General bad tune. Need help

[deviousgst]

i got my car tuned at churches automotive, and i think they tuned it bad.
after like 3k miles on that tune and couple of runs, my pistons rings went out and my pistons melted. i think they tunned me too lean. My question is that, if i turn my boost from 20psi to around 10psi, would i still be running lean, or would it richen back up...(i dont got wideband)

 

[rstchris]

How are you going to boost 10psi or drive at all with melted rings? If it is tuned properly you should see the same AFR at 10psi as 20psi. Is it misfiring? havve you done a compression check? What did you have them tune? ECUflash/Link/afc?

 

[deviousgst]

How are you going to boost 10psi or drive at all with melted rings? If it is tuned properly you should see the same AFR at 10psi as 20psi. Is it misfiring? havve you done a compression check? What did you have them tune? ECUflash/Link/afc?

Im not driving on melted rings.. i jst got done rebuilding it again. they tuned it with safc..

 

[1stGenTSi]

Turning the boost down won't cause it to run richer unless you were running out of fuel at 20psi. Get a wideband ASAP so you can actually monitor your tune. Definitely don't run more than wastegate pressure until you get the tune straightened out. Unless you wanna rebuild again.

 

[DSM_PWR]

that place must really suck at tuning if they managed to mess up an SAFC...

How do you know that your pistons are melted? or are you assuming?

Whats the point of running 10psi when you need to rebuild it and get a proper tune from people that know what they're doing..

 

[spyderturbo007]

I would buy a logger and tune it yourself. There are plenty of people around here that will be able to help you get a good safe tune. Just to reaffirm what was posted by 1stGenTSi, turning the boost down won't cause you to run any richer and might actually be worse for the car if you can believe that.

The SAFC will still be pulling the same percentage of fuel since it's corrections airflow independent, but the ECU will be seeing a lower airflow value than it was before. This is going to lead to increased timing and be even more dangerous than it was at 20psi. Either way, you need to richen things up on the SAFC and pick up a logger.

 

[Sam@RRE]

It takes a bit to melt a ring. Usually I've seen cases with melting ring lands and rings, the cylinder was already compromised. As it kept driving the combustion wouldn't stay contained in the combustion chamber but would go down into the crank case and burn the piston on the way down. Usually when detonation cracks a piston, it cracks. From there, continuing to drive it is when it starts to melt. So I'm wondering if it was already going. How long did you drive it after the tune before it started acting up? Did it start acting up during the tune?

I'm not defending Churches, have nothing with them or against them or care for them in any way. Im trying to see if there was already something wrong prior to the tune. I usually have customers do Comp test, boost leak test to 1.5 times target boost , oil change, and we go for a ride on the street before I load it up on the dyno. If anything displeases me about the car, I tell them to take it home and I wont tune it till its ready. So many people think load bearing dynos are like street driving. Depend on the setup, I can make it like you are doing 3rd gear runs up a 45* incline over the course of 14 seconds. Imagine drag racing uphill.

What were your numbers by the way @ 20psi. 91Octane?