Ok, I have been battling EGR problems for a while now as you guys are aware. I still have not cleaned the EGR ports on the elbow. However I had another question.

Short version for those that don't know: I have replaced sensor, valve, and solenoid and still throw either the excessive or insufficient flow code. I ended up taking the truck in to the shop because check engine light came back one. Well they said that my sensor was bad. It was an AutoZone sensor, which I know I should have bought one from Ford when I replaced it. He said they checked the sensor and it would not hold a reading and could literally just touch the sensor and it's reading would jump all over the place. I guess this could make sense on why I would get both excessive and insufficient flow codes. Also could help justify why sometimes I could drive 10miles and the light come back on versus other times I could drive up to 300miles before the light would come on. Also he said there was some water in the sensor, it was about 5 or 6 drops he said, and in his estimation was a lot and due to bad gas. So does this sound right as far as the bad sensor? Also the water in the sensor, is that due to bad gas?

For jbrew and bluegrass who are I know are still telling me to get off my lazy a$$ and clean the elbow and TB, I had asked if he could check the egr ports and he said they removed the valve and inspected the ports and they looked clean. I know the only way to fully inspect them is to take the elbow off. However if the sensor was the root cause it sounds like I'll be able to make till the spring when we will be in our house and I'll have my tools back.

I guess only time (actually miles) will tell if the bad sensor from AutoZone was the root cause. Yes I asked the shop for the bad sensor and plan on taking it back to AutoZone (along with the solenoid as I keep my old one) to at least help compensate for taking it up the a$$ for how much it cost me at the shop. Please don't ask I'm embarrassed to say. Lets just say that if AutoZone gives me a full refurnd on the sensor and solenoid that will be just over half of what it cost me.

 

Yes , it's possible , real bad gas or if the trucks been sitting.

Pulling the EGR , you can half a^^ clean your ports with the proper tools.

The biggest chamber 90's before entering the body - this chamber doesn't normally get clogged .

The smaller ones do.


You still getting a MIL ?

 

Truck gets driven daily during the week and normally sits on the weekend. I have been getting gas at Kroger's simply because it's closest to the apartment and we get discount since we shop at Kroger. When gas got up to $3/gallon I saw a reports on the Today Show that said that if you take 89 octane at one gas place it would be the same thing as 89 other places because they have to follow the same standards. They said where ever you find gas the cheapest buy from there. I remeber seeing this on the Today Show because I thought it was odd because I was always told to stay away from gas from the mom n pop shops. And think I just filled up yesterday from Kroger's.

Don't know yet, just picked truck up a little earlier today. Light came back on, on Monday, after I had put on the new solenoid which I did on Saturday. It was funny, this morning when I drove to the shop MIL on. But when I started the truck to drive myself to work and the shop guy to drive it back to the shop, light went off. I almost turned around to take him back. I guess the only comfort is knowing that I would have not checked the sensor because I would have assumed the new one I put on back in July was good.

I guess I had always taken it that the sensor was good. Also I have been to 3 different AutoZone's a couple of times where I live to go ahead and get some brushes for when I do pull the elbow, and they have always been sold out. I guess when I do pull the TB and elbow I need a new gasket for the TB and the elbow?

I’ll definitely post an update after either the MIL light comes back on or I have been 2 full tanks of gas (because it seemed sometimes I could go almost a full tank before the light would come back on). In my opinion it will be at least 2 or 3 tanks before I quit constantly looking down to see if the MIL is on.

 

Do this, comp might be a little buggy - Reset your the KAM. Disconnecting the negative battery cable and touching it to the positive terminal.

Keep Alive Memory(KAM) It's your PCM's short term memory,a kind of capacitor that stores things like idle data, fuel trims, trans tables, etc. It's a good idea to reset the KAM whenever you fix something engine or trans related, so the PCM will go into adaptive strategy and relearn to your latest repairs.

Touching the negative battery cable to the positive post won't result in sparks or fire. It'll just clear the PCM's memory.

 

The two most likely causes for insufficient flow are a bad sensor and clogged ports. Change the sensor. If the codes persist change the sensor. If the codes still persist change the sensor. If the codes persist change the sensor. If the codes still persist change the sensor. If the codes persist change the sensor. If the codes still persist change the sensor. I see a pattern.

JMC

 

How about I take you through how the system works, then you can begin to logic it out for yourself.
1. The tube from the exhaust manifold has an internal restriction that the DPFE measures accross for the flow tests.
2. At the EGR, this device must be able to be opened by signal from the PCM so flow can take place accross the restriction and into the intake manifold SO the DPFE can take it's measurement.
Logic says that anything upsetting this overall action results in a fault code and CEL lamp.
How to test the EGR: With engine running, apply about 5" of vacuum to the EGR. If the ports are open and the EGR opens, the engine will begin to run rough to prove the path is open. If not, there is a blockage of fault.
How to test the pipe and sample tubes: Remove the DPFE. Start the engine.
Feel for exhaust pulsing at the outer tube; check for the same but of less intensity at the other tube. You must feel this or the tube or restriction has a problem. Closely check for pipe mounting for cracks and rust holes.
These type faults will not result in sucessful DPFE reading because the pipeing in not solid and closed.
Check the DPFE hoses and that they are on the right stand pipes and not reversed.
Water: The exhaust contains a lot of water. This along with carbon is what cause 99% of the problems. You can't get away from it. In fact it is such a problem that the FLOW test must fail two times in sucession before the PCM logic decides there is a failure and is why the fail code is delayed so long after being cleared. Reason: In cold climates the restriction could freeze with water causing a temporary blockage anywhere in the tubes. This would give to many false DTC codes since engine and bay heat up and melt the blockage.
Last, if all these test prove good, the DPFE is the only possible left besides the wire and connector.
Notes:
The excess flow test is done at startup; a different time from the insufficient flow test. Both these tests usually are not done if an outright EGR failure is detected first because the DPFE tests would never pass in any event if there is a basic EGR failure to begin with.
An excessive flow usually tells you that the piping is not closed and solid because no flow is expected at that time due to the EGR 'NOT' being open for that test. The DPFE must see the same exhaust pressure intensity at both it's ports for the excess flow test to pass rather than a differencial pressure as in the insufficient flow test.
This tutor should be a sticky for most to go by in diagnosing a DPFE problem.
Its not hard if some time is taken to read it as many times as needed to get the whole picture. A clever engineer figured this all out so we must take the time to understand it.
Good luck.