1974 Imperial Emissions Systems

Corbin

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Many of these systems aren't unique to this car, but this seems to be the appropriate place to ask the questions...
Honing in on moving this car from round-the-property-a-few-times to road trip ready/commuter duty. I still have some minor drivablity issues to resolve (and need some parts. But that's a topic for a different post). For the purpose of mitigating vacuum leaks I have by-passed several emissions related systems; my question to the group is which systems can be permanently omitted/altered. This car was originally sold in California, so may have arrangements to satisfy the state's unique requirements.

1. OSAC switch/TIC have been by-passed. Vacuum advance supplied directly from the carburetor. Vacuum connection on the manifold for the TIC has been blocked off.

2. Vacuum connections to the air-cleaner omitted. Port on the rear of the carb has been plugged.

3. Air pump ( or smog pump). One of the injection tubes is broke on the passenger side manifold. The presence of the pump meant I need a shorter oil filter than the standard Napa 1515 that every other old Chrysler product I own takes.

4. The EGR system is not functioning correctly. I'm fine keeping it, but can I route the vacuum lines in a different manner, eliminating the delay solenoid? The FSM lists 3 different ways of controlling the EGR valve; 2 controlled via the carburetor (venturi) (1 of those unique to CA) and simpler, federal method. I'd like to just use the Federal method and omit the vacuum electric/connections.

I've put about a 100 miles on this thing in short 10 mile bursts, slowly whittling down its list of needs.
 
The emission system on the '74 mopars was troublesome when they were new and have only gotten worse with time.

So the first question is whether or not you need to worry about an emission inspection. If I remember correctly, CA only mandates this on vehicles that are 25 years old or less, but you need to check on this. If there is a 25 year cutoff, leave the OSAC/TIC switch disconnected, this setup was a POS that seldom worked correctly. The vehicle will probably run better of you repair the vacuum connections to the air cleaner. The air cleaner has a heat tube that draws heated air from the heat stove on the driver side manifold into the air horn on the air cleaner via a thermostatically controlled baffle that is vacuum operated. This prevents carb icing and helps compensate for lean carb settings at idle when the vehicle is cold. The vacuum motor on the air baffle may be leaking which is probably why it was disconnected. New vacuum motors are still available but the supply is spotty.
The burned out air injector tube is a wrecking yard item. If the vehicle needs to be inspected you should find a replacement. If not, remove the air pump and associated tubing and close the manifold ports with the appropriate sized plugs.
The EGR valve is probably leaking due to carbon build up. The modern moonshine blend fuels do not play well with the EGR system and the result is carbon build up that plugs the EGR passage and the seat on the EGR valve. This in turn causes a manifold vacuum leak because the EGR is stuck open and bleeding off vacuum. Result is a vehicle that runs like crap. At the very least, the EGR valve should be removed and cleaned. If the intake manifold passages are full of black goo, the manifold should be removed and hot tanked to clean it out. If the vehicle is not subject to inspection, there is an after market block off plate that goes under the EGR valve to disable it and stop the problem with vacuum leaks. If you decide to keep the EGR, You should keep a delay system for the EGR as it is only supposed to work with the vehicle warmed up and running above an idle. There were a lot of problems with EGR/Air Injector equipped vehicles with them detonating inside the intake manifold if everything was not working properly. That is the main reason that so many of the vehicles with this setup had it removed as soon as the inspection mandate went away.

Dave
 
Emissions inspections are not required for the car. The car sat for a few decades before being put back into service.
I plugged/bypassed vacuum lines that were damaged, or went to components that were damaged (i.e. a broken OSAC valve that was then epoxied back together). The bolt that secures the air injection tube to manifold is broken. Unfortunately, I'm fairly certain the manifold will have to pulled be repaired; a task I am not looking forward too. Eliminating air injection system is a non-issue for me. I don't think the EGR is opening at cruise. I can manually open it at idle and the engine will stumble. Regardless I intend to pull it and clean it. A new gasket is on order. Omitting it entirely will require re-jetting the carb? It's the stock thermo-quad that was professionally rebuilt.
 
Emissions inspections are not required for the car. The car sat for a few decades before being put back into service.
I plugged/bypassed vacuum lines that were damaged, or went to components that were damaged (i.e. a broken OSAC valve that was then epoxied back together). The bolt that secures the air injection tube to manifold is broken. Unfortunately, I'm fairly certain the manifold will have to pulled be repaired; a task I am not looking forward too. Eliminating air injection system is a non-issue for me. I don't think the EGR is opening at cruise. I can manually open it at idle and the engine will stumble. Regardless I intend to pull it and clean it. A new gasket is on order. Omitting it entirely will require re-jetting the carb? It's the stock thermo-quad that was professionally rebuilt.

