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Looking to do a complete removal of the emissions with no check engine light. I bought a 1992 f250 2wd with 5.8/E4od. Smog pump was already gone. Egr already had a flat gasket blocking it off but is all still hooked up electrically and to the evr. The cat is already gone as well. I am still getting 332(egr) and 334(evr) codes alternatively. Also I am dealing with a 452 code and the trans shifts hard. But when I put vacuum to the egr directly it cycles and the trans shifts smooth but the engine will die on coast down. I want to take off all the related solenoids,etc and I guess you put in resistors of some kind to truck the computer into thinking it’s all still there so I won’t get a CEL.
VSS is new Motorcraft and ohms out at 1800 the test point and behind the PSOM. I don’t know of a way to test the PSOM further but I took it out and it looked kinda grungy. I will probably get a refurbished one coming.
i am also having a rear ABS light most of the time but when I ground out the test port under the glove box I get no code on the light. There is another test port under there next to it but I don’t know what that’s for. I read somewhere that it’s a PSOM test port but can’t seem to find out how to use it.
I realize these are separate issues but applying vacuum to the egr that’s blocked off and making the trans shift smooth has got me scratching my head. I live in Alabama so there are no emissions or even an annual inspection on vehicles here so there are no legal ramifications for removal.
Last edited by Jhall1972; Mar 1, 2020 at 07:55 AM.
Reason: Added info
That's really interesting, do you have more information on modding the ECM to ignore emissions or links?
Also pretty much you just chop off the cats, throw air pump in trash, block off egr with a plate, plug air ports in exh. manifolds/heads. Keep the solenoids electrically connected and just remove the vac lines.
You will need a shorter belt or dummy pulley to replace pump.
You might try an off-the-shelf EGR eliminator dongle, it plugs into the EGR connector and fools the computer.
No need to remove EVAP (charcoal canister) and PCV. These don't effect gas mileage or horsepower at all and keep your engine clean inside and not smelling like a 60's car.
That’s almost where the truck is now. No cat, blocked off egr, smog pump gone completely with a shorter belt. I have been messing with the vacuum lines, trying to get things hooked up to clear the codes but haven’t been successful so far. That’s why I want to just get rid of it all. I would need to know specifically what “dongle” or resistors to use to trick the pcm.
I mean....if you truly want to rid of everything, slap a carb on there and points ignition then call it a day. Otherwise you need to keep the solenoids and wiring intact because the computer wants them present and accounted for.
the smog pump i can see its just prone to issues and not really in the way. the cat if you dont have emissions i can see also they wear out and fall apart. neither help fuel economy not that they hurt it really. egr though it serves a good purpose however and the vent canister also does.
The smog system is useless. Pull it complete and plug the heads with a threaded bolt. Cap the exhaust nub and pull out the rest of the system.
I left the pump on for now.
I plan on pulling the block a ways down the road to do a full rebuild but for now its staying put.
It does help burn off excess hydrocarbons in the exhaust but the system needs to be air tight and they seldom are in these old beasts.
The EGR system essentially keeps your engine running cooler. Its not just a "hippe emissions" add on though it also accomplishes this to some degree. Having a proper working EGR system is good for your mileage and efficiency. It keeps your cylinder temp down under normal cruising conditions. It does not activate at idle nor under high load (acceleration)
The problem is when it starts getting clogged or coming on at low idle or high output when it's not supposed to and bogs everything down lol.
I've read nothing but problems with trying to bypass the system in 89 to 96 engines. The ECM seems to lose its **** when you cap it off or cut it out lol minimum it will throw codes. Worst you may send false reads to the system and it will compensate when it shouldnt. Run rich, cause off time detonation from excess fuel in the cylinder etc usually will throw codes constantly because the PCM wants it working.
I've always wanted to cut it out. But in an EFI setup, I just leave it alone and make sure the valve is good.
The main cork on the engines are the heads, intakes, and exhaust.
I was going to say, if you want to remove the 'emissions' system, you need to rebuild the long block to pre '67 status.
And use a pre '67 ECU.
Because a significant chunk of 'emissions equipment' is in reduced compression ratio, reduced valve overlap,
combustion chamber shape and head port size and shape...
and then THAT is designed and tuned around in the ECU.
If you can get the resistor values correct to "mimic" all of the devices within the "test pass" range then that can work. The other option is to replace the ECU with something modern and tunable that's perfectly OK with none of that stuff existing (like in my signature).
The EGR system essentially keeps your engine running cooler.
If the EGR SYSTEM recirculates hot exhaust gases back into the intake tract, how can the engine run cooler? If it did cause cooler running, that must be what the EGR COOLER is for ... ?
If you can get the resistor values correct to "mimic" all of the devices within the "test pass" range then that can work. The other option is to replace the ECU with something modern and tunable that's perfectly OK with none of that stuff existing (like in my signature).
you can just put caps on the ports and leave them also. resistors clean it up under there though.
The resistors are to prevent the check engine light from coming on and to clean it up electrically so the ECU isn't aware it's removed. Resisters don't clean it up at all from a visual standpoint.
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