AEM F/IC writeup

[jdwk]

Really bad news, I logged my drive home from work today and it appears to be back to its old 16:1 self. I turned down the resistance of the potentiometer on the O2 signal before I tucked it away yesterday. When I turned it to 20kohm last week, my O2 voltage went to 1.2V. I was afraid that 50% of 1.2V would read .6V to the PCM and it would start pulling fuel again. So I figured if I went back down to 14kohm, I would be safer as I had good logs with that resistance.

I didn't measure it though, I just turned one of the two 10k pots down all the way down then turned it a few turns back so I would be somewhere around 14k. I should have measured I guess.

It is also possible with all the jostling and cramming that I caused the connection to the pot to break and wedge up against the opposite wire creating a short and essentially 0ohm, which we know won't work.

Then I guess it is possible that the PCM has somehow figured out that the O2 voltage has been reduced and now compensating, although I find that very unlikely.

I am so upset I have to take it back out of the car now. I spent most of yesterday getting it all put back together nicely and now have to redo everything. Kind of feels like I got punched in the balls.

 

[jdwk]

Ok spent a good couple hours again doing pulls/logs with various resistances on the O2. Whatever magic I got to work the other night for a few runs is gone. I tried resetting the PCM too, it made my idle crappy again for a while but didn't affect the closed loop operation. I apparently didn't mess anything up when I put it under the kick plate, and I also had the resistance on the O2 dead on at 14kohm like I had thought.

Clamping to .1 volts kind of works, but it still starts leaning out to about 13.3:1 between 2500 and 3krpms before staying rich through the rest of the normally closed loop operation. I brought it up to .2 and I started to see a little bit of that AFR cliff at 4200 rpms again. So I went back out and tried .01 and this time it only went up to 13:1 but still a small jump in fuel at 4200.

It is very frustrating that I appeared to have it working for a few runs, but I think it was more luck than anything. This read/write tri-wire crap is nonsense and even if worked exactly as advertised there would be 5ms of ever 200ms that the PCM could still potentially read the actual O2 voltage. The AFR cycles around 14.7 during idle and cruise make me think it's actually sampling around 1 second. If the PCM sampled during those 5ms you'd be screwed, but I highly doubt either are that precise, and therefore we get random behavior.

I think I'll try intercepting the O2 signal with the Analog A in and out and see if I can't control it with a real intercept instead of this tap setup. Not sure if the PCM will like the Analog output, but what do I have to lose now. This thing has already sucked away weeks of my life, what's a few more hours.

 

[Ricktalife]

****, so I might have to rewire this ******* thing AGAIN. I hate being a guinea pig...

 

[jdwk]

What resistance did you use? Have you tried clamping or modifying the O2? It would be nice to see if anyone else could verify what I am seeing.

My car started and immediately shut off this morning, CEL: MAF signal too low. I checked the connections and one of the bullet connectors I put on the maf out seemed a little loose. I re-crimped it, but it still wouldn't idle. I think resetting my PCM got rid of my LTFT which gave me my nice idle. Originally I had to bump the MAF a couple percent at idle, but I gradually removed that.

I had to get to a meeting so I just removed the harness completely and went back to stock. First time I've had to do that in a couple weeks.

I will be removing the MAF signal when I try the O2 on the analog a input. It's just too finicky. The MAF is way too sensitive to be setup like this with the resistor going to ground.

 

[Ricktalife]

I actually did not use a resistor since I had hooked it up that way the first time around and didn't know about the necessary resistor deal at that time. I haven't tried to use the 02 map yet, just the fuel table with map based load adjusting the injector duty cycle. But really I haven't done much with that either since I need to relocate my MAF and vacuum block first so I can have my car running right, otherwise my numbers won't mean s*** compared to your setup.

edit: I am trying to figure out my scan tool so I can use the freeze frame data, so I'll try to figure that out tonight after I get home from school. I also bought 2 more fittings for my vacuum block so hopefully this weekend I will be good to go.

But on that note, justanother suggested using a 1/8 thread to 3/4 hose... and I didn't think about it until I went to the speed shop. The guy looked at my like i was nuts, and I realized what I was asking him. We both assumed that 'justanother' meant to say 3/8 hose, because 3/4 is way too big of a transition to fit in a 1/8 thread. So I bought two 3/8 fittings. Can anybody verify this for me?

 

[destineal]

3/8 fittings for the BB line

 

[Ricktalife]

okay good, just checking.

