TOPIC: My 2004 Toyota Corolla

2004 Toyota Corolla
About 101,000 miles on car, but the 1.8 Liter Engine was replaced about 2 years ago with a used engine, number of miles on that engine, is unknown.
5 speed manual transmission.

Pre-groove Data:
Gas mileage has run 27 to 30 MPG for a couple of years, since getting engine replaced.
Found a reference point for exhaust manifold temp, and measured 555 degrees with laser thermometer, but not real sure if this is accurate, due to post groove measurement.(see below)

April 7, 2013:
Factory spark plug gap is .043 inches, ended up at .070 after re-gaping plugs.
Did vacuum leak check with carb cleaner, none found.
Plugged the PCV vacuum connector on the intake.

I cut the groove, but again, like on my generator, I made it perpendicular to direction of airflow, instead of keeping it next to the curvature of the throttle plate. (It’s closer to the throttle plate at the bottom-middle, than it is at the ends of the groove. see picture) I will re-cut the groove correctly, a little later. There is no good reason for this, but I did notice some improvement after doing the same thing on my Kawaski generator. I decided that I will re-cut both of them, after I collect some data, then see how much it improves after doing it the right way. I also had to get the car together, so I could get to work in the morning, instead of taking the time to correct the groove.

The idle air passage was also in the path of the groove, so you can see where I diverted the flow with JB Quik, to avoid interference, in the picture.

Even with the groove cut incorrectly, I have noticed better throttle response, and for normal driving, much less throttle pedal is required for the same speeds.
There is also a large reduction of gasoline odor in the exhaust.
Post groove exhaust temp measurement is not consistant though, it is now 675 degrees. Maybe it will improve after I re-cut the groove later.
More to come.

While this IAC is not one I normally re-route (it dumps in above The Groove), reduction is always a good thing, so long as it's not reduced too much.

Judging by the photos of The Groove, it appears you stayed too far from the plate. Many do, as it scratches the throttle plate. But the scratches don't matter so much as the placement of The Groove.

It is only in some engines the plate needs to be opened, and I don't think this is one of them. Still, with no scratches on the plate itself, it shows me you didn't use the plate as a backstop for the bits. This is a no-no. 1/16" distance from the groove's proper placement can make the difference between 5% increase and 50%.

So, I would definitely recut this one. Use the LARGE bit on all vehicles!

Ron

Will do Ron, But I'm no expert here, and I need a bit of clarification. Here's why: the throttle is cable controlled,(not fly by wire) and there is a throttle stop that it makes contact with. But as far as I can tell by looking, the throttle plate is fully closed. I don't see any daylight. How does it idle with the TP closed all the way? Does the airflow when the engine is running, force the plate open enough to idle, or is something else going on, like the ECU? I am wondering if I should do the credit card trick on this one, or just cut it where the TP is positioned now. I'm clueless.

Hep me please (yeah, I said hep)
Thanks for the hep in advance,

Joe Bryant

always on cable cut groove as close as can to butterfly some have idle air controll and some you just adjust idle screw

Hey Joe, you're on the right track, just need to fill and re-cut w/ large bit using throttle plate as bit guide as Ron said.

Thanks for the remarkably clear pics.

Though your Groove IS cut wrong, I must compliment you, for it looks like you have a steady hand!

If it idles OK now, I wouldn't worry. Idle Air control likely provides necessary air. And you can always use idle stop screw. And you say you opened the plug gaps that far, interesting that's quite a big increase. If that works go w/ it.

Keep at 'er, buddy!

Tracy G

Joe, we haven't heard back from you!

As I was looking at your picture, it seems the bit was held at too steep an angle. The optimum angle is to hold the bit at 15-20 degree incline.

Sorry for the misinformation.

Ron

April 27, 2013
Guys,
SORRY for the long time between posts. With everything that goes on at my house day to day, the only time I have been able to get to this project is late Sunday afternoons. Told the family I am going to need more time for this, but no cooperation as of yet. With that said, here we go:
In Ron’s April 10 reply, he said it needed to be re-grooved, which I kind of already knew, I expected that I needed to do it over.
On April 20th, I filled in the first groove with Permatex Cold Weld, and did it again, and reset/reprogrammed the ECU as stated in the procedures. The Permatex stuff sets up extremely fast. It says eight minutes to set up, and it’s a fast eight minutes. I had to mix twice to get the first groove filled in.
I have not had time to get on the computer and get the pictures ready to post, till now. Part of the delay has been getting a video editor, and learning to use it. Tried to post video but it failed. Posted Pics instead.
In the week since then, I have run a tank of gas through the car, and I can report:
The exhaust is odorless. There is a definite power gain, and I barely have to touch the accelerator. The throttle response is awesome. The only negative, is there has been no improvement in gas mileage yet, still just a hair under 30 MPG.
I just saw Ron’s newsletter about the resistors, but I don’t know yet how much of that will apply to this car. I am definitely getting into that next, and maybe the Mapster and EFIE route.
Additionally I need to mention a few points, mentioned previously on the first groove:
I had asked about the position of the throttle plate because it looked closed to me. I was wrong, it is at idle position, I verified after I saw the engine run. But boy, it sure looks closed to me.
The angle on the first groove was definitely wrong as Ron said, It was straight up 90 degrees, or zero, depending on your reference point. It doesn’t matter anymore, it’s gone. On this second groove, the angle is almost exactly 17 degrees. No need for an apology Ron, no misinformation on your part. I managed to get it wrong on my own. When I did the first groove, it had not sunk into my head, that the groove and the Throttle Plate work in conjunction with each other.
Two mentions were made about using the large bit. I can assure you, on both the first groove and the second, I used the largest of the three bits I have. TracyG mentioned something about a steady hand. My hands are about as steady as an old man with Parkinson’s. I’m the kind of guy that will find a way of getting it right, if I can’t get it done the standard way. I would like to speak with Ron before getting into any detail about this particular subject. Ron, if you would, please call me whenever you get time, any day, any time. I never sleep.
Please look at the pics, and let me know what you think. It ain’t perfect, but it seems to be workin’.

