Dyno'd & Problems Uncovered...

[SvilleCobra]

Dyno'd the Cobra yesterday after 5 years with a tune I inherited from previous owner. I guess you don't trust dyno sheets a previous owner passed on to you.

The sheet from 2005 he gave me showed 485 rwhp/484 rwtq...and good air/fuel in the range of 11-14.

Yesterday....rwhp was 433 and rwtq was 400. Air/Fuel was fine until 3500 rpms and then dives below 9. To top it off, when I pull my dipstick, the oil has a slight gasoline smell to it.

The dyno guy wants to tune the car badly...was all excited about it...for $625.00 w/ a handheld included.

Advice Needed......does a tune solve the problems of RWHP/RWTQ/Gas smell in oil and are there any hidden problems I should be aware of or have checked out?

How does a previous tune degrade so badly when nothing has ever been changed on the car since last tune? Does a tuned car have to be "reset" every so often?

Can I drive the car conservatively until I get the work done?

Thanks for all feedback....

 

[Ironhand]

Never heard of a tune going bad before. He could've changed blowers, pulleys etc or just given you a really safe tune. Unfortunately air fuel ratio that rich will wash out the ring lands of the pistons and get fuel into the oil. Another reason is a blown FRPS, then the computer will go into what I call stupid mode. It will just run off of stock tables and I know my car just poured fuel until the cylinders when it popped.

 

[cobracide]

Gas in your oil? Better do a change asap. Yeah a blown FRPS will dump fuel into your oil.

 

[racin4ds]

Pull the line off your fuel rail pressure sensor and see if it smells like raw gas, I'm bettin' it does!

 

[707svt]

You need to buy the FRPS ring that goes under the sensor or the FRPS will keep blowing out, you will aslo need to change ur oil, take off the air intake system and make sure ur mass air is dry cuz if it gets wet like mine did it will flood ur motor.

 

[04screamingvert]

If the car ever had leaded fuel / race fuel run thur it the O2 will be contaminated and will feed bad data to the computer and your computer will adjust the tune base on bad information from the O2. Also a new air filter with oil cotton can contaminate the mass air I had to clean mine with a spray. Race fuel info came from a VP tech.

 

[rudycobra]

I had an email tune from Rwtd and when dynoed it made 411 , guy retuned mine and it made 441 cost me 400 w/o tuner