Blocked Exhaust

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Date: Tue, 08 Jul 1997 22:44:42 -0700
From: James Brink 
Subject: EGR problems???
To: Toy4x4@tlca.org

CONRAD wrote:
> 
> This one has me stumped, I need some help.  Background...92 with a 22RE.
> The bolts holding the pipe from the cat to the muffler fell out while out
> 4-wheeling.  No spares, so I used wire to hold it in place.  It was
> anything but as tight fit.  Drove it that way for about 400 miles. I have
> no idea if this is a cause of the problem or not.  Today, on the way to get
> the bolts it started running very weakly.  Almost as if it was starving for
> gas.  Traced the problem to the hose running from the bottom of the EGR
> vacuum modulator to the exhaust pipe at the bottom of the EGR valve.  When
> the engine gets warm this hose blows off of the pipe, engine runs for
> S**T!!  I pushed the hose on as far as possible.  Cured the problem for
> about 30 seconds.  The hose then blew off of the EGR Vac Modulator.  I put
> a hose clamp on the modulator end.  That seems to be working fine.  I can
> not get a clamp on the other end, and it keeps blowing off.  All I have is
> a Haynes manual.  Good candidate for the outhouse!!   So, can anyone tell
> me why this hose is suddenly blowing off, and how I can cure the problem.
> I know a hose clamp can somehow be put on, but that cures the symptom, not
> the problem.  Any suggestions??
> TIA,
> jc
> 
> Jack Conrad,  BIG TOY, TLCA # 3851,conrad@mosquitonet.com, North Pole, AK
> 84 FJ-60, coils over  leaf-over, 350,38s, ARB
> 69 FJ40, 79 FJ40, both stock
> 92 Extra-Cab, coils over leafs, 5.29s, ARB, 35s
> Land Cruiser, don't leave the pavement without one!!

The hose you mention is from the EGR pressure chamber. Exhaust back
pressure flows from the chamber towards the vacuum modulator to open the
vacuum ports in the modulator and, depending on coolant temperature,
allows vacuum to be applied to the EGR valve.

Check for a plugged EGR vacuum modulator filter (the black cover snaps
on and off) or the modulator itself for blockage. If the backpressure
has no place to go, due to a clogged modulator, it is likely the
pressure will blow the hose off. It is difficult to say if the damage
caused this problem. The modulators are known to fail.

Hope this helps.
- --
Jim Brink				1986 Standard Bed 4X4/22R/M5
Toyota/ASE Certified Technician		32"BFG All-Terrains
(brinkjm@earthlink.net)			LockRight/4.10 Gears
********************************************************************
TLCA# (Still Waiting)                   
FOMR
MRVMA/DESERT EXPLORERS

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Date: Tue, 8 Jul 1997 22:02:04 -0800
From: "CONRAD" 
Subject: EGR problems???
To: "Cruiser List" , 

Update:  I managed to get a hose clamp on both ends.  It ran fine for about
5 minutes (until hot) then refused to go over 1500 rpm.  It almost feels ,
as I said before, like fuel starvation.  I cleaned the modulator filter,
even ran without it for a while.  No change.  What's next?
jc

Jack Conrad,  BIG TOY, TLCA # 3851,conrad@mosquitonet.com, North Pole, AK
84 FJ-60, coils over  leaf-over, 350,38s, ARB
69 FJ40, 79 FJ40, both stock
92 Extra-Cab, coils over leafs, 5.29s, ARB, 35s
Land Cruiser, don't leave the pavement without one!!

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Date: 09 Jul 1997 10:05:48 -0700
From: Robert Elsemore 
Subject: EGR problems???
To: Toy4x4@tlca.org (Return requested),

>Update:  I managed to get a hose clamp on both ends.  It ran fine for about
>5 minutes (until hot) then refused to go over 1500 rpm.  It almost feels ,
>as I said before, like fuel starvation.  I cleaned the modulator filter,
>even ran without it for a while.  No change.  What's next?

Maybe your exhaust is severely restricted.  I had an experience with my 
catalytic converter just two weeks ago.  The "honeycomb" inside began to
rattle and within a few hundred miles it completely clogged the cat.
I'm thinking that the vibrations caused from your missing bolts may have 
caused the cat to internally break apart thus clogging the exhaust resulting 
in extremely high back pressure.

- -Rob Elsemore, '85 4Runner, 

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Date: Wed, 09 Jul 1997 21:13:23 -0700
From: James Brink 
Subject: EGR problems???
To: Toy4x4@tlca.org

You probably have an exhaust system restriction. Try systematically
disconnecting the exhaust as far back as possible, working towards the
CAT. Also, a vacuum gauge is a good tool to use when checking for a
restricted exhaust. With the gauge connected to a good manifold vacuum
source, slowly raise the engine speed. The vacuum should quickly recover
after the throttle is closed. If not, there may be a restriction in the
system.

- --
Jim Brink				1986 Standard Bed 4X4/22R/M5
Toyota/ASE Certified Technician		32"BFG All-Terrains
(brinkjm@earthlink.net)			LockRight/4.10 Gears
********************************************************************
TLCA# (Still Waiting)                   
FOMR
MRVMA/DESERT EXPLORERS

------------------------------

Date: Wed, 9 Jul 1997 22:52:23 -0800
From: "CONRAD" 
Subject: EGR problems???
To: 

> From: Brandon Miller 
> Subject: Re: EGR problems???
> Date: Wednesday, July 09, 1997 3:10 PM
> Did you take off the EGR valve to see if it is blocked by Carbon?

Didn't have time this morning before work.  And, now that the exhaust is no
longer blocked and the engine running fine, I'm too damn lazy to get back
in there.  I will one day though, and thanks for the advice!
jc

Jack Conrad,  BIG TOY, TLCA # 3851,conrad@mosquitonet.com, North Pole, AK
84 FJ-60, coils over  leaf-over, 350,38s, ARB
69 FJ40, 79 FJ40, both stock
92 Extra-Cab, coils over leafs, 5.29s, ARB, 35s
Land Cruiser, don't leave the pavement without one!!

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