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Discussion Starter · #1 ·
My Grandson has an 83 w/ 5.0 and carburetor, 5 spd, single exhaust. The EGR is bad and vacuum line was plugged by the PO. The Catalytic converter is now plugged as the air pipe was disconnected. He is a college student and wanting to know what / how to eliminate the EGR and Catalytic Converter and Air injection system and what affect this has on the ECM and thus distributor control. It has the 4180 Holley not fuel injection. It does have A/C.
It wouldn't idle well and would not accelerate above 2K rpm. We blocked off the EGR and he cut a hole in the pipe in front of the catalytic converter and now it runs well and will accelerate. I am concerned the ECM is not controlling the distributor correctly and we are looking for affects and advice on what components to disconnect / plug / replace to make it drivable if possible without ECM / distributor replacements.
Has anyone done this and advice please.
Thanks
Ron
 

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If not a Ca. car, should have Duraspark II ign with a 5 speed. Only two wires that "power" it (red and white below).
The rest is internal and not really affected by emissions.

The ign module only tells the coil when to fire, based on a hall affect sensor in the distr. Other than that, it is not really
an ECM per say. It does also control dwell, so I'm told........

 
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to delete the Air Injection system you need two pipe plugs to go into the back of the heads where the lines attach. you can get a shorter belt that will let you bypass (remove) the pump.
An "Off Road" pipe will delete the cats. At this point you may want to go with a later dual exhaust system. You only need a two hump trans mount and a second hangar in the back. It is a straight bolt in.
 

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Discussion Starter · #4 ·
Thanks Gentlemen, That is the information we needed. He can do the bypass and plugging and then reverse it later when he gets the money / time if he saves the parts. He is trying to get it going for a car show at the end of the month down in St. Louis. I have searched for diagrams of the emissions system and ignition, but I guess I was looking in the wrong place. Couldn't find much on an 83.
Thanks again,
Ron
 

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to delete the Air Injection system you need two pipe plugs to go into the back of the heads where the lines attach. you can get a shorter belt that will let you bypass (remove) the pump.
An "Off Road" pipe will delete the cats. At this point you may want to go with a later dual exhaust system. You only need a two hump trans mount and a second hangar in the back. It is a straight bolt in.
Does anyone sell offroad H/X pipes anymore? I thought the EPA put the "cabash" on those.
 

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Offroad pipes seem to be mostly useless now unless you have an unregistered track only car and can prove it to a tuner or a pre-emissions era car with a newer engine. Apparently, no one will tune your computer controlled emissions era car for an offroad pipe anymore if it's able to be driven on the street.
In this case for this 1983 idk if removing the cat might make it run worse or not but it definitely won't pass any emissions test or roadside check since every car made after 1975 had a cat on it.
I wonder what the ECM is actually doing in these earlier non-feedback carbureted cars. It has an ECM and there's also supposedly an O2 sensor as well. One thing that I can think of it doing is possibly engaging the throttle positioner on the Holley 4180C. Then again older carbs didn't need an ECM to power up a fast idle solenoid so idk.
You can buy a hardcopy of a 1983 Ford Car Wiring and Vacuum Diagrams manual to help you understand what specifically goes where. A 1983 Ford Car Shop manual won't have much for electrical diagrams but would give you plenty of other specific info. A 1983 Ford Car Body/Chassis/Electrical manual will have some basic diagrams.
1983 mustang electrical manual: Search Result | eBay
I know that many Ford Shop manuals can be downloaded for a fee or bought on DVD or USB drive.
 

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Much like a pre cat car the early carbed cars have no O2 sensors no feedback because the only engine control is the duraspark ignition. Early cars had a cat as an addon stopgap measure.
Not recommending cat removal but in some parts of the country we do not need to worry about yearly or roadside emission requirements.
Its nice to live with minimun .gov intervention!
 

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I was aware that earlier vehicles have stand alone cats but Rockauto shows an O2 sensor for the 1983 Mustang 5.0. Idk if it was wrongly categorized(perhaps it was only the CFI and turbo vehicles that had them) but if it did have an O2 sensor then I was curious what the ECM was doing with the data from it.
 

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I can only say my carbed 84 didn't have any electronics except the ignition. No O2 sensors or related wires, parts etc...
I am the second owner and it was stone stock when I bought it. :unsure:
 

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I was aware that earlier vehicles have stand alone cats but Rockauto shows an O2 sensor for the 1983 Mustang 5.0. Idk if it was wrongly categorized(perhaps it was only the CFI and turbo vehicles that had them) but if it did have an O2 sensor then I was curious what the ECM was doing with the data from it.
The auto's were throttle body injection, at least in 84.

EDIT: This seems to indicate 83 also for auto 5.0's, EEC-III or EEC-IV, depending upon build date.

 

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I can only say my carbed 84 didn't have any electronics except the ignition. No O2 sensors or related wires, parts etc...
I am the second owner and it was stone stock when I bought it. :unsure:
Rockauto listed the O2 sensor for the 1983 but didn't specify auto or manual but since your 1984 is original without any O2 sensor apparently it means that only the weak CFI 5.0 cars had them.
The auto's were throttle body injection, at least in 84.

