Another reason for EGR failure

KJMedic · **Posted:** Tue Sep 05, 2006 11:16 pm

Got my 4th EGR valve installed today at 26,271 miles. On the invoice is a note stating "Noticed during exhaust inspection that vehicle has had a high flow exhaust pipe in place of muffler. Rec. replacing with factory unit because the EGR system is calibrated for a certain backpressure and a highflow exhaust reduces backpressure and may cause problems with EGR flow"

Is it me or is this total BS? I have had 4 EGR related problems. 2 with the stock and 2 with the Glass Pack.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

ec. replacing with factory unit because the EGR system is calibrated for a certain backpressure and a highflow exhaust reduces backpressure and may cause problems with EGR flow"

Man, what a load of baloney. Tired of losing money on warranty work, they feel the need to sell you a factory muffler to make up for it. Think about that dealers statement - if a high flow muffler reduces backpressure, LESS exhaust gas will flow through the EGR valve, less soot on the valve and it should last longer. No matter that the AFC valve will choke off fresh air until a certain amount of exhaust gas is pulled into the intake, but with less backpressure on the exhaust side, there will be somewhat less exhaust gas available to be pulled into the intake system. They are pulling this nonsense out of thin air. Then there's the little detail of why you lost 2 EGR's with the "right" backpressure muffler installed. What was his explanation for that fact? I lost my first EGR with the factory muffler, the 2nd with the dangerously low backpressure, high flow renegade Aeroturbine on it. Yes, using logic and common sense, I conjur up that it was the low flow muffler causing the problem.

This is right up there with "your back brakes moan because rust forms on the rotors during the nightime damp air." Of course, rust should form on the front rotors as well on 02 Liberty's, as they have drum rear brakes, but for some reason, the 02's don't moan because the rust fails to cooperate with the dealers logic. You just can't trust rust to do the right thing.

RFCRD · **Posted:** Tue Sep 05, 2006 11:55 pm

KJMedic wrote:

Got my 4th EGR valve installed today at 26,271 miles. On the invoice is a note stating "Noticed during exhaust inspection that vehicle has had a high flow exhaust pipe in place of muffler. Rec. replacing with factory unit because the EGR system is calibrated for a certain backpressure and a highflow exhaust reduces backpressure and may cause problems with EGR flow"

Is it me or is this total BS? I have had 4 EGR related problems. 2 with the stock and 2 with the Glass Pack.

As if the individual writing that statement is qualified to make this judgement. I would want to see the engineering study where Jeep calibrated this system based on a specific flow rate and backpressure. It is unlikely that the 2" constriction at both ends of the factory muffler it there by design just for the CRD.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Speaking of muffler calibration, as if by magic, the CRD muffler is also perfectly calibrated for the V6 gasolene engine. It's amazing how these things just work out so conveniently. It must be calibrated for both engines - its the same muffler! :-)

Cowcatcher · **Posted:** Wed Sep 06, 2006 12:04 am

If you just put the OEM Muffler Bearings back in the after market muffler that would probably make them happy. You might ask them if that would be OK. :roll:

retmil46 · **Posted:** Wed Sep 06, 2006 12:05 am

Ranger1 wrote:

Speaking of muffler calibration, as if by magic, the CRD muffler is also perfectly calibrated for the V6 gasolene engine. It's amazing how these things just work out so conveniently. It must be calibrated for both engines - its the same muffler! :-)

Actually, it must be calibrated for THREE engines, they also used the same muffler on the 4 bangers!! :shock:

RFCRD · **Posted:** Wed Sep 06, 2006 12:13 am

retmil46 wrote:

Ranger1 wrote:

Speaking of muffler calibration, as if by magic, the CRD muffler is also perfectly calibrated for the V6 gasolene engine. It's amazing how these things just work out so conveniently. It must be calibrated for both engines - its the same muffler! :-)

Actually, it must be calibrated for THREE engines, they also used the same muffler on the 4 bangers!! :shock:

Wow, that engineer must be a genius to optimize all three motors in one exhaust. Maybe they should be assigned to the air intake and software problem too.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Let's see, same air filter box, same air filter, 3 different engines, and same muffler. Oh yea, this air flow is so precision tuned that the delicate balance will be upset if a high flow muffler is used. Now using a 4 cylinder gasser, a 4 cylinder 2.8 liter diesel and 3.7 liter V6 gasser won't bother anything though. That's one heck of a self-calibrating muffler. Do you suppose they sent the muffler specs to VM Motori in Italy so they could design the 2.8L R428 diesel engine around it?

DZL_LOU · **Posted:** Wed Sep 06, 2006 12:22 am

KJMedic wrote:

Got my 4th EGR valve installed today at 26,271 miles. On the invoice is a note stating "Noticed during exhaust inspection that vehicle has had a high flow exhaust pipe in place of muffler. Rec. replacing with factory unit because the EGR system is calibrated for a certain backpressure and a highflow exhaust reduces backpressure and may cause problems with EGR flow"

Is it me or is this total BS? I have had 4 EGR related problems. 2 with the stock and 2 with the Glass Pack.

The EGR used on our CRD's is not a vaccum pressure regulated system that is dependent on back pressure. The EGR is an electrically operated pin and seat orifice that allows precise control by the ECM and much faster response of the pin than an "old school" vaccum pressure EGR.
This "component swapper" called a tech needs to understand what components he is swapping out before making blanket statements that turn out to be false. :evil:

RTStabler51 · **Posted:** Wed Sep 06, 2006 8:45 am

I had a Ford dealership try to void my emissions warranty (cats came apart) on my Contour SVT because I had put a catback exhaust on the car. These guys are idiots.

naturist · **Posted:** Wed Sep 06, 2006 9:08 am

My guess, and this is only a guess, is that all those swaps have been of the valve in the exhaust system, and that the REAL problem is that the valve on the intake side is really the problem. It appears the two valves throw the same error codes, and since the one is half the price of the other, they throw the cheap one at the problem -- multiple times -- in hopes that solves things.

