Lean Burn all the way!

[stevey_frac]

Originally Posted by brucepick

not enough exhaust in the intake air??
Hmm. Does it have EGR that pulls from post-cat converter?

Even aside from the intake air bit, I'm sure that the leak just aft of the cat messed up the O2 readings. And I bet that leak was building for a while and finally became clearly audible.

OK, I have to admit to CRS syndrome; I'm now past 55 and I don't mean mph. I"m PRETTY sure I ran it for about 40 mi. with the grill block back in and had trouble keeping LB. But I will put the lower grill block in for tomorrow's 60-mile ride up to work and we'll see how it goes. No inconvenience at all - it's sections of foam pipe insulation bundled together to fit the grill openings. Easily removable and reinstallable.

CRS syndrome?

I'm was thinking the leak was dropping exhuast pressure, and this was causing EGR action to slow down, and throw things off. Didn't think about a post cat O2 sensor. Perhaps I should just stick to code? :P

Either way, try 'er and see!

[brucepick]

Originally Posted by stevey_frac

CRS syndrome?

I'm was thinking the leak was dropping exhuast pressure, and this was causing EGR action to slow down, and throw things off. Didn't think about a post cat O2 sensor. Perhaps I should just stick to code? :P

Either way, try 'er and see!

CRS = Can't Remember S**t
Happens to all of us eventually.

Yeah you're right - any leak in the exhaust certainly has the potential to mess up fuel management. I didn't think about EGR foul-up but that's a possibility. The main O2 is in (just before??) the cat and the 2nd one is just after it, or at the back end of the cat. I'm pretty sure the job of 2nd O2 is to verify the final exhaust is clean enough.

[Christ]

The 1st and 2nd O2 sensors work in comparison with each other to make sure the catalyst is working properly.

[LeanBurninating]

Here is the link

http://ecomodder.com/forum/showthrea...nsor-5204.html

It basically watches what the 02 sensor is reading and lights up according LEDs on your dash. Its a non numeric readout but its no matter to me.

Bruce, I also noticed the same thing with my car, it seems like sometimes LB will not engage below 2200, 2300, whatever. What a mystery this lean burn is! I understand that you don't want to get mixed up in the wiring and stuff but it is really quite simple! I am not an electrician, Ive only soldered stuff on cars a handful of times and I almost always ask somebody more knowledgeable to explain how to do stuff first. But this kit is really not hard to install. I am glad that I got the MPGuino because it reads accurate instant MPGs, whereas the scan gauge measures instant MPGs assuming a constant air to fuel ratio. But whatever.

I have been getting so frustrated with this LB not working the way I wish it would, Im going to try a couple of things first but I am considering getting illegal and buying a $30 non CA ecm. Its gas mileage versus the EPA!!!!!

Right now I have a PVC pipe hardware store intake thing goin on... hey, it was cheap. I just had my buddy crush bend a 2.5" exhaust pipe for free. Im gonna see if the warmer air through the intake is what it takes. And beyond that, a grill block, and undertray. Aero mods mean less throttle needed. yipee.

[brucepick]

Thanks, LeanBurninating.

Now for tonight's installment in the quest to understand the HX lean burn logic:

The switch to not allowing lean burn under 64/65 mph is determined by a distance clock. Yup. A simple counter that kicks in after about 23 miles or so (~37 km). Keying off the ignition for 10 seconds reset the counter, after which full lean burn was again available. Hopefully only a brief shutdown is needed; for this test I wanted to be sure to be over 10 sec. to try to ensure a full reboot.

As I watched for LB failure (that is, losing it below 65 mph) I paid close attention to engine and intake air temps and they were moderate. ECT was 182 deg. F which is where it always stabilizes unless it's over about 75-80 degrees outside, or if I'm running the cabin heat. Intake air was about 75 deg. which is about as moderate as you could get. Nothing else going on that I noted. Keying off the ignition and bump starting it brought it back to full lean burn operation - as long as I kept the throttle below about 30 tps, it would maintain LB down below 55 mph in 5th. After a restart it does require a mile or two of driving before LB will kick in, but I can deal with that.

