F'n EGR....but its required.

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pishta

pishta

I know I'm right....
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OK, non Mopar related but perhaps its general knowledge. Should my 82 Mazda EGR valve be the slightest bit open during idle? It idles at ~650, uses ported vacuum for the distributor so its at 8 BTDC with no vacuum on advance pot at idle. Im getting a rough idle and found that the EGR is raising about 2-3mm with barely any vaccum on the EGR valve itself. I pull the EGR line and plug it and the idle clears up considerably. I can barely feel a vacuum on the line. Im thinking the EGR spring is worn/weak or it does have an adjuster on it, a very small nut and a threaded pintle. Are they adjustable? I cleaned it and it seems like its in good shape seal wise, cleaned the carbon off the pintle and seat.
 
Should not be open at all at idle. IMO. Causes poor idle. As you know...
 
pishta said:
OK, non Mopar related but perhaps its general knowledge. Should my 82 Mazda EGR valve be the slightest bit open during idle? It idles at ~650, uses ported vacuum for the distributor so its at 8 BTDC with no vacuum on advance pot at idle. Im getting a rough idle and found that the EGR is raising about 2-3mm with barely any vaccum on the EGR valve itself. I pull the EGR line and plug it and the idle clears up considerably. I can barely feel a vacuum on the line. Im thinking the EGR spring is worn/weak or it does have an adjuster on it, a very small nut and a threaded pintle. Are they adjustable? I cleaned it and it seems like its in good shape seal wise, cleaned the carbon off the pintle and seat.
Click to expand...
Some people use a beer can cut to gasket shape and then drill a tiny hole or two in order to restrict flow.
 
Just had to replace mine in my ram truck. $202 of pure fun. Took 45 minutes, not too bad.
 
Is the ports clean, at both ends ? Carbon buildup, might be a problem.
 
port is clean, Im seeing a slight 1-2mm rise in the pintle at idle. Whats up with the vacuum amplifier, what does it do? green is EGR vacuum, yellow is manifold vacuum, orange is bernoulli (velocity) vacuum? I assume the orange is the 'trigger' to open the manifold vacuum up to the EGR via the amplifier? Im lost.......
vacuum82.jpg
 
pishta said:
port is clean, Im seeing a slight 1-2mm rise in the pintle at idle. Whats up with the vacuum amplifier, what does it do? green is EGR vacuum, yellow is manifold vacuum, orange is bernoulli (velocity) vacuum? I assume the orange is the 'trigger' to open the manifold vacuum up to the EGR via the amplifier? Im lost....... View attachment 1715160456
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Vac amp ,is for low vacuum engines... You're spot on , have you tailpipe it yet ?
 
OK, I was almost right...
EGR venturi vacuum amplifier
A device that uses a relatively weak venturi vacuum to control a manifold vacuum signal to operate the EGR valve. Contains a check valve and relief valve that open whenever the venturi vacuum signal is equal to or greater than manifold vacuum


tailpipe it yet? Like smog check? No im trying to get everything ship shape to smog it as I kinda told myself if it dont pass smog, its out a here. scrapper or part out.

PS>> interesting Mopar tie in: My part number is used in 74-76 Dusters, as well as a ton of other 74-76 Mopars cars and 86 Ram trucks. WELLS 4F1184
 
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pishta said:
OK, I was almost right...
EGR venturi vacuum amplifier
A device that uses a relatively weak venturi vacuum to control a manifold vacuum signal to operate the EGR valve. Contains a check valve and relief valve that open whenever the venturi vacuum signal is equal to or greater than manifold vacuum


tailpipe it yet? Like smog check? No im trying to get everything ship shape to smog it as I kinda told myself if it dont pass smog, its out a here. scrapper or part out.
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Theoretically correct ,what is the vehicle actually responding to?
 
I'm thinking the orange line should have no vac at idle . Pull it and plug it , set idle speed , check timing with vac line disconnected and plugged , Test orange line for vac . If no vac hook it up and see what happens.
 
Plug the hose going to it with silicon and let it dry. It will look hooked up. You really don't need to re-burn your exhaust gasses. Most bigger trucks have a block off plate. Same as plugging the hose.
 