EDIT: This seems to indicate 83 also for auto 5.0's, EEC-III or EEC-IV, depending upon build date.

Yes, I was aware of that and they also had noticeably less HP than the Holley equipped versions. I had actually read thru that very article recently but the question still remained whether the carbed version had an O2 sensor or not since both auto and manual cars have an ECM.
 

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Carbed models (stick shift) did not have O.2 sensors. The CFI (Automatics might have had O2 sensors since they were a leap into Fuel Injection for FORD. IMHO the carbed engines had better all around drivability then the CFI, But., You had to know how to set up the carb for peak performance.
I chose using a Holley 1850 (600cfm vacuum secondary's). A friend that raced pure stock wanted the Autolite and said there were ways to "Tune" them also . They are just not easy as the Holley
 

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I have a set of E7 heads Mac shorties and 2.5 in out the back duals and a two plane intake.
Car dyon'd at 225 hp at the wheels. Much better then the 160hp they claimed at the crank.
 

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Carbed models (stick shift) did not have O.2 sensors. The CFI (Automatics might have had O2 sensors since they were a leap into Fuel Injection for FORD. IMHO the carbed engines had better all around drivability then the CFI, But., You had to know how to set up the carb for peak performance.
I chose using a Holley 1850 (600cfm vacuum secondary's). A friend that raced pure stock wanted the Autolite and said there were ways to "Tune" them also . They are just not easy as the Holley
The CFI models definitely had an O2 sensor in them since it's really necessary for the system to work. Though you confirmed that there's no O2 sensor in the carbureted cars it's still not clear what exactly the ECM is doing in these carbureted 5.0 models. That's what I'd really like to know.
The automatic equipped CFI engines were just lacking. It wasn't until the modern multiport fuel injection came along in 1986 that the 5.0 had a really good fuel delivery system.
That factory Holley 4180 wasn't designed to be tuned so there wasn't all that much that could be done with it though it was a decent carb as it was pretty similar to a 4150/4160. The mixture screws were plugged, the choke was nonadjustable, and the metering blocks were unique to it. Some modifications were possible to do but likely not worth it.
A 1984 GT manual had a whopping 175hp at the crank: 1984 Mustang Specs, Horsepower, & Features - LMR.com It was a bit better than the earlier 10 years but not spectacular from a 5.0.
 

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Rockauto listed the O2 sensor for the 1983 but didn't specify auto or manual but since your 1984 is original without any O2 sensor apparently it means that only the weak CFI 5.0 cars had them.

Yes, I was aware of that and they also had noticeably less HP than the Holley equipped versions. I had actually read thru that very article recently but the question still remained whether the carbed version had an O2 sensor or not since both auto and manual cars have an ECM.
Going to have to show me that 83-85 carb 'd ECM. A friend had a new 83 GT, 5 speed and another had a new 85 5.0, 5 spd Capri (I got my Capri, 5.0, 5 spd new the next year and we spent a lot of time comparing). Don't recall either of those carb'd fox's having any type of ECM, in the typical sense.


And I think that article is wrong. I had thought CFI started in 84 on the 5.0 auto, but that article said 83 also. 84 makes more sense as that is when the LTD LX popped up with it (which I have as a parts car for my dad's 84 LTD). I'll take these guys word @ 4 eyes, especially on early foxes, over pretty much any article.

 

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And I think that article is wrong. I had thought CFI started in 84 on the 5.0 auto, but that article said 83 also. 84 makes more sense as that is when the LTD LX popped up with it (which I have as a parts car for my dad's 84 LTD). I'll take these guys word @ 4 eyes, especially on early foxes, over pretty much any article.
I think that you're right about this. The 1983 Mustang sales brochure doesn't mention anything about EFI at all for the 5.0. It does in the 1984 brochure though. I also just looked on another site for HP ratings and it only shows the F code 4v 302/5.0 for 1983.
This seems like another case of repeated error to me. It's sad when a publication like Motor Trend doesn't do their homework. Apparently, the 1984-85 5.0 auto had CFI fuel injection but the 1983 auto got the Holley carb. 1983 seems to be the one year in the 1980s that the Mustang 5.0 automatic got a 4v carb.
Going to have to show me that 83-85 carb 'd ECM. A friend had a new 83 GT, 5 speed and another had a new 85 5.0, 5 spd Capri (I got my Capri, 5.0, 5 spd new the next year and we spent a lot of time comparing). Don't recall either of those carb'd fox's having any type of ECM, in the typical sense.
As far as the ECM goes I'm only going by what others are saying to gather my info here. I don't have a 1983-85 Ford Shop manual laying around and the parts sites aren't 100% reliable. Here's looking at you Rockauto(infinitely better than Amazon though). I suppose a Ford parts catalog might also shed some light.
The OP said he had an ECM(or at least he thought he did) so I'm assuming that there is one for some kind of limited function. Some people are saying yes and some people are saying no. I'd love for the OP here to verify if there is an ECM in the car or not. Idk where it would be located in these earlier Fox bodies but the later ones had it in the passenger kick panel from what I remember.
 

