Intake Manifold Air Surge Tank Question

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Gerrha

Gerrha

Joined
Jan 2, 2024
Threads
30
Messages
200
Location
Houston, TX
I am starting the engine rebuild on my 97 and for no real reason, started with the intake manifold air surge tank. I wish I had taken a before photo, but once again I forgot. A photo of it is below. At this point, I have two questions.

1. As you can see, the gasket surfaces are pitted. I used 220-grit sandpaper to get them to this point. Is that level of pitting a problem with the gaskets?

2. The two blue circles are for the EGR system with the inlet on the right and outlet into the manifold on the left. When I took this thing apart, the left outlet area was not just blocked, it was completely filled with very tough solid black stuff. I had to chisel through it, and it took over a month of soaking with Jasco paint & epoxy remover to get it to the point in the pic. That can't possibly be normal, so what might have caused that? Am I correct that there is no engine warning for this issue?

Thanks


IMG_6977.webp
 
doc_random said:
There is a malfunction indicator for insufficient EGR flow: P0401.
View attachment 4117237
Click to expand...
Is there a way that warning could be deactivated? I bought this LC and had it shipped to my address. After that, I drove it for maybe 5 miles for a safety inspection. I did not see a warning. Since then, I have been rebuilding it and discovered the totally blocked EGR line. Seems weird that no warning was shown.
 
Gerrha said:
Is there a way that warning could be deactivated? I bought this LC and had it shipped to my address. After that, I drove it for maybe 5 miles for a safety inspection. I did not see a warning. Since then, I have been rebuilding it and discovered the totally blocked EGR line. Seems weird that no warning was shown.
Click to expand...
I think "air surge tank" in your title may be confusing to some.
Yes, there are many threads on the EGR delete topic. Sometimes the EGR fails and people disconnect vacuum and add a 4.7K-ohm resistor to the harness side of the thermistor. The EGR pipe has been known to scorch the wiring harness and cause many problems.
One starting point:
S

Thread 'EGR delete step by step'

Hi everyone im new to the fzj80 world bought one over the summer for a camping rig and my winter tank to get to the hospital on the days I work. I know im going to make some of you mad by asking im looking to get rid of the egr system and was wondering if someone had good pictures and instructions for getting rid of it. I live in WI and there's no emission's testing. again sorry I know the topic has been brought up before and I have looked through the serch bar and its not clear just spaced out and with different models. I have a 1994 with the 4.5 and the obd1 reader. Thanks for any help...
 
doc_random said:
I think "air surge tank" in your title may be confusing to some.
Yes, there are many threads on the EGR delete topic. Sometimes the EGR fails and people disconnect vacuum and add a 4.7K-ohm resistor to the harness side of the thermistor. The EGR pipe has been known to scorch the wiring harness and cause many problems.
One starting point:
S

Thread 'EGR delete step by step'

Hi everyone im new to the fzj80 world bought one over the summer for a camping rig and my winter tank to get to the hospital on the days I work. I know im going to make some of you mad by asking im looking to get rid of the egr system and was wondering if someone had good pictures and instructions for getting rid of it. I live in WI and there's no emission's testing. again sorry I know the topic has been brought up before and I have looked through the serch bar and its not clear just spaced out and with different models. I have a 1994 with the 4.5 and the obd1 reader. Thanks for any help...
Click to expand...
I was not sure what the normal name was, but that is the Toyota name for it. What is the normal name?

I am not looking to deactivate the EGR system monitoring. I was wondering why did I not see it? If the previous owner deactivated it, that will make me wonder what else was deactivated.

Would you happen to know what would cause it to be so badly plugged?
 
Gerrha said:
I was not sure what the normal name was, but that is the Toyota name for it. What is the normal name?

I am not looking to deactivate the EGR system monitoring. I was wondering why did I not see it? If the previous owner deactivated it, that will make me wonder what else was deactivated.

Would you happen to know what would cause it to be so badly plugged?
Click to expand...
This is the thermistor location. Vertical plug going to the back of the EGR flow channel in the intake manifold.
There is carbon in the exhaust gas. I haven't seen this posted, but my theory is the intake manifold is much cooler than the exhaust and this will condense the soot into carbon build up. It coats the inlet from the sides, eventually blocking the flow. Some have said it was an oily depost, but it may harden over time.
1775506444198.webp
 
doc_random said:
This is the thermistor location. Vertical plug going to the back of the EGR flow channel in the intake manifold.
There is carbon in the exhaust gas. I haven't seen this posted, but my theory is the intake manifold is much cooler than the exhaust and this will condense the soot into carbon build up. It coats the inlet from the sides, eventually blocking the flow. Some have said it was an oily depost, but it may harden over time.
View attachment 4117247
Click to expand...
This is the wiring harness by the EGR pipe. Mine had to be repaired, and was wrapped in insulation at that time. The large nut on the EGR can be very difficult to remove.
1775507068391.webp
 
doc_random said:
This is the thermistor location. Vertical plug going to the back of the EGR flow channel in the intake manifold.
There is carbon in the exhaust gas. I haven't seen this posted, but my theory is the intake manifold is much cooler than the exhaust and this will condense the soot into carbon build up. It coats the inlet from the sides, eventually blocking the flow. Some have said it was an oily depost, but it may harden over time.
View attachment 4117247
Click to expand...
I agree with you on the deposition concept. That might explain all the problems people have reported for the EGR system. In my case, it was not oily. It was shiny deep black in appearance and almost crystalline. That is why I chose the paint & epoxy remover, but even then, it took over a month to get it out of there.
 
This is a good write up with many pictures and labels.
cahill

Thread 'PO401 and EGR/air intake manifold with pictures'

So a few months ago I got a P0401 and did a lot of reading on mud and the FSM in an attempt to get things lined up for taking care of the problem. I am a poor mechanic but want to learn so figured I'd give tackling this problem a try.
I had a week to get it done (it shouldn't take that long) and didn't have time to do as much diagnosis/trouble shooting as I would have liked but was pretty certain my EGR regulator and valve were ok. I wasn't sure about the VSV and decided to replace it as well as the other components as they weren't looking great. I just didn't want to have to come back and...
  • Like
 
doc_random said:
This is a good write up with many pictures and labels.
cahill

Thread 'PO401 and EGR/air intake manifold with pictures'

So a few months ago I got a P0401 and did a lot of reading on mud and the FSM in an attempt to get things lined up for taking care of the problem. I am a poor mechanic but want to learn so figured I'd give tackling this problem a try.
I had a week to get it done (it shouldn't take that long) and didn't have time to do as much diagnosis/trouble shooting as I would have liked but was pretty certain my EGR regulator and valve were ok. I wasn't sure about the VSV and decided to replace it as well as the other components as they weren't looking great. I just didn't want to have to come back and...
  • Like
Click to expand...
Thanks!
 
take the dowel pins out and keep sanding on a sanding block until its smooth.

drill bits go right though that EGR carbon, pretty normal happens on alot of other engines too.
 
TheBussman said:
take the dowel pins out and keep sanding on a sanding block until its smooth.

drill bits go right though that EGR carbon, pretty normal happens on alot of other engines too.
Click to expand...
Thanks, would you happen to know the part number for the pins if they need replacement?
 
doc_random said:
This is a good source for part numbers. It takes a while to get the hang of the navigation as it was all worldwide models.
Click to expand...
Thanks, I have used Partsouq many times and others like Impex and Amayama. But, in this case, regarding the intake manifold, there is no part shown for those pin rings. For the cylinder head, they do show them, but they are a different size.
 
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