73 Wagon 440- Vacuum Hoses, Emissions System

[imperigal]

Got the starter installed, gas tank sealed, fuel lines flushed. Started right up but I'm guessing I have some valve issues (tick) as well as a possible vacuum leak.

This 440 has a temp operated vacuum by-pass valve (next to the distributor). Three vacuum hoses lead to it. One hose is red, comes from the OSAC valve. The next is white and leads to the back of the engine block (auto-temp?) . The third is black but is blocked off. ????

At the OSAC valve on the firewall, the distributor vac hose (aforementioned red vac hose) is hooked up to the bypass valve, but the carb side is plugged off.

Lastly, the CCEGR on the radiator only has one hose going to it (blu, from vac amplifier). The other one is missing. Would that cause issues?

Should I make an effort to return the vacuum hoses to their original positions? I know that de-smogging these has been a hotly debated topic, but I just want to eliminate any possible vac leaks.

(Please be patient...l only have the 72 manual, so maybe that's whats throwing me off)!

 

[Carmine]

Sounds like you're waking something up that hasn't been run for a long time?

Consider this temporary to rule out other issues...

Cap/plug anything you don't recognize or understand the purpose. I know you have the skills to recognize things like the power brake booster, PCV, HVAC feed. Your '72 manual may help here. Then take a vacuum feed from a port on the carb base. Verify that the idle increases when connected to the dist vacuum advance. (This will assure you that the advance works.) Use this as your baseline and see how it runs.

The tick might clear with use.

 

[imperigal]

Thank you - good starting place!

 

[Carmine]

I'll give you a personal tip... I could never navigate that jungle of vacuum crap "under a hood". If you have the womanpower, take off the hood for this kind of work. Also a good opportunity to powerwash the engine and firewall, which aids troubleshooting.

 

[saforwardlook]

There was usually a vacuum hose routing diagram under the hood or maybe on the inner fenders of those cars. Do you have one? If so, it would be helpful to see it, as it has been decades since I last worked on those systems, and then there were California versions and Federal ones too. With that, I could likely help more. Do you have a vacuum amplifier behind the carburetor that controlled the EGR valve movement? You know the OSAC and CCEGR terminology, so you are reasonably informed to start with it seems to me.

One thing I can definitely recommend is to get anything hooked up to the OSAC valve out of there and just go directly from the carburetor port to the distributor vacuum advance can. That lousy valve did more to destroy any fuel mileage you might have otherwise and hampered around town acceleration and responsiveness. It was a dumb 26 second delay in getting vacuum advance to the distributor - Chrysler should have never used it as a way to pass emission regulations back then, as there were much better approaches available.

 

[Carmine]

I don't think the vacuum routing guides came along until the Formal era.

 

[imperigal]

No vacuum diagram. I wish there was!!

The wagon also has Auto-temp II, so there's a whole lot of vacuum hoses. Noticed the two electrical harnesses that feed into the AT2 control valve (it's on the heater valve) are unplugged. I'll save that for another day!

 

[Davea Lux]

Got the starter installed, gas tank sealed, fuel lines flushed. Started right up but I'm guessing I have some valve issues (tick) as well as a possible vacuum leak.

This 440 has a temp operated vacuum by-pass valve (next to the distributor). Three vacuum hoses lead to it. One hose is red, comes from the OSAC valve. The next is white and leads to the back of the engine block (auto-temp?) . The third is black but is blocked off. ????

At the OSAC valve on the firewall, the distributor vac hose (aforementioned red vac hose) is hooked up to the bypass valve, but the carb side is plugged off.

Lastly, the CCEGR on the radiator only has one hose going to it (blu, from vac amplifier). The other one is missing. Would that cause issues?

Should I make an effort to return the vacuum hoses to their original positions? I know that de-smogging these has been a hotly debated topic, but I just want to eliminate any possible vac leaks.

(Please be patient...l only have the 72 manual, so maybe that's whats throwing me off)!

If you are interested, the '73 service manual is available on E-Bay for about $30 in the CD format. Used hard copies are about $40. There were quite a few changes from '72-'73 because of tighter EPA standards.

Dave

 

[jct]

Cd format is the best

 

[imperigal]

CD format is best....if your laptop still has a CD drive. :-D Mine does not, so I had a decision to make today....either buy an external CD drive OR buy the hard copy manual. Found a good used one for $35 and ordered it. Thing is....I already have a 73 CD manual, but I'm a fan of the paper version. Except for the fact that there's no search option lol

 

[jct]

I like the fact i copied the pdf file off the cd onto my phone

 

[CBODY67]

The OSAC probably can be deleted. Run the dist vac adv from the "ported vacuum" port on the carb base. Very little, if any, vac with the carb at hot base idle.

