No fuel trims in evoscan?

[Twofastoocatch]

Hello everyone,
I have gotten stuck again on this PnP ecu; it has completely stopped logging my fuel trims. When first started playing with it, at the beginning of the summer, I did have the rears to look at, but for about the past 3 weeks, they are all just 0. There's no way they're actually 0. It's about 1300feet elevation here, I don't see 0 fuel trims being remotely logical.

I do have a battery disconnect on the car I usually leave disconnected overnight BUT, for the past 2 weeks I've been driving the car every day (waiting on parts for the DD... Doing the head gasket on a 93 mirage) and have left it on the whole time.

I've searched through the evolutionm forums, and the closest thing I can find is a non responsive O2 sensor, but according to my logs, I do have variance from 0.2v to 0.7v.

I've tried un installing and re installing evoscan, but that didn't make a difference.

I'm also having an issue with a low load misfire (@ 9in/Hg vacuum, and from 2-5psi boost) that's definitely in the tune somewhere that I can't get rid of as well. I know it's in the tune, because when I put the factory computer back in(non flash ecu), it runs absolutely perfect. I have no idea if these issues are related, but I figure they're worth mentioning anyways. Does anyone have any idea why every other aspect of evoscan/ecuflash work, but logging the fuel trims? Any help would be greatly appreciated. Thank you.

[NOMIEZVR4]

bump...my fuel trims are stuck at 0. All of them. everything else seems to be working fine...I disconnected the battery, restarted the laptop, reflashed the car, still stuck on zero. Lo, mid and Hi's.

I did replace the rear o2 sensor, originally I was sent the wrong sensor, didn't work so I replaced it with the right one now. Denso unit. Still no difference.

[Greg E]

The battery disconnect is why the trims reset. Once the ECU loses power, all memory is erased.

[NOMIEZVR4]

I started driving the car and the trims started working...:)

[Twofastoocatch]

I was driving with the flash ecu for almost 3 weeks every day, (had to do the head gasket on my usual DD, and waited on parts for 2 weeks) not disconnecting the battery, and my trims never did come back. I gave up, put my stock ecu back in, next thing you know, my 700rpm idle came back, and the car ran 300% smoother. No low load misfiring, no issues what so ever. I'll give it another try next year, Hopefully the trims sort themselves out. I'm not sure what to do otherwise. If I can't tune the ECM, I might just sell it and the tactrix cable, and go arc2.

[Greg E]

So let me get this straight because the flash ECU needs some fine tuning to be perfect, it's not worth having and the ARC is the best alternative ?

[Twofastoocatch]

No, because after a whole summer of messing with it, almost $400 in gas to try and get fuel trims, to even BEGIN to start tuning it, I'm almost completely fed up with it.

I understood when I bought this set up it wasn't bolt on. And I do want to stick with it, because it's a far cleaner setup under the hood, but nobody else has had this issue stick, and nobody can help me with it. The walk through says the fuel trims must be done before any further tuning can be done. I can't see fuel trims, so how am I supposed to tune everything else? To top it off, my idle is way off, and won't take, no matter how I do it, with evoscan, or the service manual way. It just goes back to 1100+ rpm when sas mode is disengaged.

Plus I have a low load misfire issue that I can't tune out either with the flash ecu. When I could see the fuel trims, it did start to get better for the misfire, but now I can't see trims and I'm stuck again.

I put my stock ecu back in, the car idles perfect, runs fantastic, and the wideband readings make way more sense to me. What would you do? Can you help me?

[Greg E]

So you have fuel trims with the stock ECU but not the flash?

There is something we are missing here. I don't see how that's possible unless there is an issue with the ECU or the adaptor harness.

[Twofastoocatch]

I don't have access to the fuel trims on my stock ECM. Or rather, I've never looked for them. I hadn't needed to tune the car before when I was using it, as it was still stock.

Since then, I've done a mbc, downpipe, cat delete, and 4" from the car back and conical air filter. I just finished a blow through conversion, but I've never even tried to start it on blow through. (The rest of the clamps just showed up today)

I'm running the PnP flash ecu, so I'm assuming there's nothing wrong with the harness.

