New OBD-II scanner and a million questions

[Sluggo]

I purchased the Auterra OBD-II scanner, and played with it some today. My truck has the continuing problems as described in this thread

Now my new toy says that it is running lean on both banks. After a bit of research, this can be traced to vacuum leaks, intake gasket leaks (seems common on my truck) and EGR valve among 100 other things.

Here is a screenshot of the scan I was playing with SCAN Test at idle speed about 550 RPM

Temp seems OK
O2 sensor #1 is wild, and I guess thats what is causing the fault code
I also checked the short term fuel trim

Is there a way for this to check the EGR valve? I didnt see it in the test parameters.

Just trying to learn a bit and of course get my truck running better. Any thoughts or suggestions? Yes, I am RingTFM as we speak.

 

[boomerang]

I read your other thread. It looks like you've been throwing a ton of parts at it.

First off, based on the mileage, I would replace all the O2 sensors. If they're original, with that many miles on them, you've gotten your money's worth out of them. Some mechanics recommend changing them every 30,000 miles. Me, not that often. They have a tendency to get "lazy" as they age.

If this does not fix your problem, I would suggest this;

You say that your truck is prone to manifold vacuum leaks. Why ignore this? Do you have access to a propane torch? The handheld tank with an adapter on it is all you need. With the engine running at idle, crack open the valve on the tank (don't light it!) and move it slowly over the area where the intake manifold meets the cylinder heads. If the idle jumps up, you know you've got a leak. Have you looked at the spark plugs? Any sign of an overly lean condition?

With the miles you have on it, I'm betting you have a manifold leak. Replace those O2's too. On a side note, O2 sensor readings will normally be fluctuating madly. This means they're doing their job. They should be very actively sensing how much oxygen is in the combustion gases.

 

[dud]

Originally posted by: Sluggo
I purchased the Auterra OBD-II scanner, and played with it some today. My truck has the continuing problems as described in this thread

Now my new toy says that it is running lean on both banks. After a bit of research, this can be traced to vacuum leaks, intake gasket leaks (seems common on my truck) and EGR valve among 100 other things.

Here is a screenshot of the scan I was playing with SCAN Test at idle speed about 550 RPM

Temp seems OK
O2 sensor #1 is wild, and I guess thats what is causing the fault code
I also checked the short term fuel trim

Is there a way for this to check the EGR valve? I didnt see it in the test parameters.

Just trying to learn a bit and of course get my truck running better. Any thoughts or suggestions? Yes, I am RingTFM as we speak.

I got a similar reading on my wifes (now totaled) '99 protege. I did about 5 minutes research and found a message thread by a person with similar problems. It turns out that the plastic air intake is cracked in a few spot underneath ... where you cannot see it. I plug them up with some duct tape and the leak is fixed. $45 and a visit to the dealer to pick up the part and it is fixed. At that point my wife actually thought I could walk on water.

My problem was that because of the air leak the MAF sensor was turning the fuel too lean because the air was missing the sensor entirely. As soon as I returned the airflow to the norm everything worked perfectly. The MAF sensor returned the correct reading and the fuel flow to the injectors was corrected.

 

[Sluggo]

Originally posted by: boomerang

You say that your truck is prone to manifold vacuum leaks. Why ignore this? Do you have access to a propane torch? The handheld tank with an adapter on it is all you need. With the engine running at idle, crack open the valve on the tank (don't light it!) and move it slowly over the area where the intake manifold meets the cylinder heads. If the idle jumps up, you know you've got a leak. Have you looked at the spark plugs? Any sign of an overly lean condition?

Well, I didnt have a propane bottle, so I used the same system with some WD-40. I sprayed it all around where the intake runners meet the heads, and there was no change in the idle speed or sound. I also sprayed it all around the vacuum hoses hoping to identify a leak there, and nothing.

Maybe I'll replace the O2 sensors this weekend, at least the upstream ones, silly things are kind of expensive.

I read up on replacing the intake gaskets, it really doesnt seem too difficult, but wo knows if thats even the cause.

On a more positive note, my wife's Expedition has both banks lean codes and an EGR flow code. I found a few forums mentioning the DPFE sensor for Fords that will often go bad and give thaose codes, so maybe getting her CEL off is in the cards.