The CCEGR thermo-vacuum switch keeps the EGR valve closed until the engine coolant temp reaches a particular level. IF the EGR valve is still there and you desire a stock look, should anybody be concerned, a ball bearing inside the vacuum line can be an incognito "plug". Did I say that? OR you can play like the car has the "floor jets" without an external EGR valve and block it off with a factory block-off plate, possibly from a '76 Lean Burn engine? Remove the temp sensor in the radiator and plug the hole. If the engine might have a bit of trace rattle on acceleration, with the EGR not functioning, then back the timing back about 2.5 degrees or so from the base timing spec.

Manifold vacuum will run the power brakes, cruise control, and hvac (AT2, in your case) system. This can be from a fitting on the rear of the carb or a combination "vacuum tree" that screws into a rear port of the intake manifold, or both.

Once you under the various emission system items and how they work, it kind of all falls into place. '73 was the first "real year" for Chrysler "external" emissions controls, with thermo-vacuum switches and such. The first year for the "vacuum amplifier", too, as I recall. 1974 was "more of that" and somewhat similar, with a few tweaks. There might be a service manual download at www.mymoper.com and a Chrysler training film on the '73 "New Product Info" in the service lit area of www.onlineimperialclub.com, too.

Enjoy!
CBODY67

 

[Davea Lux]

The OSAC probably can be deleted. Run the dist vac adv from the "ported vacuum" port on the carb base. Very little, if any, vac with the carb at hot base idle.

The CCEGR thermo-vacuum switch keeps the EGR valve closed until the engine coolant temp reaches a particular level. IF the EGR valve is still there and you desire a stock look, should anybody be concerned, a ball bearing inside the vacuum line can be an incognito "plug". Did I say that? OR you can play like the car has the "floor jets" without an external EGR valve and block it off with a factory block-off plate, possibly from a '76 Lean Burn engine? Remove the temp sensor in the radiator and plug the hole. If the engine might have a bit of trace rattle on acceleration, with the EGR not functioning, then back the timing back about 2.5 degrees or so from the base timing spec.

Manifold vacuum will run the power brakes, cruise control, and hvac (AT2, in your case) system. This can be from a fitting on the rear of the carb or a combination "vacuum tree" that screws into a rear port of the intake manifold, or both.

Once you under the various emission system items and how they work, it kind of all falls into place. '73 was the first "real year" for Chrysler "external" emissions controls, with thermo-vacuum switches and such. The first year for the "vacuum amplifier", too, as I recall. 1974 was "more of that" and somewhat similar, with a few tweaks. There might be a service manual download at www.mymoper.com and a Chrysler training film on the '73 "New Product Info" in the service lit area of www.onlineimperialclub.com, too.

Enjoy!
CBODY67

The usual reason that the engine might "ping" with the EGR disabled is that the EGR was designed to inject inert material (exhaust) into the the intake manifold to keep combustion temperatures down. This was supposed to reduce the formation of nitrogen oxides which contribute to acid rain. When the inert material goes away, The result is a leaner fuel mixture due to an increase of reagent material (Oxygen) in the intake manifold. Usually you can compensate for this by going one size larger on the primary carb jets. That would be my preferred choice to stop the pinging rather than going to TDC on the timing and your engine will not suffer a performance loss as a result.

The other good reason to get rid of the EGR is that with modern alcohol blend fuels these valves tend to carbon up readily and leak due to a build up of carbon on the seat of the valve. Your engine will run like crap if that happens. If you want to maintain a stock appearance, You can cut a piece of sheet metal using the valve base as a template to block the valve's intake port and then reinstall it. That is how the EGR can be disabled without any obvious signs that it had been done. Also check the routing in the temp activated vacuum switch to be sure you have a functioning connection to the heat riser if you have the vacuum operated type. (FYI heat riser passages also get plugged with carbon from the blended fuels)

Dave

 

[CBODY67]

Back when I was in college AND found the SAE Transactions volumes and related Chilton magazines on engineering "things", I found an article on the use of EGR and how it affected engine performance. This was before any EGR valves showed up as standard emissions equipment, circa 1972. The particular study was by a GM division (I suspected Olds at the time, but it could have been Buick, as the engine sizes were 350 and 455; doubt it was Pontiac).

