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2.9L EGR Questions


DankTank

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I have a '86 Ranger running a '87 V6 and want to check the EGR system. I've heard most cars can detect if the EGR is inactive/not connected and can correct timing, fuel, etc... accordingly. Although I'm not sure if my '86 computer can do that or not. I'd like to be able to disconnect the EGR to see if it works better, but I'd rather not have it misfire and then not get my answer anyway.

If it is the EGR, how safe is it to delete? Apparently deleting the EGR can cause an engine to run hot and misfire. If that's true, how do the '88+ engines run without it, and with the same V6 as the older trucks?

For reference, the issue I'm having is an idle issue when the engine transitions from 'warming up' to 'warm.'
 


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swynx

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I have a 94 running a 96 engine. The egr is deleted. I just plugged all of the hoses off and disconnected the lines. You'll get a cel. I got better throttle response and it overall runs better. Engine bay looks cleaner too.

As for sensors I'm only running tps, iac, 02, maf and crankshaft maybe I'm missing one.

I would delete the egr craps 100x over

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DankTank

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I have a 94 running a 96 engine. The egr is deleted. I just plugged all of the hoses off and disconnected the lines. You'll get a cel. I got better throttle response and it overall runs better. Engine bay looks cleaner too.

As for sensors I'm only running tps, iac, 02, maf and crankshaft maybe I'm missing one.

I would delete the egr craps 100x over
Running the same ECU?

No CEL on the first gens, and the exhaust light is already on courtesy of the previous owner. Lucky me, apparently the '88 computers plug right up to my engine and essentially 'turns off' the EGR since '88 Rangers don't have EGR.

I've got quite a few options here!
 

RonD

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EGR system is used only when engine is under load, it lowers cylinder temps to keep NOX(toxic gas) from spiking at the higher temps when accelerating or cruising.

Normally when you accelerate, add more fuel, the cylinders get hotter, i.e. engine temp goes up when climbing a longer uphill grade.
You can change spark timing to lessen this heat up or you can add exhaust gases which slow down the burning which reduces the heat.
Either reduces the NOX emissions.

1994 and earlier computer(EEC-IV) is setup to either change spark timing or open EGR valve, but not both.
The 1995 and up(EEC-V) "can" do both but not all are programmed to do both.

You can delete EGR valve operation by simply removing its vacuum hose and plugging that hose.
You would have to remove the EGR valve to see if it is leaking exhaust into the intake when it should be closed, i.e. at idle EGR valve is closed.

If you eliminate EGR valve(disconnect hose) on some engines you may get "pinging/knocking" under load, you just need to try it and see.
It is not a universal YES or NO, because each engine will have different conditions internally, i.e. compression, carbon build up.

As a cylinder heats up Regular gas can start to pre-ignite(ping/knock) under load, the EGR system prevented that or more spark advance did
 

DankTank

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As a cylinder heats up Regular gas can start to pre-ignite(ping/knock) under load, the EGR system prevented that or more spark advance did
So if I were to find a '88 ECU, which does not control EGR, it would only advance the spark under load and, in theory, prevent ping without EGR?
 

swynx

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Running the same ECU?

No CEL on the first gens, and the exhaust light is already on courtesy of the previous owner. Lucky me, apparently the '88 computers plug right up to my engine and essentially 'turns off' the EGR since '88 Rangers don't have EGR.

I've got quite a few options here!
Yeah same ecu. As Ron said 96 was obd2 and 94 was obd1 so I swapped the upper intake to make it work. Had some issues with the vacuum lines and a intake leak so I started deleting stuff. Noticed it ran better and a cleaner engine bay. I did leave the egr tube from exhaust manifold to intake. Only because I couldn't get it off.

Idk if that means it's permanently closed now. But idc it runs better and easier to work on.

I say just unplug the wires, and plug the air lines. and treat it like an old engine. It's just an air pump give it what it wants not what engineers made it use.

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DankTank

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Yeah same ecu. As Ron said 96 was obd2 and 94 was obd1 so I swapped the upper intake to make it work. Had some issues with the vacuum lines and a intake leak so I started deleting stuff. Noticed it ran better and a cleaner engine bay. I did leave the egr tube from exhaust manifold to intake. Only because I couldn't get it off.

Idk if that means it's permanently closed now. But idc it runs better and easier to work on.

I say just unplug the wires, and plug the air lines. and treat it like an old engine. It's just an air pump give it what it wants not what engineers made it use.
Nice! I think I'll try it tonight and see what happens. If it works out I'll get to work tomorrow cleaning out what I can. Thanks for the input!
 

RonD

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Yes, but more spark advance reduces power, same as EGR system can do, so just a trade-off.
EGR system doesn't rob power, unless it is broken, or too expensive to fix.
 

swynx

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My cel code kept saying I had high voltage or low voltage on the egr craps after replacing it all.

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My cel code kept saying I had high voltage or low voltage on the egr craps after replacing it all.

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You probably had the same problem I do, there is a frayed wire going to the DPFE sensor.
 


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