And I'm Back

mustang70

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Nov 15, 2001
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After almost two months I finally got my ECU back from DIY. I put everything back together today and of course it doesn't seem to be working correctly. I swear I had this thing pretty dialed in before I sent the ECU off. So I have a couple quick questions. First is about the flex fuel sensor. I went ahead and added one since I had the time. It's plumbed into the return line and the signal wire is connected to pin M on the aux plug. But I kept getting a sensor code while running the car. So I decided to disable the sensor for now until I feel like troubleshooting it further. But as soon as I do that the idle starts to wander. Why would disabling the sensor cause the idle to wander?

Another question I had is about the warm up enrichment. I know this is dumb, but should the WUE should be lit up green when the engine is fully warmed up? I thought it would be green while the engine is in WUE and then once out of that the WUE light would go out. I was seeing green the entire time the engine was running and the coolant temp was up to 192 degrees I have it set to exit WUE at 160.

As a side note I'm not sure I totally trust my widebands. At times they seem to work fine, then suddenly they'll drift apart. I've noticed at times when sitting in a KOEO situation they don't always go full lean like I've seen other widebands do. I've reached out to Zeitronix to see what they say. To be honest I haven't been overly impressed with them so far.

I was going to attach a couple logs with the flex fuel sensor on and off, but apparently I messed something up and they're an mlq file instead of msq. And the site won't let me upload the mlq.
 

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  • 2020-02-28_17.17.23.msq
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mustang70

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I finally got to drive my car again today. I learned the decel adjustment is really sensitive. I had it at 75% and every time I would lift my foot off the gas it would go full lean. That made shifting really interesting. It looked like I didn't know how to shift.

Does anyone have a good how to for setting the accel enrichment? I'm just not seeming to grasp that one. And I think it's the next one I need to do. When doing a quick stab say from 1/4 to 3/4 throttle the car hesitates for a second. I'm guessing that's the enrichment.
 

a91what

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Even if it goes rich when I lift off the throttle? I'm guessing there's an adjustment somewhere else I'm missing.
If you are going rich when you lift and drop into the decel area you need to look at the fuel map. Do this, if you lift without clutching in does it go rich? If it does the expected and goes lean you are good on decel and you need to look at the accel enrichments not the decel like you have been. If you tip the throttle in from idle with the clutch in (or any rpm) and you go excessively rich then there is an issue with the enrichments being to aggressive.
Map based and tps based.
Map delta enrichment is based on semi constant tps position but increased load, like starting up hill from cruise.
Tps is throttle delta and is based on how quickly you open the throttle.

Ideally you will get these setup so that the r as te delta is no change in afr during tip in or slightly rich from target.
The more aggressive tps enrichments are meant to get you around a full point rich from target, this is typically where the throttle will feel nice and crispy.
 

mustang70

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It's been a few weeks, but I remember before when I would lift off the throttle, say like coasting in traffic on the freeway, it would go rich. Like into the 11's rich. But after a second or so it would come back to commanded A/F.

I'll have to double check when accelerating, but I remember it bouncing between rich and lean at first tip in then settling once a constant throttle position was reached. This includes taking off from a stop.

I'll check the enrichments tomorrow after work. I should have some free time.
 

mustang70

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Did some driving today and tried to keep an eye on things. I didn't think to datalog and I cleared my SD card. But I played around when I was on the freeway a little. When lifting off the throttle while cruising the A/F would go a couple points rich for a second or two then go full lean. If I coasted a bit it would go into Overrun. The Overrun is set at 20kpa and I think I see 21kpa unless I let it really coast. Such as going down hill or coming up on traffic without hitting the brakes.

I noticed when going from coasting back to part throttle there was a slight hesitation. The A/F would go lean then catch up to the commanded A/F. Small changes in throttle position only seem to move through the VE table. It takes moving the throttle from something like part throttle to 3/4 throttle shows the A/F going a couple points richer before returning to commanded A/F. Something I did notice is that no matter how fast or how much I moved the throttle the Accel indicator never came on.
 

Attachments

  • 2020-03-08_11.07.30.mlg
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  • 2020-03-08_20.33.49.msq
    273.8 KB · Views: 39

a91what

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Apr 6, 2011
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Well there we go, your transient fueling is not working as it should.
I dont have a video for this yet... I am working on getting the test mule back on the road. I can however help you directly if you would like, just shoot me a PM or an email at [email protected]