Megasquirt tune and log files, What can you make of this? Options

[ericoneal]

Took my car around the block last night after a 7 month engine rebuild process. Seemed to run somewhat ok, but got kinda hot (350) very quickly while just idling and going up the street.

I'd like some opinions on my attached tune and log files at idle. Everything seems ok to my untrained eye, but would like a clue as to why its running hot.

Its either this tune or the timing is off. Maybe we can rule out the tune, or someone can tell me if there is any glaring issues.

Thanks


(IMG:http://www.914world.com/bbs2/uploads_offsite/i190.photobucket.com-14795-1427215829.1.jpg)

[stugray]

When you say "hot" you must mean head temps right?
If that is an oil temp, you are screwed..

And your AFR is stuck at 13.40 that seems highly suspiscous.
And your alternator is not working...

[toon1]

Took my car around the block last night after a 7 month engine rebuild process. Seemed to run somewhat ok, but got kinda hot (350) very quickly while just idling and going up the street.

I'd like some opinions on my attached tune and log files at idle. Everything seems ok to my untrained eye, but would like a clue as to why its running hot.

Its either this tune or the timing is off. Maybe we can rule out the tune, or someone can tell me if there is any glaring issues.

Thanks


(IMG:http://www.914world.com/bbs2/uploads_offsite/i190.photobucket.com-14795-1427215829.1.jpg)

I cannot open your file but:

are you triggering with a 36-1 wheel?

What is your advance curve? (can't open your file)

What is your AFR?

What are you seeing for MAP at idle? this is also cam dependent.

Also, it may be just that the motor is new, but even with that short drive it should'nt get hot

[neilca]

You need to change your AFR table. You should be around 12 for AFR not 15. The car is way too lean and that is why it is heating up.

[flash914]

The second download IAT I think is suspect to be Intake air temp. but if it is are you preheating your air or missed wired. Gordon. P.S. building one myself at the present time. (IMG:style_emoticons/default/popcorn[1].gif)

[toon1]

The AFR table doesn't matter UNLESS he is using autotune.

even at that, IF the AFR was at 15.1, a drive down the street would not yield 350* head temps. BTW, 12:1 is too rich for normal driving

If he was driving like he stole it,(which is highly unlikely on a new engine) yes you'd see high head temps.

Not enough to the story to make decisions yet.

IAT temps has a slight change in fueling. I normally see mine pegged when the engine is up and running. The air intake is so far down in the engine compartment it's hard to get cool air to it without a scoop

[ericoneal]

Thanks everyone,

Yes I am speaking of CHT, NOT oil temps which appear to be fine.

I have to say, embarassingly, that I drove it around the block with the parking brake on (IMG:style_emoticons/default/poke.gif) (hey this new engine is a bit sluggish) maybe that contributed also?

Neilca, I was under the impression that a lower AFR is leaner, and higher is richer. Are you sure about that?

Stugray, why do you think my alternator is dead? (IMG:style_emoticons/default/biggrin.gif)

No autotune, I tried it and it tunes my car at idle to the point of killing it.

Will retime, and do another drive with no brake.

[jd74914]

Neilca, I was under the impression that a lower AFR is leaner, and higher is richer. Are you sure about that?

Higher AFR is leaner (14.7 is stoichiometric or perfect fuel/air mix). Generally you can run near stoich (say 14:1) at light cruise and dip into the 13s when loaded.

[crash914]

if autotune is killing your idle, look at your regfuel value...might be too small...

[McMark]

A few things before you get too far along in tuning.

Make sure all your calibration values are set correctly.
--- The CHT temps are not really temps at all, but a resistance value. It's up to you to correctly set the relationship of what resistance equates to what temp. You can set it up incorrectly and make it look like the engine never gets hot or make it look like the temp gets too high.

Make sure the timing you see on the computer is what's showing on the engine.
--- You need an adjustable timing light and one that's compatible with wasted spark if you're not running a distributor. I usually then set the whole timing table to 10 degrees. That way nothing will change the timing while you're trying to set it. Then use the timing light to confirm that you're seeing 10 degrees on the engine/fan. If that's off, then you need to adjust something.

Turn off warmup enrichment and throttle enrichment while tuning.
--- These settings add extra fuel. If you're trying to tune the engine while warmup enrichment is on, then you're getting false values. Turn these settings off, then let the engine warm up for quite awhile (20m) before starting to play with tuning. Also, with throttle enrichment turned off, you have to accelerate very very very slowly. Stomping on the throttle will lean the engine out (as it should) and give you a false reading.

Finally, take your car to a dyno shop for tuning.
--- I tuned my car a little bit at a time over a couple years and it ran pretty well. I took it to a dyno shop and in 2.5h they had it a million times better than I did. The dyno shop I use has a machine that they can setup to hold the car at specific values. So the can very simply hold the engine at a specific RPM and MAP value, set the bin to the correct mixture, then move to the next bin. This is NOT just a 'power pull'. He didn't actually do a WOT pull until just at the end. The dyno shop also illuminated a few minor issues that needed attention. Things I probably would never have picked up on. So even if you have to drive a few hours each way to find a dyno shop familiar and capable of tuning MegaSquirt, it's completely worth it. It will save you massive amounts of headaches.