dhsavage

Hi, I am complete newbie when it comes to Toyota trucks...I had a Subaru STi before, so a bit of a different car, but a lot of similar technology.

I noticed on my used 2002 Tacoma that the previous owner did a hack-job on the intake (not deckplate mod), and I am convinced that the hack job is hurting my fuel economy substantially.
I decided to take the opportunity to get an aftermarket intake, and after a lot of research, ended up going with the Outlaw Power Intake. Was really impressed with the engineering they at least said went into its design. I recently found out that the intake diameter was increased...which from a subaru I was always told was a big no no for the possibility of running lean. Is this a problem with the yota too?
I noticed the MAF has a tapered inlet, so possibly this taper is what controls the diameter to get an accurate reading????
If not, is it also OK to do the MAF mod without having any fuel management?

Elton

if you didint hook up the fpr line it well run if lean post up a few pics of the intake

midiwall

No, the ECU has enough room to handle this.


True, but you're not making changes to the intake side of the MAF. As well, the ECU will also be looking at the TPS and the O2 sensor to make fuel adjustment decisions.


Yes, the ECU has enough room to handle this. But it wouldn't hurt to do the "Free FMU" mod:

http://www.gadgetonline.com/Fuel.htm#Free%20FMU:

And, which MAF mod are you talking about? The one where folks are hacking up the MAF, or installing a Supra MAF? If you're hacking up the MAF, then the hack is to the back side of the MAF - the airflow metering won't be affected.

If you're talking about the Supra replacement, then the element in the Surpa MAF is tuned for that MAF - it works fine.

rimpainter.com

It should be noted that my mpg dropped by 2 (15.5mpg on average) with the Free FMU mod "installed" on my rig. You know the saying, "There is no such thing as a free lunch."

I have since reversed the mod thanks to Mark's injectors and am enjoying a steady 17.5 mpg.

Elton

and is it good to mod ur maf on a n/a motor ?

midiwall

Ummm, so isn't your FPR connected to the S/C?

Glad to hear you got the injectors in!

midiwall

Well, Johnny (Weasy2k) was gonna look into that, but it'll certainly feed more air which will burn more fuel which will make more power.

rimpainter.com

Yeah, it's just not T'd anymore. The scan tool confirmed that it was an ok move. It runs really strong now. Thanks.

Elton

any updates ?

SLC97SR5

I'm in the process of modding my MAF. I'll post results when I'm finished.

dhsavage

Thanks for the helpful responses...I'll get pics once I get it installed!

ONE LAST QUESTION:
Does the stock N/A tacoma naturally run lean or rich?

Elton

could do both depends on what goes wrong

dhsavage

OK. So the tacoma will only run lean or rich if something is wrong...
With my old Subaru STi, they come pretty dang lean from the factory...so confusing the computer and by adding more air when it thinks it's the same amount caused issues. Sounds like it won't be a problem with the Tacoma. It is weird coming from a very tempermental turbo charged four banger...it just makes you very cautious about making changes to your setup.

midiwall

We're talking about the 3.4L engine, right? Any specific year?

In general the ECUs that drive the 3.4's are quite good at keeping the engine to running at Stoich. It may take some time for the ECU to settle in after a reset, but it's usually closely dialed in after 200 miles or so.

Where things will go south is if you run the truck outside of it's normal operating range, things like high RPM no load (reving the engine while running downhill), low RPM high low (chugging up a mountain towing a trailer), hard accleration, etc. During those times, the ECU will be running in an area of the fuel maps that haven't gotten any attention - so, the stored trim values will be 0 and as such the engine will _temporarily_ run rich or lean. The ECU will "immediately" correct for it, but the correction won't be exact until the engine has spent "some time" in that zone.

This is why it's recommended that you run the truck under all sorts of conditions, so that the the ECU can see a larger portion of the fuel map and thus compute more correction values.