EGR Mystery

Pluton

 
Joined
Oct 12, 2004
Messages
418
Searched this, but need suggestions, please. '87 FJ60, stock under hood. Ran fine, all emissions stuff hooked up and running. Carb starts to leak gas, had FORMER trusted, experienced shop drop on rebuilt carb.(I know,I know, I shoulda had it rebuilt by a real person like Jim C. or Mark A., but...) Comes back with ball bearing inserted into vac hose between EGR Vac Mod and EGR(disabling the EGR). I remove BB and now egr valve opens when it's not supposed to...idle, gentle acceleration, etc. All EGR components check good, according to the tests in the Emissions Manual. What would cause EGR to operate when it's not supposed to? Besides checking the vac port connections on the v/c side of carb(which APPEAR to be hooked up correctly...but they're hard to see and I kinda don't know what I'm looking at in there), what else? Some posts had the HAC valve affecting the EGR, etc, any suggestions would be extremely appreciated. Thanks, in advance.
Keith B.
 
Joined
Aug 2, 2004
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San Francisco Bay Area
I think the EGR valve gets its vacuum from the one the 4 hoses on the inside side of carb. I would pull the air clearner and double check the hoses are right.I think the EGR one should be the first one closest the front of cruiser. On the first main page in the emmisions manual with all the pictures it shows the order. It seems like something has to be hooked up wrong or your modulator is bad. Also the VSVcould be bad. Did you check that out good?

Goodluck
 
Joined
Nov 16, 2004
Messages
844
EGR Vac Lines...

EGR valve DOES NOT get vac 'directly' from Carb . . .

It gets vac applied via a control valve that is connected
via a VSV to carb and a vac line thru one of the thermal vac contol valves then to the carb.

Ya need FSM, Emissions....

Scanned a page for ya . . .ain't smart enough to figger out how to upload to 'mud' site . . . :crybaby:

send e-mail to pete@flca.org and I'll send the pdf image....
 
Joined
Mar 12, 2004
Messages
688
Sounds like a bad egr vacuum modulator or BVSV.
Seems you have access to an emissions manual. I'd check those items again.
A bad egr valve with a weak internal spring, or carbon causing the valve to stick open could cause egr flow at inopportune times as well.

.
 

Pluton

 
Joined
Oct 12, 2004
Messages
418
Thank you all for the replies, I'll let you know how it all ends......it will end, won't it?
 

lovetoski

SILVER Star
 
 
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Jul 13, 2003
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Pluton said:
Thank you all for the replies, I'll let you know how it all ends......it will end, won't it?
Yes. Given enough patience, logic will prevail.
 
Joined
Jul 8, 2004
Messages
996
Location
Portland, OR
not that it's any consolation, but it took replacing both BVSV's, the EGR Vacuum Modulator, and the EGR valve itself to solve an almost identical problem with our truck.

started with the modulator and that didn't cut it. next pulled the EGR valve itself and found that the diaphram was heavily carboned up and toast - replaced the valve which helped but problem still existed. replaced both BVSV's along with a couple of sections of vacuum hose and bingo, the problem was completely eliminated and the truck runs great. passed emissions with flying colors/no issues where it had struggled before....

hth,
-dogboy- '87 FJ60
 

Pluton

 
Joined
Oct 12, 2004
Messages
418
Mystery Solved

For anyone who gets a misbehaving EGR system after installing an out of the box "rebuilt" carb, take heed: SUSPECT THE CARB! Finally installed a OEM new carb[$603 at 1sttoyotaparts.com...GAK!...such a deal...that was a chunkochange] and the truck runs perfectly, just as it had before. No flat spot @ 2500rpm, no hesitating, no odd acceleration behavior, with all emissions stuff hooked up and working. My lesson for today: If your carb is worn out or starts leaking from old age, either have it rebuilt by an actual[expert] human being or get a new one...but stay away from the out of the box rebuilts. Thank you, and Good Night!
 
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