EGR questions Why Why Why?

[bnb1023]

I have read the many forum entries on cleaning the EGR and Throttle Body to eliminate stalling on my '96 4 cyl. It worked once, but is doing it again. I'm one that must understand why things are as they are, and so have the following questions:

1. If the EGR is bad, why does the problem only occur intermittenly vs. acting up all the time? I thought originally it was a temperature issue, but being in Ohio, it does it on both hot and cold days.
2. Before I get a new EGR on ebay for $125, can someone tell me what goes bad on an EGR? There are no electrical parts than can go bad, so why would not just a good cleaning to the trick, AND continue to do the trick?
3. How hard is it to get the EGR unthreaded off of the vertical pipe under it, as well as the two bolts going into the TB? It looks like a tight area to work in.
4. Can an EGR blockoff kit be used instead? If so, what lines must be kept in use in order to keep the check engine light off?
5. Oh, one more. I've got an oil leak and am hopeful that it is the valve cover, although I do not see any problems there yet. If I take off the cover, will I likely need to get a new $40 gasket?
I do actually like Toyotas, but starting to wonder!! Thanks.

[Kep]

1. If the EGR is bad, why does the problem only occur intermittenly vs. acting up all the time? I thought originally it was a temperature issue, but being in Ohio, it does it on both hot and cold days.

The EGR is controlled by the engine temp not the ambient temp.

2. Before I get a new EGR on ebay for $125, can someone tell me what goes bad on an EGR? There are no electrical parts than can go bad, so why would not just a good cleaning to the trick, AND continue to do the trick?

The valve has a diaphragm that can leak but most commonly they get crudded up. EGR stands for Exhaust Gas Recirculation. It is routing exhaust back to the engine. The exhaust causes heavy carbon build up. Before you buy one you could probably clean this one. Go to my previous post to you about how to clean. You have to remove the EGR in order to clean it and by your next question, you haven't done that yet.

3. How hard is it to get the EGR unthreaded off of the vertical pipe under it, as well as the two bolts going into the TB? It looks like a tight area to work in.

I was able to do this with an open ended crows foot type wrench. It wasn't bad. The vertical pipe is probably clean enough but do inspect it to make sure before you put a clean EGR valve back on.

4. Can an EGR blockoff kit be used instead? If so, what lines must be kept in use in order to keep the check engine light off?

Don't know. But the EGR helps the engine run better so why would you want to with the price of gas what it is?

5. Oh, one more. I've got an oil leak and am hopeful that it is the valve cover, although I do not see any problems there yet. If I take off the cover, will I likely need to get a new $40 gasket?

First try to re torque the spark plug tube nuts down again, they come loose. If the existing gaskets (plural, the valve cover plus the spark plug nut gaskets) are nice and pliable you could probably reuse them. However, they are usually brittle and need to be replaced.

Kep

[bnb1023]

Kep...Thanks for the reply. What bugs me the most is still the intermittent problem vs. it happening each time she drives it (it is my daughter's '96, not my '98).

[nukem678]

Awesome DUDE

[Bear95]

Originally Posted by bnb1023

I have read the many forum entries on cleaning the EGR and Throttle Body to eliminate stalling on my '96 4 cyl. It worked once, but is doing it again. I'm one that must understand why things are as they are, and so have the following questions:

1. If the EGR is bad, why does the problem only occur intermittenly vs. acting up all the time? I thought originally it was a temperature issue, but being in Ohio, it does it on both hot and cold days.
2. Before I get a new EGR on ebay for $125, can someone tell me what goes bad on an EGR? There are no electrical parts than can go bad, so why would not just a good cleaning to the trick, AND continue to do the trick?
3. How hard is it to get the EGR unthreaded off of the vertical pipe under it, as well as the two bolts going into the TB? It looks like a tight area to work in.
4. Can an EGR blockoff kit be used instead? If so, what lines must be kept in use in order to keep the check engine light off?
5. Oh, one more. I've got an oil leak and am hopeful that it is the valve cover, although I do not see any problems there yet. If I take off the cover, will I likely need to get a new $40 gasket?
I do actually like Toyotas, but starting to wonder!! Thanks.

I removed my throttle body when I changed my EGR valve. This will allow more room to work and a better view of what you are doing.
Bear

[Kep]

Originally Posted by bnb1023

Kep...Thanks for the reply. What bugs me the most is still the intermittent problem vs. it happening each time she drives it (it is my daughter's '96, not my '98).

You have a diaphragm trying to move up and down in a chamber between a spring and a vacuum. If the chamber gets dirty it might hang up one time and not another.

Similarly, you have a metal tip sealing and unsealing a metal opening (not too unlike an engine valve in the piston chamber). This is what gets coated with the carbon crud. If a chunk of carbon blocks it one time and then gets crushed the next time it would be intermittent.

Kep