Question about a Sloppy tune

[kunta0908]

Been having some issues building a base tune for a build I have going into an LS swapped Z32.

Running a 3bar OS with 80lb Dekas.

Currently using a Corvette regulator in the engine bay, but have a BRAFPR to install shortly.

Anyways, couldn't get this thing to idle, just crank over and die, sometimes would stay alive with some throttle play. Ended up pulling some horribly fouled plugs and replacing. Was able to get an idle out of it, but exhaust told me it was rich, while the wideband was jumping around giving me sketchy data. This was all with the injector data for the 80's I found from some internet searching.

I ended up finding the John Potucek tune on the sloppy site and copied pertinent data over to my tune. At first, same outcome. Increasing my base airflow numbers gave me a stable idle. EQ error histogram told me I was lean though, in the +16 to +20 range in the cells it would idle at. Thats as far as I got tonight.

My question is the injector data. While it states that this Potucek tune is for 3 bar and 80lbers. It also states that its been scaled, which shows in the flow rate table. As opposed to the 94lb - 104lb numbers through the kpa scale I was seeing in the injector data spreadsheet, Potucek's numbers show 36lb - 40lb. Am i correct in assuming that the flow rate has been scaled down? If so, why does stoich still state 14.68? All the other numbers in the injector tables are relatively close to what the Deka spreadsheet states, though nothing exactly the same.

Anyone able to shed some light on this? Should I go back to the spreadsheet numbers and see if I can get idling with increased base airflow numbers?

Attached is successful idle log and current tune.

300zx 3bar Potucek.hpt
19-05-10 20-54-14.hpl

[5FDP]

Not sure why they scaled the injectors that way, I'd personally go back to using the real data you had before.

Are you running 43.5 or 58psi of fuel pressure?

Which 3 bar MAP sensor did you buy?

Those timing tables should be returned to stock, it should idle and drive way better with the stock timing curves. Just slope the timing way down after .80 cylinder airmass where you'll be in boost. Like if you want to run 10-12 degrees, slope it down to there. Have the low octane table be like 3-4 degrees less because both timing tables should not be the same, the low octane table needs to have less timing in case it knocks and will allow it to run less to help the engine.

Your wideband in that log at least doesn't seem to be working. Stay at 1.19 then drops to 1.12 and stays there the whole time. It's not moving at all.

[kunta0908]

bump.

Came out this morning and car would die after startup. Played with base airflow again and got it to idle for a bit before it would die.

Logged IAC step counts and key on engine off it read 310. Starting engine, would go to 199. Couldn't keep it idling long enough for it to show anything different than 199. Noticed only one screw was holding the IAC motor on. Pulled it to check it out, should it have any plunger play? This one didnt budge in or out upon a bit of playing with it. Normal?

[kunta0908]

58psi

On3 Ls3 style 3bar map sensor

Not sure what happened to the wideband in that log. Saw that it stopped reading in that log, but hasnt reoccured since.

I was under the impression that the PCM reverted to low octane tables when put into speed density, though that just may be outdated info I'm going off of.

[5FDP]

Never ran that MAP sensor before, I was just seeing if you linear/offset data was correct.

The factory OS when put into speed density would run off the low octane table. Using an upgraded OS makes it like factory but with add extra's. The high/low timing tables work like stock and hell if you wanted too, you could even run the MAF in a 3 bar OS. It's kinda pointless, but you could.


If you can get to idle on it's own and not die when you get it in gear, keep it that way and stop messing with anything idle airflow related for the time being. Anything more can make it harder to fix later. Once it can run, getting the airflow model corrected is key. The VE table needs to be pretty well dialed in for idle and part throttle before trying to mess with idle timing and idle airflow settings. It makes it way faster if you aren't fighting a lean/rich fuel condition.

Also making 100% sure you have no vacuum leaks as well.