This message has been edited by buddycraigg (edited 07-16-2006).]