[TECH] Need HELP! Dyno-Tune results in FAIL

[jEEd]

okay so today at GRCPerformance while everyone was getting pleased with their results... my car ran like SHlT literally...

my mods:
# PI Swap (H/C/I) '03 Heads/Cams [reconditioned/ valve jobs w/ 12k miles] '04 Intake w/ crossover [15k miles]
# Magnaflow X Pipe
# Flowmaster CB
# JLT CAI
# Accufab 75mm TB/Plenum

post tune : 226rwhp 265rwtq (first 2 runs were 222 & 226)
after tune: 215rwhp 250rwtq (fixing A/F Ratio to 12.8 and advancing sparkplugs 14*)
then after that it just keep getting shittier and shittier... to 210rwhp and 246rwtq

so pretty much every time after we started to tune the car... it would keep dyno-ing less and less... and whats odd is that it would dyno like it was an NPI Engine, falling flat on its face after 4800rpm... which i know its not because i did the pi swap myself.

# did a dyno run w/o my CAI adaptor and made it a RAI. still same results. (210ish)
# checked the filter and then did a dyno run w/o the filter and made the same results
(210ish)
# MAF sensor was cleaned.. the engine knows its going WOT soo thats accounted for
# checked all injectors / sparkplug wires
# O2 Sensors were replaced just recently and so were the intake manifold ones.
# changed the sparkplugs to NGK V-Power TR55 and gapped to .054 (i had Autolite Platinum before swapping these in) and resulted in the same as all the rest...
# then we turned the timing back to stock and kept the A/F and dynoed the same
# took out the chip and ran it stock and it ran like it did post tune (210ish)
# and we checkd for exhaust leaks and if any wires were arching but nope they were okay.

so now i wonder whats wrong with my car? any ideas? no cel pops up, idles fine, not misfiring, firing order seems fine... he knows theres something wrong w/ my car but it was getting late and a whole day of dynotuning. its just bugging me really bad and we wont be able to do more tests on it til monday since the shop is closed sunday.


:'( thanks for any help you can give...

 

[voidfinger]

heat maybe... also is it a manual or auto?

 

[AaRoN]

if your car was the last one dyno'd maybe there's something wrong with his equipment :dunno:

 

[jEEd]

my car was first to dyno at 10:30AM and the last to dyno at 6:30PM and the results were no different...

and my car is auto as of now but theres nothing wrong w/ my tranny that i know of... so even still anticipating 18-20% drivetrain loss, it should yeild more than 210-215... when it baselined 226 w/ a messed up A/F and stock timing.

 

[voidfinger]

ok so it dynoed less after the tune... ok i got the problem now. I was thinking something else.

So was the tune for 93 oct. gas or whatever they sell there? Um auto's dyno lower too... i calculated that i have about 22-25% loss in my car when i dynoed on a mustang dyno...

 

[AaRoN]

my car was first to dyno at 10:30AM and the last to dyno at 6:30PM and the results were no different...

and my car is auto as of now but theres nothing wrong w/ my tranny that i know of... so even still anticipating 18-20% drivetrain loss, it should yeild more than 210-215... when it baselined 226 w/ a messed up A/F and stock timing.

Are you sure this guy knows what he's doing? Sounds to me like he's making your car worse. :dunno:

 

[FUK_N_JUNK]

I'm going to say you might have a leaking head gasket? I know it's kind of outta left field, But I had that problem with the S-10. It just appeared out of nowhere, and you could not even tell. It did not smoke or leak into the oil at all, but it was enough at running speed to F* everything all up. If I let the truck sit for a week, it would gather about a 1/2 quart of coolant in the #4 cyl. and cause it to smoke a bit at start-up, but it actually knocked 1.2 sec off my 1/4 times. I tore the gead off, replaced the gasket and all was good again. Just a though since you did a PI swap..... just go to Auto Zone and rent a coolant pressure tester, well worth a shot?

 

[jEEd]

you would think that but see he's done a bunch of pi swaped sn95's mustang and tuned them and they said they are ATLEAST 240 tuned even on an automatic

and we took off the chip and reflashed the ecu pretty much to stock retarded A/F Ratio and Timing - resulted in the same dyno 210ish...

 

[jEEd]

yeah im going to do a compression test on the car on monday hopefully and go from there :[ its not making any sense how it would dyno higher before a tune and then just keeps falling flat on its face as if it was an NPI at 4800rpm... and dyno-ing less each time.

 

[AaRoN]

yeah im going to do a compression test on the car on monday hopefully and go from there :[ its not making any sense how it would dyno higher before a tune and then just keeps falling flat on its face as if it was an NPI at 4800rpm... and dyno-ing less each time.

any updates??