No egr or vacuum advance operation at WOT, because its ported vacuum. No vacuum, no operation.
How did EGR work with a Qjet?
- Thread starter Supercharged111
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also the ECM will be looking for a change in o2 values if you have the model with the egr solenoid. if it doesnt see a change after commanding it to open, it will throw a code.
yes that was later on efi engines. they weren't that sophisticated in the early 80's with carbs.
In a round about way, this is true. It's not just nox, though. The engine gets another stab at burning some of the unburnt fuel from the first time around by injecting a little exhaust gas into the engine.
Can't speak for how other engines do it, but a mid-80s VIN 9 Oldsmobile uses 2 ports underneath the Qjet for it's on or off, but also regulated, EGR valve. The EGR valve is not a straight up valve like on some other cars. There's a P or an N on top of the valve head meaning Positive or Negative back pressure operated (no P or N means it's a simple ported EGR valve that should respond to simple vacuum check).
And P EGR valve are the only ones that don't respond to testing by simply putting a vacuum source on the operating diaphragm. VIN 9 uses a positive pressure EGR valve. It's noted by the P as the very last stamping on the head of the EGR valve (talking ACDelco/GM valves only). 85 CSM says VINY and 9 use a Negative pressure EGR, but this is incorrect. They may have before, but not for 85 model year.
Contrary to most other solenoids people are used to, the V8 solenoid, when energized, CUTS OFF the vacuum signal to the EGR valve. When de-energized, the solenoid opens the vacuum supply to the EGR valve.
ECM looks to control the EGR solenoid by evaluating the inputs. 1) Coolant temp 2) TPS 3) RPM 4) TCC state of operation 5) Barometric pressure
That's ALL the ECM does for the EGR system on the V8 Oldsmobile G-cars with ECM. Sorry, never looked at other cars so I couldn't tell you how that gets interfaced. I'm sure there are other variances, but mid-80s is where I live and breathe.
I made a post about it before here, and has links to TOMCO information about Positive and Negative backpressure EGRs and how they work...
Know your EGR's (tech tips)
My old computer took a dump on me, sort of, so after I got it into "limp-home mode" I went through and ensured I put whatever files that were on the hard drive onto my external hard drive where I keep most of my crap (I call it my personal "cloud"). Then I ran across some EGR information I had...
gbodyforum.com
Who runs a EGR. LOL. I’m running a Edelbrock. With their dumb logo filed off, painted Corp blue, looks stock, but adds to global warming, win win. No EGR there, And it’s made in good old USA.
I didn't ask cuz I wanted to run one, I was just curious how they did it with non-feedback carbs.
Well that's good, I think California does but I don't live in the US so I could be mistaken.
For those who need those part for testing, I ran across a guy in cal, he’s a bit a rip off, and he doesn’t know his parts but he has all the emission stuff. hes Sleezy though. Lol
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