red hot exhaust manifold in 4Runner

1987 4Runner with newly remanufactured engine (which was replaced due to
damage from overheating) still has trouble with the exhaust manifold getting
red hot. The EGR valve was shot so I suspected the catalytic converter was
bad. Haven't replaced it (or EGR) yet. Instead I have hollowed it out.
The problem remains, though. Whatever ruined the first engine is still a
problem here.

One interesting note is I had to get help setting the timing. The
distributor needed to be ground out to get the timing exact as it wouldn't
advance enough. Bad distributor? Never had to replace a distributor...can
that be a symptom of failure?

Anyone have any input, questions, or ideas here? I am at wits end with this
vehicle. I am not a mechanic.

Update: I have a reman distributor, new cat and new muffler. I'll see if
that helps. Will an exhaust blockage of some sort cause this red hot
exhaust manifold? I am skepical. But the muffler is cheap enough so I will
go ahead and replace it.

I will update this with the results but still would appreciate any wisdom
any of you can provide.



"GAZ" <...@...yahoo.com> wrote in message
news:3-6dnXeQl9px79vZRVn-jA@centurytel.net...[color=blue]
> 1987 4Runner with newly remanufactured engine (which was replaced due to
> damage from overheating) still has trouble with the exhaust manifold
> getting red hot. The EGR valve was shot so I suspected the catalytic
> converter was bad. Haven't replaced it (or EGR) yet. Instead I have
> hollowed it out. The problem remains, though. Whatever ruined the first
> engine is still a problem here.
>
> One interesting note is I had to get help setting the timing. The
> distributor needed to be ground out to get the timing exact as it wouldn't
> advance enough. Bad distributor? Never had to replace a
> distributor...can that be a symptom of failure?
>
> Anyone have any input, questions, or ideas here? I am at wits end with
> this vehicle. I am not a mechanic.
>[/color]

94 Toyota 4x4 P/U 114K miles:

I think I have a similar problem. Also at wits' end.

Engine idles fast, and misses at running speed. I have multiple
problems with the engine though (the coolant lines in head corroded
into 2 firing chambers in addition to the fast idle) so it's hard to
diagnose. I replaced the head myself and now I'm down to just the fast
idle. I broke down and took it in to a mechanic who couldn't figure it
out. Now I have taken it to the Toyota dealership and they are telling
me the catalytic converter is bad. I don't understand why that would be
the case, but you noted you think yours might be causing problems.

The engine is NOT throwing any trouble codes though and does not
register overheating, so I am suspicious that this might not solve the
problem. They want $600 too.

One other problem that relates to yours: the first remanufactured head
I put on warped without the engine registering elevated temperatures,
but the heat tab on the head was melted, so it got hot somehow, which
means other parts could have warped, including the intake manifold.
This could be your problem. If the intake manifold is warped, unmetered
air gets in and the engine runs lean=hot. This could also go
unmonitored by the sensors if the fuel pump is not supplying enough
fuel. Along these lines, your fuel filter could be clogged as well.
Most of the sensors are set up to detect a running lean problem if one
cylinder is off of the others, not if all are off together, so you
don't get a trouble code. These are not common problems though, so I
would first check if the engine is running lean...a mechanic can check
the exhaust, or you can add fuel to the mixture through the intake
manifold and see if the rpms drop. I ran out of patience and took mine
in.

Are you having high idle? Throwing codes? Temp sensor reading hot? If
the exhaust manifold is red, I can imagine your head and intake
manifold could be hot enough to warp. Try checking if you're running
lean. Once one thing goes wrong though, the engine starts trying to
compensate, which will throw you off in trying to diagnose.

Also, I have a question: why did you suspect the catalytic converter?
How do you diagnose if its bad in your case?

Try posting at [url]www.toyotanation.com[/url]. There's lots of tinkerers there.

