I have to assume what looks like an EGR on the drivers side intake on my 350 motor is an EGR? If so what are the changes it is working this many years down the road? If it is not working what is it causing to to work properly then? I assume I can get one for this car? Can the existing one be cleaned?

 

ok I do see them on EBAY. How can I check to see if mine is working?

 

hook up a vacuum line to the nipple on the EGR and suck. If the piston and diaphragm move, it's working.

 

If you ever get an off-idle stumble, I can about guarantee your EGR is functioning.


Personally, I'd put a BB in the end of its vacuum hose if there isn't already one there, then reconnect the vacuum source hose. That way it looks functional.


The 1974 EGR is a fairly complex system with several components, any of which can make it do weird things. Put the BB in the hose, disable it, and I think you will be much happier with your car's performance.

 

Don't know if it is working but I was able to push the diaphragm with it giving a little resistance. Maybe I will try the BB thing (if I can find one). The whole system is still intact on my car. Working, well I don't know. The only stumble I get while driving at most any speed if I stomp the gas a little it would stumble.

 

on my car, there is a black cover attached to the oil fill tube on front of motor. There are some vac lines going into and out of some round thing. What is that thing?

 

This assumes, of course, that the EGR valve is sealing the port in the intake when it's closed. Sometimes carbon can build up on the seat and hold the valve open slightly all the time, causing problems. Also, if the shaft rusts, the valve can stick open.

While I don't have experience with the mid-70s EGR, I do know that if you disable it on the 1980s 307s, you will get a part-throttle pinging. The carb is purposely set lean when the EGR is supposed to be active. Without that mixture dilution, the mixture gets too lean and the death rattle results.

 

I may pull it off the intake and clean it up. I got odds it has never been taken off. The diaphragm moved by hand it is not froze up. None the less the car runs well as is now, well having nothing to compare it too of the like car, it runs well, ha ha ha

 

EGR temperature sensor and delay valve. It operates the EGR depending on engine ambient temperature. It has the cover on it to supposedly keep a constant temperature around it. If it's still in place odds are system has not been messed with.

 

yea it all is there, all vac lines connected when I took it apart to get WP off the car.

 

putting a BB in there does what to make the car run BETTER?

 

It plugs the hose so the EGR is disabled. Any plug would do the same thing. Glenn suggested a BB so the hose could be reconnected and APPEAR to be hooked up.

 

I understand that part but he said it would let the car run better. In what way does it run better?

 

EGR flows exhaust gas back into the intake under part throttle conditions. This is intended to dilute the air/fuel mixture entering the cylinder and thus cool the combustion products. The result is a reduction in NOx emissions at the expense of increasing HC and CO2 emissions due to the inefficient combustion. NOx reduction is typically ad odds with HC and CO2 reduction, and lowering all three requires careful balancing of the mixture ratio. Unfortunately, lowering NOx requires making the combustion process less efficient, which lowers both performance and mileage. Disabling the EGR thus improves combustion efficiency at the expense of higher NOx emissions.

Yes, this is EXACTLY what VW did with their diesel cars...

 

If the EGR is not functional, thereby not recirculating exhaust gases into the cylinders, you are not trying to reburn exhaust gas. You're getting a true fresh fuel/air charge to the engine instead of one diluted with already burned exhaust gas.


To put it simpler- with EGR you're trying to burn smoke.


Depending on how good your area's fuel is, you might be better off leaving the EGR functional. Ethanol fuel tends to burn lean which could aggravate a pinging condition as Joe noted for the 80s carbureted cars. A 1974 carb is calibrated leaner than earlier units, but not as lean as 75-later.


You mentioned a stumble on throttle tip-in at road speed. Sounds like you may have a weak accelerator pump, or carb may need cleaning. Off-idle stumble is characteristic of an EGR that opens too quickly.

 

Started when cold or at running temp, off the line 99% she has no stumble, pulls from a stop really nicely for an old car that appears nothing has even been touched or if so has been MANY years ago. It did have a complete tune up right before I got it (recpts bare this out). That was it.