Disconnecting power to the EGR valve solenoid Will it hurt anything? - Diesel Forum

BogSpores · 10-29-2009, 04:47 PM

I had my EGR cooler pop, causing a severe coolant leak and required replacement ASAP! The bill was over 2000, but warranty covered it!

Now I'm wondering whether or not disconnecting the electrical plug from the EGR solenoid will hurt anything? I live in BFE and have no emissions issues.

I've unplugged it before, and didn't notice ANYTHING, not even a Check Engine light!

Ideas? Suggestions? Thanks in advance!

Strokin' 6.0 · 10-29-2009, 04:57 PM

If you unplug it, while the truck is off, then the EGR will stay closed.

That said (so that this post doesn't get deleted), if you do that you're breaking the law.

BogSpores · 10-29-2009, 05:06 PM

*** FOR INFORMATIONAL USE ONLY!***

Right on, that's what I thought, the EGR valve would stay closed if disconnected after sitting over night (cold) and that would keep those nasty exhaust fumes from being ingested by the engine....And, it might prevent the EGR cooler from breaking again?

Although, I would never EVER recommend ANYONE from doing such a thing because it is illegal!

I have never driven my truck with the EGR valve power disconnected either! Only while parked, and for testing purposes only!

21xdbullet · 10-29-2009, 08:07 PM

What would be the advantages of unpluging the EGR?
Not that I would ever do this. But say that you had a 07 550 in the shop right now with a Egr cooler being changed. And you never wanted to have it changed again would unpluging it solve that problem.
And also lets say you had a 06 250 that is out of warrenty and you didn't want to have to pay this out of pocket.

**teamroper60** · 10-29-2009, 09:19 PM

Hopefully, this response will suffice to answer the questions raised here without violating site rules...

Should that valve fail to open, it will not significantly reduce the possibility of cooler failure. The cooler itself remains in contact with hot gases and coolant continues to circulate through it. So the very conditions that lead to cooler failure remain in place. The valve only serves to allow the inert gases flowing through it to enter the intake and subsequently, the cylinders where it serves to lower combustion temperatures and effectively retard timing.

outlawpony · 10-30-2009, 05:27 PM

i am a for diesel tech i have an 04 6.0 i welded my valve shut if you think of it like blowing in to a bottle if the valve is shut and not flowing the gas will not flow through the cooler and too much flow from the egr valve is what ford is relating the egr cooler failers to due to the statige from the iat2 sensor the check engine will not come on due to this but po401 and po404 will be stored in the pcm ford master tech and deisel tech

**teamroper60** · 10-30-2009, 06:39 PM

Quote:

Originally Posted by outlawpony

i am a for diesel tech i have an 04 6.0 i welded my valve shut if you think of it like blowing in to a bottle if the valve is shut and not flowing the gas will not flow through the cooler and too much flow from the egr valve is what ford is relating the egr cooler failers to due to the statige from the iat2 sensor the check engine will not come on due to this but po401 and po404 will be stored in the pcm ford master tech and deisel tech

Low coolant flow through the cooler (generally caused by a plugged oil cooler), allowing the coolant to superheat is what is causing the EGR cooler related puking and, ultimately, the cooler failures.

The cooler is made out of metal and can only accept so much volume of exhaust gas into it. So, while it is entirely possible to have a valve stick open and send excess EGR gases into the engine, it is not possible for there to be too much flow through the cooler itself. Blocking the flow of exhaust gases going through the cooler will allow the coolant to wick some of the heat out of the cooler, but that heat will only be marginally reduced due to the heat soak from the exhaust gases that are attempting to get in.

