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US, 89, 5.8,C6, 1356 BW (manual), 5 Bolt Hub (automatic) No modes like to keep it or
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279 Posts
Discussion Starter · #1 ·
I have a CODE 33 Verify Vaccum is at EGR Valve, I have been reading the EGR opens when the engine heats up to recirculate exhaust back into the air that goes to the combustion chamber to burn up "bad" air particles.

I followed the Tech Manual Pin Point Test Procedures for Code 33.
Has vacuum with the incoming line, EGR holds a good vacuum and valve moves freely. Could not swap out with a good sensor, since I don't have a spare.
So I used SeattleFSB's post on trouble shooting EVP Sensors and compared to the Tech Man Pin Point Test Procedures.
It passed.

So I am trying to see what else could cause the code. Seems like the the EGR activates at a certain air temperature? So the could the Air Charge Temp affect the EGR opening. Or when the PCM reads certain air particles, it makes the EGR open to burn off the bad air particles, so the O2 sensor would cause that?

How does the EGR differ than a SMOG pump? It seems they both redirect air back to the intake to burn up "bad" air?
 

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Yo First,
"...Ford EGR systems "...PCM will not operate the EGR valve unless it sees: The engine warmed up to normal operating temperature. TPS at partial throttle. TPS not at Wide Open Throttle (WOT). MAP or MAF must be indicating light or moderate load. A certain amount of computer clock time has to be elapsed..."
Source: by tomco-inc.com

PCM will not allow the EGR valve to open until the engine has warmed up to improve driveability. If the EGR is allowed while the engine is still cold; it may cause a rough idle; stalling and/or hesitation.
An open thermostat or the wrong thermostat; may be preventing the coolant from reaching its normal operating temperature.
Source: by Ford

163225


With the engine idling, tap intake manifold vacuum tree to the EGR. If the engine suddenly coughs & sputters, the valve just opened, and it's good. If the engine runs basically the same, either the valve was already open, or it didn't open, or the pipe is blocked up.
I assume you inspected vacuum hoses.
 

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Premium Member
US, 89, 5.8,C6, 1356 BW (manual), 5 Bolt Hub (automatic) No modes like to keep it or
Joined
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279 Posts
Discussion Starter · #3 ·
With the engine idling, tap intake manifold vacuum tree to the EGR.
Do this after the engine is at normal operating temp?
Would taping the vacuum tree affect the TAB/TAD or EVR since they all come off the same vacuum tree port?
 

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Super Moderator
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Yo
Do this after the engine is at normal operating temp?
Yes, according to temp gauge
Would taping the vacuum tree affect the TAB/TAD or EVR since they all come off the same vacuum tree port?
No, and the biggest vacuum flow is to brake booster and all the other users see same vacuum levels.
 
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