OhioLariat

I've never heard of an intake tract change making the 2V motors go lean (with or without a complimentary exhaust change) like the 4V engines can. And unless that tuner has a canned tune for those mods, I don't see it being able to make the proper corrections.

I've looked at/for a tuner off and on for awhile, but only for the tire-size/speedo offset capabilities. If I go ahead with my gear swap and J-mod the transmission for better shifting, that should eliminate my (perceived?) need.

My.$.02, and worth about that.

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jprevat

iTrader: (1)

I hadn't heard of that either but when I swapped it back my afr went back to less than 3 on my leaner bank so who knows.

2thousand5.4

How do you know it was lean? Just from the DTC? Do you have any way of dataloging it?

2thousand5.4

An intake shouldnt make it go lean as long as there is enough headroom in the MAF for it to adjust for the incoming air flow, which on a stock motor there is. The only thing I can think of that would cause a lean condition is either an intake leak, or the new intake has a substantially larger or smaller MAF housing that is throwing off the MAF transfer curve

2thousand5.4

Basically how it works is the MAF outputs a signal from 0-5 volts, the computer then takes this voltage and references it to a table (MAF transfer function) that converts it to AD counts (think of this as air flow). This will tell the computer how much air is coming into the motor and it then computes how much fuel to inject. In reality it's much more complicated but that's the jist of it. Anyways, let's say the MAF pegs out at 5v (in reality it's a little lower) and that equates to 1000 CFM (no clue on this actual number, just picked 1000 for simplicity sake). Really the MAF reads Ad counts not CFM tho. I'm order for it to throw a lean code you would either A) have to be flowing more than 1000 CFM, B) have a leak somewhere that introduces unmetered air into the system, or C) the transfer function is off.

Case A isnt going to happen on a stock motor. even if you were flowing more air than a stock MAF could account for, it would only happen at higher loads and 3/4+ throttle.

Case B is pretty self explanatory

Case C will happen if the volume of the MAF housing is changed from the stock volume (other things can cause this as well. So let's say the MAF puts out 5v and that means 1000 CFM, but that is 1000 CFM through the stock size tube. If the tube is increased or decreased and it isn't accounted for in the tune then the flow numbers are going to be off at all loads and throttle positions.

Really the MAF reads Ad counts not CFM. CFM is determined by the intake, heads, exhaust, etc. But whenever you substantially change how a motor flows air it needs to be accounted for in the tune. The computer also learns changes, but it only will do so to a degree. That's why changing exhaust or intakes normally doesn't need a tune, but when the changes are to great for the computer to adjust then it needs a new tune. Hopefully this all makes sense

jprevat

iTrader: (1)

It did and thank you for taking the time to walk me through it. I was watching the live data on torque so I could see what was happening. I may go back over it just to see what happened.

2thousand5.4

It's no problem, Can you monitor short term and long term fuel trims on torque? They read in lambda. 1 is 14.7 afr, anything below one is richer than 14.7 and anything above 1 is leaner. Just curious to see how lean it was running

jprevat

iTrader: (1)

I can view both and probably run graphs as well. I'll throw the other intake back on today or tomorrow and get some actual numbers. Thank you for the help.

Bell Blue Raider

So I accidentally posted this picture in the wrong thread last night.
I started installing the radio yesterday and finished it today.
I added 2 usb ports and a aux input in the console also.

OhioLariat

Looks good, Blue. I think an Expy console is in my future.

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