Inconsistent results after restart

[treyjack]

I don't even really know where to start but hopefully you guys can take a look and let me know if my tuner guy and I are missing anything.

Car is a 1994 Cobra. Intercooled Turbo'ed 347, AFR heads, ported Cobra intake, 36# injectors, blah blah blah. WB is an Innovative with the LC-1 controller, and of course the MS2.

So what happens is with the tune (attached) it runs great. Once I stop and restart it wants to run very lean. It can be a cold or hot restart. I've made sure there is no heat soak. I can run the auto-tune and it runs okay but the same thing happens with that. I've had my tuner modify the tune to get it right for that instance but then again when I do a restart it is back to acting up. So he changes that one and it happens again. I'm at a loss. I'd be glad to answer anything I can I'm just not sure what else y'all would need. Thanks again!

[Matt Cramer]

Please attach a data log of the issue as well. This will give me more to go on.

[treyjack]

You got it. I'll take the kiddo to school in it this morning and get that.

[treyjack]

For some reason it didn't save my file. However, after a little poking around I found two log files and have attached them in the original post. They are both running the same tune in question and are ones I sent to my tuner after the dyno session when it started acting up.

[Matt Cramer]

The problem is that it appears the engine was tuned around a point where the ECU grabbed the barometric correction value after the starter had begun turning. And now if you start it correctly, it will run too lean. Try multiplying the fuel table by 1.1 and turning baro correction off or adding a dedicated baro sensor.

This isn't connected with the problem, but is your idle advance timing commanding 53 degrees at 100% load?

[treyjack]

The barometric correction is set to initial MAP reading. So change that to "none"? I'm just getting into this. Can you elaborate on how to multiply the fuel table by 1.1?

As far as idle advance timing if that's what you see then it's probably what he has set.

Thanks for helping out a super noob.

[treyjack]

Alright. I multiplied the fuel table by 1.1, Turned off the barometric setting, turned idle advanced timing on and to "load" and set it to:

Load deg
0.0 20.0
30.0 14.0
48.2 14.0
75.0 14.0
100.0 20.0

Seems to be a little better at idle now. It will just take me driving it and a few start and stops of the car to know for sure.

Attached is the tune now and a log. It started raining so the log is just sitting in the garage with a couple revs. I'll get another one once I can take it out. Let me know what you think.

Thanks again!

[Matt Cramer]

Looks like it's idling rather lean. Probably needs some more VE tuning, but this should give you a more consistent basis to tune from.

[treyjack]

Here is a better log for you. I updated the firmware in the LC-1 controller, did a heater and open air calibration, and installed a new WB sensor then went out and beat on it a bit. From watching my gauge it seems like it's a tad lean under boost. It starts and idles better now for sure.

[treyjack]

So I drove it to work this morning and it ran fine. Go to leave work and it's back to running like crap. I logged my drive home which I have attached. Thoughts?

[Matt Cramer]

Both logs look like they're idling pretty lean.

[treyjack]

What would cause the inconsistent "temperament" between starts though?

[treyjack]

Anyone? I'd love to get this figured out so I can enjoy driving the car this summer.

[yzn]

Did you increase the ve values in idle area?
On basic/load setting>engine-setting you could try to put correct number there, as injectors size are set to 0cc. Maybe try to Autotune after that even at idle just to see the effects.
Also your warmup is always ON as in the warmup curve the last two value are 105% putting 100% should fix that.

[jsmcortina]

Did you follow this advice?

Looks like it's idling rather lean. Probably needs some more VE tuning, but this should give you a more consistent basis to tune from.

James

[treyjack]

Richen'ed up the idle area, and put in the injector and engine size. Forgot to change the warmup to 100% though. Just went out and beat on her a a little. Attached is the tune and log. I noticed it cutting out under boost at high RPM. Any thoughts on that?

[yzn]

I'm not sure if you have looked at the log file, but you are running too lean on boost, your target is 11.8 but the afr reading is between 13.5. The ecu still need tuning, the VE table still lean on all area.
My suggestion is first to multiply the VE table from 70kpa and above by 1.15, and idle area from 400-1400 rpm by 1.05, and from 1400-3600 by 1.1, and if you have the paid tunerstudio the tune analyze live should help you after doing the multiples. And make the Decel Fuel Amount 100% for now until you finish tuning the VE table.

And to be honest i don't think you need a 16x16 ve table you can tune it just fine with 12x12 table or at least make a better load and rpm value, ans with include incorporate afr target. but you can do that later.