Tuning Issues...

BigDave06

New Member
May 22, 2007
39
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Felton, DE
Today I took the stang about an hour north to purchase a Predator tuner and have my car tuned on the dyno. The tune installed, we ran a dyno run and I came out with 245/275 with a horrible air fuel ratio... It started around 15 until about 4k then fell to 13 at redline. After some adjustment he tuned it down a tad bit (not more than .5), and my numbers went up to 256/289. The A/F ratio however was still what he called 'dangerous.' We adjusted the fuel tables and couldn't correct the problem after 8 pulls. It then occured to me that I got this car used and it may already have a tune preventing us from changing things.. The tuner agreed and said he will have Predator send them a custom tune and I can flash it sometime next week. So on my way back home my Service Engine Soon light start's flashing.. Am i safe to drive for a few days? It currently has the predator tune running lean. Please bear with my inexperience.
 
unless the car was tuned using a chip and it's still in, there is no reason an older tune on the ECM would prevent a new tune from being flashed.

if he's changing fuel tables to correct for the a/f ratio, he's not tuning the car properly. he should have the fuel table set, then calibrate the Maf until the actual a/f ratio matches the programmed a/f ratio.
 
unless the car was tuned using a chip and it's still in, there is no reason an older tune on the ECM would prevent a new tune from being flashed.

if he's changing fuel tables to correct for the a/f ratio, he's not tuning the car properly. he should have the fuel table set, then calibrate the Maf until the actual a/f ratio matches the programmed a/f ratio.

exactly
 
$400 usually for a mail order tune included.

You can have a car dyno tuned for that much, and its more accurate. Its helpful if you want to pull codes or mess with it yourself though.