EGR vacuum line (Page 1/2) damittron MAY 02, 08:28 AM 87 GT - I have noticed an odd thing happening when I open my engine cover (hood?). I notice that once in a while the EGR vacuum line is disconnected when I open the cover. It appears to share the same mysterious function as a refrigerator light...I can't see what is happening, because the cover is closed, but when I open it, it is just disconnected. I tried opening the cover slowly to see if it was being caught by something, but can't see anything catching it, I did it several times, one time it is fine, the next time, it is disconnected. I replaced the EGR valve a month or two back and never noticed it happening, but I had the engine cover off for quite a while, doing lot's of stuff in the engine bay. I did put new A/C on it, but put the engine cover back about the same time, so I don't know if that has anything to do with it. Very odd...anyone ever have this happen? fierofool MAY 02, 08:38 AM Sometimes the rubber fitting loses it's ability to grip the nipple or the aftermarket EGR valve has a smaller nipple. I have seen at least 1 V6 that had a small cable tie clamped tightly onto the rubber fitting for the purpose of keeping it on the nipple. damittron MAY 02, 08:41 AM quote Originally posted by fierofool: Sometimes the rubber fitting loses it's ability to grip the nipple or the aftermarket EGR valve has a smaller nipple. I have seen at least 1 V6 that had a small cable tie clamped tightly onto the rubber fitting for the purpose of keeping it on the nipple. That's funny! I was thinking about using a very small cable tie to hold it in place, but wasn't sure if it would snap the vacuum, due to it being caught by something on the engine cover. I think I am going to use my boreoscope to record a video of it to see if I can capture what is happening before I do that. Thanks for chiming in! fierofool MAY 02, 07:56 PM There should be nothing on the engine cover unless you've added something to the underside. There's lots of room between the EGR valve and engine cover, anyway. damittron MAY 11, 12:23 PM This is still happening. I used one of the squeeze clamps on the rubber vacuum line connector that connects to the nipple on the EGR valve, it popped right off, then I tried some fairly small wire, wrapped it around twice, spun the ends and got it nice and tight. Still popped off. I don't have a check engine light, but I haven't used my scan tool to see if there are any codes that aren't firing the light. I have had this happen on a Ford when the catalytic converter is clogged, but my Fiero has a brand new cat, so it isn't that. I have noticed that the EGR valve get VERY HOT in a fairly short amount of time...like driving 2-3 blocks at low speeds. Could this indicate a bad EGR solenoid, or something else that I haven't thought of? When it pops off, the idle surges on a fairly regular cadence by around 100 RPM or so, and has a throttle hesitation on take off, otherwise, it seems to run pretty well D. Patrick MAY 11, 03:58 PM quote Originally posted by damittron: I have had this happen on a Ford when the catalytic converter is clogged, but my Fiero has a brand new cat, so it isn't that. I have noticed that the EGR valve get VERY HOT in a fairly short amount of time...like driving 2-3 blocks at low speeds. There's no way a vacuum hose should be blowing off of an EGR valve. Pressure from somewhere is doing this. Perhaps the contents of your old cat have plugged up your muffler. Gall757 MAY 11, 04:12 PM quote Originally posted by Patrick: There's no way a vacuum hose should be blowing off of an EGR valve. Pressure from somewhere is doing this. Perhaps the contents of your old cat have plugged up your muffler. Maybe a blocked EGR tube is contributing also. fierofool MAY 11, 08:47 PM The EGR valve has a leak in it that's allowing exhaust pressure to flow through it. I suggest that while the engine is cold, remove the hose, feel underneath the valve for the diaphragm. Push up on it and while it's up, cap the hose nipple with a finger. Release the pressure on the diaphragm but keep your fingers in contact with it. If it drops, the valve is defective and needs to be replaced. If you have a Mighty-Vac pump you can test it to see if it holds a vacuum. Pull just a few hg. Don't overdo it. damittron MAY 11, 10:23 PM quote Originally posted by Patrick: There's no way a vacuum hose should be blowing off of an EGR valve. Pressure from somewhere is doing this. Perhaps the contents of your old cat have plugged up your muffler. I have an entire new exhaust. damittron MAY 11, 10:25 PM quote Originally posted by fierofool: The EGR valve has a leak in it that's allowing exhaust pressure to flow through it. I suggest that while the engine is cold, remove the hose, feel underneath the valve for the diaphragm. Push up on it and while it's up, cap the hose nipple with a finger. Release the pressure on the diaphragm but keep your fingers in contact with it. If it drops, the valve is defective and needs to be replaced. If you have a Mighty-Vac pump you can test it to see if it holds a vacuum. Pull just a few hg. Don't overdo it. The EGR is one of the new after market ones, you can't push up on it like you can the old ones. There are only small 1/4 inch holes (4 I believe), not enough room to get to the diaphram. I will try the mightyvac, I have one of those.