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73 emissions questions


QcodeAl
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Hi All, I recently joined the site after purchasing a 73 mach 1 q code with a C6 auto. This looks like a great place for info. Long story short the car only has about 22,000 miles on it and the 351 Cleveland but it has sat for a long time. The previous owner in his efforts to get it running decided to change the intake manifold to an edlebrock but never finished the job. I am working on putting it back to original as he included the original 4V intake and carb. Unfortunately a couple of the emissions parts are missing or broken. I have found a couple vacuum hose diagrams on line, purchased the set of shop manuals and the 73-79 parts manual. I cannot for the life of me chase down the parts numbers for several of these parts. I have the vacuum tree for intake and the loop is on the firewall. I have the PVS valve near the water pump, the temperature controlled vacuum valve that goes into the heater hose but am missing the "normally open solenoid valve" It looks like some cars had 2. One on the right rear of the intake ( I have this one but the nipple is broken off) and one on the left mounted on the valve cover. (Mine is missing) It appears as my wiring harness has terminations that would go to the one mounted on the valve cover. Curiously, the vacuum diagram I have found shows the cobra jet (which my car is) as only having one of these normally open solenoid vales. My car was built late. June of 1973 if that makes a difference. I am also missing the Spark delay valve and check valve if I am going by the non cobra jet diagram. So my questions are:

 

1) Should my car have 2 of the normally open solenoid valves ?

1a) are they the exact same ? The termination styles would tell me no. But ?

1b) what is the factory part number for them ?

1c) does any one know of a supplier ?

 

2) Does anyone know of someone that can help me through this issue and finding these parts ?

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One of our tech guru's should chime in shortly, or perhaps PM Don at Ohio Mustang Supply (one of our sponsors). He's forgotten more about Mustangs than I'll ever learn.

Doc

Project started 8-7-10

Completed: All new suspension, rebuilt 351C H Code bored .030 over with mild cam and intake, new 3.50 TracLok, custom exhaust system

Current "mini-project": interior upgrade :-/

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Here is the Q code vacuum diagram for a 73. I also have a June 73 Q code and have researched a fair amount. The 4V vacuum and sensors seem to be quite a bit simpler than the 2V cars. Happy to help if I can.

 

2mnoz2b.gif

Jeff

1972 Q Code Convertible

 

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Here is the Q code vacuum diagram for a 73. I also have a June 73 Q code and have researched a fair amount. The 4V vacuum and sensors seem to be quite a bit simpler than the 2V cars. Happy to help if I can.

 

 

 

Thanks Jeff !

 

I have that diagram also. Does it match your June built Q code ? That does make it a lot simpler.

 

If that diagram is correct for June built Q code, I need part #4 in the drawing or the part number so I can hopefully chase it down.

 

I will also need to take some pics of my engine wire harness that runs down the left (drivers side) valve cover. Maybe you can help me determine what goes where. I think I have most of it figured out but there are a couple mysteries. I would really appreciate it. Thanks again !

 

Al

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Hi Al,

 

When I got my car it was somewhat in pieces and have had to figure out what was missing and how it hooks up. Car is currently under restoration so not completely hooked up but we should be able to figure yours out. This diagram appears to be the correct one for my/your car as I have all the items in the diagram.

 

The solenoid part number 4 shows up on ebay every once in a while but I just checked and did not find one. You can contact Don at Ohio Mustang as I am sure he has one. They are not reproduced.

 

Here is a pic of the solenoid...

 

2rdw4f7.jpg

Jeff

1972 Q Code Convertible

 

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Hi Al,

 

When I got my car it was somewhat in pieces and have had to figure out what was missing and how it hooks up. Car is currently under restoration so not completely hooked up but we should be able to figure yours out. This diagram appears to be the correct one for my/your car as I have all the items in the diagram.

 

The solenoid part number 4 shows up on ebay every once in a while but I just checked and did not find one. You can contact Don at Ohio Mustang as I am sure he has one. They are not reproduced.

 

Here is a pic of the solenoid...

 

 

 

Great pic Jeff. That looks just like the vacuum solenoid on my car and is in the same place. Of note is that mine has a spacer under the bracket to hold it up off the manifold. I see your car also has the vacuum loop on the fire wall with 4 ports where the drawings define 2. (mine has 4 also)

 

I am attaching a pic of vacuum diagram drawing 3-14A which is a 351 Cleveland with auto trans. I am suspicious that my car was set up this way because I have part number 2 in the heater hose circuit and part number 1 in the water pump. I also have some terminations in my engine harness that look like they were hooked to part number 5. I will take some pics of those connectors and post them to see if I am just not identifying them correctly. I'll get the wiring diagrams as well to see what clues are there.