So now I want to find how to wire an ignition cutout. My regular commute is about 60 miles so it would be nice to be able to maintain lean burn. Maybe the easiest is to find the power wire to the ECU circuit at the ign. switch and put an intermittent-off switch in that line, either before or after the ign. switch.

[LeanBurninating]

That is really interesting... I wonder why it works that way? Why would it kick out? So you watch it kick out every time at 23 miles? How many times has it done this for you? Have you seen it on more than one route? Maybe its the driving conditions of your commute?

For CA spec cars, supposedly it kicks out when the NOX gasses build up to a certain level, so the motor can burn out the NOX gases. I could be wrong. I don't think that non CA hx's do this.

I just got my air fuel ratio toy in the mail today, I hope to get it hooked up soon to join in the game.

Thanks for posting up, Bruce.

[brucepick]

Originally Posted by LeanBurninating

That is really interesting... I wonder why it works that way? Why would it kick out? So you watch it kick out every time at 23 miles? How many times has it done this for you? Have you seen it on more than one route? Maybe its the driving conditions of your commute?...

Happened the last time I had it on a long run also, semewhere between 20-30 miles into the trip - I wasn't paying close attention to the distance yet. I wasn't thinking mileage, I was thinking cat temp and engine temp etc. Tonight it was very cool out; I figured I'd take a run and see what happened. Tomorrow I'll drive 60 mi. to work. You can bet that I'm going to pay close attention to exactly when I lose LB.

[brucepick]

Since my last post I've had the HX out for two 60-mile commute runs plus other driving.
On one long run, it went into Lean Burn stayed there.
On some of the other trips, it developed the "rpm sensitivity" I described.
I wasn't able to identify yet what causes it.

Anyway, the 23-mile thing is not consistent. RPM-restricted Lean Burn has kicked in at other distances that were further than 23 miles.

In the time since the last post I had a shop do an injector/valve/upper cylinder cleaning. Because my good wife heard "ping" - I want to get all the carbon cleaned out to help eliminate early detonation. They put the last of the cleaner into the tank so that fuel is not standard fuel - I think I can smell the cleaner in the exhaust.

I'll be driving again the next three workdays so I'll see how it goes.

[LeanBurninating]

May I recommend sea foam to you.

I can't give you professional advice for it, but I would definitely look into it. Its a clear liquid in a can, you can get it at kragen/schucks and you can use it to clean out deposits.

You pop off the vacuum line for your fuel pressure regulator and literally suck this stuff into your vacuum system. While your engine is idling you suck up a prescribed amount, you have to let the line sip at it as dunking the line will stall the motor, and then when you have enough sucked into your engine you then dunk the line and stall the motor and leave your motor off with all of this stuff in the engine, it will be all over your valves, pistons, heads, intake runners, etc.

Then after letting it sit when you start it back up it will burn out all your carbon deposits. Just drive it hard till all the smoke stops coming out. The more smoke, the more carbon you are burning out. I know that this works because the first time I did this I made tons of smoke and the next times were less and less.

[Christ]

Use the vacuum line from the brake booster... it fits into the top of the can, usually, and make sure you dump out 2/3 of the can into something else first. (you only need 1/3 of the can in your engine).

Fuel based "engine cleaners" do not work, simply because there are already so many detergents and additives in your fuel that adding a little more is like adding soap to the suds on your hands.

The other reason they don't work is because so little fuel gets injected at such a high temperature into your engine, that it's nearly completely vaporous by the time it actually gets to the combustion chambers... vaporous cleaning supplies do next to nothing, unless they're steam.

Another thing you can do to clean out your engine (that actually works) is just a light mist of water into the intake pipe, before the filter. It's just like steam cleaning, and will eventually loosen any crap that's built up in your engine.