As Davea mentioned, the exhaust gas is "inert" and cools the heat of combustion (related to NOx production). As such, it can take MORE spark lead to get the mixture to combust well and not lose power. Not unlike what Chrysler did with their Lean Burn system several years later . . . more spark lead to get a 16:1 fuel mixture to combust well, which ALSO didn't need an EGR valve as at that mixture lean-ness, CO and NOx were basically "zero" already, so no Cat Converters needed, either, for those years as HC was also decreased enough to pass the emissions standards (basically HC and CO, at that time).

So, what they found was that more spark advance would regain the lost power inflicted by the EGR, which was optimum at 15% of mixture volume. I never did compare carb metering specs for the EGR and prior non-EGR engines, so I can't address the added jet size orientation, BUT I also know that by that time, the main jets had been leaned from prior times, so the jet increase might work well, anyway.

The spark advance curve for the EGR engines probably had some tweaks for those applications. If they were "advanced" slightly for the EGR applications, then getting a "better charge" in the cylinders might result in a slight "over-advance" situation for the fuels being used. Hence, the slight decrease in base timing. BUT a better option might be to see if the vacuum advance has the internal adjustment in it. Reason is that there should be NO EGR at base idle, which is why the idle quality decreases when EGR does happen at idle and lower road speeds (rpms).

I remember reading of tuners who'd go a little richer on the emissions-leaned engines of the later '60s and earlier '70s and get better performance and fuel economy as a result. No instrumented testing of exhaust emissions was done, though.

Problem with many emissions controls is that they make the exhaust emissions "cleaner", but use MORE fuel doing it! When efficiency is increased, NOx is increased as HC and CO decrease. Decrease NOx and the other two increase as the engine becomes less efficient (lower heat of combustion). At least that's the way it was before we got the currently sophisticated computer controls of the later years, plus other engine design orientations for a better balance of operation, aided by "after-treatment" catalytic converters.

On the adjustable vacuum advance can, the part throttle acceleration clatter might be decreased by stiffening the spring adjustment of the vac can itself. Insert an Allen wrench into the nipple on the vac can. Just small enough to fit the opening. When it is fully inside, gently turn it to see if it might index with an internal hex Allen bolt head. When it does, rather than meeting a flattened rivet holding the diaphragm in place, turn it about 1/4 turn clockwise, at a time, until the clatter might decrease slightly or completely. The vac advance will not be operating with the engine at hot base idle, so that setting would not be affected (on vehicles which use ported vac to run the vac advance). There should still be enough vac advance for good fuel economy at cruise, though. I haven't done this myself, but I believe the theory is good for it to work. But the key is an adjustable vac advance, which is a hidden thing that many might not know about or know of, even at the auto supply level of things.

An easier option, possibly, might be to look for a vac advance can for a '72 440 with "Federal" emissions, which should have been non-egr (without "floor jets" in the intake manifold plenum). If the supplier shows the '72 and '73 units to be the same, not sure if they've using a "will fit" orientation or not, or to which specs the unit might be. BUT it might be that it'll yield an adjustable vac advance unit.

Just some thoughts,
CBODY67

 

[imperigal]

Today's update: While the ground was still dry, I got underneath the wagon to replace the rear shocks and flex fuel hose. Rear brakes were done a few weekends ago. Managed to get wrapped up just before more rain moved in!

Thanks for the info on the EGR. I can see why having the 73 FSM will be useful, especially if there are significant differences from the prior year. This afternoon, I plan on eliminating any non-essential vac hose connections temporarily to see if there's an impact.

I did notice that I have an oil leak at the top passenger side of the motor. Appears to be valve cover gasket, so those are next on the list.

I'll also be checking the timing. Should have been one of the first things I did, but I can't find my timing light :-( Off to the parts store I go!

I just have to say... I am SOOOO glad the weather is finally nice enough to work on the wagon! Want to get the T&C on the road asap!

 

[Davea Lux]

Today's update: While the ground was still dry, I got underneath the wagon to replace the rear shocks and flex fuel hose. Rear brakes were done a few weekends ago. Managed to get wrapped up just before more rain moved in!

Thanks for the info on the EGR. I can see why having the 73 FSM will be useful, especially if there are significant differences from the prior year. This afternoon, I plan on eliminating any non-essential vac hose connections temporarily to see if there's an impact.

I did notice that I have an oil leak at the top passenger side of the motor. Appears to be valve cover gasket, so those are next on the list.

I'll also be checking the timing. Should have been one of the first things I did, but I can't find my timing light :-( Off to the parts store I go!

I just have to say... I am SOOOO glad the weather is finally nice enough to work on the wagon! Want to get the T&C on the road asap!

While you have the valve cover off, this would be a good time to check the valve train to see if you can locate the source of the "tick". Might have a sticking lifter or valve.

Dave