Ice_Wolf

Yea, I was looking at that article about getting the most MPG, and I completely forgot about changing the O2 sensor. I'm going to be changing that and the fuel filter here pretty soon. Also, I'm gonna pick up some LED's and spade connectors to check the TPS. I think it's actually a bit off, but I do know it is functioning correctly because if I work it with my hand, the car revs up and down. Strangely, I'm able to pull 28 MPG average out of my car without CC, but I'd love if I could get up to 30.

What I'm thinking is that I can try soldering this resistor in and see what happens with the car. It's not like it'll take very long to do it, and I've got some free time today to try it out and maybe put a resistor on that one that HAILERS was talking about. If it messes with the car, I can always remove them and resolder the wire back. I did use the CSM to adjust the idle air screw and the variable resistor and got the car idling pretty smoothly at 750 RPM. Just a quick question. What's the point of using the jumper wire? It really didn't seem to do anything.

I already advanced my timing to 10 degrees advanced ATDC when idling at 750 RPM, which I was told is the farthest you can go safely without possibly having detonation issues. I did notice it takes a little less pedal effort now though.

Ice_Wolf

Well, I soldered in the resistor today and noticed it did give the car just a slight bit more power from what I can tell. I know it did something because now the car doesn't tell me to shift up as soon anymore from what I can tell. Also, after adjusting the idle using the variable resistor and intake screw, the car idles almost perfectly. When I step on the brakes now, the car doesn't try to stall out anymore at all. It constantly maintains a 750 RPM idle with just a very slight bit up surging up and down, 50 RPM's at the most. I was really surprised how much of a difference it made.

What exactly would you have to do to adjust the ATP sensor that HAILERS was talking about? Would it be another resistor type deal or is it actually adjustable somehow? Also, RotaMan99, do you have any pictures on how the LED/spade terminal setup goes together? I'm having trouble understanding how you set it up and hooked it into the test connector from reading the CSM.

NZConvertible

It's really simple.

Adding a resistor to the AFM temp sensor makes the ECU think the air is colder. If the air is colder it's denser, so more fuel is needed for the same AFR. The ECU therefore injects more fuel. But the air is not actually denser so the AFR goes up (i.e. richer). Richer mixtures result in LESS POWER! This has been proven over and over again. Any improvement in power are in your head.

The idle improved because you made it richer, both with the added resistor and (properly) messing with the variable resistor. This probably means it was too lean before due to a vac leak.

HAILERS

About the ATP in the series four engine. Your at about the same altitude as in Ft Worth, so not much will happen on the rich side. I only saw a few tenths richer afr when I put it at sealevel using a RTEK2.0.

You can do the same just by removing the plug from the ATP. The ECU defaults to sealevel if you do that. So not much change doing that.

I know you can make the mixture leaner by inputing a higher altitude coming out of the ATP to the ECU. I've done that using a RTEK2.0 and inputing various altitudes. I live at about 650ft altitude. I can input a three thousand ft altitude and make the afr change close to a full AFR point. Such as from 13.2 AFR to 14AFR while sitting at idle. Looking at a wideband as I adjust the altitude.

If I didn't have a RTEK2.0 I would have to do it another way. STEVENA88 above gives a clue as to how. I have no need to do so.

The location of the ATP in a series four is shown in the FSM. It's in the interior on the passengers side foot well.

I don't have the RTEK set at an altitude above 650 ft on a regular basis. I just noticed this function of the RTEK after I bought the unit , and then realized that if someone set his altitude to a figure above where he really lives, then the change will lean out the mixture throughout the full rpm range. It's just a thought. Something to play with and ammuse me.

Ice_Wolf

So about this ATP sensor, how would I possibly make it run leaner? Would it be another resistor type experiment? From what it seems like, the resistor in the AFM sensor seemed to give the car a little more power, but nothing serious.

NZConvertible

With a fuel controller...

Did you read my post above (#28)? Your butt dyno is reading in the wrong direction.

RotaMan99

Hey NZ where ya been? Take a look at the howto below "wiring an electric fan" and scroll down to where I typed up about the SVS. Let me know what ya think.

RotaMan99

I don't but you can look at the link below and it runs you through on how to wire up the LEDs and also gives you a list of error codes.

http://teamfc3s.org/info/articles/errorcodes/main.html

HAILERS

You buy a 100K Trim Pot from Radio Shack.

One leg to the Green/Yellow wire coming to the pin 2H of the ECU. What you do is depin the wire at the ECU and attach it to the pot leg.

The other leg of the pot goes to ground.

