24% of STFT is not totally abnormal.

But a sustained LTFT at that level is just stupid.

I have monitored my LNF for several years. +or -5% is about all you should see on a mostly stock or GMS1

 

mine varies +/- between 0 and 3. When I was on stock tune with CAI my trims were in the 11s.

 

After I had my discussion with the mechanic I waited an hour and he came back out with 20 copied pages from the service manual. He said it seems like I like to do my research so he printed it for me. He showed me that it says 0-20 is normal but anything over should throw a cel if other conditions are also met. So he agreed that something is wrong. He also gave me diagrams of the whole turbo system. I thought that was real nice of him.

Then after he let the turbo cool he pulled it and determined it was bad. I'm now in a rental and the new one will be here by monday.

Btw the chevy captiva is a nice little suv but boy is it gutless. Same 2.4l 4 banger but not tuned the same. I was having trouble passing people on the mountain passes lol.

 

Got the trick from my dad when we were fixing up the Judge.

Tried all over with no luck back before I even found the charge pipe leak.

 

Like I said, he didnt say "no" right away so he seemed like a good guy lol. 0-20 is a Range, not what I consider normal though.

If I went to a doctors office and got blood work done to check my Potassium levels. The range is from 3.5 to 5.2 mEq/L. If I read a 4.4, the doctor would say thats normal and nothing to worry about. If I read a 5.2, the doctor would show concern and tell me thats a HIGH normal and tell me to take certain precautions. If I read a 5.3, he'd prescribe me something probably along with monitoring my levels for a week.


20 is not normal... Lets Identify what normal or average means. If it resembles the majority of the other LNF fuel trims than it meets the requirement of normal. Im between 0 and 7 at the most in any given circumstance. You've seen what others have written as well. Everyone expressed concern for the crazy fuel trims, evidence that its not normal.

Sorry about the rant, lol. Drives me nuts when someone follows everything by the book without using their brain like the tech did to you for a small instant.

Glad he pulled the turbo for you! I thought for sure he might not since there was no CEL

 

Ask the tech if he thinks an engine is designed to last when running 20% too lean.

The answer is NO.

 

Oh I still agree that something is up. I'm going to call the, up today and have them do a valve cleaning while it is in the shop for the next week since I don't have time to do it for sure.

I will also ask and confirm if there is anything new on why it is so high. When he showed me the document he did say that something wasn't right so he'd look into it.

 

Called the dealer and according to them they never take the I take manifold off for valve cleaning and just use chemical/air mix through the throttle body. The service guy I spoke with said he's never heard of manually cleaning the valves...

 

Tell them to use a borescope before and after their cleaning. Bet it doesnt do much

 

Ill just do it myself. I just need the phenolic spacer right? No new gasket?

Ill also take my valve cover off to tap off the pcv vent hose so I can install my pcv system. Ill also take the time to check to make sure my rockers are all intact.

 

I would pass on the phenolic spacer. Just install new OEM gaskets. Put some grease on the tap to keep most of the chips from getting into the valve cover. Taking the cover off is a great idea too, like you said.

 

UPDATE

Got the car back from the dealer today. New turbo. They broke off like 2 of the exhaust bolts and had to order new ones so I just now got the car back. They changed the oil and the coolant but did nothing as far as taking the valve cover off.

Drove it the hour and a half home. It drove much smoother and sounded much better. I was boosting to 19psi on the regular but still never 20psi. Trims were still right at averaging around 16-17psi under throttle.

Installed the K&N intake and fired her up. The car sounded just fine. Fuel trims went up to about 20%. Took it on a test drive and the fuel trims went up to about 25 for an average and hit a shocking (and frightening) 53 PERCENT at when I put it in neutral for a downhill. I quickly put it in a low gear to get it to drop.

Drove the car back, took the intake off, put the OEM one back on and the trims slowly worked their way back into the 30s where they now sit (I just idled the car after reinstalling the OEM).

Im thinking that my adapter/torque have to be bullshit. I can't believe I wouldn''t notice any engine problems with that much of a fuel trim increase.

I remember adding the equation/code thing in the settings area of torque when I first got it after reading what to put in on the official torque thread. I am thinking of clearing out all of that and starting anew. Does anyone have any suggestions on how I am supposed to set Torque up or is it just plug and play?

I am also going to see if Z Sport in Everett can do a log for my car to see exactly what is up.

 

Did the dealer say what the fuel trims were while your car was there?