Joe Bryant
K4BRY
Pembroke Pines, FL











PLEASE GUYS!
To Insert pictures, simply place the cursor in the place you want to insert your pictures and click "Insert" next to the uploaded files. This is a job I would rather not have to do.
Ron

Nice work and great pics too Joe!

Scratchin' my noggin here 'bout no MPG gain, maybe the ECM needs more time/miles to settle in.

Odorless exhaust and better throttle response tell me your re-Groove is working right. Have not re-read this thread, so apologies if story already told about PCV re-route?

Maybe she needs a Mapster. Personally I'm an Ignition fanatic, I think strongest spark possible within reason and the Groove are like tuna and fish.

I'd also mention about any possibility of any manifold vac. leak? Modern ECU's will just add fuel to "cover" any vac. leak and you might not even suspect a small one as might not even feel it in idle quality and driveability.

Last/not least get a scanner hooked into OBD11 port and check upstream O2's for how fast voltage switches up/down, "cross counts". But others could chime in on O2's I dont know which type your Corolla uses.

Anyhow thanks for the update, Joe!

Tracy G

Tracy,
Thanks for the feedback. As far as vacuum leaks and the PCV, see from my first post:
April 7, 2013:
Factory spark plug gap is .043 inches, ended up at .070 after re-gaping plugs.
Did vacuum leak check with carb cleaner, none found. (sprayed it everywhere)
Plugged the PCV vacuum connector on the intake.
After plugging the PCV, and checking for leaks, I noticed an immediate improvement with the engine running smoother. I think I got them all.

Also, yesterday, I Pulled the MAF out, and restricted the airflow through it, using small tie wraps. I can post the pics later, not available at this moment. The MAF lb/min on the scanner is now reduced an average of 22%, in the range of 700 to 3,500 RPM.

I thought I saw somewhere that reduced airflow makes the ECU deliver less fuel to the injectors. Is that correct? I thought I would try it to see if I can get some MPG improvemnt. Am I on the right track here, or have I messed up doing this? I got an error code(P0171) stating:
"System too Lean Bank 1." I interpreted this as a good sign. I will be trying a mapster or some of the other rigs I saw on one of the sites Ron mentions on the Mapster page, if MPG does not improve soon.

I am curios about the O2's voltage switches and "cross counts" are all about. I would not know what is fast or slow, and I'm wondering what effect it has.

Thanks
Joe Bryant

Very sorry about the pictures Ron, I had no clue about using the "insert" function.

Joe Bryant

First, not to worry about it, Joe. It has happened a lot. I only posted that part of the comment in the hopes of reducing this part of my work load.

On to your post.

First, you may have your gap too wide. Reduce it to say .060 and then test again. What concerns me most is the lean error code. This indicates (REMEMBER THIS!) a vacuum leak. There is no other cause (save sensor failure-RARE).

Provided it wasn't there before The Groove, then you have either left a leak or caused on with your labors.

Check the intake air stream from the MAF/IAT and do it thoroughly, paying attention to cracks and loose hoses. A can of Carb Spray will help, Propane is better.

Now, reducing the perceived air over the MAF may have a slight effect on the causes of the lean code. Try reducing the obstruction. And "YES" the ECU will respond by adding less fuel. Of course, less is always the goal, but if it's reduced TOO much, the ECU will cry FOUL! and throw that lean code.

This is another example of "Make your changes small and incremental or you will complicate the diagnostics."

One change at a time, please. That will eliminate wasted time for all of us.

Good job!

Ron

I'm thinking the error code is because of the tie wraps on the MAF tube. I have driven the car for a week since the groove, with no errors. I will remove the MAF restriction, and see if the code clears, like I think it will. I thought the restriction was causing the lean condition because the injectors were not supplying as much fuel, which is what I was trying to do. Is it possible that I'm correct here, if removing the tie wraps clears the error code?

I will remove the tie wraps, and wait a few tanks of gas, before I try them again.

Thanks,
Joe