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egr cold start


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chas
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Mar 14, 2015, 12:00 AM

Post #1 of 20 (1278 views)
  post locked   egr cold start  

when i start my car cold the EGR system and vsv is open.
as the temp rises it closes then opens under load or throttle up.
is it correct for the EGR system and vsv vacuum open on cold starts?


(This post was edited by chas on Mar 14, 2015, 12:08 AM)


Hammer Time
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Mar 14, 2015, 5:30 AM

Post #2 of 20 (1250 views)
  post locked   Re: egr cold start  

Is this a Ferrari or a lawnmower?

You should know how it works. YEAR? MAKE? MODEL? ENGINE SIZE?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chas
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Mar 14, 2015, 10:41 AM

Post #3 of 20 (1240 views)
  post locked   Re: egr cold start  

yes, i know how it works.
it functions but vacuum is on when cold start.
should it not be closed on cold start?
all EGRs and vsv work the same, no?
as an experiment i did this.

with engine stone cold.
1. open hood
2. turn key to "on" with panels lights for oil and CEL on. did not start it up.
3. go back around to front. disconnect vacuum line out from the vsv at the vacuum rail to EGR and modulator.
3. draw through it with my mouth. vacuum was open through the vsv. i could draw through the vsv
4. removed the plugin to the vsv.
5. draw on the vacuum line again with my mouth. vsv vacuum was closed. could not draw through the vsv.
6. plugged the vsv plugin back in. it opened. could draw through it again.
this test was done stone cold.

when at running temp i removed the vacuum line again from the out port to the EGR and modulator.
at idle it is closed.
when i rev it a little i put my mouth on the vsv outport. it opens. i can draw through it. then closes as it returns to idle. could not draw through it.
when it warms up a little the vsv opens and closes and seems to function normal.
is this normal?
is the vsv vacuum and EGR supposed to be a closed circuit on cold start?
thanks H.

94 toyota pickup 22re.


(This post was edited by chas on Mar 14, 2015, 10:57 AM)


Hammer Time
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Mar 14, 2015, 10:50 AM

Post #4 of 20 (1236 views)
  post locked   Re: egr cold start  

When I said you know how this works I was referring to the forum and your lack of vehicle information but now that you have expanded, no, you do not understand how this works and no, they do not all work the same.
If this is all still hooked up properly it will work the way it was designed. The valve is open because it is supplying a bypass for the vacuum back to the manifold and when it closes, it basically forces vacuum to the EGR valve.

All this is assuming that this is Federal/Canadian emissions and not California.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Mar 14, 2015, 10:53 AM)


chas
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Mar 14, 2015, 11:06 AM

Post #5 of 20 (1227 views)
  post locked   Re: egr cold start  

ok, so the vsv vacuum is supposed to be open on this model vehicle when stone cold?
its a calif car.
i used the the vacuum hose diagram under the hood for CA.
i was not sure if the EGR and vsv was working proper on cold start.


(This post was edited by chas on Mar 14, 2015, 11:08 AM)


Hammer Time
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Mar 14, 2015, 11:08 AM

Post #6 of 20 (1224 views)
  post locked   Re: egr cold start  

Yes, closing it applies EGR vacuum if the vacuum modulator allows it.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chas
User

Mar 14, 2015, 11:10 AM

Post #7 of 20 (1222 views)
  post locked   Re: egr cold start  

H, i dont think were on the same page.
is the vsv vacuum and EGR supposed to be open or closed when cold start on the toyo pickup 22re?


(This post was edited by chas on Mar 14, 2015, 11:11 AM)


Hammer Time
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Mar 14, 2015, 11:17 AM

Post #8 of 20 (1216 views)
  post locked   Re: egr cold start  

Yes







PURPOSE
The exhaust gas recirculation (EGR) Valve is a vacuum operated valve which opens and closes a passage from the exhaust manifold to the intake manifold. This allows flame temperature in the combustion chamber to be lowered by diluting the incoming mixture with exhaust gases limiting the formation of nitrous oxides (NOx) .

OPERATION
At specific times determined by the Thewrmal vacuum valve (TVV) the EGR Valve opens and allows exhaust gas to flow to the intake manifold. The amount of exhaust gas introduced to the intake system is directly relative to pressure in the exhaust system.


PURPOSE
The exhaust gas recirculation (EGR) Vacuum switching valve (VSV) controls the regulated vacuum applied to the EGR valve. The Engine Control Module(ECM) uses the VSV to prevent EGR operation when the engine is cold to improve driveability.

