Hi, all. I've been experimenting with unplugging the EGR and find that doing so really improves both performance and mileage. However, I think I'm getting more "regen required now" messages on the overhead than previously. I have a theory as to why, but I'll leave it up to the experts for the answer. My theory:

1. The intake air temperature is lower when the EGR is unplugged so there are less passive regens and more active regens become necessary.

2. The motor somehow produces more soot when the EGR isn't activated.

I know these are just "educated" guesses but I'd like to get some input as to whether there is any truth to these statements. I'd really like to leave the EGR unplugged since the results are gratifying regardless of the extra perceived regens.

 

I can't explain why but in my case the regens are less often.
About every couple hundred miles under most conditions.

 

That's what I'd expect, too. EGR unplugged should equal less soot into the engine and exhaust. Truth be told, I've been driving mostly in town lately and the weather is cooler, which could explain what I perceive to be more regens. However, I tried the EGR unplugging experiment about a month ago in warmer weather while driving somewhat longer distances and still observed more active regens than normal. I guess I'll have to wait a while to see if this is really the case. Even so, I like the performance and mileage gains.

Isn't it true that EGR unplugging results in lower EGT's? Couldn't that theoretically lead to more active regens unless the vehicle is driven far enough to allow passive regens?

 

[Isn't it true that EGR unplugging results in lower EGT's? Couldn't that theoretically lead to more active regens unless the vehicle is driven far enough to allow passive regens?]

My egt's have dropped under all conditions including while under regen.
Intake air temps are much cooler also.
My mpg's improved 2-3 mpg's depending on conditions. This puts me about in the range of my old 12v '98.
Haven't yet taken off the crossover tube to check for soot but truck runs real well. Might be that the programmer I use helps since I believe it advances timing.

 

So, how many miles (or how long) have you been driving with the EGR unplugged? I agree with everything you said about mileage increase, etc. I don't know if there are any long term ramifications but the engine sure runs better.

Back to my original thought: theoretically, if the EGT's are lower wouldn't that equate to less soot being burnt off in the DPF since this is dependent on higher temps? More soot in the DPF means more regens, either passive or active, are necessary. Does my theory make any sense?

 

Been running with EGR unplugged for 50k.
It has to be making less soot by not having exhaust gas put back into the intake hence fewer regens. My thinking anyhow.

 

I would agree. Thanks for sharing your mileage. 50k is a lot of miles with the EGR unplugged. You've no doubt saved a pretty penny on fuel during all that time!

 

I guess I'm unplugged... I've been deleted for about 3 years now. No issues what so ever, oh, and no regeneration... I heard somewhere that over 1 gallon/per tank of fuel is used to keep your stuff clean...

I've saved a lot of $, lots of performance, longevity, etc. Never needed or used the warantee (except for P2262 code before the deletes)...

I think one's regen frequency probably has more to do with how one drives than the EGR...

 

Thanks for your input, Mega-engr. I've since re-plugged the connector to my EGR back in (still experimenting). I know it's not good to remove and re-plug often but I think the EGR is stuck, anyway. The CEL remains on and the codes P0405 and P0401 (both related to EGR function) remain.

Perhaps you can answer this question: I want to try cleaning the EGR myself and have printed out the instructions on how to do this. It doesn't look difficult but I don't have the cleaning fluid the dealer uses and am nowhere near a dealership. What would you recommend as a cleaning fluid? I have brake cleaner that I use on the MAP sensor. Would that work without damaging anything? Thanks again for your assistance.

 

Sorry for the hijack but I have a related question. I haven't tried to unplug my EGR yet because I don't want to drive around with a CEL all the time (no programmer yet). I do have a code reader though, can I just clear the code and that's that?

 

You can clear the code but it will come back at the next startup.
There are programmers available that will auto clear the code on startup or for less money there are units available that you can clear the code with by just punching a few buttons at every startup.
For me , I've gotten used to the cel for around home driving and only bother erasing the codes when going on a longer ride or if I'm towing.

 

Also, if a code comes up (that is unrelated) you want to be able to see and know this. Erasing it at start up is not good for the computer and one may not find another potential issue. Similar goes with having it on all the time. Just get the programmer and delete it. Even the Smarty has an S version and you don't have to delete anything...

 

OK, back to my question. What can I use to clean the EGR valve once I have it off the engine. I have brake cleaner that I use to clean the MAP sensor. Since it dissolves carbon is there any reason why it can't or shouldn't be used on the EGR??? I know the dealer has a special chemical they sell in the parts dep't for this use but I'm out in the boonies right now.

So, can I use the brake cleaner or some other easily obtainable product to clean the EGR???

 

Well, don't take this as anything but an idea. Maybe simple green might work. Also, I've heard that Z-max is supposed to do something like that...

 

Thanks again, Mega-engr. I plan to clean the valve tomorrow. Before I use the brake cleaner (non-chlorinated) is there reason you feel that any parts in the EGR could be damaged? I'm thinking probably not since it's all metallic and, besides, the brake cleaner causes no harm to the MAP sensor.

I should have picked up a bottle of the stuff the dealership uses while I was near one. They want $20 for a small bottle but at least it's what's recommended. I'll remove the valve tomorrow and see if I can perform a "partial cleaning", at least to the point where it will operate a while longer until I'm near a dealer...

Sheesh, the things you have to do on these trucks to keep them running properly. I know, I know.....delete (eventually)