 

Drawing 3-16A (351 cobra jet) does not have a part number 1 in the water pump. I am trying not to get hung up on that even tho my car only has 22,000 miles. The water pump could have been switched at some point with a used one in 41 years as it obviously had a rough life, even tho it sat a lot. I still have to solve the harness question if that is true.

 

An update to the search for the parts, Colorado Mustang has let me know that they have everything I need. I went ahead and purchased the extra solenoid and check valves just in case diagram 3-14A ends up being correct. Hopefully I will be able to post the part numbers when they arrive as he said they were new. I assumed nos but I should have asked......

 

I called Bob twice at Ohio Mustang. For all the good words I see about him here he has not returned my calls. I am disappointed but I am guessing he is busy.


578661527_3.14Avacuumdiagram.thumb.jpg.a72c46bbc380cfc76536878a01ef7a6f.jpg

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Al,

 

Despite what may be on car some 40 years later the 4V vacuum diagram is correct. I have seen a number of Q codes that I used to verify what would be correct for mine and they all used the 4V diagram.

 

One way to tell for absolute certain is to see if the ambient temp switch is there #9 on diagram...if NOT then you don't have that setup.

Jeff

1972 Q Code Convertible

 

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Al,

 

Despite what may be on car some 40 years later the 4V vacuum diagram is correct. I have seen a number of Q codes that I used to verify what would be correct for mine and they all used the 4V diagram.

 

One way to tell for absolute certain is to see if the ambient temp switch is there #9 on diagram...if NOT then you don't have that setup.

 

We are thinking alike. Lol. I spent more than a few minutes tonight peering into the door jamb on the right side. I read somewhere that it is only visible if the fender is off. I will pull it if I absolutely have to. I took some pics of the terminations that run down the left side valve cover that I will post tomorrow. I have the coil, temp sending unit, oil pressure switch, choke, the always open solenoid valve on the right rear of the manifold and the idle solenoid connectors identified. "I think" there are 2 others that make no sense to me. Is it possible they were just unused ?

 

Thanks for your input Jeff. Knowing that you have looked at a lot of them makes me much more confident in the 4 V diagram


yeah I'm glad i didn't get a 1973 model

 

tumblr_ll5yzoMAcx1qall69.gif

 

Lol I hear ya coupled with the fact this is my first Ford I am wondering myself. But I have always loved this body style. Friend of Mine had one in high school and I always thought it was one of the sharpest cars in the parking lot

 

Luckily I enjoy this part of it !

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Are you sure you wish to return to factory specifications here? You could bolt down a 1971 M-code intake to avoid the EGR and multitude of vacuum lines (which will inevitably wind up in a vacuum leak within 6 months if you use cheap vacuum hose).

 

-Kurt

satellite-valiant-mustang-license-tags-signature.png

How to buy a '71-73 Mustang:

Rule #1: Assume all classic car sellers are guilty until proven innocent.

Rule #2: No classic car dealer is ever innocent; thus, they are all guilty.

Rule #3: Buy from trustworthy people: Fellow forum members. Visit 7173Mustang's For Sale forum.

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wire1.JPG.aac6c08c5df2888487bb4135af35f7b7.JPG

Are you sure you wish to return to factory specifications here? You could bolt down a 1971 M-code intake to avoid the EGR and multitude of vacuum lines (which will inevitably wind up in a vacuum leak within 6 months if you use cheap vacuum hose).

 

-Kurt

 

I seriously considered that. The car also came with a 4V edelbrock intake that I could have used. My reasoning was, flawed or not but it came down to the fact that it is a documented 22,000 mile car, rough as it is. I just felt like it deserved to be put back together the way it left the factory. At least as best as my time and resources will allow. Sometimes I get on to mysteries like this and although it can get frustrating. It is also very rewarding when I learn from research how it all goes and is supposed to work. Call me crazy, but I can spend days chasing this all down and then take 5 minutes to install the correct parts.


Al,

 

Despite what may be on car some 40 years later the 4V vacuum diagram is correct. I have seen a number of Q codes that I used to verify what would be correct for mine and they all used the 4V diagram.

 

One way to tell for absolute certain is to see if the ambient temp switch is there #9 on diagram...if NOT then you don't have that setup.

 

Here is the pic of the wire harness connectors that I can't tell what they are for. I have pulled the harness forward and in reality it sits more rearward. The connector that is oval shaped and laying near the front of the valve cover is for the idle solenoid on the carb. The small round female and the flat female spade hanging down a bit I thought were for another always open solenoid. Per diagram 3-14A. This would be another oddity because they should both be female flat spade, lol....So what is the small oval female and flat spade female for ? Help !

wire1.JPG.aac6c08c5df2888487bb4135af35f7b7.JPGwire1.JPG.aac6c08c5df2888487bb4135af35f7b7.JPG

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in all honesty, the EGR and all those extra vacuum and electric solenoids is just asking for problems.

if your trying for factory concourse that is one thing or if you have draconian state emissions laws that require the car maintain all original emissions i could understand.