CA tests EGR operation with a vacuum pump off its feed line. strike one.
My distributor uses ported vacuum (@0) so there is no 'pull, plug and time', strike 2
(darn thing idles better with a little advance, but not allowed)
So maybe cheat by plugging the orange venturi line, is that what you meant? Hmmm....
Truck idles right at 8 BTDC, no prob there, its just a nasty idle, like a vacuum leak...EGR leak!
I need EGR as one of the test that it failed is NOx and that is high Combustion temperature (lack of cooling EGR) during the 3000 RPM loaded dyno run. Could the Amp be bad/leaking? Maybe bleeding manifold vacuum to the EGR side? Supposed I could draw a vacuum and see if she holds or bleeds out. Well, once I find my mighty-vac.......Or the tongue.
 
pishta said:
CA tests EGR operation with a vacuum pump off its feed line. strike one.
My distributor uses ported vacuum (@0) so there is no 'pull, plug and time', strike 2
(darn thing idles better with a little advance, but not allowed)
So maybe cheat by plugging the orange venturi line, is that what you meant? Hmmm....
Truck idles right at 8 BTDC, no prob there, its just a nasty idle, like a vacuum leak...EGR leak!
I need EGR as one of the test that it failed is NOx and that is high Combustion temperature (lack of cooling EGR) during the 3000 RPM loaded dyno run. Could the Amp be bad/leaking? Maybe bleeding manifold vacuum to the EGR side? Supposed I could draw a vacuum and see if she holds or bleeds out. Well, once I find my mighty-vac.......Or the tongue.
Click to expand...
Try that ,or simply cool the combustion chamber down ,via a cooler thermostat, or something alcohol in the tank



https://www.google.com/url?sa=t&sou...FjADegQIBhAB&usg=AOvVaw1gYZY06GtQMysHlOsLepzq
 
I'm guessing it's a B series truck,this is from Alldata. I hope it helps



  • Testing and Inspection
  1. Remove air cleaner.
  2. Start engine and run it until it reaches normal operating temperature, then shut off engine.
  3. Disconnect vacuum hose between EGR valve and water thermo valve at EGR valve.
  4. Disconnect vacuum hose between intake manifold and vacuum amplifier at vacuum amplifier.
  5. Connect hose disconnected at vacuum amplifier to EGR valve.
  6. Pinch hose connected to EGR valve and ensure engine idles smoothly.
  7. Release pinch and ensure that engine idles rough or stalls.
  8. Connect all hoses to proper locations.
  9. If test results are unsatisfactory, clean or replace EGR valve as necessary
 
82 B2000 beater. it will pass that EGR function test as I pulled line and idle cleared up. apply vacuum and it roughens. Its just the EGR raises a little at idle with almost no vacuum to it. Ill play with the EGR, it may have a little threaded pintle that I can lower, increasing the closed spring tension. The thermo valve may be stuck open too as it shoud be blocking the EGR vacuum under 122F coolant. but thats small potatoes as the test is done warm anyway. Thanks.
 
What is your base vacuum reading? Being carbed, with added vacuum it should roughen up.On a B2 I wouldn't expect less than 19"hg without a leak
 
Will check. But I remember I had great vacuum with every vacuum hose disconnected, fresh valve job. anti backfire dash pot, distributor pot and egr all holding a vacuum. They say the egr valve is changed out more time than its the actual problem but I'll check vacuum tonight.
 
the test I posted ensures the valve is seated during no vacuum and opens(vacuum leak) with vacuum applied. You've already tested the diaphram,so there's either another leak which is made worse with egr open or it would seem the temp control valve might be leaking allowing at idle egr
 
Well, I think I figured it out:
The vacuum amplifier must be bleeding a small bit of manifold vacuum into the EGR as it was raising it 2mm without any venturi idle signal. Probably a bad seat in the vacuum amplifier (serviceable?) . So I worked with what I had and found that the EGR pintle was indeed adjustable! So I measured how much it raised with the residual vauum from the amplifier and lengthened it a tad more so now even with the bleeding vacuum, its still remains seated and now my idle has totally cleaned up @ 22 inches. Timing spot on at 8 BTDC and the Thermo switch did in fact hold under 122F. Life is good ! Here is a vid of the adjustable EGR valve (great to dial in the opening) and another vid of the engine at idle with the EGR fixed. Its a loud engine by nature as it has pulse air injection, sounds like an outboard motor right nest to the intake snorkle or worse when the air cleaner top is off.


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