Checkers

So I have an 02 Z06 and just put a upp twin turbo kit on it. Just sent it to the tuner and he says the throttle body slams shut at 5 psi. Its an 8 psi kit. Why would it do this?

Old Geezer

iTrader: (3)

Setting any codes?
What's the tuner seeing on a data log when this happens??

NoGo

iTrader: (2)

Possibly the cars not making the MAF sanity check and going into 'limp mode'.

I forget the code number, 1518, something like that.

You have to increase the tolerance for this test in order to be able to stuff boost into the thing.

NoGo

iTrader: (2)

...or you need to tell him to stop being scared and keep his foot to the floor.

Checkers

Ha! I think he is scared. Kind of an *** too. Its putting the engine into reduced power mode at 5 psi instantly and he refused to pursue it. Said I need an ls2 throttle body instead. But yes its throwing a code. Also said he shut off the maf sensor except for the internal temp sensor. Feel like I got totally screwed.

Old Geezer

iTrader: (3)

"Feel like I got totally screwed."

Go get the car, before you REALLY get screwed w/ the pistons in the oil pan...
Possibly, the DTC that NO GO is referring to, is 1514.
Here's the description:
The PCM calculates the amount of airflow it expects for a given RPM and throttle position, if these values are exceeded then DTC P1514 will set.

Another bit of info on the topic:
http://forums.corvetteforum.com/c5-s...ont-start.html

BOBS99SS

iTrader: (2)

Yes after that call i would have said dont do anymore with the car ill pick it up in 5mins, ya know i dont see why people will let anyone tune there car, from what he said he obviously doesnt know much,i have read alot of horror stories on tech from a bad tuner not know what he is doing,i just dont wanna see that happen again,all thats going to do is cost you money, go pick up the car and search for a ls tuner that can do the job right,the post above couldnt be more right

Checkers

I even asked this guy about that. I did pick up the car immediately! And lets say I'm less than happy! This tuner came highly highly recommended and is only an lsx guy. So now idk who to trust. Expecting 750 whp. Anyone in the st louis area I can trust?

NoGo

iTrader: (2)

Probably not the popular opinion here: Alternatively, you may want to work with the tuner.

We are just a bunch of know-it-alls on a forum throwing stones at what we think the problem is. In reality, it could be much more complicated.

I can't count on my fingers and toes how many cars I've inherited in tuning where my initial thought was the first tuner was a retard, then after I get into it, I see why they were doing what they did.

Possibly, the guy has no clue what he is doing, or there may be something more complicated going on. If the person is a dedicated LSx tuner the 1514 code is possibly the first thing you modify in a vette FI application. If the car is throwing that code, then I agree, take it somewhere else. If not, there may be something more complicated going on.

Checkers

So I called around other tuners and the first one I called said his guy actually tuned my car. Drove to the shop I left my car. Says my throttle body motor is too weak and slams shut because of a spike in the boost pressure. And that's why he recommends an ls2 top end. Also said he did mess with the tps and didn't help.

NoGo

iTrader: (2)

At the risk of 50 people coming in immediately after this post and saying "wtf this is a common problem!!!!"

I've never had it happen to me and I've tuned a ton of forced induction C5's.

I dabble with a 2003 Z06 regularly that runs anywhere between 16 and 18 psi and never had a problem like that.

So, what I'm trying to say is that the TB slamming shut sounds like a load of crap to me....but I'm not close to the car.

I would still guess some type of limp-home-mode is being activated.

72montecarlo

Do yourself a favor put a rich tune in it and drive it out of state for a tune

Checkers

Hey im looking for someone! I really don't think its a TB problem. That's why I wanted to post this and help make an educated decision. I really appreciate all your guys input.

Slowhawk

iTrader: (12)

It could be a weak tb but I've haven't seen it yet with a turbo or centrifical blower.

The limp mode is very common if not tuned out correctly.

BOBS99SS

iTrader: (2)

Yeah you spend all that money to mod your car you should take a lil trip to someone that can get things figured out for ya,or get some vitamins for that weak tb lol

1BADAZZSS

iTrader: (23)

Could always trailer it to kc. I know of a very reputable tuner in my area that has dealt with turbo lsx stuff and him and Skinnies have done many lsx turbo swaps for ppl.

Checkers

Pm me a name and number if ya would. Won't hurt to give him a call.