 

I you have the choice i would not start putting all that stuff back on the engine.

some things you should use, like the PVC and the Distributor Vaccum Control Valve, ported vacuum is fine, having a duel vacuum advance distributor is fine, fuel vapor canisters all fine.

 

but things like the EGR just clog everything up with Exhaust soot a smog pump is a nightmare and a joke.

spark delays cause ignition problems. speed sensors and extra vacuum motors with the age on the parts is asking for vacuum leaks and malfunctions.

you might want to just restore back to an early 73 setup that eliminates half that emissions control stuff it will look factory to people looking over the engine but you will have less issues and a better running engine.

 

if you really do have all the speed sensors and ambient temp sensor it might be cute to get them working, but understand that those were designed to keep the exhaust temp high to try to burn off exhaust gases then part of that is fed back into the motor intake for re-burning(before the catalytic converter) they will have negative effects on the motor running cool and clean internally, and performance wise. you could get a EGR block off plate and eliminate most of the controls under the hood and still have something that looks correct when looking under the hood. some of the stuff should be kept as it does some good but the rest is a short circuit and a vac leak bomb.

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in all honesty, the EGR and all those extra vacuum and electric solenoids is just asking for problems.

if your trying for factory concourse that is one thing or if you have draconian state emissions laws that require the car maintain all original emissions i could understand.

 

I you have the choice i would not start putting all that stuff back on the engine.

some things you should use, like the PVC and the Distributor Vaccum Control Valve, ported vacuum is fine, having a duel vacuum advance distributor is fine, fuel vapor canisters all fine.

 

but things like the EGR just clog everything up with Exhaust soot a smog pump is a nightmare and a joke.

spark delays cause ignition problems. speed sensors and extra vacuum motors with the age on the parts is asking for vacuum leaks and malfunctions.

you might want to just restore back to an early 73 setup that eliminates half that emissions control stuff it will look factory to people looking over the engine but you will have less issues and a better running engine.

 

if you really do have all the speed sensors and ambient temp sensor it might be cute to get them working, but understand that those were designed to keep the exhaust temp high to try to burn off exhaust gases then part of that is fed back into the motor intake for re-burning(before the catalytic converter) they will have negative effects on the motor running cool and clean internally, and performance wise. you could get a EGR block off plate and eliminate most of the controls under the hood and still have something that looks correct when looking under the hood. some of the stuff should be kept as it does some good but the rest is a short circuit and a vac leak bomb.

 

Thanks for your input and all of that may very well happen. I'll decide as I chase the parts and systems. Do you happen to know what those terminations I have shown above go to ?

 

I can't see any evidence of a smog pump being on the car. But maybe those terminations are a clue.

 

I am hoping it is the simple Q code 4 V diagram above

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I think the only thing hooked to my intake is a vacuum advance and PVC. No a/c, aftermarket carb, manual brakes and manual trans play a big part. Runs like a dream.

 

 

Sent from my iPhone using Tapatalk

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Thanks for your input and all of that may very well happen. I'll decide as I chase the parts and systems. Do you happen to know what those terminations I have shown above go to ?

 

I can't see any evidence of a smog pump being on the car. But maybe those terminations are a clue.

 

I am hoping it is the simple Q code 4 V diagram above

 

Al, if you're missing any check valves, let me know. I have all the smog fittings and check valves that I pulled off my '78 Lincoln Mark V (equipped with a 400 - all 400's were 2V with exception to a few experimental Broncos, so I can't help you out with a carb plate), which may be similar to the '73 equipment on the Mustang.

 

Can get you a photo of what I have.

 

-Kurt

satellite-valiant-mustang-license-tags-signature.png

How to buy a '71-73 Mustang:

Rule #1: Assume all classic car sellers are guilty until proven innocent.

Rule #2: No classic car dealer is ever innocent; thus, they are all guilty.

Rule #3: Buy from trustworthy people: Fellow forum members. Visit 7173Mustang's For Sale forum.

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Thanks for your input and all of that may very well happen. I'll decide as I chase the parts and systems. Do you happen to know what those terminations I have shown above go to ?

 

I can't see any evidence of a smog pump being on the car. But maybe those terminations are a clue.

 

I am hoping it is the simple Q code 4 V diagram above

 

Al, if you're missing any check valves, let me know. I have all the smog fittings and check valves that I pulled off my '78 Lincoln Mark V (equipped with a 400 - all 400's were 2V with exception to a few experimental Broncos, so I can't help you out with a carb plate), which may be similar to the '73 equipment on the Mustang.

 

Can get you a photo of what I have.