FYI, when you're traveling at speed and let off the gas while in gear, the car goes into DFCO (deceleration fuel cutoff), there is no fuel being burned.

 

They didn't but as soon as I picked up the car, the trims were the same as when I dropped it off.

 

Are you looking at long term or short term fuel trims?

 

that means they didnt reset the ECU, which they didnt really have too but it also means they didnt disconnect the battery before working on the car :/

I too believe their something up with the torque app.. you should have been throwing codes like crazy. If you put any sort of equation in, check it. Its probably whats making your fuel trims look so rediculous. Its probably multiplied by 10 or something. lol.

 

Long terms

And no equations for extra pids. Not even predefined.

 

well does the Torque app read AFR? What does that look like? 14.7 hopefuly give or take +/- 0.5 at cruise and idle.

Your probably okay with the intake, but like you said it might be a good idea to follow up with that tuning shop to see if they can just log the car and see where your fuel trims are at for real.



Oh and does your start up with the intake on sound the same as it did in that last video you posted? If it sounds better, then it was the turbo the whole time that was giving you the wierd stutter noises.

 

I only use Torque now and the LTFT is close to +2 with K&N.

Torque was spot on with my DashHawk that's why I stayed with it.

 

I'm thinking its my 15 dollar bluetooth adapter that's screwing things up.
Car starts up and sounds BEAUTIFUL in comparison to how it used to sound. The new turbo feels so much smoother and quieter. No harsh noises.

I will check afr but I remeber it being ok.

 

Hmm, Yeah need to find another way to monitor.

Can you take a screen shot and show us your LTFT STFT?

 

Afr without intake averaged 14.7 on my rpd. Ill see what it says with torque.

Ill take a screenshot of torque. Would you like it as idle, load, or coasting? Or all three?

 

AFR should always be 14.7 even if there is a problem, besides above 80% throttle. That's what the fuel trims try to achieve.

LTFT should be nearly the same for all three so it doesn't matter. When coasting in DFCO, LTFT holds until you're out of DFCO. Just another FYI.

 

IMPORTANT UPDATE

It seems like we are finally getting somewhere.

I installed the intake again and decided to disregard Torque and just drive the car tomorrow. I took it for a quick five minute test drive from all different throttles and gears and it ran just fine. On my way back I lost a lot of power and would only boost to around 2.5 psi. I took it back into the garage, shut it off and looked for leaks. Could not find any.

Had my friend monitor the torque app and went for another drive. The car was back to boosting just fine to 19psi. Magically the LTFTs hovered around -3 to 7 the entire drive. Never have they been this close to zero! My first thought was that the wiring for the MAP sensors is buggy as why would the trims suddenly change?


Then we stop for some deer in the road and then start in first slowly, I loose most power again and see that I am only boosting to 1.5psi, and a check engine light pops up. FINALLY.

It was a P0101,

"MAF Sensor Performance Conditions. No MAF or TP sensor codes set, system voltage over 11v, engine running, then the PCM did not detect any MAF input for 2 seconds. Inspect the MAF sensor wiring and connectors for damage."

I am thinking that some crappy connections in my butt connector 3bar map sensor wiring are causing the problem. That or my MAF is bad.

Thoughts?

 

There are a number of things that can cause that code. Some related to the MAF sensor, some not.

Since you're using butt connectors for the 3 bar sensors, that would be a good place to start. The best possible way to wire the sensors is to use OEM stuff.

Two of these
Home » Shop » Connectors / Harnesses » Bosch » 4-way sealed Plug Bosch BSK Connector Kit for Bosch MAP Sensor

One of these
Home » Shop » Tools » Crimp & Strip » Standard » Wide-Range Crimper - Excellent for crimping Weather-Pack ( Weatherpack ), Metri-Pack ( Metripack ), GT Style and most Terminal Types *RECOMMENDED*

It will look OEM (because it is). A potential problem I can see if you do that is the wire length. If the wires have already been cut for the butt connectors there may not be enough left.

That's what I used when I installed my new engine wiring harness. I had some wiring issues of my own last year, so I'm particularly careful with wiring and I know how annoying it can be.

Another thing to watch for (if Torque can monitor it) is the MAF frequency. It should smoothly follow engine load. If you see a sudden spike to 65,xxx or it constantly reads that value, there is a break in the MAF signal wire. IAT1 comes from the MAF as well. IAT2 from the lower TMAP (temperature+manifold absolute pressure). Etc, etc. It could be a number of things like I said.