Along that same vein, your analogy of blowing into the bottle got me to thinking.... If you blow into a plastic soda bottle, it will attempt to expand due to increased pressure. Obviously, it can only expand so much, since the plastic itself only has so much "give" to it. Enough pressure on that bottle (probably more than the average person could provide, but not more than an air compressor could, for instance) and the bottle ruptures. The same phenomenon may well apply to the EGR cooler... Gases would be trying to get in but would be blocked by the closed valve, raising the pressure inside the cooler.. I don't know if the engine could provide enough pressure to rupture the cooler, but as we know, heat has a tendency to weaken metal and in addition to the exhaust heat, pressure also creates heat (the very principle upon which a diesel engine operates). So it may be possible that over time, the cooler could fail from this combination of heat and pressure.....

Again, that is just something that occurred to me. Since I don't know the stress failure point of the components that make up the cooler or the amount of pressure being applied to the cooler by the exhaust gases, I have nothing concrete to back that up.

Strokin' 6.0 · 10-31-2009, 11:56 AM

Roper,

It would seem to me that the exhaust cooler inlet gas pressure would equalize, if the EGR were shut permanently, so you would never have to worry about the cooler bursting. Like you said, though, the hot gases are still in there and can still melt the soldering, which is what happened to my cooler.

Now that my EGR and EGR cooler are permanently "fixed", I don't need to worry about them ever again.

blizzardwarrior7 · 10-31-2009, 06:42 PM

Id have to agree that the pressure would equalize, but is it true that this really doesnt lower the chance of a cooler failure at all? I always thought that it would help a little bit. My truck always seems like it has slightly better throttle response when I unplug it, but maybe Im just imagining it.

Strokin' 6.0 · 10-31-2009, 07:04 PM

No, unplugging it will not stop the EGR cooler from failing...the hot gases will still be there to melt the solder and cause a leak.

You're not dreaming...unplugging the EGR does give you better throttle response....nothing spectacular, but still a bit.

I know it's a bit apples and oranges comparison, but I remember my dad deleting the EGR from our brand new '78 Buick Skylark...the car went from 18 to 22MPGs.

"Fixing" my EGR and cooler got me better MPGs, but we're only talking about a couple....still, I'll take what I can get.

**teamroper60** · 11-01-2009, 02:01 PM

Quote:

Originally Posted by Strokin' 6.0

Roper,

It would seem to me that the exhaust cooler inlet gas pressure would equalize, if the EGR were shut permanently, so you would never have to worry about the cooler bursting.

You may well be right about the pressure equalizing but I wasn't talking about constantly increasing pressure. Even if it equalizes, it will do so at some pressure level... What I am getting at is the constant pressure, combined with heat stress over an extended time.. With most of the factory flashes, the EGR valve is open to some extent while doing anything other than idle or WOT. When the valve is open, there would be minimal pressure since it has an escape point to move the gases through it. Keeping that valve closed constantly will keep a certain pressure on it all the time.. At least, that was my theory, which may be completely wrong........

Strokin' 6.0 · 11-01-2009, 03:00 PM

I would hope that that pressure isn't enough to pop the cooler, but you may be right, Roper.

F250crazy · 11-01-2009, 05:06 PM

Roper I agree with you. EGR serves only one purpose. To lower the combustion temps. It also serves to reduce nox gases in gas engines.

Strokin' 6.0 · 11-01-2009, 08:10 PM

Call me nuts, but don't you want higher combustion temperatures, in order to have a complete burn of the fuel? The more complete the burn, the more efficient the engine.

Nah, that's just crazy talk!!!!

**teamroper60** · 11-01-2009, 08:49 PM

Quote:

Originally Posted by Strokin' 6.0

Call me nuts, but don't you want higher combustion temperatures, in order to have a complete burn of the fuel? The more complete the burn, the more efficient the engine.

Nah, that's just crazy talk!!!!

Maybe, maybe not... You definitely do for the most efficient burn. But, with the headbolt setup on the 6.0, you have to be careful, since higher heat/more complete burn will lead to higher cylinder pressures and those higher cylinder pressures can cause blown headgaskets....

The thing is, we know that removing it increases cylinder pressures but we don't really know how much. Without knowing how much, we don't know if removing it has a significant negative impact on headgaskets or not........