rlynchster

Hello, .. . . .1986 N/A S4 Non-Turbo

I hand vacuum pumped my EGR valve by taking the vacuum line off the top side of the "yellow" solenoid and using that line to pull vacuum on. Apparently the line does not hold vacuum and immediately comes up to atmosphere. (I assume the line comes from the top of the solenoid valve and goes directly to the EGR valve)

Assuming it does not hold vacuum, is this an indicator that the diaphragm in the EGR valve is bad?. . . I am getting really a crappy idle

. Will the EGR valve leak to outside air and into the engine if the diaphragm is bad on the EGR?

If the EGR is bad, and needs to be replaced, where do I get one and can I replace it without taking everything off the top of the motor?

Will I be left with the only remedy of blanking it off and plugging the line if I can't find an EGR valve.

FYI. .I recently installed a TPS and dialed in 1 volt and I still have a rough idle. .. . I blanked off my brake booster cause it was a leaker. . .I blanked off my double diaphragm valve cause it was a leaker. . . .. . The EGR is the next component I have found that seems to be a leaker.

Additionally, I noticed somebody took the plug out of the Mass Flow Meter adjustment screw and it is screwed all the way down. . . Isn't this for bypass air adjustment in the MFM?. . . Because that's the next thing I plan on checking and the FSM says not to mess with this screw but apparently somebody did at one time.

j9fd3s

iTrader: (3)

the EGR valve is really annoying. it is NLA from Mazda, but there is some guy who rebuilds them and in California, if the smog guy tests the valve, and it tests bad you have no choice but to buy the valve from this guy, for like $300.
for $300 you get a spray painted POS...

um so yeah it can cause a rough idle, vacuum leak. are you dyno smog, or the idle/2000 rpm test?

WondrousBread

Sounds like it's gone bad based on your description. There's an easy way to test if it's your problem though, just cap the port on the solenoid rack that the EGR goes to. If it your idle improves it was at least part of the issue.

rlynchster

Dyno smog in my area.

Historically I have high CO and do the denatured alcohol thing to remedy that.

I am assuming high Nox is what a bad EGR will cause when the valve doesn't work.

Vacuum leak through the broken EGR valve diaphragm is another problem avenue .. .The valve don't work, and I get an air leak.. . . . .Maybe i just blank it off. I've never had a guy crimp the line to see if they work. Typically I get a young guy who doesn't know jack about rotaries.. . . .They barely know where to capture the timing.

Thanks for the reply. .. .RL

rlynchster

Yep . . Did that. . .Idle still sucks *****.

.. .This is what love looks like trying to keep one running in CA.

RL

j9fd3s

iTrader: (3)

the EGR valve isn't on during the test so it does nothing

rlynchster

Is that because the ECU doesn't trigger the EGR solenoid till 3,500, or more, RPM?

j9fd3s

iTrader: (3)

and 5th gear