 

[justanothermp5]

oh s***...yea my bad, meant 3/8

 

[Ricktalife]

oh s***...yea my bad, meant 3/8

No problem lol, I should have thought about it instead of just repeating what others say. Makes me think of...

...but that's a little off topic.

 

[ogsp5]

Just a thought If I am wrong OOPS , but our cars have a map sensor also(the little block box on passenger side). Does this conflict with the map sensor in the FIC and maybe causes the readings to go off.

 

[Ricktalife]

I've never heard anybody stating our car has a map sensor? Can you post a picture?

 

[thecrash91]

I've never heard anybody stating our car has a map sensor? Can you post a picture?

its officially termed "Pressure sensor module" or something like that. we do, regular pros dont i believe.

 

[Ricktalife]

Well isn't that a b****. I think that affects the way we hook up the MAF sensor wire so that probably explains the problem I was having. I will have to check that out.

 

[thecrash91]

open your hood and look toward the windshield and all the way on the left, its right near the solenoid with the mitsubishi logo on it (may even be that sensor, its been a while since i saw the diagram)

 

[jdwk]

Man there is a lot of bad information on this site. That is not a MAP sensor, and notice there are two of them. Those are EGR sensors. Our cars do not have a MAP sensor, it's simply determining if there is pressure to the manifold from the EGR. It is an on/off sensor, and it is only for cruising. The EGR closes during high loads.

Ricktalife, those mitsubishi boost sensors have nothing to do with your problem.

 

[thecrash91]

Man there is a lot of bad information on this site. That is not a MAP sensor, and notice there are two of them. Those are EGR sensors. Our cars do not have a MAP sensor, it's simply determining if there is pressure to the manifold from the EGR. It is an on/off sensor, and it is only for cruising. The EGR closes during high loads.

Ricktalife, those mitsubishi boost sensors have nothing to do with your problem.

http://www.asashop.org/autoinc/sept2002/techtips.htm

"Mazda's "boost sensor" is just a fancy name for a manifold air pressure (MAP) sensor."


also
http://www.tomco-inc.com/Catalog/egr boost sensors.pdf
look under "What they do"

yes they regulate the pressure between EGR and the mani, it is technically a MAP sensor

also read the bottom of this where it says EGR testing

http://en.wikipedia.org/wiki/MAP_sensor

it sounds exactly like the protege if you ask me...

 

[StealthWyvern]

http://www.asashop.org/autoinc/sept2002/techtips.htm

"Mazda's "boost sensor" is just a fancy name for a manifold air pressure (MAP) sensor."


also
http://www.tomco-inc.com/Catalog/egr boost sensors.pdf
look under "What they do"

yes they regulate the pressure between EGR and the mani, it is technically a MAP sensor

also read the bottom of this where it says EGR testing

http://en.wikipedia.org/wiki/MAP_sensor

it sounds exactly like the protege if you ask me...

Is it me or do I not see anything 3rd gen related in any of that?

 

[thecrash91]

Is it me or do I not see anything 3rd gen related in any of that?

yes... the first article go to the bottom, it starts talking about the 99 protege (3rd gen), the second one makes a reference to 96-97 MX6 and 626, which both share the FS-DE engine.. the third one is just a general definition of MAP sensor which proves that some vehicles run a MAF sensor AND a MAP sensor but use the MAP sensor for EGR related activities... i mean aformentioned sensor (MAP sensor or not) is still a pressure sensor... which is what a MAP sensor essentially is... it only makes sense..

 

[ogsp5]

Hey did not mean to start a flame war, the sensor says KL47.It is attached to the bracket that holds the cruse control system. When i did my engine swap I got a code Map sensor not hocked up. I forgot to attach the vacuum line.

 

[StealthWyvern]

yes... the first article go to the bottom, it starts talking about the 99 protege (3rd gen), the second one makes a reference to 96-97 MX6 and 626, which both share the FS-DE engine.. the third one is just a general definition of MAP sensor which proves that some vehicles run a MAF sensor AND a MAP sensor but use the MAP sensor for EGR related activities... i mean aformentioned sensor (MAP sensor or not) is still a pressure sensor... which is what a MAP sensor essentially is... it only makes sense..

I should of worded that differently.. I dont see anything mentioned about the 3rd gen 2L engine. In 99 I dont think the protege ever came with a 2L but I could be wrong.