2ShotTuck

I recently purchased a 2000 tacoma with the 3.4 (Whoo!) And I was looking to get some gains on gas mileage as well as some horse, so like most people I purchased a flowmaster exhaust, tbs from airaid, and a spectre cold air ( couldnt afford the k&n). Now after I made my engine breath alil better my check light flicked on. Took it to a buddy and ran a diagnostic on it and said I had a bad o2 sensor. We checked the sensors and even mass airflow and everything seemed fine. What I'm thinking is all these mods made a higher flow rate and my ecu thinks I have a problem with a sensor. Could the ecu be this sensitive to changes? If this is the case I'm really about to piss it off with Jba headers and magnaflow cats... Also, Jba headers, does anyone have any complaints? Or a dyno sheet for me to see? I really want to get rid of those logs

Mitchell12

Which O2 sensor? Did you delete your cat converter? My bet is that it's your 2nd O2 sensor or something in which case you'll need to replace it and/or do the anti-fouler trick if you deleted the cat.

22RE4WD

Which code are you getting?

2ShotTuck

The diagnostics weren't specific to which sensor it was, I haven't deleted either of my cats... As bad as i want to. Why do you you say the second sensor Mitch?

Mitchell12

The second sensor is basically just to make sure your exhaust/cat is functioning properly. If you switched to a catless system then it'll be sending alarm bells. Honestly I am not familiar with your specific setup but if you can provide the exact code we can prob tell you if it's pre or post cat converter.

vital22re

iTrader: (2)

air raid spacer is crap. Is the spectre filter exposed? Most "cold air intakes" only gain you looks and sound and do nothing for power. texas ace has dyno's to prove it.

2ShotTuck

Well Vital, my spacer bumped me up 1.5 mpg, so I'm not complaining about it, and yes the filter has the heat sheild around it and I'm going to fabricate a heat sheild for the tube as well just to see if it may help. My theory is for short distances it will work but over extended trips it will warm up.
I do not remember the specific code. I can ask my friend what it was exactly and get back to you on it

motocrossaddict223

I agree, cold air intakes are useless. I had one on my 3vze and i think i actually lost power due to poo quality filter. My advice, do what i did; ditch the cone filter and put the factory box on but keep the polished intake tube. This is how i feel i got the best results. Look into the deck plate mod for your 3.4. Your cel is PROBABLY coming from you exhaust upgrade, go to urd and get the o2 sim. Thats my $.02 from never owning the 3.4 just from reading yotatech.

Mitchell12

Nah, don't bother spending on an o2 sim if it is your second sensor. Just do this http://www.civicforums.com/forums/22...on-w-pics.html

Basically you just bore out an antifouler to fit your O2 sensor. It's worked for me on 2 cars that I bored the cat out on. Your second sensor isn't really there for anything important other then to tell you if your cat is borked.

motocrossaddict223

Yea or do that, on my buddy's beamer i basically made the o2's a closed circuit and they worked fine. But in retrospect, it took me a solid weekend and hours of wire research ...it wasnt worth it. Id say do the thing from the civicforum

Texas_Ace

Get rid of the cold air intake and the TB spacer, both are worthless on our trucks.

Here is a back to back comparison I did on the dyno with the stock intake with elbow removed and a cold air intake:

Blue line = Stock
Red line = "cold air"



Go back to stock intake with the elbow removed and you will get more power.

Did you remove the Cat when doing the exhaust? If not then you don't need an O2 simulator and your issue is something else. If so then build your own for $10 in radioshack parts like me.

In a nut shell, on our motors, there are no easy ways to get power. You are stuck with what you got from the factory. The only way to really get more power is a supercharger.

2ShotTuck

That's fine with me tho as long as I'm spending less at the pump, power is a bonus to me. The rig is fast enoug, any faster and I'd be a danger to society lol. I'll I'm happy about is I get 24 highway with a 3" lift going up and down all the hills I drive on to work, where as before I got 19 highway. Now I have not touched the cats yet, the exhaust was a cat back installation. As for the code I'm still waiting on his response, thank you for the input tho regarding the cold air, that's something I didn't know, as for the spacer I know they do nothing for power haha its just a hunk of aluminum with some bodatiouse threads. But does anybody know if the higher flow would set off a alarm in the ecu? I know several rice rocket hondas, Nissans, and suburus that have this problem

Texas_Ace

That large of a gain in MPG is most likely due to a placebo effect from the new exhaust/intake. With a louder exhaust guys will generally drive the car easier, keeping the RPM's lower, Throttle closed more ect so as to not make it too loud when driving around.

This can and will lead to those kind of gains but it is not a direct effect of the mods.

I actually saw a pretty big improvement in MPG when I was supercharged, which is not uncommon. This is since I don't need to give it as much gas or RPM's to get to the same speed.

The throttle body spacer works on the princeable of enlarging the plenum which can effect power on the top end on some cars, mainly old carberated cars. Our plenum/runners are already so big as it is that you will not see any noticeable gains from it.

It never really helps MPG except in carberated cars where it gives the fuel more time to atomize before hitting the runner walls, on an EFI car this is not an issue. Won't hurt performance though.

Most likely the intake is what is causing the CEL, Not from flowing more but from being the wrong size and messing up the MAF calibration. I would go back to stock, reset the ECU and then see if it comes back.

2ShotTuck

I drive with cruise control on most of the time on Highway, and in town I drive pretty rough, weaving thru traffic and my town mileage has Stayed the same.

2ShotTuck

I'm actually glad to hear finally that forced induction improved mileage, I've never been able to hear an answer for it because nobody cam keep their foot out of the floor board

Texas_Ace

Well actually that makes a bit of sense with what you are saying about the MAF sensor CEL. If the intake size is wrong it will screw up the MAF sensor reading. This in turn will effect the tune of the truck and cause it to run leaner.

This will raise your MPG but can also cause you to throw a CEL and can even melt your cats if you are not careful.

Texas_Ace

Naturally it depends on how you drive. In my case I drive the same boosted or not (which is driving it like I stole it). Some guys will drive real easy without it though and then when boosted will start hammering it and complain of worse MPG.

Generally driven in the same manner, with the only change being some boost, a boosted car will at least not loose any MPG and in many cases gain some. I would say I gained ~2mpg from the SC myself.

2ShotTuck

Alright that makes sence to me. I'm going to wait till I hear from my friend with the code before I try any solutions. I don't want to start reverting, fixing and spending money on time on the wrong leg of the system

So why is it that cold air intakes drop power?

Texas_Ace

The "cold air" intakes are actually Short ram intakes technically. The stock airbox pulls int he coldest possible air you can get and is not restrictive to start with once you remove the elbow.

When you go with the aftermarket intake you are sucking in hot engine bay air instead of cool fender-well air so that is why you see a drop in power. Colder air = more power.

The stock airbox is not restrictive anyways, the piping is the same size as the throttle body, so anything larger won't help, and will screw with the maf reading. With a good filter the stock system flows great with no restrictions or harsh bends. Simply no reason to change and like the dyno I posted shows.

I ran that test twice, back to back to back to back since I could not believe the results. Sure enough, same results the second time around.

2ShotTuck

See I have a hard time understanding this because the filter is located in the same spot, with a heat sheild and the tb spacer literally puts the filter right next to the hole in the fender to pull air from. And the heat sheild with the hood down souls nearly completely sit flush with the hood, if not 3/16" of a gap at most. I'm not trying to arguing with you, I saw the dyno haha I'm just really confused.