Good luck,
Will

"wlud" <wlud@yahoo.com> wrote in message
news:1145590347.876301.88650@j33g2000cwa.googlegroups.com...[color=blue]
> 94 Toyota 4x4 P/U 114K miles:
>
> I think I have a similar problem. Also at wits' end.
>
> Engine idles fast, and misses at running speed. I have multiple
> problems with the engine though (the coolant lines in head corroded
> into 2 firing chambers in addition to the fast idle) so it's hard to
> diagnose. I replaced the head myself and now I'm down to just the fast
> idle. I broke down and took it in to a mechanic who couldn't figure it
> out. Now I have taken it to the Toyota dealership and they are telling
> me the catalytic converter is bad. I don't understand why that would be
> the case, but you noted you think yours might be causing problems.
>
> The engine is NOT throwing any trouble codes though and does not
> register overheating, so I am suspicious that this might not solve the
> problem. They want $600 too.
>
> One other problem that relates to yours: the first remanufactured head
> I put on warped without the engine registering elevated temperatures,
> but the heat tab on the head was melted, so it got hot somehow, which
> means other parts could have warped, including the intake manifold.
> This could be your problem. If the intake manifold is warped, unmetered
> air gets in and the engine runs lean=hot. This could also go
> unmonitored by the sensors if the fuel pump is not supplying enough
> fuel. Along these lines, your fuel filter could be clogged as well.
> Most of the sensors are set up to detect a running lean problem if one
> cylinder is off of the others, not if all are off together, so you
> don't get a trouble code. These are not common problems though, so I
> would first check if the engine is running lean...a mechanic can check
> the exhaust, or you can add fuel to the mixture through the intake
> manifold and see if the rpms drop. I ran out of patience and took mine
> in.
>
> Are you having high idle? Throwing codes? Temp sensor reading hot? If
> the exhaust manifold is red, I can imagine your head and intake
> manifold could be hot enough to warp. Try checking if you're running
> lean. Once one thing goes wrong though, the engine starts trying to
> compensate, which will throw you off in trying to diagnose.
>
> Also, I have a question: why did you suspect the catalytic converter?
> How do you diagnose if its bad in your case?
>[/color]

The ERG valve may have been involved with the red-hot exhaust manifold. If
that goes bad, the cat can get clogged. A clogged exhaust can cause the
heat, but it is timing. I ordered a new cat and hollowed out the one on the
vehicle now. I can't get the damn thing timed correctly and neither can a
hired mechanic. I am taking it somewhere else when I have the time and
money.

Perhaps the cam is off which would make sense since it is a newly
remanufactured engine. How can you diagnose a poorly aligned cam?
Compression is very good on all cylinders. Does that tell anything?[color=blue]
> Try posting at [url]www.toyotanation.com[/url]. There's lots of tinkerers there.
>
> Good luck,
> Will
>[/color]

On Wed, 19 Apr 2006 16:21:01 -0700, "GAZ" <...@...yahoo.com> wrote:
[color=blue]
>Update: I have a reman distributor, new cat and new muffler. I'll see if
>that helps. Will an exhaust blockage of some sort cause this red hot
>exhaust manifold? I am skepical. But the muffler is cheap enough so I will
>go ahead and replace it.
>
>I will update this with the results but still would appreciate any wisdom
>any of you can provide.[/color]


It is not unusually for a exhaust manifold to get pretty hot and glow
at times under load but if it is getting really hot, there is only a
few things that can cause this. The main ones being over retared
timing or lean mixtures or both. Insuffecent airflow under hood can
aggrevate it. Never seen a bad EGR valve cause this though. EGR valve
is likely a causulty not a cause.
-----------------
The SnoMan
[url]www.thesnoman.com[/url]

I am still struggling with this. I have replaced/adjusted every damn thing.
I should have just sold it to the junk yard. Several Mechanics have looked
at it and can't figure it out. I have replaced every sensor, the distrib,
fuel injectors, cat, muffler, thermostats, radiator cap, every damn thing
under the hood. All fifteen miles of vacuum tubes have been checked or
replaced. Some of the sensors cost approximately $110 billion dollars.

never again...I will never work on a car again.

Still poor power and red hot exhaust manifold.

On Fri, 12 May 2006 22:26:02 +0800, "GAZ" <...@...yahoo.com> wrote:
[color=blue]
>I am still struggling with this. I have replaced/adjusted every damn thing.
>I should have just sold it to the junk yard. Several Mechanics have looked
>at it and can't figure it out. I have replaced every sensor, the distrib,
>fuel injectors, cat, muffler, thermostats, radiator cap, every damn thing
>under the hood. All fifteen miles of vacuum tubes have been checked or
>replaced. Some of the sensors cost approximately $110 billion dollars.
>
>never again...I will never work on a car again.
>
>Still poor power and red hot exhaust manifold.
>[/color]


You need to check the timning because if it is not set or advancing
correctly it will afterburn in exhaust manifold and heat it very hot
and also have poor power even though mixtures are correct. I feel you
problem lays there. You need to cure it though because it will fry the
exhaust valves and make thing worse. (you might do a compression check
too)
-----------------
The SnoMan
[url]www.thesnoman.com[/url]