Fuel Trims p0171 New intake

Dayton86

Dayton86

Greenie N00B Member
I have recently installed a new JBR powerpath intake. Since the day I put it on I have been fighting with high positive fuel trims.

I could remedy the situation by running the Cobb OTS intake map on both my hypertech and accessport but that isn't the correct map to use. When I run a Stratified map (OTS the free one and no longer supported but is correct) for the JBR intake I have Long term positive fuel trims that stay in the ranges of 9-12 at idle, 10-13 under load, but under no load deceleration where the car is still commanding fuel it goes to 17-18 (with short terms pushing 15+) and at that point I get a p0171 code. AFR and knock is fine, all the way up to full commanded boost. Even both the stage 0 and stock maps have issues with fuel trims.

I have performed a leak down test and found no leaks, I have also put the factory air box on (with the JBR hoses) and the trims settle back to what the car was before, on both the Stratified and stock tunes. I am beginning to think the MAF housing isn't stock sized though it is supposed to be. I am not really suspecting a leak, but would like opinions.

I have attached a sample log pulled from Torque pro that shows just some of this.

Anyone have any ideas?

Thanks.
 

Attachments

In my experience, fuel trims with Stratified Flash tunes have always been high. By high I mean it goes up to 7-8 on my car. Obviously, that is not high enough to cause a problem like you have though.

I know this is not a solution for your issue, but have you considered just getting a flash tune with data log correction from Stratified or Dizzy Tuning or Freektune? They are not that expensive.
 
Of course we want our trims to be as close to zero as possible, the end result is the same if it`s meeting afr. Trims are just a reaction to what the ecu expects, and we calibrate it by changing what it expects. The amount of fuel delivered won`t actually change. With a high positive trim it means the engine is getting more air than it`s expecting (or measuring, in the case of a leak), so we tell it "hey, instead of X g/s of air at this voltage it`s now Y g/s" so its default fuel delivery is for Y amount of air vs X amount with an adjustment to meet afr.

That was a wordy way of saying "yeah, it`s off. But it`s not a big deal and it`s fixable". LOL. You might even contact the guys at Stratified and express your concerns just to see what they say. I seem to recall paying them like $25 to review a log and send me a single revision.
 
I wouldn't run an OTS for anything more than grabbing a mafcal and getting a real tune started. That said, @JBR supposedly has a no CEL guarantee, so you might bug them about it if you bought it new.
 
Just an update on the situation....

After many attempts to get this to work and many combinations of the stock and JBR intake I have learned this. This was all attempted on both a Cobb OTS stage 1 map, and Stratified OTS stage 1 map.

1. I can run the full intake and just have the MAF in the factory air box on the end, and the trims are right.

2. I can run the full factory intake tract and just shove the MAF housing and filter on the end and the trims go crazy again on any map, as does the full aftermarket intake.

3. I measured the MAF housing with a digital caliper and come back with measurements of 2.55 with straightener in, and 2.66 without. I have read the factory is 2.63 so that doesn't seem too out of spec.

4. The weirdest thing is at least when it concerns idle fuel trims, I can run the intake with no filter in the garage and it is perfect, trim-wise, soon as the filter is put on it they shoot over +12 and stabilize there.

I did get a Stratified Flash tune for this intake and it hasn't help with the situation. Not to blame them, I feel the issue is with the MAF housing.

That being said I am stuck with two choices, 1. get a datalog/MAF revision on an intake I am becoming unhappy with, or 2. do as I should have from the start and buy a full corksport intake and have the Flash tune remade.

Unfortunately, I don't think returning it is possible as I took apart the MAF housing to reseal it and had no change in how it all acts.

Sorry for the long post but thanks again for any opinions or advice.
 
Ok so this is kinda complex and long to explain so here it goes...

Get a maf cal or deal with the high trims. Whew sorry that took a long time to type! /sarcasm

If you are 100% there are no leaks around the maf oring and all the connections are not leaking then playing the intake swap game may not help you out.

Some times intakes are touche so once you have the intake for a bit you will want a tune and the etuner will fix it. Car parts are like a drug. You take one pill then you take the next dose early. Soon your sucking dick for fuel pump internals with another dude watching..... trust me i know.....
 
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