I, too, went through 3 EGR valves before the intake-side one was replaced, and that seems to have done the job. ALL the replacement EGRs on the exhaust side threw failure codes and tripped the CEL within a couple hundred miles. 6,000 miles on the changed out intake-side valve, and no sign of trouble. That's further than it went on the first EGR.

s_allcroft · **Posted:** Wed Sep 06, 2006 9:10 am

I am sure that the highly calabrated OEM Muffler, must also some how be involved with Ball Joint Failures and Torque Converter Failures!!!!!!! :shock:

BLake · **Posted:** Wed Sep 06, 2006 9:30 am

How does the exhaust get injected into the intake? The intake is under up to 25PSI and the EGR gas can't be under much as much pressure, even with the crappy stock muffler. Just wondering.

RFCRD · **Posted:** Wed Sep 06, 2006 10:12 am

BLake wrote:

How does the exhaust get injected into the intake? The intake is under up to 25PSI and the EGR gas can't be under much as much pressure, even with the crappy stock muffler. Just wondering.

True, boost pressures are 25psi+ but the engine is sucking harder. To develope that pressure (under flow) you need to create airflow resistance. The airflow control (anti-shudder) valve partially closes and essentially creates a dam. The EGR port is on the opposite side of the dam, causing a draft effect pulling exhaust gasses from the tube. One of the reasons for "EGR flow" codes is the AFC valve is failing. Its control gearing/mechanism is not strong enough to move (or hold) the dam plate under the force of the pressure differential.

kjfishman · **Posted:** Wed Sep 06, 2006 10:15 am

KJMedic wrote:

Got my 4th EGR valve installed today at 26,271 miles. On the invoice is a note stating "Noticed during exhaust inspection that vehicle has had a high flow exhaust pipe in place of muffler. Rec. replacing with factory unit because the EGR system is calibrated for a certain backpressure and a highflow exhaust reduces backpressure and may cause problems with EGR flow"

Is it me or is this total BS? I have had 4 EGR related problems. 2 with the stock and 2 with the Glass Pack.

You should call customer service and ask them to come up with an explanation of the above theory and press them as to to what they will do when you hit 36k and your warranty is up on the egr system. The basic extended warranty doesn't even cover it. Since you are on number 4 a visit withe the zone office is probably in order.

RFCRD · **Posted:** Wed Sep 06, 2006 10:45 am

kjfishman wrote:

KJMedic wrote:

Got my 4th EGR valve installed today at 26,271 miles. On the invoice is a note stating "Noticed during exhaust inspection that vehicle has had a high flow exhaust pipe in place of muffler. Rec. replacing with factory unit because the EGR system is calibrated for a certain backpressure and a highflow exhaust reduces backpressure and may cause problems with EGR flow"

Is it me or is this total BS? I have had 4 EGR related problems. 2 with the stock and 2 with the Glass Pack.

You should call customer service and ask them to come up with an explanation of the above theory and press them as to to what they will do when you hit 36k and your warranty is up on the egr system. The basic extended warranty doesn't even cover it. Since you are on number 4 a visit withe the zone office is probably in order.

What do you have for an extended warranty that excludes the EGR hardware? Do you mean the time balance from when the 3/36 expires to the end of the 7/70 powetrain only warranty? The extended warranty I have is worded to the effect that if something is covered under the basic 3/36 b2b, then it's covered under the 7/100K extended (without deductible). The only thing that would be excluded in this case is the actual aftermarket muffler.

retmil46 · **Posted:** Wed Sep 06, 2006 10:57 am

Just remembered something. This is basically the same BS I got from a gent at a local speed shop. He was trying to convince me to buy one of the Flowmasters he had in stock, versus ordering an Aeroturbine (which he WAS also a dealer for). Gave me the same line, it'll screw up your enissions, burn out your EGR and valves, burn out your piston rings, yadda, yadda, yadda. Looked like a fool when the co-owner of the shop butted in and asked him why it was they were installing Aeroturbines on every diesel that showed up at their door and never had any complaints about them.

When the regional rep for Aeroturbine found out about the line this guy had fed me, he found another shop in short order to be his local dealer.

KenJennings · **Posted:** Wed Sep 06, 2006 4:37 pm

s_allcroft wrote:

I am sure that the highly calabrated OEM Muffler, must also some how be involved with Ball Joint Failures and Torque Converter Failures!!!!!!! :shock:

You forgot to add the dreaded transmission shudder, acid rain, and extinction of the dinosaurs.

huxrules · **Posted:** Wed Sep 06, 2006 5:21 pm

I think it might be how you drive. Here is my story- Wife ran over a curb in her mazda 3 while I was offshore. She had to drive the libby for a month. When I returned I was suprised to notice that I could generate HUGE black clouds. Noticable in the day. They were gone within a few full throttle episodes. Could it be that the egr valve gets clogged on some libbys because of a different driving style? Just a guess

HUX

s_allcroft · **Posted:** Wed Sep 06, 2006 7:27 pm

KenJennings wrote:

s_allcroft wrote:

I am sure that the highly calabrated OEM Muffler, must also some how be involved with Ball Joint Failures and Torque Converter Failures!!!!!!! :shock:

You forgot to add the dreaded transmission shudder, acid rain, and extinction of the dinosaurs.

Yes I guess I overlooked those... Thanks for pointing out!!!!

Another reason for EGR failure

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