OPERATION
The VSV receives voltage whenever the ignition switch is turned on. When EGR is required, the ECM grounds the remaining terminal which opens the VSV vacuum passage allowing vacuum to the EGR valve.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Mar 14, 2015, 11:24 AM)


Tom Greenleaf
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Mar 14, 2015, 11:23 AM

Post #9 of 20 (1214 views)
  post locked   Re: egr cold start  

Is the truck and this engine running properly now and you just stumbled on this somehow?


Being a Toyota especially (others too) are good at custom engineering specs for these things for the destination they will be sold (or expected to be) as well any vehicle makes does.


General on EGR times to operate would be less to none cold and at idle and none again at full throttle. Exactly what temp and load on engine would vary. If not running properly and you think this is the reason I would have to buy some real detailed info for the specific engine sold to where with what specs.


What is the problem you are having if any?


T



chas
User

Mar 14, 2015, 12:01 PM

Post #10 of 20 (1207 views)
  post locked   Re: egr cold start  


In Reply To
Is the truck and this engine running properly now and you just stumbled on this somehow?


Being a Toyota especially (others too) are good at custom engineering specs for these things for the destination they will be sold (or expected to be) as well any vehicle makes does.


General on EGR times to operate would be less to none cold and at idle and none again at full throttle. Exactly what temp and load on engine would vary. If not running properly and you think this is the reason I would have to buy some real detailed info for the specific engine sold to where with what specs.


What is the problem you are having if any?

T

chuck>>>>
the EGR had a problem.
the EGR VSV was bad and had a few bad vsv plugins on the vsvs'...the vsv plugins were worn out and broken wires at the plug to the vsv.
i got some good ones in good condition.
wired them in taking note of which wire on the harness goes on top and bottom to the harness.
the EGR vsv still did not work.
i switched the wiring polarity on the EGR vsv plugin.
now it worked. i guess the polarity was backwards. bthuom how i got it wrong.
but i still suspected a problem because the EGR vsv vacuum is on when cold start.
Hammer said all is good so i guess ill leave it alone.
any more suggestions Tom?
is it working proper?

ever since the conceptiion of the car it became a source of polution.
in the turn of the century in the early 1900s that were not many cars on the road.
as the population grew and more cars on the road.
air polution became a problem.
also get rid of leaded gas and TEL



Link deleted not allowed


and i think there was another called MSB?
they were all poison


im all for clean air.
alot are to young to remember way back in the 60s and 70s what it was like.
the air was terrible.
there was a dark grey almost black muck in air.
my eyes watered and chocking on the bad air.
the air is much better now.



(This post was edited by Hammer Time on Mar 14, 2015, 12:13 PM)


Tom Greenleaf
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Mar 14, 2015, 12:13 PM

Post #11 of 20 (1197 views)
  post locked   Re: egr cold start  

Sorry for posts stepping on post with this thread now I have run out of time and have to go. We all want engines to be clean running and well all the time.


Link you posted really isn't allowed and probably be removed. Saw some of just the garble saying LEAD in fuel and TEL is the same thing BTW "TetraEthylLead" was the product used to make cheaper low octane fuel have the "anti-knock" rating of same fuel without cheaper than using more % of real crude oil to make it. Lived all thru all that mess and politics of it. Was a real problem upon introduction no longer a single thread about a lead contaminated fuel issue on this site that I can recall and was a routine problem back when.


Gotta go - sorry - will read the rest quite a bit later,


Tom



chas
User

Mar 14, 2015, 12:16 PM

Post #12 of 20 (1193 views)
  post locked   Re: egr cold start  

why did you delete that link?
whaddya mean not allowed?
this is part of the history of the car and why things are the way they are.
i lived through it too.
put it back please.


(This post was edited by chas on Mar 14, 2015, 12:19 PM)


Discretesignals
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Mar 14, 2015, 12:21 PM

Post #13 of 20 (1189 views)
  post locked   Re: egr cold start  

I'm looking at the diagram above and the VSV has nothing to do the the EGR system. Maybe it is the wrong diagram or something. The VSV according to the diagram is used for the pulse air injection reaction valve.

Thermal vacuum valve should be closed when the engine is cold, so vacuum can't reach the valve. EGR valve should never ever be open at idle.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Mar 14, 2015, 12:48 PM)


Hammer Time
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Mar 14, 2015, 12:41 PM

Post #14 of 20 (1185 views)
  post locked   Re: egr cold start  

I guess it's time you read the rules.

FORUM RULES



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Hammer Time
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Mar 14, 2015, 12:48 PM

Post #15 of 20 (1182 views)
  post locked   Re: egr cold start  

Here's a different diagram.

The valve stays open and vents vacuum back to vacuum. When the valve is closed it allows vacuum to build and then open the valve. It works opposite of other valves.





