Help with deleting emissions.

2003 mustang gt modded · Jul 22, 2024

Hello. Is it easy as just removing all hardware , hoses and valves, sealing up what ever is left open. Those metal tubes that go to back of the head, just seal those?

And cap all the plastic vacuum lines?

Reason I think I need to do that is because pump went out, rendering system non functional, and hoping to remove any vacuum leaks, because car seems a little sluggish and knocks sometimes.

Revs are hanging between shifts, ACV seems clean.

2003 mustang gt modded · Jul 22, 2024

Thank you.

keel · Jul 22, 2024

Yeah pretty much is that easy. You'll need an EGR delete plug for your EGR valve connector or ECU recalibration if you want to turn off your check engine light after deleting the EGR valve.

You may find that deleting the EGR system will not fix your issues though. I don't think a bad smog pump would cause those problems.

nickyb · Jul 22, 2024

I know the smog pump is at a crazy price ,but maybe easier to replace it with a lifetime rebuilt one from auto parts store.
I have been daily driving mine for 17 years now and I'm on my second pump( first one was $49.99 lifetime) it lasted 12 years ( replacement was free to me but went up by five fold) yes $249.99 .
Good luck in whatever you do.

Noobz347 · Jul 22, 2024

Another option that to me, is best of both worlds:

Delete the smog pump
Install 3-way cats
Keep the EGR and PCV systems intact

2003 mustang gt modded · Jul 23, 2024

Noobz347 said:
Another option that to me, is best of both worlds:

Delete the smog pump
Install 3-way cats
Keep the EGR and PCV systems

A heard a lot of people say that egr increases carbon build up.

Does it really help with pinging that much that it's worth keeping?

2003 mustang gt modded · Jul 23, 2024

nickyb said:
I know the smog pump is at a crazy price ,but maybe easier to replace it with a lifetime rebuilt one from auto parts store.
I have been daily driving mine for 17 years now and I'm on my second pump( first one was $49.99 lifetime) it lasted 12 years ( replacement was free to me but went up by five fold) yes $249.99 .
Good luck in whatever you do.

I appreciate that. The previous owner deleted cats and welded up emissions plumbing.

2003 mustang gt modded · Jul 23, 2024

keel said:
Yeah pretty much is that easy. You'll need an EGR delete plug for your EGR valve connector or ECU recalibration if you want to turn off your check engine light after deleting the EGR valve.

You may find that deleting the EGR system will not fix your issues though. I don't think a bad smog pump would cause those problems.

Do I have to delete it completely or can I just disconnect the egr electical. It should just remain closed right? Reason is because I can't delete it. That nut won't budge and I'll brake egr metal pipe if I try to get it off.

keel · Jul 23, 2024

95 mustang gt 302 said:
Do I have to delete it completely or can I just disconnect the egr electical. It should just remain closed right? Reason is because I can't delete it. That nut won't budge and I'll brake egr metal pipe if I try to get it off.

I believe that is correct, it will remain closed if you disconnect the power.

2003 mustang gt modded · Aug 28, 2024

I blocked egr by sandwiching sheet metal with the gasket.
Now it's very smooth at idle, before it was little shaky.
It felt like it had a huge vacuum leak before I did this.
Now only con is it's feels like it's leaner or timing advanced. And not comfortable to drive. Had the plunger thingy pushed in half way. I'll try to disconnect the egr potentiometer/resistor, maybe it will stop it from changing timing and fuel trims etc.

I hope I will not hurt the engine, as Its running leaner now. Maybe good idea to retard timing.

89ripper · Aug 28, 2024

Its better to leave egr disconnected, if not in use. To delete it completely will require a tune.
Shouldnt hurt anything except for a CEL

2003 mustang gt modded · Aug 29, 2024

I spent few hours reading about egr. Some said that you'll overheat the engine, melt stuff due to extra heat, with egr disconnected. The mpg are noticeably worse. I think this a mpg related device. When cruising car is tuned to run lean and egr is cooling combustion, may opinion.

Small knocks (detonations) are audible...

I'm thinking of trying to clean the egr and give a go.

2003 mustang gt modded · Aug 29, 2024

The huge egr nut, does it turn clockwise or counter? I'm going to try to clean it.

Mcmahst · Aug 29, 2024

Have you check your codes? It might be an easy to solve issue.

Bullitt347 · Aug 29, 2024

If the EGR system is working correctly, it is only used at part throttle. Exhaust Gas Recirculation (EGR) is used to cool combustion temps to lower NOX emissions. The only way the EGR valve can cause poor idle quality is if is not working correctly. Vacuum application to the EGR valve causes it to open. If the EGR valve is stuck open, then you can have driveablity/idle issues. Proper use of the EGR will have no effect on MPG/Performance. It is strictly a emissions device to control NOX. Make sure the vacuum controls, vacuum lines, EGR valve and EGR valve position sensor are working properly.

2003 mustang gt modded · Aug 29, 2024

With egr blocked with plate I made, engine idle very smooth and has good response.

Before egr unblocked had rough idle and drive sluggish.

My egr is stuck and leaking bad.

I heard pinging and feel like I should have egr cleaned and be functional.

I need to know which way the huge nut turns so that I don't brake the tube.

I know they turn opposite on other cars, wanted to make sure.

2003 mustang gt modded · Aug 30, 2024

Mcmahst said:
Have you check your codes? It might be an easy to solve issue.

I did, 212 , 327, 10

EGR was already disconnected when I ran test.

2003 mustang gt modded · Aug 30, 2024

Bullitt347 said:
If the EGR system is working correctly, it is only used at part throttle. Exhaust Gas Recirculation (EGR) is used to cool combustion temps to lower NOX emissions. The only way the EGR valve can cause poor idle quality is if is not working correctly. Vacuum application to the EGR valve causes it to open. If the EGR valve is stuck open, then you can have driveablity/idle issues. Proper use of the EGR will have no effect on MPG/Performance. It is strictly a emissions device to control NOX. Make sure the vacuum controls, vacuum lines, EGR valve and EGR valve position sensor are working properly.

From my research it does help with mpg. Your post is very informative neverthe less

Mcmahst · Aug 30, 2024

They usually only put L/H threads on things were forces would act on the threaded component and cause it to loosen if not for the L/H thread. I can’t imagine what force would be on that valve, so I would say it’s typical, R/H threads.

2003 mustang gt modded · Sep 1, 2024

I just tested to see if car runs better with position sensor disconnected and EGR blocked. No knocking. It does seem like there is timing advance.

With it connected if feels like you have a lot of timing advance, and can hear knocking, which is what computer is doing.

I wanted to confirm if this is safe to run engine this way.

I guess if it doesn't knock then combustion temp arent really high.

One user claimed that without EGR combustion temps can be too high and damage to head gasket and pistons can occur.

Help with deleting emissions.

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