The middle leg is attached to a wire and goes to socket 2H of the ECU. How you do that is up to you. I have an old harness and just depined a wire from the ECU plugs and cut it off a couple of feet from the ECU. You then install the pin of that wire to the 2H on the ECU and the other end of that wire gets soldered to the middle leg of the 100K pot.

1st jpg is the pot
2nd jpg is the voltage at 3.93
3rd jpg is the voltage at 3.75
4th jpg is the voltage at 2.75
5th jpg is out of order and shows the voltage at 3 vdc.

Adjusting this sensors output effects the afr across the board. Personally I wouldn't screw around doing this unless you have a wideband to look at.

I'll concede the SAFC or whatever is the *right* way to lean things out, BUT this is a low budget method to lean things out, for us po folk or folk who like to just screw around with the car.

Only cheap way to use this sensor to make things richer is to just unplug it and let the ECU default the ATP to sealevel. Sealevel being richer than any??? anything higher.

The output from the ATP on my car read 3.96vdc prior to installing the pot. The fully warmed up car read a AFR of something like 2.8 AFR. This is with a STOCK ECU, not the RTEK2.0.

Then I used the trim screw on the 100K pot (I've mentioned this three times and won't again), to adjust the voltage DOWNWARDS. At quarter volt increments I scanned the Palm that is in turn attached to a Zeitronix Wideband, to record the difference in AFR.

I'm attaching a couple of jpg of the difference in AFR as the trim screw turned the voltage downwards. I started at approx 2.8afr and stopped at 15 something AFR. I could have stalled the car out if I kept on screwing around.

This was on a series four car. Series five??? Got me. I think they have an internal ATP. Internal to the ECU. Maybe. Got me

Ice_Wolf

Thanks for that information HAILERS. You're right about it being a good idea to only do it if you have a Wideband to look at so you get accurate results. From the looks of it though, this would be a cheap way to adjust the AFR instead of getting a SAFC or other system. I think I'm going to take the sensor out of my AFM and see how the car drives to see if I notice a difference. Thanks for the info guys. Is there any other "easy" ways to lean out the AFR? Also, what does a good Wideband run on price nowadays?

HAILERS

*******I'm going to take the sensor out of my AFM and see how the car drives to see if I notice a difference. Thanks for the info guys. Is there any other "easy" ways to ****************

Errrr, ahhhh, there's a misunderstanding here. The ATP on a series four is in the passengers foot well to the right and up. It looks similar to the boost/pressure sensor in the engine bay but has no *nipple* for a vacuum hose.

You'd be hard put to find a cheaper way to lean things out other than what I described.

Widebands cost dough. On THAT car I've a Zeitronix that came with no display, and I use the Palm in the picture using software from Pocketlogger folk. It can display, rpm, AFR, EGT, TPS, Boost/pressue/vacuum and has an analog wideband output to the ECU if needed and takes out the garbage each Wednesday morning.

Actually, on a n/a car you probably could adjust it using a narrow band 02 sensor and not get hurt doing it. Hard to destroy a n/a in my humble opinion.

HAILERS

Or if you have a digital multi meter you can backprobe pin 2D (memory here), and look at the output of the 02 sensor. It'll range from 0000 to approx 1vdc. At idle with no airpump working it'll read around 0.7 -0.8 vdc if memory serves. Driving at a steady speed or cruise it'll display, rapidly, b/t 0.4 to 0.5 if memory serves. I was using a cheap, under fifteen bucks Radio Shack meter when I was doing that a couple of years ago.

Again, hard to hurt a n/a in my Humble opinion.

And while here, let's remember that in just six or so hours from now, Casey Stoner on his Ducati will TROUNCE Valention Rossi at LeMan. Rossi's old and worn out. Talking MOTOGP. https://www.rx7club.com/forum/showth...51#post6958051

Just rambling. This has squat to do with this thread. None at all. Too lazy to put it on the Lounge area.

Ice_Wolf

No no, I meant my AFM sensor. I put a resistor in that sensor and tried it out, but am going to remove it and see how the car runs. I know I could probably tune it with a narrowband, but if memory serves me right, they aren't very accurate since they are just reading voltages and display out in bars on the gauge.

NZConvertible

A wideband just reads voltages, and can display is bars if you want. The difference is the completely different output characteristics of the sensor, and the electronics used to interpret the readings.

Ice_Wolf

Alright, thanks for the info. I wouldn't mind getting a wideband, but for the money I could buy a few other things that would be much more important and without a sure fire way to tune the AFR without a wideband and SAFC, it's pretty much pointless. I believe I'm done with this thread.