Most of the time, getting rid of an EGR will not cause carb issues such as re-jetting. Quick test would be to plug the EGR vacuum line and take the car for a drive. If it still runs ok, you should be good to go the way it is.

Dave
 
If you might desire the OEM look, remove and clean the EGR valve and its sealing point on the manifold. Put it back together and disable the vac supply to the valve.

In some cases, disabling the EGR system might cause some part-thorttle pinging, so you can watch for that. If it happens, just try retarding the base timing 2 degrees or so and see how that goes. But you could well notice better throttle response and eagerness to move with no EGR.

GM used to sell some pipe plugs with a 1/4" or 3/8" socket indentation in them, on the top side, for plugging the exhaust manifold AIR tube holes (for vehicles which did not have AIR systems from the factory, but all replacement manifolds came with the holes). Makes for a lot cleaner (and a bit less obvious situation than the normal pipe plugs) look of things. I suspect they might be available elsewhere, though. Usually, there can also be a tube/nozzle under where the external manifold screws into the manifold.

For general principles, you might want to take a picture of the vac hose routing decal under the hood, for reference purposes. Then casefully remove it, maybe with some heat. Most would have been deteriorated by this time, anyway, by observation.

Just some thoughts,
CBODY67
 
Timing is set to stock (10 degrees BTDC). I feel it needs to be advanced as it sits now. Vacuum is low (but steady) and the exhaust manifolds are a few hundred degrees warmer than my '64.
No under hood diagram in '74, but the FSM has nice schematics.

FWIW this what it looked like when I picked it up....
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The added temperatures you mention is probably due to the lower compression ratio. Reason I say that is that one of my shadetree methods to fine-tune the idle mixture and speed was to place my hand in the exit flow of the tail pipe, then smell my palm for hydrocarbons, which would be minimal if any. But the exhaust temp on the '72 Newport 400 2bbl was noticeably hotter than our '66 Newport 383 2bbl. With the '72 at 10degrees BTDC and the '66 at 12.5degrees BTDC base timing. Both with 180 degree F thermostats. Only real difference was that the '66 had 9.2 rated CR and the '72 had 8.2 rated CR. The hotter exhaust also can tend to continue the burn of the hydrocarbons and such after the mixture leaves the cyl, not unlke what the AIR system did, too.


Take care,
CBODY67
 
So to close the loop on this (and bring up another issue)...

Air injection system has been removed (11/16 plugs were used to close off the openings on the rear of the manifolds). EGR system is intact, but by-passed. As mentioned previously OSAC/TIC valving has been omitted and distributor advance taken from the base of the carb.

Timing and A/F have been adjusted so that I have a 'steady'(I still get a small flutter on occasion-like less than .25 mmHg) (and respectable)18.5 mmHG at idle. Exhaust manifold temperatures are very even. The manifold and bottom of the EGR valve were heavily pitted. The valve I was able to clean up perfectly. The manifold not so much; I think I still have a small exhaust leak from there, even with the new gasket. I'll reassemble with some high temp RTV.

The car drives so much better. Decent power off the line and a nice pull from cruise. I have an AF meter, and as soon as my longer cable arrives (because the folks that buy the meters don't tune large cars) I can see how close to perfect I got using a vacuum gauge and tachometer.

Now for the next problem.....

The charging system was completely non-functional when I got the car. I replaced both the VR and the alternator with parts from NAPA. Charging system seemed to over charge initially however when checking randomly at other points voltage values seemed reasonable. A few weeks ago I noticed sparks from inside the alternator case and about a week ago the car stopped charging. The alternator was replaced under warranty from Napa and all seemed right.
Except it's not. I've been checking the voltage at regular intervals and it's all over the place...mostly 13.6 at the battery at idle and 14.5 at cruise. But I've seen it as high as 15.3 at the battery. I've also seen it as low as 13.0. Voltage at the ballast is usually about 7/10 of a volt less than at the battery. Checking the voltage drop from the alternator field to the battery I get something like 7/10 of a volt. Too much. Is there a way to temporarily by-pass the ignition switch to eliminate that as a culprit? Or just buy the Dodge truck one as process of elimination?

Soo close to getting this thing road-trip-ready.
 
Voltage should be more even than what you observe at various engine part locations. Check the voltage loss in the battery + and - cables, for good measure.

