Just to give a little background on the motor:

- head and block are stock
- JM Fab tubular exhaust manifold
- JM Fab tubular intake manifold with all EVAP related sensors/solenoids disabled along with the
FP solenoid
- CBRD FMIC and AMS IC piping
- Forge recirc valve with custom return piping to suction pipe to allow placement of the
valve closest to TB
- Perrin filter and suction pipe
- Forge MBC
- Forge internal wastegate
- Stock VIII turbo
- O2 housing and TBE with straight pipe
- MIL.SPEC 65mm TB

ECU (96530006) wise the following is done:

- my tune
- Mr. Fred's MAT patch and LC-1 hardwired patch (O2 sim in Tephra's mods)
- Tephra v5.10 mods

The issue I'm having is that the LTFT low, mid and high are not reading (they are pinned at .1008). The 02 feedback is actually in line ranging from +1 to +3. The LC-1 a/f at idle is a tad rich, ranging front 14.3 - 14.5 (nothing major there and I suspect the MAF may need a slight tweak).

For the life of me I can't figure out what's up with the trims and why they will not read. I've tried disabling the rear O2 sim as previously suggested but, to no avail. I haven't eliminated the MAT patch yet as I don't see anything in that patch that is related to trims, however, hopefully Mr. Fred reads this and can comment on that. I've also checked the primary O2 sensor for an funkiness as well as the DP and everything seems fine. I've also checked for any vacuum/boost leaks and found nothing.

From what I understand about trim calculations the ECU uses the primary O2 sensor and fuel maps in order to obtain a target afr of 14.7 at idle. Is there anything else involved in trims (directly or indirectly)?

Thoughts??

 

So, an idle log shows STFT from +1 to +3 and LTFT Lo stuck at .1008? What does the maf Hz, front O2, and wideband look like at this same time?

The fuel maps aren't used...they are open loop fuel maps. Maybe mrfred or jcsbanks or someone who has been through the disassembly can comment more, but the trims are determined from the O2 feedback (STFT) and the range of airflow Hz. A certain range covers LTFT Lo, then a higher range for LTFT mid, etc, which usually equates to LTFT Lo being for idle and LTFT mid being for cruise. LTFT Hi usually isn't encountered.

Also, you don't have the car running in full time open loop, do you? Fuel trims will only be active during closed loop. There may be quite a few other conditions that I don't know the specifics to, such as coolant temp, etc.

Have you tried logging the fuel trims with other logging programs, to be sure Evoscan (if that's what you're using) is configuring properly? Are the requests and formulas for STFT, LTFT Lo, and LTFT Mid configured correctly?

 

My guess is something is messed up with your LC-1 O2 sim patch.

When you disabled it, did you disconnect the battery, ground the pos cable, then leave it hang then try starting the car to completely clear any stored memory?

Once the memory is completly cleared reconnect the battery and start the car and let it idle for at least 20 mins. This will ensure 4 to 5 cycles to pass.

Another thing to consider is your injector scaling. If it is too far off you won't get an LTFT reading. I know this because of my constant tinkering with the latencies to get my car to idle with Revolver cams and an HKS suction intake.

Once you get the injectors scaled as close as possible, then it is on to the MAF to fine tune the idle.

 

First off, thanks for the help on this and other one. Coincidentally I'm having similar problems with both cars but, different symptoms. The other car I need to put OEM injectors in and check the MAF scaling as I think its way off.

Anyway, during idle the MAF hz are steady at 30, the wideband is between 14.3 to 14.5 and the front O2 sensor is at (is MUT 13, right?) is oddly reading any where between .33 to .64?? Strange though since the LC1 is close to spot on the the O2 feedback is in line. IPW are at 1.536 with a rock solid idle of low to mid 900s.

Now that I read you mention about full time Open Loop I think that may be the issue. I needed a few of the periphery hexes and was provided the .xml stuff from another member but, I noticed he had stuff enable and disabled. I went through and doubled checked and found FAA bit 04 to be set to 0 (disabling closed loop and forcing full time open loop). This is definitely something I've got to look into.

For FAA what bits should be enabled? All I'm showing is bit 01 as being enabled.

I did confirm with my personal car that EVOScan was logging trims correctly as I was able to log everything without any issues.

 

I did not disconnect the battery but, I've performed the LC1 sim on numerous cars in the past with no issues logging trims. Currently the stock injectors are installed with the OEM latencies and scaling.

 

Nevermind that I was looking in the wrong Periphery. Full time open loop is NOT enabled in the ROM.

 

My low trim takes several key cycles to start to make adjustents. You should see mid trim change after about 10 mins at idle.

 

From the data that you presented from idle and if STFT is only +1 to +3, I wouldn't imagine the LTFT Lo would move much, if at all. Your LTFT Lo may end up from +1 to +3. So, you may not have a problem. Your long term trims will end up being whatever non-zero value your STFT is averaging.

What about cruise? How does STFT look for a steady cruise? If it's bouncing around 0, then your LTFT mid won't change either.

 

Yeah, during cruise STFTs are bouncing between 0 and -2. I presumed that trims would show even if it was at or near 0. I guess not huh .... wow this saves me some grief.

At cruise LC1 afrs are in the high 13s to low 14s with STFT between 0 and -2.

 

Why aren't the cruise and idle AFR stoich? It sounds like the car is always in open loop if it cruises at high 13- low 14 and idles at 14.3.
Unless of course you have a narrowband output from your wideband and you actually set it up to be 13-14 or whatever instead of 14.7?

 

Something isn't making sense here. If the curise AFRs are in the 13s and low 14s, then the STFT should be pretty negative. Cruise and idle should be stoich.

I think there is a way to log whether the car is in open loop or closed loop. That would be some good info to have.

Although I'm not sure if STFT bounces around or not in open loop.

 

Now that I think about it, the cruise logs may have been skewed a bit. Since I deleted all the EVAP stuff but, I left the vacuum line leading to the rear canister supplied with vacuum from the manifold. Because of this, the car was idling WAY lean (upper teens). Once I realized the mistake, I removed the line, capped both ends and the idle came into check but, I didn't get a chance to do a cruise log.

I'll do another cruise log tonight to see where the cruise afrs are at now.

Other than using periphery FAA bit 04 and raising the minimum coolant temp figures (which isn't showing up in ECUFlash v4.1?), how else can the car be forced into open loop? I'm nearly positive its not running open loop full time as I did not set the car up for that.

Possibly a bad front O2 sensor, or at least signs of its impending failure?

 

evodad- I just read an injector thread that mentioned this specific issue. There is an RPM settings somewhere that is set higher than idle and messing things up. Ill try and find it again for you to check.

*Having trouble finding it. And it's time to leave work. LOL.. Will search more tonight.

 

Interesting, let me know what you come up with. I'll try searching as well.

 

Awww dang it. I can't find it cause I can't remember the search criteria I used. I've only found this about 50 times:

from:

https://www.evolutionm.net/forums/ec...rim-issue.html


Maybe worth a try I dunno. Sorry man if I new the ECU better I would have remembered cause I would have known where they were talking about. I only kinda halfway remembered to remember (lol) cause my buddy has the same issue. If you find something out would you please post it?