 

-Kurt

 

Perfect ! Thanks Kurt, right now I think the priority is the 2 terminations (connectors) in the pic and figuring out what they are for. After that I will be able to figure out what devices I need. I have the 73 through 79 parts manual on a PDF but with 6000 plus pages it is not the most maneuverable document. The knowledge on this board is impressive ! You guys are awesome.

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Are you sure you wish to return to factory specifications here? You could bolt down a 1971 M-code intake to avoid the EGR and multitude of vacuum lines (which will inevitably wind up in a vacuum leak within 6 months if you use cheap vacuum hose).

 

-Kurt

 

Im with Kurt

after mucking around with my 73 Q i ended getting rid of all that rubbish and the car runs way better and still looks killer

I ve kept the original look with air cleaner assembly and standard rocker covers but upgraded intake and carb

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Are you sure you wish to return to factory specifications here? You could bolt down a 1971 M-code intake to avoid the EGR and multitude of vacuum lines (which will inevitably wind up in a vacuum leak within 6 months if you use cheap vacuum hose).

 

-Kurt

 

Im with Kurt

after mucking around with my 73 Q i ended getting rid of all that rubbish and the car runs way better and still looks killer

I ve kept the original look with air cleaner assembly and standard rocker covers but upgraded intake and carb

 

Just out of curiosity. What did you do about the wiring for the devices you removed ? Even for me with my limited experience, if I see terminations laying around unused in the engine compartment, I wonder what's missing. There is no doubt I am the minority probably but some things like that bother me. I did consider un wrapping the harness back to where I could remove them cleanly.

 

Another thought I had was to discretely disable the systems but keep the original look. I have done something similar with vacuum systems in the past and just used silicone to plug the vacuum hoses in strategic places. So the hoses are there but not doing anything. I would then have to figure out how to de energize the electrical but possibly not. With no vacuum signal they may just be along for the ride.


Al,

 

I am out of the country until early next week...I can look for you then but the connections all look familiar. If I get a minute will look up on my wiring diagram.

 

Thanks Jeff !

 

I am traveling next week till Thursday, but will still be checking here for info and will probably have more questions also. lol

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Just out of curiosity. What did you do about the wiring for the devices you removed ? Even for me with my limited experience, if I see terminations laying around unused in the engine compartment, I wonder what's missing. There is no doubt I am the minority probably but some things like that bother me. I did consider un wrapping the harness back to where I could remove them cleanly.

 

The Mark V was converted from a 2-barrel factory intake to an Edelbrock 4-barrel (painted to match the block), so the EGR plate was deleted right then and there. Deleting the EGR plate resulted in the removal of 70% of the vacuum lines to start with, which were doing nothing other than diverting vacuum to operate the thing.

 

The other 30% were do-dads designed to adjust the vacuum response in one way or another - including a check valve on the thermostat outlet which 72HCODE will point out is rather beneficial for adjusting timing based on temperature, but I haven't had any problems using vacuum straight off the carb.

 

That, and I'd rather have a slightly rich mixture than a lean one from shot Chinese vacuum lines that dry rot in 6 months.

 

The air/smog pump was removed from the block, so that also took care of the hoses and canister that hooked to the intake manifold.

 

Other than running a line from the carb to the vacuum advance, and the plethora of vacuum junk for the headlights off the manifold's rear T, I don't think there's any other vacuum line running off the engine. The V has Hydroboost, so I don't even have vacuum going to a brake booster.

 

This is what it looked like when done. The spark suppressor is there for tests only:

markv_4160_1.jpg

 

-Kurt

satellite-valiant-mustang-license-tags-signature.png

How to buy a '71-73 Mustang:

Rule #1: Assume all classic car sellers are guilty until proven innocent.

Rule #2: No classic car dealer is ever innocent; thus, they are all guilty.

Rule #3: Buy from trustworthy people: Fellow forum members. Visit 7173Mustang's For Sale forum.

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  • 5 years later...

Here is the Q code vacuum diagram for a 73. I also have a June 73 Q code and have researched a fair amount. The 4V vacuum and sensors seem to be quite a bit simpler than the 2V cars. Happy to help if I can.

 

2mnoz2b.gif

 

Any chance this image is still available? Sounds like what I’m looking for!

Unless it’s 3-14A. That has two solenoids.

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  • 1 year later...

image.png.cd97832ef8811453343f99043c33e302.png

If I want to omit the solenoid at #5, then the middle hose from #1 will feed the single vacuum distributor advance directly. 
 

Is the #6 Spark Delay Valve still needed?

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9 hours ago, RC92234 said:

 

If I want to omit the solenoid at #5, then the middle hose from #1 will feed the single vacuum distributor advance directly. 
 

Is the #6 Spark Delay Valve still needed?

 

You can safely bypass the entire system and feed directly from the PVS valve to the advance unit. 

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Music to my ears. Thank you.

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