TOPIC: Re: No improved gas mileage

I grooved a 2004 Dodge Caravan with a 3.3 v6. I checked the vacuum before and after the groove and it definitely made a difference.I did a code check and there was none.
I then conditioned the ECU which helped smooth it out a lot because it was very jerky after the groove. I also keep getting a EEC code all the time.
My problem is I have gone through 3 tanks of gas and haven't gotten any mileage increase.
Has anybody come across this? Does anybody have any ideas or suggestions what could be wrong?
Nathan

did you plug pcv vaccum? can you list the fuel trims long and short dan gadgetman mo.

yes I did plug the pvc vacuum. I don't know the long and short fuel trims. How do you get this info?
Nathan

If you capped the PCV then you would have seen gains, unless there is/are more leak(s) in the vac system.

I would be double-checking my work, as I overlook stuff just like everyone else. Sometimes, amazingly simple things!

Take another look at what you've done and then report back. You are bound to find it.

Ron

yes, Ron is right, but if you have access to a car scanner to read what the computer is doing look for LTFT and STFT and post the readings and I can lead you to the area to look for the problem. Also the load factor at idle this will give me an ideal where to lead you. Usually it is a vaccum problem. Dan gadgetman mo.

I checked all the vacuum lines again and found no leaks. I don't have access to a car scanner yet to check the LTFT and STFT.
Here's some pictures of the groove maybe it's not done right.

Hi Nathan,

Your fourth picture, the opening in the upper left part of the Throttlebody, That is the idle air intake.

You need to reduce the air flow from that opening down to about a 1/8th inch opening.

It is basically a major vacuum leak that needs to be reigned in.

You can use candle wax wrapped with cellophane to cover the inlet so the JB Qwik doesn't seep into the inlet and packing tape (or other type) to create a wall and fill the void with JB Qwik. Once it has hardened you can pull the cellophane out and remove the tape... Wha La... wall.

Then just put a 1/8" groove from the inlet side to the venturi.





If the motor idles rough, then you may need to open that up to about 1/4" but try the 1/8" first.

Karl Fortner
Tacoma, Wa.

Thanks Karl, that's great info,but isn't that opening at the top left hand side for the evaporation emissions to the fuel tank because I plugged that off on the outside with a cap.
The opening at the bottom left hand side goes to the IAC. Wouldn't that be the one I fill in?
Nathan

Hi Nathan,

I was more curious about the area that I marked up... what is the function of that opening?





Okay, from what I have seen, what I thought was the IAC opening seems typical for most but if the IAC is the lower left, then yes, it would be worthwhile to reduce that opening at whatever point is most convenient.

Another question, where does the IAC feed to. Does it go directly to the manifold or that spot there inside the venturi wall?


Karl Fortner
Tacoma, Wa.

The opening on the top left goes to a nipple on the outside where the fuel vapor line hooks up to.
The IAC feeds diectly to the manifold. I will reduce that opening. I also changed the spark plugs and I will condition the ECU again.
Thanks for the help, I will let you know how I make out.
Nathan

Ok Nathan Ive been studying your pictures and I may have come up with a solution try plugging the egr line at the top of the intake were just testing not permanent.It is possible that the egr is staying open to long leaving us with less vaccum. Try this and then get back with me and we`ll go from there. This should be getting some gains and yes your groove looks fine. Dan gadgetman mo.

This is GadgetmanNebraska Aron Cheek, I would also try to reset computer after you go with Dan's idea(We love our techs and troubleshooters people).

Take off pos and neg cable from battery and attatch the two together for a couple of hours or overnight.

Turn on anything that is electrical including your keyswitch.

Before you hook up battery cables remember top turn off everything then hook up cables and start car and let it run for a while, then do your conditioning cycle.

You should see an improvement then.

If I can we can help you in any way let us know please.

Grooving and grooving, Aron.