EGR is starting to open while parked in garage at 1300 rpm. Changed egr & control still does it

[Blue Wrench]

The EGR control just vents vacuum unless the ecu adds voltage , right? I pulled the vacuum off the egr and could feel pulses holding the rpm around 1300. Ive changed the egr & controller. I have checked both parts worked proper with a hand held vacuum pump. ecu problem? any advice?

 

[General karthief]

What issues are you having?

 

[Blue Wrench]

Taking off easy from a red light at like 10 mph the engine stumbles. All I have heard is that the egr only opens at cruise speeds.

 

[General karthief]

I doubt the EGR will cause that,can you monitor the fuel pressure while driving?
Have you checked the sweep on the TPS?
A vacuum leak can cause common issues and lean codes.
Check for codes.

 

[Blue Wrench]

With the vacuum line plugged to the egr the engine runs perfect. The last time i checked tps voltage & sweep was in specs. The same with fuel pressure, but havnt checked while driving, With your foot in it, it pulls strong for a box stock 34 year old engine Cant imagin a vacuum leak . Hot idle i have a steady 20 inches.

 

[General karthief]

Does the vacuum change between plugged and unplugged?
You're on to something with 'runs ok when unplugged ' test.

 

[Blue Wrench]

not sure i have watched vacuum gauge while plugging in, and un plugging vac line to the egr. Id bet at idle its the same, and while holding at 1300 rpm it wanders . At that rpm i am getting 3 inch vacuum pulses to the egr. The deal is everything i have heard is the egr only opens at cruise speeds. Which is why i suspected the ecu was sending voltage to the egr vacuum controller and starting to open the egr. or its " something completely different" lol

 

[Noobz347]

If the EGR diaphragm, the diverter, or bypass valves are malfunctioning they will throw a code. Same with the canister and EGR.


Have you checked the codes?

 

[Blue Wrench]

Month ago I ran a full scan for codes up to the cylinder balance test. was golden

 

[Noobz347]

Were you having this issue a month ago?

 

[Noobz347]

Amazon product ASIN B000EW0KHW
View: https://www.amazon.com/INNOVA-3145-Ford-Digital-Reader/dp/B000EW0KHW/ref=sr_1_1?keywords=EEC-iv+code+reader&sr=8-1
They're cheap. You can also pull codes with a paper clip.

 

[Blue Wrench]

Just ran a scan, #33 EGR not opening properly. Big surprise.... Since the vacuum is line is off lol Now if i hook it back up the code goes away and the EGR starts opening when it shouldnt again

 

[Mustang5L5]

Sounds like the EGR regulator is not regulating properly. It's either partially stuck open, or just faulty in general. Remove it. Connect a rubber line to one port and blow through it. It should be closed. Now take a 9v batter and some alligator clip leads (great tool to have for automotive diagnostics in general) and clip to the solenoid and blow. Does air easily pass now?

If that checks out, verify the vac lines are correct and they pass through the regulator first. Wouldn't be the first time i've seen an EGR connected straight to direct vacuum which causes it to open as you go under load (starting from a stop)