Wikipedia - In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique used in petrol/gasoline and diesel engines.
Because NOx forms primarily when a mixture of nitrogen and oxygen is subjected to high temperature, the lower combustion chamber temperatures caused by EGR reduces the amount of NOx the combustion generates.

We know for a fact that the temperatures drop with the Gadgetman Groove, we also know from Ron's video's that the NOx numbers are reduced, in many cases to zero.

Ron's initial marketing of the Gadgetman Groove was a better running engine and Reduced emissions, the fact that with some manifold vacuum adjustment that efficiency extends to the mpg of the vehicle it does not negate the prior results.

All of Aron Cheek's reports indicate that the temperatures drop.

I would doubt very much that there is pressure behind the EGR gases, in fact, if you are going to unplug anything I would unplug what ever device is controlling the EGR gas flow.

Unplugging any sensors is going to throw a code.

disconnect it in the driveway, plug the port on the manifold, start the engine... see what comes out if anything...

Won't know unless you try it...

Karl Fortner
Tacoma, Wa.

Sorry - I misspoke. I meant disconnect the module where the EGR exits the block, not a sensor further down the line. Although, the check engine light did go on, so maybe that was a sensor!

I did that and ran a quick 25 mile test. Except for a Check Engine light, the wasn't any noticable difference in the MPG (digital) or performance.

I can't run it this way longer (for a better average/evaluation) because of the Check Engine light. It would be just my luck a critical CE code would be thrown while I was ignoring the light

I'll see if I can figure out some way to block that line. I don't know how I'd block the hole where it enters the manifold; the EGR has a 1/2 inch or so diamater pipe, and the manifold has an even larger hole.

Thanks again!

OK - status report.

I've put about 100 miles on since disconnecting/blocking the EGR, and it may have shown a slight increase - .5 to 1 mpg. Again, short distance, so "actual" changes may be higher or lower, especially on highway travel.

However, I'm now getting a constant Check Engine light - P0401, P0403, P0406, and P2305. The P04* codes are all related to the EGR. Most indicative is the P0401 - insufficient airflow through EGR.

The P2305 is insufficient ionization on number 2 coil. That's spark plug related, and I'm not too worried about this one right now (I think it's a code thrown while testing something, and not a constant issue).

But, I digress.

Since I get a code if I disconnect or block the EGR to eliminate its vacuum loss, it's apparent I can't do that without running with constant Check Engine light - not good for a variety of reasons. Does this mean the only gains I can get from Grooving must be those (actually, none) with the EGR in the system?

I'm at a loss of what else to check or try.

Thanks again!
Harry

Hi Harry,

First of all you need to get back to the basics. We do not recommend ever capping the EGR system or unplugging it. So get the EGR system back to normal.

Are there any other things you changed since the Groove? If so, put them back to normal.

Next, place a cap on the intake where the PCV line was connected.

Third, disconnect the positive cable from you battery, attach the cable to engine ground and turn on the key to the run position. Leave it this way for at least 15 minutes. This will reset your ECU and erase all the things that have happened out the the computer memory. After at least 15 minutes, reattach the positive to the battery (after you have turned of the key).

Now do your mileage tests. Make sure you use the actual miles driven divided by the gallons of fuel used as mentioned here in the forums. Run a couple tanks through and report the results back to us here on this forum. If you have a way to get the fuel trim measurements, report them here.

Do not change anything while you are doing the tests. If you haven't already, check every line for a vaccum leak.

If you have any questions, give me a call. Look forward to hearing the results.

I must have misunderstood earlier posts (#5 and #7) - didn't they say to plug it?

I've already plugged the PCV valve and done the battery reset - the results are zero improvements, if not a slight drop, in MPG. That's been consistent after 4 months of driving.

Earlier posts led to the belief (at least mine) that the vacuum loss from the EGR tube may be the issue - closing the PCV valve off doesn't make much of a difference if the EGR is creating a vacuum leak.

I've also checked all the vacuum lines I can find for leaks - none that I can find. I'm still trying to figure out how to do a smoke test, but I've done the carb cleaner (?) test over the intake with no change in idle.

The only "issue" I've found so far, with the help of earlier posts in this thread, is the EGR pipe.

I've made it a point to absolutely nothing to the engine (except air filters, etc) while trying to diagnose the lack of improvement (since November 2011). I'm planning on trying the spark plug gap mod later, but not until I've figured on the Groove or had it removed.

Thanks!
Harry

I was told to plug the PCV valve, not redirect it. Is it better to redirect it, or is plugging the way to go?

I'd hate to redirect it (I assume it would have to go here) to the atmosphere side of the throttle body since some oil spray goes through mine as well as gasses.

Unless there is somewhere else it's supposed to be redirected to?