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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Mar 14, 2015, 12:48 PM

Post #16 of 20 (1181 views)
  post locked   Re: egr cold start  

If this is CA emissions, it probably has a VSV for EGR. I do know that Toyota VSVs will not be activated by the engine computer unless the ECU sees vehicle speed.

I usually T in a vacuum gauge into the hose that goes to the EGR valve and drive the vehicle. When the engine is warmed up, you should see 5-7 inches when you accelerate.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Mar 14, 2015, 12:50 PM)


chas
User

Mar 14, 2015, 3:08 PM

Post #17 of 20 (1173 views)
  post locked   Re: egr cold start  


In Reply To
DS>>>>>If this is CA emissions, it probably has a VSV for EGR. I do know that Toyota VSVs will not be activated by the engine computer unless the ECU sees vehicle speed.

I usually T in a vacuum gauge into the hose that goes to the EGR valve and drive the vehicle. When the engine is warmed up, you should see 5-7 inches when you accelerate.


DiscreetSignals>>>>>I'm looking at the diagram above and the VSV has nothing to do the the EGR system. Maybe it is the wrong diagram or something. The VSV according to the diagram is used for the pulse air injection reaction valve.
Thermal vacuum valve should be closed when the engine is cold, so vacuum can't reach the valve. EGR valve should never ever be open at idle.

chuck>>>>>it is a CA model. i usedd the vacuum diagram under the hood for CA.....i think the diagram is ok or close. this 1994 CA model does have 2 vsv in the EGR system and does have a PAIR valve. the first vsv is the one im looking at because it's open on a cold start. the EGR should be closed when cold start or idle.

the vsv is open on cold start then closes after it warms a little then seems to function normal at operating temp.
im pretty sure the EGR vsv is supposed to be closed on cold starts and at idle. it's supposed to open when throttle up under load.

is it possible the vsv plugin is wired backwards? is there a + - polarity or dont matter how it is wired with the 2 wires in the vsv plugin?




(This post was edited by chas on Mar 14, 2015, 3:14 PM)


Hammer Time
Ultimate Carjunky / Moderator
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Mar 14, 2015, 3:51 PM

Post #18 of 20 (1166 views)
  post locked   Re: egr cold start  

One more time I will tell you how this works and then I'm going to close the question.

The valve bypasses the vacuum so it doesn't build up when open. When it closes, it seals off the vent and causes vacuum to reach the EGR. Thus, it is open when the EGR is not applied.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
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Mar 15, 2015, 1:27 AM

Post #19 of 20 (1154 views)
  post locked   Re: egr cold start  

A clip from post #17 ">>
chuck>>>>>it is a CA model. i usedd the vacuum diagram under the hood for CA.....i think the diagram is ok or close. this 1994 CA model does have 2 vsv in the EGR system and does have a PAIR valve. the first vsv is the one im looking at because it's open on a cold start. the EGR should be closed when cold start or idle.

the vsv is open on cold start then closes after it warms a little then seems to function normal at operating temp.
im pretty sure the EGR vsv is supposed to be closed on cold starts and at idle. it's supposed to open when throttle up under load.

is it possible the vsv plugin is wired backwards? is there a + - polarity or dont matter how it is wired with the 2 wires in the vsv plugin? <<"


********************
chas: Going blind trying to read your script. Whatever the reason a device or knowing how to use it or a forum it lacks and is confusing everything


So far I can make out that nothing is wrong but you've found wires and a plug damaged to a VSV (Just a valve that opens and closes) that could be for assorted things for assorted reasons.


So - there's nothing about this that is really wrong except now a question that if wires were reversed polarity because of the damage you thought the could be so asked if that would matter. If just two wires to a plain switch I say it wouldn't matter, especially for model year 1994.


It's thought to be a CA vehicle and that does change things. Sticker under the hood if you believe it's original to the truck (might not be at all) should match other info and VIN# around the truck which also identifies what it was when new.


OK: In these years and before as well vehicles did put diagrams on stickers under the hood for common info as well. Tons of repair manuals would default to suggest going by any info under the hood over theirs.


You have rewired and a good used plug I understand one thing you found and continue to wonder if it should be open or closed and when and have been told that in this thread so unless you have a problem why are we dragging on this thread over something that isn't broken?


chas: Some suggestions for used plugs, wiring pig tails when needed especially when not available new with original colors match them up with the used item and your own vehicle as best you can.


Are we all done with this now?


Tom



Hammer Time
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Mar 15, 2015, 4:13 AM

Post #20 of 20 (1144 views)
  post locked   Re: egr cold start  

Question answered multiple time.

Closed now



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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