Reason I say that is that I chased an intermittent power loss in my '77 Camaro for months. I could hear the radio make a motor-boating noise before the car would die. IF I got the rpm back up, it'd keep running. I got a nice digital VOM to check things with. One day, as I drove home for lunch, the car died in front of the house. I got my meter out and started checking voltages. I discovered a .4volt loss (IIRC) between the battery and every where else on the engine I checked the voltage. Then, the a/c fan clicked on and the voltages were all right at battery voltage. That's when I checked the negative cable and determined that it had an internal fault (although it was OEM production and looked great on the outside). I replaced it with a new OEM cable and that was the end of the issue.

I even replaced/wired around the neutral safety switch, to no avail. Once it died, the starter would not energize until it had cooled off a bit. Then, it would act normal until the next random time it decided to not act correctly.

The voltages you mention when the car is running are pretty much "fine as is", compared to what the digital readout of "Voltage" is on my 2005 LeSabre Ltd. Do your voltage variation checks on valid engine ground locations/bolts, rather than anything which might bolt to a body part. Those should be the most reliable places, I suspect.

Please keep us posted on your progress. Glad you've got things running as good as they are, too!

Just some thoughts,
CBODY67
 
Remove all that nonsense. The only thing remotely useful for drivability is the EGR and vacuum advance(not really a emission piece, but you did mention it). The EGRs short trip cloggability makes it a maintenance problem.
Most of that stuff was put on to patch a emission issue that the government made in the first place. I'm for clean air, but as with many government programs the short sightedness becomes very apparent down the road. The emissions skyrocket when these systems quit working properly. The engine uses more gasoline, which results in more unburned gasoline in the air and more rapid engine wear, which again increases emissions.
 
I've decided that whatever problem there is is intermittent (until it's not). I'm just going to put some miles on the car (more things will need sorting as it's used again). Closing the loop on tuning with the emissions equipment removed: my initial vacuum gauge and tachometer tuning got me close (A/f of 12:1). The meter got me a little better; 12.8:1 at idle, 15.5-16 at cruise. Vacuum was bumped up to a very respectable 19 mmHg and some change.

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Wow Imperial LeBaron Crown Coupe. Rare machine, one of 57 made. What a looker!
 
Looked like rust was about to eat through it, good save.

I used to read Motors manuals and marvel at how compression ratios and HP both plummeted from 1970-75, nevermind the emissions garbage, later Lean Burn...

Back in '88, we had the 1st year Tune up instructor's mom's green '70 Polara 4dr boat (zero emission controls) doing better than current year CO limits (2%) on a Bear analyzer, was running at 1.8% with the instructor who I work studied for marveling how it was running as clean or cleaner than cars with cats.

I went on to be a State Certified Emissions Specialist before even leaving school, $10k per offense of cutting a cat or similar tampering with emissions control, and while it all had to be there and look good, my hack for the EGR and other systems that would cause trouble was little ball bearings in the vacuum lines, no one would ever know unless they were really looking, and noticing that the EGR valve never moved.
 
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Back when the emission tailpipe checks were on the horizon, there were stories around of instructor's vehicles (in this case, a '58 Chevy 6-cyl car) which had lower emissions than the newer standards were, which I found interesting, until you might realize that a low-lift, low-duration cam (as most were back then) with a short overlap period, were decently clean as is.

One day, at the local Chry dealership, while the CAP system was in existence, we'd gotten the '66 Newport 383 2bbl tuned-up. One of their final deals was to "Solvize the carb" and set the idle speed and mixture, toward the end.

"Solvize the carb" was a quick dousing of the carb and choke linkages from a nozzled can of a Acrisol solvent. Then the idle speed was set using a tach. Sometimes a mixture check with a portable/wheeled Sunn a/f ratio meter, mainly to see that at "cruise" that the mixture needle would swing into the 14.2+ part of the gauge, which it did.

I asked to see if the carb idle mixture could be adjusted to that, too, per CAP specs. AND it was possible to do that, but with a bit more quiver at idle, so it was set back to what it was before. Mystery solved, interestingly.

In John DeLorean's book "On A Clear Day, You Can See General Motors", he mentioned how that the GM accountants did not understand the need for the emissions system GM was using (A.I.R., and such, at a $40+ cost/car) when Chrysler could do it with less stuff and less money. At the time, I thought the Chrysler CAP system of engine calibration modifications was pretty neat and demonstrated their "better engineering" orientation. As things got tighter, everybody ended up with pretty much the same equipment, though. And they had to warranty any issues for 50K+ miles (later 100K miles to match the CA regulations). Still, Chrysler's approach to things seemed more high-tech to me than GM and Ford's more crude (to me) items. Although in this case, "more crude" seemed to affect the driveability less, by observation, and when THEY did kaput, the customers seemed to give Ford and GM "a pass" as they were not happy at all with Chryslers (especially the newer Chrysler owners).