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I think that you're right about this. The 1983 Mustang sales brochure doesn't mention anything about EFI at all for the 5.0. It does in the 1984 brochure though. I also just looked on another site for HP ratings and it only shows the F code 4v 302/5.0 for 1983.
This seems like another case of repeated error to me. It's sad when a publication like Motor Trend doesn't do their homework. Apparently, the 1984-85 5.0 auto had CFI fuel injection but the 1983 auto got the Holley carb. 1983 seems to be the one year in the 1980s that the Mustang 5.0 automatic got a 4v carb.

As far as the ECM goes I'm only going by what others are saying to gather my info here. I don't have a 1983-85 Ford Shop manual laying around and the parts sites aren't 100% reliable. Here's looking at you Rockauto(infinitely better than Amazon though). I suppose a Ford parts catalog might also shed some light.
The OP said he had an ECM(or at least he thought he did) so I'm assuming that there is one for some kind of limited function. Some people are saying yes and some people are saying no. I'd love for the OP here to verify if there is an ECM in the car or not. Idk where it would be located in these earlier Fox bodies but the later ones had it in the passenger kick panel from what I remember.
From everything I can find (including that 4 eyes link), there was no auto trans for 83 GT period. Many call the Duraspark module an "ECM" and that is most likely what OP is doing.
 
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Discussion Starter · #19 ·
I do not know if my grandson's 83 5.0 has an ECM. I was just let to that assumption from various GOOGLE searches I performed trying to get a diagram of the electrical system to determine what effect the deletion of the EGR and catalytic converter would have on the distributor and fuel system. We did remove the converter and found it plugged. But, I also noted that there is what appears to be a second converter off of the passenger's side manifold, yet none on the driver's side. If it is a converter and not a resonator or something, it would make sense that it is also plugged. I assume the 5.0 has a cross over thru the intake similar to a Chevy and thus it may increase the heat under the carburetor by forcing all of the exhaust to the driver's side. All I can find is a diagram for a dual exhaust. This car has single exhaust. What am I dealing with? Is this a BUBBA mod by the PO?
The car runs like new with the EGR blocked off and the main converter gutted. Temporary measures as he wants to go to dual exhaust. I don't think the 5.0 has a ECM but rather an ignition control module in the distributor. Didn't look behind the kick panel. He took the car back to St. Louis where he is going to school, so I can't get pictures or do further investigation at the time. I am way out of the ERA let alone manufacturer comfort zone.
 

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From everything I can find (including that 4 eyes link), there was no auto trans for 83 GT period. Many call the Duraspark module an "ECM" and that is most likely what OP is doing.
After looking again at the 1983 brochure it doesn't show any specific option for an auto trans with the 5.0(despite the 5.0 being available in the GL, GLX, and GT trim level). Only the 3.8 shows the auto and the way it's listed it looks like you could only get a 3.8 with the auto with no manual available.
An unrelated minor option missing from any of the 1983 trim levels was fog lights which I believe would make it the only Mustang made since 1979 to not have them available.
From his last post 83Frd50 does seem to know the difference between an ignition module and an ECM. He just didn't know if he also had an ECM or not. It would seem likely that there's no ECM in the carbureted 5.0 cars of this era but there's still no verification here.
I do not know if my grandson's 83 5.0 has an ECM. I was just let to that assumption from various GOOGLE searches I performed trying to get a diagram of the electrical system to determine what effect the deletion of the EGR and catalytic converter would have on the distributor and fuel system. We did remove the converter and found it plugged. But, I also noted that there is what appears to be a second converter off of the passenger's side manifold, yet none on the driver's side. If it is a converter and not a resonator or something, it would make sense that it is also plugged. I assume the 5.0 has a cross over thru the intake similar to a Chevy and thus it may increase the heat under the carburetor by forcing all of the exhaust to the driver's side. All I can find is a diagram for a dual exhaust. This car has single exhaust. What am I dealing with? Is this a BUBBA mod by the PO?
The car runs like new with the EGR blocked off and the main converter gutted. Temporary measures as he wants to go to dual exhaust. I don't think the 5.0 has a ECM but rather an ignition control module in the distributor. Didn't look behind the kick panel. He took the car back to St. Louis where he is going to school, so I can't get pictures or do further investigation at the time. I am way out of the ERA let alone manufacturer comfort zone.
Electrical schematics are notoriously hard to find on the internet that are actually correct for the car you're looking them up for. 9/10 of search results are usually for other models, years, and even car brands.
The ceramic matrix inside the converter is worth some $ but if it's broken out of the steel shell then it's worth a lot less. An intact Ford converter might be worth $200 or more.
Idk exactly what you were looking at on the passenger manifold but my 1975 302/5.0 had a very strange shut off valve installed on that manifold. It was a butterfly valve that closed off the exhaust from passing thru and as I recall it was vacuum operated maybe for some kind of cold start assist. Whatever it was for it was a bad idea. If you could get a pic of it from your grandson then it might be able to be identified.
 
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