Hi all,

I have a 1982 Pontiac Trans Am with CFI and a dead EGR Control Valve Relay Solenoid, or more simply, an EGR Vacuum Solenoid. Since this piece broke last week, the car's idle is running all over the place, sometimes as low as 600 RPMs and as high as 1600 RPMs at times, regardless if the engine is hot, warm, or cold. The exhaust just sounds totally fubar'd and it stalls when braking now (not fun losing power brakes on the road whilst moving 40 mph), and as such, has become undriveable . Oh yeah, and there's a lovely shake to the whole car now. Joy.

Anywho, the part has been discontinued from GM, AC Delco, Borg-Warner, Wells Manufacturing, Standard Motor Products/Standard Ignition, Duralast, etc. This EGR Solenoid goes by different part numbers depending on the manufacturer. For instance, EGR200, EVS22, VS29, and CRB 22275 are all the same part from different companies. All are discontinued. I called/emailed all of them and they all told me I'm outta luck, including GM themselves. S I am totally stuck.

What I'm trying to figure out is, how do I get around my EGR system? My car is too old to be required to take part in the Emissions tests out here in Massachusetts, so I don't have to worry about that. So I was figuring that there might be a good/easy way for me to just remove/bypass the EGR bits all together. My concern is that the ECM will go looking for it, or more correctly, see that it's missing and knock and ping all over the place, which is more than likely what's happening now.

How do I overcome my dilemma folks? Suggestions? If I take my wife's car to work one more time and leave her stranded with a 10-month-old, she just may kill me!

 

Most likely the broken valve has introduced a vacuum leak at the TBI. Go to your local auto parts store and in the help section get a package of vacuum "plugs" like the one on the center vacuum port on the TBI.

Remove the vacuum line from the TBI to the valve and replace it with a plug to seal the port. I would also remove the vacuum line from the valve to the EGR and plug it also. That should get the car running again.

To remove the EGR you will need to get a cove plate to bolt onto the intake manifold to replace. I think most folks make their own, but am not sure. For now, I would just leave the disable EGR in place.

You might want to visit this board, join, and ask where they get their EGR cover plate. A lot of the guys are vette owners, but they have 82-84 CFI engines and are quite knowledgeable.

http://www.crossfire.homeip.net/

In the attached photo is the right TBI. The vacuum hose to the valve is at the top and the "plug" is in the center. Your setup should look the same.

Dave

 

Hi Dave, that's exactly what mine looks like, except imagine squirrel teeth and broken plastics on your EGR solenoid. >:-/ I tried signing up on the CFI Vault website awhile ago too, but never got my confirmation email, guess I should try again.

Anyways, I just went out and tried that, and the idle started at about 600 RPM and then climbed to 900-1,000 and then sat there for about 15 seconds. The idle and exhaust still sounded off, but not nearly as bad as it did last week when it was running through the defunct EGR system.

Then after 20 seconds, the idle dropped to around 400 RPM and it nearly stalled but jumped to 600 and then climbed back up to around 900-1,000. When it dropped down to 400, the car throw up the Check Engine light, which has now not gone off.

Besides the hose that ran from the EGR valve to the first Throttle Body, there's another hose that runs from that TB to its partner, and then from there into a box with the EFI Fuel Pump relay, the MAP Sensor, and the A/C Compressor Control relay. I'm going to guess that the hose is plugged into the MAP Sensor, as that seems the most likely canidate.

I could try plugging the ends of the second Throttle Body and the MAP Sensor, but I'm out of plugs now. :P Will that even do the trick? I know that the MAP Sensor is watching for pressure in the Intake and then sends that data off the the ECM, but I heard that if the ECM notices that the mixture is to lean or rich due to the EGR, that it is supposed to just compensate on its own. And if no data is being sent to the MAP Sensor do to it being plugged up, isn't the car going to go nuts? Plugging just the EGR Valve and the first TB seemed to just do that now.

Another option is that maybe I could just plug up the TBI and run a tube from the EGR Valve to the MAP Sensor, but to be honest, I'd rather not do that because if I'm going to have a defunct EGR system, I'd prefer to just remove it and plate it off.

Sigh... Thoughts?

 

let me know if that works...my car is doing the same thing and im going crazy trying to figure this crap out

 

Connecting the EGR valve to the MAP sensor is a bad idea. The likely result will be two systems that do not work. Note also the the MAP sensor is connected to the computer, so causing it to malfunction may have unwanted consequences for the car.

You need to verify that the engine does not have any vacuum leaks. If all your vacuum hoses are original, inspect them closely or remove them and test them with a vacuum pump. It may be best to just replace them. Also re-torque all the cover plate bolts. Some may have come loose, creating a vacuum leak. They should be torqued to 15-25 ft-lbs. Note that there are two studs among all the bolts holding the cover plate to the intake manifold. One is the stud for mounting the EGR vacuum solenoid. The other is used to connect the two ground wires from the computer to the engine. It also supports the alternator bracket. Torquing the top nut on these two will not insure a tight connection of the stud to the cover plate. I can post pictures of both if you need to see them. I have my engine about half apart at this time.

How old is your fuel filter? It could be blocked with dirt, causing uneven fuel flow and rough idling. The fuel line could also be partly blocked, accumulated stuff from the tank, including pieces of the sock on the fuel pump in the tank. Fuel pressure, measured in the fuel line between the two TBI units on the CFI engine should be ~13psi.

Problems with the TBI units themselves could be causing the rough and uneven idle. The throttle busing may be worn and require replacement. Or the unit may need to have their flow rates balanced. There is a link in one of the messages in the forum describing how to balance the units. I have never done that yet, but it does not look too complicated. I will look for the message thread this weekend and post a link to it.

These CFI engines are old now and if everything is original it will start to fail. Sorry that I don't have a quick and easy fix for your problem.

Seems like your best bet is to remove the EGR valve and the vacuum solenoid and block the associated vacuum port. The check the vacuum lines and re-torque the cover plate. If that does not solve the problem, look at the fuel supply and having the TBI units rebuilt and rebalanced.

Dave

 

Here is the link on how to balance the flows in the CFI throttle bodies...

http://www.thecubestudio.com/CrossfireThro...dyBalancing.htm

You also might want to purchase the Sept issue of Corvette Enthusiast, as they have an 8 page article on the CFI engine, and how to deal with a number of problems that you may encounter with it. The magazine is supposed to be on the newsstand now.

Dave