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1984 egr delete question

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Old Mar 7, 2018 | 09:13 AM
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Default 1984 egr delete question

hello, ive found good info for every c4 except 1984..
question is if i delete the egr with a block off plate do i need to reprogram ECM since there are no codes (32) for 1984 c4...Anything else im missing besides vacuum lines?

thanx
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Old Mar 7, 2018 | 09:26 AM
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I drove mine with it disconnected for a little while. It occasionally ran a little weird. Without get you'll get slightly hotter combustion chamber temps as the exhaust helps cool it a little. The plate and vacuum lines should be sufficient.
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Old Mar 7, 2018 | 09:36 AM
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Originally Posted by 84 4+3
I drove mine with it disconnected for a little while. It occasionally ran a little weird. Without get you'll get slightly hotter combustion chamber temps as the exhaust helps cool it a little. The plate and vacuum lines should be sufficient.
Basically im better leaving it on? Ive read about the hotter temps and such but I havnt read anything from anyone that it actually caused any adverse effects..
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Old Mar 7, 2018 | 10:05 AM
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Technically, removing the EGR w/o re-tuning the ECM could/should result in pinging at part throttle/cruising -the mode during which the EGR should be functioning.

In reality, I disabled mine (left it in place) and saw no negative effects.
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Old Mar 7, 2018 | 10:40 AM
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Originally Posted by Tom400CFI
Technically, removing the EGR w/o re-tuning the ECM could/should result in pinging at part throttle/cruising -the mode during which the EGR should be functioning.

In reality, I disabled mine (left it in place) and saw no negative effects.
thanx for your input.i will leave it off for now and see how it goes..
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Old Mar 7, 2018 | 11:15 AM
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Originally Posted by gnj3963
thanx for your input.i will leave it off for now and see how it goes..
If anybody out there has actually had any negative effects from deleting the egr without reprogramming the ecm please let me know

thanx
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Old Mar 7, 2018 | 11:25 AM
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Originally Posted by gnj3963
Basically im better leaving it on? Ive read about the hotter temps and such but I havnt read anything from anyone that it actually caused any adverse effects..
All it did was give me a slight idle surge, other than that no issues. It did run hotter. Usually in the cold it's down against the thermostat but it stayed around 5 degrees warmer than it and seemed to creep up faster at idle. Not nothing I'd write home about. since it all works I left it attached. Just trouble shooting was all.
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Old Mar 7, 2018 | 11:28 AM
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Originally Posted by 84 4+3
All it did was give me a slight idle surge, other than that no issues. It did run hotter. Usually in the cold it's down against the thermostat but it stayed around 5 degrees warmer than it and seemed to creep up faster at idle. Not nothing I'd write home about. since it all works I left it attached. Just trouble shooting was all.

hey thanx..just curious where in jersey are you..im in wayne (passaic county)
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Old Mar 7, 2018 | 11:36 AM
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Originally Posted by 84 4+3
All it did was give me a slight idle surge, other than that no issues. It did run hotter. Usually in the cold it's down against the thermostat but it stayed around 5 degrees warmer than it and seemed to creep up faster at idle. Not nothing I'd write home about. since it all works I left it attached. Just trouble shooting was all.
Something is amiss here;
1. The EGR should be completely at idle, anyway. So there should be zero diff EGR on or off, at idle.
2. EGR shouldn't have any meaningful impact on coolant temps.
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Old Mar 7, 2018 | 11:41 AM
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Originally Posted by Tom400CFI
Something is amiss here;
1. The EGR should be completely at idle, anyway. So there should be zero diff EGR on or off, at idle.
2. EGR shouldn't have any meaningful impact on coolant temps.
hey Tom, quick question..the fact that combustion temps go up without EGR connected..Would that temp change show up as higher coolant temp reading or no?
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Old Mar 7, 2018 | 11:51 AM
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I've never seen that...and no it shouldn't anyway. I've heard others claim the opposite; dumping "hot exhaust into the intake heats the engine up". Neither is true, in a measurable or meaningful way. Car requires x amount of hp to cruise down the road at any given speed. If EGR opens, power goes down, you have to open the throttle more to maintain speed. Net result is same hp made at same RPM, same total heat. PEAK combustion temps may lower some, which reduces emissions (NOx), but net power and heat should be the same.
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Old Mar 7, 2018 | 11:53 AM
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Originally Posted by Tom400CFI
I've never seen that...and no it shouldn't anyway. I've heard others claim the opposite; dumping "hot exhaust into the intake heats the engine up". Neither is true, in a measurable or meaningful way. Car requires x amount of hp to cruise down the road at any given speed. If EGR opens, power goes down, you have to open the throttle more to maintain speed. Net result is same hp made at same RPM, same total heat. PEAK combustion temps may lower some, which reduces emissions (NOx), but net power and heat should be the same.

ok. so basically all i have to worry about is pinging..long as that doesnt occur i should be safe..
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Old Mar 7, 2018 | 12:26 PM
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Originally Posted by Tom400CFI
Something is amiss here;
1. The EGR should be completely at idle, anyway. So there should be zero diff EGR on or off, at idle.
2. EGR shouldn't have any meaningful impact on coolant temps.
1. On mine the egr valve always opened slightly at idle as the engine warmed up.

