Legally speaking, it's the tuner that's responsible. However, you will need to seriously fight in court. When the car is brought to a tuner, he must inspect the car. IF he CHOOSES to continue with the tune, he is agreeing to take responsibility. Now, the tuner can also fight back, if you didn't inform him that you had some sort of problem that he could see (something internal) but again, it all depends. Having the tuner give you a piece of paper to sign means nothing. 9 times out of 10, it won't hold up in court. Tuners are considers "shops" in the eyes of the law, and taking custody of said vehicle does put responsibility on their parts.

In conclusion, it's not cut and dry. Both parties have a range of liabilities and responsibilities.

 

no reputable tuner is going to tune a car without you signing a waiver first.

I wouldn't go to a tuner who doesn't have a waiver, personally.

 

If both parties are understand what happened, in most cases I would think each party would come to a agreement. Having a engine blow up while tuning could be from many things. In the case the tuner made a serious error in the map you would be able to understand what happened. If for some reason you blow a head gasket, loose a valve, its very hard to determine what the cause was. You should choose someone you trust and that has experience tuning. The key thing is to understand what is going on during the process.

 

Ok, an example.

A car runs lean, and the engine goes kaboom. That's with 2 widebands, one on the pillar, and tuner's in the exhaust pipe. Wouldn't that make it tuner's fault?

 

Again, you don't seem to understand that signing a waiver means nothing. You cannot sign away all liability.

 

Yes it would. If the engine blew up because of the tune itself, you can have 500 waivers, and it won't mean a thing.

 

All shops ive been to dont accept any liability for things going boom . Its the nature of the beast . Most will have you sign a waiver prior to destruction . If its a competent shop you should have no trouble .

 

you also have to remember tuning a car for the streets is illlegal!, modifing the emissions of any kind (even a cold air kit) is a federal law, so most waivers the tuners have states, this is for off road use only, any tuner who know what they are doing should never let a car go so lean while tuning it would go boom. If the car has the correct parts, and they are setup corectly if the ecu sees a lean condition it should pull timing and dump full, its all in the tune!

 

This post is the most informative

 

You'll be fighting an uphill battle trying to get a shop to pay for any engine damage that occurred.

You're the one who is modifying the car. If you want a warranty leave it stock.