MSefi.com read only forum (Jan.15,2018)

Here's the setup:
'67 Chevy pickup, inline 250 6cyl with TBI from 4.3. 45lb/hr injectors, narrowband O2 and standard big cap HEI. Doing a fuel only setup for now. Initial timing is ~12 degrees.

Truck starts after a second or two of cranking, then idles up and dies. I've worked with the ASE but can't seem to get any results either way. I'm attaching my .msq and catalogs for the last attempt. I'm still trying to get my head around all the tuning parameters, so I'm suspecting that I'm overlooking something dumb. I would appreciate some more eyes on my config to help me get moving along. The first minute or so of the data logs are me reconnecting the tach and spark plug wire that I had removed which caused the MS to reset. Anyway, any help is certainly appreciated.

If it starts and then runs a little and dies, then you need to adjust the warm up enrichment.
I got everything running on mine then the mega controller quit running my coil so I lost my spark. Hummmmm.....
Robin

Also, next time it fails to start, pull a spark plug and see if it's wet with fuel or dry - this will give you an idea of which way to go when you adjust the fuel.

Check your timing as it tries to start. See if it's really what you would expect ~12 BTDC. Check your dizzy advance offset.
Check plugs see if they are wet (too rich).
The datalog was understandably short.
Move the PWM for the injectors to 35%, that seems to work fine for my TBI.
Set it up for 3, simultaneous.
Your AE threshold is very high, try 50 from 200 and see what happens after the above has been verified. I see no TPS movement.

Getting it started is the hard part. After that it's easy.

Let us know how it goes and what you find.
Holl

You can have a look at mine in Success stories.
"16 MPG around town, 502 powered '59 Cadillac"

Holl

Thanks for the feedback guys. As soon as I get my latest project out of the shop bay, I'll spend some more time on getting the truck running, and hopefully get some better data logs.

Shawn

Gentlemen... I am back with new results...

After frying a few components several months ago on the controller, I replaced them, and went on with my business... but it seems that the firmware was corrupt which was causing my startup and die issue. I recently reloaded the latest code, setup my base settings and now have the truck idling. The problem is, it's idling at about 1700 rpm, and won't settle down. I've set the idle screw down as far as it will go, but it seems that the IAC isn't closing enough, even at normal engine temp ~180f.

I just have the base settings for the IAC - Start value at 160, cranking value at 100. After reading through the manual, it almost sounds like the values are reversed, as the manual states that the starting value (all the way open) should be 0, and it steps through 10 steps based on coolant temp to the fully closed position (GM IAC 160 steps).

Can someone point out where in TunerstudioMS 1.004 that I can set the position of the IAC while it's running so that I can tune the idle? It seems like I'm missing something easy.

Thanks guys... it's getting closer!

Shawn

After the engine is warmed up, pull the IAC connector off. Shut down the engine and pull the TBI unit, look at the position of the IAC pintle. Set IAC to "always on" and make your last setting about 250-300. that should ensure that the air valve is closed.

Oh, you did check this on the STIM didn't you? The IAC could be wired incorrectly.

Keep us posted
Holl

Finally complete success! I finally got the IAC valve 'zereoed' in, so that it is completely closed at 180 degrees F, and now the truck idles nicely at about 850 rpm. I've since installed an MTX L wideband sensor and controller which has helped me get a pretty decent map using Tuner Studio and the auto tune function.
I'm still having some poor idle issues during the WUE cycle, but I'll keep fiddling with it as I move forward.

I do have one nagging issue with the wideband... it seems to be jumping all over the place from time-to-time. I've never used one of these, so I'm not sure how stable they are supposed to be, and perhaps it's indicating an issue with an exhaust leak somewhere upstream.

Overall though, the truck runs better than it ever did with a carburetor, and I've put a little over a hundred miles on it just running around town.

I'm doing another tuning session tomorrow morning when traffic is low, and then I'll attach some logs and you can see how jumpy the wideband seems to be.

Thanks all for the help and encouragement, it's been a fun ride!

Under "Fuel" / "general" / Lambda lag factor, I set mine to 50. That kept it down to a reasonable jumpyness.
I've gone down to 20, but that slowed it down more than I needed.

Good Luck.
Holl

Holl,
Thanks for that. I assume since you 'slowed' yours down, that it's normal for the controller's gauge to be a bit erratic while running?

The gauge is digital. Lagging factors smooth it out, like shocks do for your suspension.
This picture shows it fairly well.

Holl