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A/C, smog and cats deleted. Will the ECU still function properly?

1K views 9 replies 5 participants last post by  evintho 
#1 ·
Now I've decided, I'm back to using the '93 5.0 as a donor drivetrain for my '54 Customline.

I'll be deleting the entire A/C system including WOT relay. In addition, I'll be dumping the smog pump along with TAB & TAD valves/solenoid/head airtube. Also, a new exhaust system will be created WITHOUT any catalytic converters.
The ECU and all engine compartment wiring harnesses will be transferred to the '54.

Question: Will that have any ill effects concerning the ECU? Will the ECU still function properly with those systems deleted?
 
#5 ·
Yes the ecu will work fine with those items deleted.Nope you will Not have any fuel mixture issues.Just make sure to plug the thermactor passage ports on the rear of both heads unless you wanna leave the crossover pipe in place and just cap it off where the diverter valve hose was attached.The deletion of the smog pump and the other thermactor system parts may trigger codes.If it does,codes 33,81,82,84,85,44 & 94 will be the ones you would likely get.These codes are called “Soft-Codes” & they dont affect the engines fuel spark programming.The codes harmlessly remain dormant in the computer.Their only purpose is to help you repair those systems back to original factory specs (if you ever decide to add them back to the vehicle) Soft Codes will not turn the check engine light on,but even if they did,it wouldn't matter in your application anyway,since you're dropping everything into a 54 which doesn't have a cel.As far as removing the cats go,it won't create any issues with the ecu,but you and the car will smell like raw gas or exhaust fumes during/after every drive. When you get the harness in the engine bay,make sure you remove the AC WOT relay and not the fuel pump relay,since they're located beside each other on the harness.Make sure you buy a oem type negative battery cable or buy some 10ga black wire to use for the following.The oem cable has the 10ga wire added to it already,so it makes things easier,but you can use a seperate wire if you want.The wire runs from the neg battery post to the driver fender apron then splits off and runs a few inches before dead ending at a black tubular plug.This plug connects to a matching plug at the end of the main engine harness.This is your EEC Ground & its imperative on efi setup Its also the ground that completes the ground loop.Also dont forget to ground the orange wire (in the injector harness) with the ring terminal to a intake bolt,a crossover pipe bolt or to another good ground.Its the ground for the o2 sensors.Dont forget the ground strap between the driver cylinder head (rear) & the firewall too.
 
#6 ·
Excellent! I was hoping you'd chime in. You've explained everything to a tee, thank you!
Question: With cats deleted, why would the car smell like raw gas or exhaust fumes after every drive?
Also, I do plan to fab up a CEL for the dash to let me know of any issues.
 
#7 ·
I don’t have the scientific answer but cats help burn off unburned hydro carbons, and convert oxygen and carbon dioxide into carbon monoxide. I think it’s called the carbonaro effect..
When I had my ‘90 it came with an off road x pipe and the cabin smelled like a gas pump. Come inspection time I had two “high flow” cats added and the smell went away. Are the unburned hydro carbons fuel vapors, and that’s what we’re smelling?
 
#8 ·
I sourced the following from Jrichker at Stangnet.

"The Reduction catalyst is the first converter in a 5.0 Mustang, and the Oxidation converter is the second converter. The Oxidation converter uses the extra air from the smog pump to burn the excess HC. Aftermarket converters that use the smog pump often combine both types of catalysts in one housing. Both converter types depend on heat to function correctly."
(Now for the Chemistry)
"The reduction catalyst is the first stage of the catalytic converter. It uses platinum and rhodium to help reduce the NOx emissions. When an NO or NO2 molecule contacts the catalyst, the catalyst rips the nitrogen atom out of the molecule and holds on to it, freeing the oxygen in the form of O2. The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N2. For example:
(2NO => N2 + O2 or 2NO2 => N2 + 2O2)"

"The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas."

If the fpr or an injector is leaking or the engine is running rich with too much fuel, the excess fuel is unburned and escapes with the exhaust gasses into the exhaust.Exhaust emissions are composed of carbon dioxide, nitrogen, water vapor, and oxygen in unconsumed air. Carbon monoxide, unburned fuel, nitrogen oxides, and particulate matter such as mercury are also present in vehicle exhaust emissions in smaller quantities.
 
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#9 ·
The Customline, sure brings back memories from youth. You have to post some pictures as this progresses. Pop had a blue 53 and spent countless hours polishing the abundant chrome trim, hub caps, and bumpers. He had that for over 10 years at which time he sold it and got feeling back in his fingers not having to polish it.

We have a few parked out in the Texas fields where they were laid to rest decades ago when owners died and homesteads abandoned. Most are too rusted and missing parts and glass to restore and others became targets for shooters. One thing nice about Calif is the appreciation for classics that are restored or turned into Rods.
 
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#10 ·
I recently finished the roadster (9 years in the making) and have been enjoying it all summer........



Now it's time to begin the '54 project.......



And, just to keep it Mustang related, I picked this up for $1500 and have been enjoying it for the last 3 years. It'll be donating the 5.0/AOD/ECU/wiring harness and various other parts and pieces to the '54 cause.



In the last couple of days I stripped the '54's front sheetmetal and built a blast barrier to contain the media when sandblasting.







Today I blasted the interior floorpans and front clip. No pics though, I was too busy blasting! Next up is get it into the garage and cut out the rusted floorpans then fab and install new ones. After that, rebuild and update the front and rear suspensions. At some point I'll be making a build thread over on the HAMB and I'll provide a link to that.
 
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