EGR/Stalling

[900LXI]

Hello to all. Newbie here. Most recently purchased a 87' LXI FI for my daughter. I've been working out all of the neglected issues that came with car. One remaining item relates to the EGR valve. The electrical part was unplugged, and the vacuum line was capped off when we got the car. I attempted to diagnose the problem by plugging everything back in. After a few minutes of running, this caused the engine to run rough, and stall. The EGR tube also heated -up, and started to burn off the insulation. Here's where ya'll come in. I've replaced the EGR valve, but haven't plugged anything back in. I would like to identify what is causing the EGR tube to heat-up before I plug everything back in.Is it possible that it's clogged? Or could there be a problem I'm not seeing? Any help would be greatly appreciated. BTW, great forum. It's been very helpful, and user friendly.

[Dr_Snooz]

Howdy and welcome to the forum.



I've been hoping someone else would answer this, but so far no takers, so here goes. I'm not sure I know about this one. It does sound like a restriction though. Those EGR valves like to plug up, so that's nothing unusual. You might pull it off and have a look to see how plugged it is. Try cleaning it out and checking its function:

1. Warm the car up to operating temp (cooling fan comes on) and pull the vacuum line off the valve. Connect a vacuum pump to the valve. It should hold vacuum and cause the engine to stall. If not, replace the EGR valve.

2. If the valve checks out, check for manifold vacuum at the #24 vacuum line connector (don't know where this is, but, judging from the picture in the manual, it appears to be in the middle of the intake plenum, toward the top). If no vacuum, there's a restriction in the vacuum line somewhere or possibly in the connector on the plenum.

3. Next, check the vacuum line connecting to the EGR valve. There should be vacuum. If not, replace your EGR control solenoid valve.

The EGR troubleshooting section goes on, but if you don't have it by this point, let us know and we'll proceed further. You can also download the manual from this site and read up for yourself, which is probably best.

Try checking for any crud in the manifold too when you pull the EGR valve. If you have a lot of buildup, you might need to pull that tube. I'll warn you though, I tried removing it when I did my engine swap and couldn't get the exhaust manifold side to budge. Just FYI that you're in for a fight there.

It's also possible that you have the wrong vacuum line connected to the EGR valve, so you might double check your routing as well.

Anyway, hope that helps. Let us know how it turns out.

[900LXI]

Thanks for the welcome.
I've been doing some more research on the subject. The service manual mentions one of the first steps is to test the Thermovalve. Which relates to the EGR Valve, because it enables or disables the vacuum function. Here is a link to the valve I've mentioned.
http://www.autozone.com/R,APP421984/...ductDetail.htm
This is one of items I had to replace while working out the neglected issues. Unfortunately, I had no reference to which vacuum line went to which port on the valve, because they were unplugged and capped. Not to mention, the part of the valve with the ports was broke-off. I believe my first step to testing the EGR valve would be to confirm my vacuum lines are connected properly to the Thermovalve. So my next favor to ask is: Would any of you have a pic of this valve with the vacuum lines hooked up? Any help would be greatly appreciated.