Now, what DID surprise me and make me smile was that Fenner Tubbs C-P took some of their new-car demos and did a mileage check, about 50 miles or so, with the cruise at 55mph (the national speed limit of the time). They filled the tanks at a Shell station across the street from the dealer, then drove the cars south to the edge of the Caprock, turned around, headed back north to the same Shell station and filled the tanks. The '74 New Yorker returned 20.66mpg, the '74 Newport returned 20.33, and a Gran Fury 360 2bbl was 19.__mpg. They had some results printed up on company letterhead and then had them all notorized . . . as handouts at the dealership. Owners of Oldsmobile 98s, for example, who obviously might question the results, were given a New Yorker to drive for the weekend. On Monday, they bought the New Yorker for fuel economy alone, almost every time. It was a good cotton crop that year and it was time to trade.

I CAN related that when GM went to cat converters and their "re-tuning" of the engines to seemingly earlier calibrations, letting the cat do the work of cleaning the exhaust, those cars DID run a bunch better than the '74s. '74 Chevies which allegedly needed to have the spark plugs changed at 6K miles (!!!) to maintain emissions compliance. Rather "cleaned", but most techs changed them anyway. Guess how many times those mileage intervals were extended to what they used to be???

Think of how many gallons of fuel might have been saved IF Chrysler (and their Bendix EFI associations) and GM (with their Rochester products division) had gone EFI in the middle 1960s. Sure, Chrysler had some issues with radio frequency interference (which might have easily been shielded against!), but the Rochester systems were mechanical. Only "problem" was their additional cost and training techs to work on them. And nobody wanted to give Ford a cost advantage back then OR spend hundreds of dollars on something a $30 cost carburetor could do and such. But when it became necessary, even for the less expensive TBI units, as the cost of the cars also increased each year, too, it was easier to hide those additional costs in the basic price of the car.

The Imperial 318 EFI system had ONE big fault. The mass air flow sensor was located (logically) in the air cleaner snorkle. Problen with that was that when the air cleaner top was removed, the TBI got its air from the newly-openned area, so air flow through the snorkle stopped, so the system figured the engine died,k so with no MAF signal, the engine DID die. Plus, not getting the air cleaner top and band clamp back on correctly could cause driveability issues for the same reason.

Consider, too, that when Chrysler Aerospace designed that system, Chrysler HAD to do something and quickly, plus with little time OR money to design a "normal" system, with little additional assembly cost/complexity. So that system was basically an underhood "bolt-in" replacement for the Carter BBD carb, with some extra supporting hardware. But seemingly like some other Chrysler issues of the time, they tended to seem to not source things for the best durability, which caused problems as the cars aged. One friend who had one of those Imperials was looking to get rid of it by 20K miles, to get ahead of those "problems", for example.

To me, the Chrysler ELB system was a better way of doing things, which took cat converters out of the mix, which was an "advance" for 1976. But it seems that component issues started to happen. It seemed that if any sort of problems came up, the Chrysler "computer analyser" indicated the need for a new computer. A simple fix, usually, as it was. But later versions, which evolved into the "Electronic Spark Control" system in the later 1970s and earlier 1980s, seemed to be better, by observationl.

As with many OEM "problems" and what those might be, it usually gets back to how much money they were willing to spend and how long they (secretly, seemingly) wanted the components to last. Plus what the failure rate might be and how that might impact warranty costs, regardless of the OEM. And, by observation, in hindsight, as Chrysler's financial issues of the later 1970s and earlier 1980s got to be worse, some of their decisions seemed to covertly parallel those issues. Possibly one of the worst was the Carter carb base gasket on the Slant 6 Aspen/Volare cars. A part that NEVER had caused any problems suddenly did . . . AND it got coverage in the newspapaers, too!

Chrysler tended to "break ground" for new technologies back then, got "talked bad about" by some of the customers, but then Ford and GM had the same things (seemingly dumbed-down a bit for lower costs), which ALSO caused customer issues, but Ford and GM did NOT seem to get hammered by their customers nearly to the extend that Chrysler did, as I recall.

Just the things I observed to have happened back then, fwiw.
CBODY67
 
I knew I needed some quiet time to read this, @ 6am Sunday morning.

I still have mixed feelings about any and all emissions controls.

Do you see any under the hood of a '61 Jag XKE?

Of course not, they don't usually jive with performance.

Interestingly, we have 2 older Subaru wagons (his/hers), 1995-2000, coincidentally both "Cali emissions", sold new in that state, both very surprisingly EGR delete cars, both run much better than the average example.

Locals are now cutting their own cats off - before somebody else does - because of fairly benign read meaningless CAT inefficiency codes, cutting off the wires to the 02 sensors, apparently the codes are still there afterwards like phantom pain...
 
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