TOPIC: 2002 Olds Silhouette tops 31 MPG!

Our trip to Madison was good. I watched the gas gauge, hopefull for a slow mover. I ended up getting about 27 MPG on the trip to Madison. Not bad, but not stellar. The check engine light came back on about 180 miles into the trip. I could still feel the power surge, so I felt the O2'2 were still working.

Aron and I met and learned a lot. He capped off the pcv better and redirected the pcv to the passive side of the TB. No change was made to the groove.

On my return trip, I filled up in Madison and drove over 220 miles on 1/4 tank of gas! My on-board computer was reading 34.6 AVERAGE mileage! Instant was 35 to 40 going 55 mph down the road. I was/am estatic!

Aron and I learned that you can do the Groove, but the functions, sensors, performance of the engine must be working well or the groove will suffer greatly.

My advice is to look at the sensors first, before you do the groove, to determine how they might effect the performance of the groove. Still do the groove, but MPG's might be affected.

Scott Castleberg
Pellston, MI
Gadgetman Michigan

Looks like you got your first success story. Great job Scott.

Now just keep duplicating the process and keep on a roll.

I got that paragraph thing going Ron LOL!!!!!!!!!!!!!!!

Dan gadgetman Mo.


Do the Mods!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hey Scott,
When you said that Aron capped off the PCV better, does that mean that it previously had a small vacuum leak? This, and besides the T'ing in, were any other changes done? What would you attribute the major increase in performance to?

Thanks very much,

Luke

Hey Scott, thats Awesome MPg for a vehicle that size! Congrats! I second Luke, what was the secret sauce on you Silhoutte mod? TracyG.

Secret Sauce - let me see....

First, I had replaced the front Oxygen sensor earlier and noticed a large negative change in the fuel trims, but still no MPG response. I rechecked the groove and polished the surfaces, thinking the flow of air will flow better over smooth surfaces. The Oxygen sensors should have been replaced long ago. As a rule of thumb, I would recommend every 80,000 miles on these sensors.

Second, I had capped off the pcv originally, but about 8" from the vac source and had let the pcv itself vent outside. Aron capped off the vac source as close as he could and redirected the pcv valve to the passive or pre-throttle body side - T'd in to the exsiting other port.

Nothing major, but something DID happen. I'm hoping to take another trip to confirm my results.

Keep Grooving!

Scott Castleberg
Pellston, MI
Gadgetman Michigan

Hmm, well that sounds like a recipie for Groove Secret Sauce to me... Or perhaps did you get a burger on this trip...what kind of sauce might have been on it...?? Ok back to Reality, the O2 Sensor, Polishing the Groove ingress/egress on the TB bore wall, and dialing in the PCV re-route that all sounds good and tasty to me:P anyhow, Scott your Shilloutte thought it tasted Great, congrats!! thanks we all learn from one another, TracyG Gadgetman Reno

Hey Scott,
Re. the PCV placement, if the cap was done 8" from vacuum source, or 1 inch, if there were no leaks at either site, then re-routing theoretically would have made no change to the outcome, correct? Did you erase the ECM or leave it, and if you left it, did the STFT suddenly change to the neg. more than previously?

There is a great Utube video showing the relationship between the long and short fuel trims and how they work with corrections for vacuum leaks or rich conditions. I found it very good:

Thanks for your experiments Scott, and Tracy, for your most excellent, and unique description of Scott's work!

Luke

Something I have learned from Dan Merrick - if you reset the computer and the fuel trims don't quickly begin to go negative, mileage gains will probably not come

As we have learned, even the best groove may not produce mileage results if the rest of the engine is in need of maintence. As Aron and I talked last weekend, this may be why so many of the personal license holders have had limited to no success. If we don't look at the big picture, the groove may suffer.

Bottom line - keep grooving and don't give up!

Scott Castleberg
Pellston, MI
Gadgetman Michigan

WOW!! Thank You Luke for that youtube vid!! That is an Excellent class! Very useful, can't thank ya enuf!! TracyG

Hi Scott, and Happy Father's Day.

I did a little experiment on Bud Kester's 2004 Explorer Sporttrac.

I allowed a vaccuum leak on the manifold to happen, and fuel trims went from

short trim: -7 to plus 9!!!! long trim went from -4 to plus 10!!!.

What a change the vaccuum has and how quickly we see it affect gas mileage.

This vehicle I changed 02 sensors on and the throttle response is phenominal(comment by owner Bud Kester).

I will post fuel trims in the next 2 days because they also drastically changed.

Kepp on groovin guys, but please, like Scott said LOOK AT THE BIG PICTURE OR THE GROOVE WILL SUFFER!!!

GadgetmanNebraska

Good day to all gadgetmen.

This a very good video to explain the ecu,as I have said the ecu is always looking for zero,however with the groove the ecu is also trying to figure the raw gasoline not vapor form and the air fuel ratio on liquid to air is different.
What the groove does that allows us to increase the mpg is change the gas to vapor afr,lets say we have two different fuels!!! If any of you are familiar with hp tuner or efi live you can shut down the long term fuel trims meaning it has no memory to find.
With the long term gone the mileage is what the short fuel trims are doing so after you reset the ecu it will go neg cutting fuel as the groove is causing rich vapors .This will cause an increase in mpg. Happy Grooving and Fathers Day!!!
Dan Gadgetman Mo.