At the beginning of the summer I did have fuel trims on the flash ecu, only on the rear, but I did have them. Then I lost the high, later the mid, and finally the low. So now whenever I try and log fuel trims, they all read 0, from the beginning to the end of the log.

[Greg E]

Do you have 2 cycling primary narrowbands?

[Twofastoocatch]

My car is a jdm. I only have one narrowband. But it does cycle from .2 to .7v. I do have an extra new O2 sensor I could throw in, if that would make a difference?

[Greg E]

Ah so the issue is quite simple.

Disable bit 2 of periphery 0 and flash. Turn the key and drive like stock.

The reason for the stumbling is because the code is looking for 2 narrowband inputs and its only seeing 1.

[Twofastoocatch]

I've tried both ways on that periphery, and it didn't seem to make a difference. When I get home again I'll give it another shot, and see if anything changes. I'll throw my new O2 sensor in too, and report back tomorrow.

[Greg E]

If that doesn't work then we need to make sure the o2 is going into the correct pin.

What year is your car?

[Twofastoocatch]

She's a 91. The weird thing is in evoscan, and my logs, I can see that it's cycling. Once i get home i can post up a log. I was under the impression the ECM uses the signal from the cycling O2's to determine the fuel trims?

[Greg E]

Correct.

Post a screen shot of your periphery 0 setup for me please.

[Twofastoocatch]

Hey, sorry for the delay. Life's been kind of hectic here, and I've just gotten time today to get back at the car. I found my new o2 sensor, and also the potential problem with (assuming it's done) why the last one only lasted 2000kms... The obx down pipe I purchased put the o2 at the 4 o'clock position. So I put a new bung on my test pipe @ the 1 o'clock position (about 10 degrees separate from my wideband) and we'll see where things go from here. I really, really, really hope the O2 isn't sending the right signal to the ECM. I'd sure rest a lot easier knowing I put the car away running before I start the left hand drive swap...

I'm just headed to my garage now, if I get lucky I might be able to get it back together for a quick once around the block. I'll have to pull off my blow through setup too, I haven't ever run it in blow through, and I don't think adding that into the mix at this point would be remotely a good idea. I'll post up my peripheries as soon as I get the car running, fingers crossed, with fuel trims.

[Twofastoocatch]

OK, so I got it all back together, and the car does run a little better. After about 5 minutes of driving, the low load misfire slowly went away, and it kind of smoothed out. So I ended up doing a half hour run, and at the end I still did not have any ltft's. The short terms were going, but nothing from any of the long terms. Again. And the idle STILL won't take. It will drop to 650 while the logger is running, but as soon as you stop logging, the rpms go back to 1000 for the remainder. I'm trying to upload the logs, but even zipped, they're to big for the forum, so I'm not sure what to do about that. Attached is the picture of my peripheries, as requested. Any help? It seems I'm almost back at square 1. Again.

[Greg E]

Which o2 sensor is cycling? Front or rear?

[Greg E]

The comment about the idle with the logger got me thinking. Is your ECU stuck in SAS mode? That would explain both the idle and the fuel trims.

SAS mode is where the ECU disregards all fuel corrections so you can properly set the BISS. There are 2 ways the ECU can be put into SAS mode:

Custom Request in EVOScan
Ground Terminal by the battery is touching Earth.

You have a Jesters 1G PnP ECU right?

[Twofastoocatch]

Its the rear O2 that's cycling. I do have a 2 minute log I can post up if that helps? The 20 minute ones are to big to post up, unless there's somewhere better to post them to?

If it is the ECU stuck in SAS mode, how can I test to verify? Is there a fix for that? That makes sense to me, that it's not coming completely out of SAS mode, that it would ignore the fuel trims... But, isn't the ECM just a bunch of tables? If the ECM is ignoring the fuel correction tables, they're still there, are they not? Shouldn't evoscan still be able to look up and pull the values from the tables, even though the ECM is ignoring them?

I'll head back to the garage tonight, and make sure the connector is away from a frame ground, but I always put the plastic cap back on.

Yes, this is a 1G PnP from Jester.