2. And technically it should, you're providing less oxygen by adding in the exhaust gas, it's effectively slowing the burn rate so you should have lower cylinder temps. If you can measure that or not is another story. (I'm agreeing with you, see below)

That all being said I was paranoid as hell having it disconnected because people told me about melting pistons, excessive pinging etc that I may have tuned into an anomaly that wasn't actually there. I've messed with so many other vehicles and changed so many things on all of them since I did that I may not even be remembering the right car at this point. Between school and that and all the family issues I've been dealing with I'm just about burnt out. Sorry everyone. Need to think a little more before I speak.
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Old Mar 7, 2018 | 12:43 PM
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Originally Posted by 84 4+3
1. On mine the egr valve always opened slightly at idle as the engine warmed up.

2. And technically it should, you're providing less oxygen by adding in the exhaust gas, it's effectively slowing the burn rate so you should have lower cylinder temps. If you can measure that or not is another story. (I'm agreeing with you, see below)

That all being said I was paranoid as hell having it disconnected because people told me about melting pistons, excessive pinging etc that I may have tuned into an anomaly that wasn't actually there. I've messed with so many other vehicles and changed so many things on all of them since I did that I may not even be remembering the right car at this point. Between school and that and all the family issues I've been dealing with I'm just about burnt out. Sorry everyone. Need to think a little more before I speak.

no problem...hope all works out for you..
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Old Mar 7, 2018 | 12:50 PM
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Originally Posted by gnj3963
no problem...hope all works out for you..
Thanks. BTW I am Down in Jackson out by Great Adventure. Ocean county.
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Old Mar 7, 2018 | 12:52 PM
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Originally Posted by 84 4+3
Thanks. BTW I am Down in Jackson out by Great Adventure. Ocean county.

cool..ive been there a few times
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Old Mar 7, 2018 | 12:55 PM
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Originally Posted by gnj3963
ok. so basically all i have to worry about is pinging..long as that doesnt occur i should be safe..
Correct.



Originally Posted by 84 4+3
1. On mine the egr valve always opened slightly at idle as the engine warmed up.
Something was wrong with it then, or more accurately, something was wrong with the control solenoid. That is not how it's supposed to operate. EGR shouldn't be open at idle.



Originally Posted by gnj3963
2. And technically it should, you're providing less oxygen by adding in the exhaust gas, it's effectively slowing the burn rate so you should have lower cylinder temps. If you can measure that or not is another story. (I'm agreeing with you, see below)
You're not providing less oxygen. When EGR starts to function, you're going to depress the gas pedal...that opens throttle plates, and lets in more...oxygen. You need to do that in order to maintain the same speed. If you only open EGR and nothing else changed, car would slow down.



Originally Posted by gnj3963
Sorry everyone. Need to think a little more before I speak.
Don't be sorry man. Everyone's input on these forums is helpful...your input is too!
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To 1984 egr delete question

Old Mar 7, 2018 | 01:03 PM
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Originally Posted by Tom400CFI
Correct.



Something was wrong with it then, or more accurately, something was wrong with the control solenoid. That is not how it's supposed to operate. EGR shouldn't be open at idle.



You're not providing less oxygen. When EGR starts to function, you're going to depress the gas pedal...that opens throttle plates, and lets in more...oxygen. You need to do that in order to maintain the same speed. If you only open EGR and nothing else changed, car would slow down.



Don't be sorry man. Everyone's input on these forums is helpful...your input is too!
Got you. It makes sense since it's vacuum operated and electronically controlled. If I were to lightly press up on the egr diaphragm at idle it surges. That takes very, very little force. Much more than when it is off. Guess that means I have something else to add to the list.
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Old Mar 7, 2018 | 01:07 PM
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Originally Posted by Tom400CFI
Correct.



Something was wrong with it then, or more accurately, something was wrong with the control solenoid. That is not how it's supposed to operate. EGR shouldn't be open at idle.



You're not providing less oxygen. When EGR starts to function, you're going to depress the gas pedal...that opens throttle plates, and lets in more...oxygen. You need to do that in order to maintain the same speed. If you only open EGR and nothing else changed, car would slow down.



Don't be sorry man. Everyone's input on these forums is helpful...your input is too!
thanks for all the help!!
much appreciated
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Old Mar 7, 2018 | 01:34 PM
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blocked off mine 5 years ago , no problem , the same engine temp. no pinging
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