Can't get tune right
10-01-2018, 12:40 PM
#42
A 224/232 on a 115 LSA really should drive damn near stock if tuned properly and everything is mechanically sound. It sounds like a great daily driver combo that should have only minimal driveability quirks and certainly no dying coming to a stop. A competent tuner should also be able to diagnose any mechanical issues that could be causing these issues as well...
10-01-2018, 12:56 PM
#43
This thread made me recall a job that was a literal tune nightmare. In the end it turned out that the hose from the fuel pump to the sending unit had a failed clip ( the plastic double tooth alligator kind ) causing the fuel pressure to intermittently change. Guess how long that one took to figure out because fuel pressure was tested at the rail and working fine, once.... We blamed the three tuners we used over that summer for that one too. Just saying, aint blaming anyone, saying it happens and in my experience its seldom related to the computer or tune up at all. Except washed rings, that definitely happens quick and that one is on the tuner, or crappy injectors
10-03-2018, 03:39 AM
#44
Most problems with the tune are not with the commanded values, they are with a mechanical or electrical oversight and sit in the hands of the builder. Many times there is also badly mismatched parts. This is the standard that happens all the time, and the tuner catches the flack when it doesnt run right.
10-03-2018, 04:17 PM
#45
Re: drilling out the TB... if aftermarket with a smaller IAC port, then yes, you may have to drill a hole (many don't include and don't have equivalent to stock air passage) and requires opening the throttle blade and either clocking the TPS or drilling a hole since the value may be larger than what the PCM will accept as "idle voltage."
But then you have to tune the IAC transfer table. Darth and I have gone over this quite a few times. And it's totally worth doing it.
Also fuel pressure issues are easy to diagnose if repeat-ability from run to run is nonexistent. And these cars make it easy to check fuel pressure at the rail both stock and aftermarket.
And finally, most tuners tune for WOT on the dyno. Not for drivability. It takes a few days of cold starts and driving in traffic and transient conditions to get the car tuned properly. And if SD tuned, huge swings in temp could require some cleanup tuning.
But then you have to tune the IAC transfer table. Darth and I have gone over this quite a few times. And it's totally worth doing it.
Also fuel pressure issues are easy to diagnose if repeat-ability from run to run is nonexistent. And these cars make it easy to check fuel pressure at the rail both stock and aftermarket.
And finally, most tuners tune for WOT on the dyno. Not for drivability. It takes a few days of cold starts and driving in traffic and transient conditions to get the car tuned properly. And if SD tuned, huge swings in temp could require some cleanup tuning.
10-04-2018, 11:27 AM
#47
Cable throttle body adjustments are simple, if you reach the limit of opening up the TB and it showing positive throttle that you can't reset back down to 0% (~.78 V TPS) and the IAC counts are still not in range then you get to drill, period. It's not uncommon with a lot of the medium/larger cams now a days and the only people who think it's a bad thing or the wrong way just don't know any better or read the internet too much. Throwing in a larger aftermarket TB with a smaller IAC passageway that flows less than stock is also a big problem. That being said the OP's combo with the stock TB and relatively small cam should not need to be drilled, just cracking open the TB a bit should give it all the additional airflow it needs even with the a/c on for the IAC to be in range and working properly.