Brandon, here's an article about fuel trims that might help with the thought process. From what I think I understand, the AFR is at 14.7 when the STFT is at 0. When it shows +14%, then the ECU is adding 14% more fuel to keep the AFR at 14.7. That would indicate that additional air is getting in from somewhere, so that smoke test would be a good idea, along with making sure that the MAF connector is making good contact.

I'm still in progress with my project, and I keep finding more things that need attention. I ended up doing a new carrier bearing on the driveshaft along with new flex couplings; the rear roll bar needed attention, so new links and all the bushings; and last weekend I found another problem: the left side mount for the front subframe was separated. I found that when I went to put new gaiters and bushings on the dampers and the engine came down when I lowered the jack under the spring pan. That was a big WTF moment. I had not had any need to mess with the subframe until now, so I had always thought that the bolts holding the frame in place were attached directly to the frame. Nope, there's a mounting in there that's pretty well hidden, until the frame is lowered and you can see it. It looks like it will be fairly easy to replace the mounts and the new ones should be here today. And, I'll have to change my method of putting the car on jack stands. I had been raising the the front end by jacking under the front wishbone bolt housing then putting the stands under the jack points (as you can see in the below picture.) In the future, I'll raise the car from the jack points and put the stands somewhere under the subframe.

I have the new downpipes installed, which was a lot of fun; actually it took longer to get the old ones out than put the new ones in. I will say that the Nameless Performance downpipes were the easiest after-market pieces to fit that I have come across. The only problem that I had was with the studs. Nameless uses 5/16 x 18 studs instead of the M8 x 1.25 that were on the original downpipes. And they sent M8 nuts. I didn't notice the difference in the threads until I started putting the nuts on, so I called them to whine and they sent me $50 in beer money for sending the wrong nuts. That also covered having to go get the right nuts for $3.75. My only other concern now is having the 2.5" downpipes going into the stock 2" inch pipes. I plan on doing the rest of the exhaust soon, but for now I want to see how this thing does with the 200 cell cats. Hopefully, no CELs.



New downpipes an O2 sensors


All buttoned up !!

 

Looks great! I'm sure they'll sound great and improve power through the whole rev band. If I can fix my car before Christmas, I'll order some of the supersprint part, 1.5psi pulley and Bosch 010 I /C pump.

 

I have had the Nameless cats on my car for 6 years and have never had a CEL from them.

 

rocklandjag: that's good to hear; did you do any other exhaust mods?

Brandon: I'm still thinking about what to do with the rest of the exhaust. I looked at the Super Sprint setup and those look like a good choice, especially since it's a total bolt-in job. Kind of expensive, but I could probably spend as much, if not more, having an exhaust shop build a setup using Borla mufflers. My only concern with the Super Sprint is eliminating the center muffler as I don't want to get too loud.

 

It is very expensive for their full kit.
Quick questions. When I am coasting, you know, going at speed, and let off the throttle. Is it normal for my MAF reading to read what it reads at idle?

Also, my MAF reads 5.2 g/s at idle(park, neutral). Warm engine, AC off.
But when you put the car in reverse or drive, the maf reading goes to 6.2 g/s when at idle. That to me, seems wrong?
Shouldn't the lower RPM in D or R make the MAF reading go lower?

 

No, only the cats. The rest is stock all the way back.

 

Brandon: That's another "Maybe" answer. It all depends on what the electronic TB is doing, and I'm not as familiar with that thing as much as some other members. I believe that it will adjust to keep the idle at 650-ish, so yea, the MAF reading would go up somewhat. When coasting, does the TB close the butterfly all the way, or does it stay open a little (?) I routinely use the lower gears when coming down the hills around here to avoid braking when entering the curves and accelerating through the turns, or having to slow down behind the idiots. The rpm's are usually between 2000 and 3000 when I do that, so I'll have to check MAF readings whenever I get it all back together; hopefully, that's before Christmas, the way things are going here ...

Rockland: sounds like you're happy with the setup. Did you get better performance? Did the new cats change the sound level? I still have a lot of work to do before getting back on the road and seeing how the car performs.

 

I actually used my mom's 2014 Accord as a MAF reference. And yes, the MAF on her car would do what I was questioning above. I also floored her car, and the AFR went to 11.70. So yeah, was just making sure my app is reading correct.

So anyways, I got my old MAF. Bent the pins just slightly. Did a hard reset. Drove the car about 50 miles. I did see that my fuel trims were pretty spot on. But car is still too lean at WOT.
What I did notice on occasion, my car would go rich when coming to a stop. I'd look at the MAF reading, and it'd be 6.5-7.5 g/s. Should be around 5 g/s at idle. So when, I got home(car still being too rich at idle) I pushed in quite hard on the connector of the MAF. Everything went perfect when I did that. Screenshots below to prove it.


Higher than usual maf g/s idle reading. And see the rich afr.

In this pic, you can see the rpm at 640. Maf g/s being at 6.76 And short term fuel trims crazy.

This is after I pushed in hard on the MAF connector. Notice how afr and fuel trims are near spot on. Also, the maf came to 5.48 g/s

Showing the same rpm of 640.

 

I've been looking for new MAF connectors, but no luck.

 

Toyota 5 pin maf connector. Just search 2003 Corolla. This one has about a foot of all white wires.

eBay. Same car search as list in prior picture.

 

You can also use a small flathead pocket screwdriver to gently push the pins in behind the connector while it’s still plugged into the maf for a more positive connection.

 

A new connector might solve your problem, but I should check the wires as well.
Might be an internal break inside the insulation, just like the trunk light issues ....

 

Installed the new MAF connector this morning. Then did a hard reset. Drove the car for 25 miles. All readiness monitors were green. So I floored it for like 2 or 3 seconds. Still lean. I have questions about WOT. But I feel like that is for another thread.

If you have kept up, you'll know that my MAF g/s would be at 6-7.xx g/s at idle. Which is too high. And I would wiggle the connector, or push it in. Then the g/s and afr would go back to perfect at idle. Well the new connector seems to have fixed that. At least I know how to change pigtail connectors know

 

Congratulations, Brandon !!! That lean reading at WOT is a little concerning as that second fuel pump should kick in to compensate for the increased demand for fuel. I know that you have new fuel pumps, so a quick check to make sure it's working properly would be to set your instant read on the trip computer to fuel mileage, then floor it. The reading should drop quite a bit.

 

Interesting, I'll have to try that. Thank you.

 

Instant mpg was showing 17. I got it enough for a kickdown. Mpg instant reading went down to 4.9
MAF readings at idle are still stable with the new connector.
I tried to get my car a smoke test for vacuum leaks. But they were charging $180. I'm not cheap by any means. But I figured I may as well spend a little extra, and buy my own smoke machine.

 

Well, the second fuel pump is definitely working! And, yea, spend that $180 on the equipment and do it yourself; that's what we do ...