Engine 08 GT The tale of two heads

8RedGT

Member
Aug 29, 2018
6
1
13
24
Florida
Left head broke a rocker follower, valve dropped and damaged a piston, replaced piston and head. The problem is, the right head is the 16 mm plug and the left is the 12 mm plug, the first time the car was driven the power was good but has been loosing power, runs fine.
Have been searching and everyone says the heads are the same and the power is the same.
I changed the fuel pump, no change
Change the TB due to a bad ISC motor, no change.
Changed to IMRC motor because the stuck closed code, the intake is clean and the rods are moving freely, but the code still there.
Don't know what else to do
 
  • Sponsors (?)


Bullitt95

10 Year Member
Jun 13, 2007
1,482
46
79
56
Cyprus
www.angelfire.com
The heads from Early '05 to Nov '08 have the 16mm two-piece plugs, while the heads from Dec '08 onwards have the 12mm plugs.
In terms of valve size, port design, and airflow, both heads are the same. However if your engine has two different heads, two different sets of plugs, but only one set of COPs, the plugs and COPs will be mismatched on one side and you could have misfires.
 
Last edited:

08GT500

Active Member
Jul 12, 2018
184
23
28
Massachusetts
Sorry to hear that ..Is the Car running a Tune? If so, you may want to Reflash it back to Stock, then Reflash back the Tune it was running (Worked for me, clearing issues after partial teardown’s like yours on a few different Mustangs of this Genre’)
Take it for a good ride. If no different
you should plug in o a Scantool to view what your CPU & Sensors are doing when Idling, and do a drive-cycle Datalog..if nothing unusual is discovered- disconnect your Battery for 15 Minutes, reconnect and take it for another ride. Hook your Tuner up & monitor another Drive Cycle. Jot down BOTH Drive Cycles pertinent Info..including your max Spark advance, where it was at different RPM’s, as well as Short and long Fuel Trim- load %’s at both Idle and WOT., Compare the differences. As it’s an adaptive Strategy (Learning) ECU, !it may take up to 50 Miles of
driving- or more for it to run its best after the 1st Battery disconnection, when you’d replaced everything.
On the incompatibility regarding your Heads: If it ran right, as it did the 1st time you spoke of, I’d think the Head is OK, makes sense that if that were true, it’s likely it would have never. run right for you- Period.
I’d be looking around the area where the actual Work was done to locate the issue if nothing is yet revealed, a Connector, Cracked Plug, pinched Wire, bad Ground, Weak or intermittently firing Coil for each Cylinder on where you worked and the other Bank (may show a flashing Check engine light under significant acceleration if a Cylinder isn’t Firing, or erratic, disappears when just Driving or sitting.).
See what you come up with, Do a Compression Test on the Problematic/Repaired Cylinder vs others, check Plugs for proper Color (Tan) and Gap. Could have Fouled the/a Plug
if the excess fluids from the repair had coated it.
Did you go get Fuel when you ran it the First Time? If it was at a different Station, it may show a change in Performance, my 08’ GT only likes Sunoco- I went to Shell & it ran AWFUL..Give those simple things a shot. If you don’t have a Scantool, ACTRON makes nice ones that are capable of doing the above- and much more. Every OBD2 Vehicle Owner should have one. Get one with the “Code Connect” feature. Advanced A.Sells them.
Hard to tell how knowledgeable someone is online, not trying to insult you, only help best I can in Stages. I’ll check back- good luck! John
 

8RedGT

Member
Aug 29, 2018
6
1
13
24
Florida
Thank you Bullitt95, I used the same COPs, didn't know there's a difference, how can I know the difference?
 

8RedGT

Member
Aug 29, 2018
6
1
13
24
Florida
Hi John, than you for your response.
I'm going to start by the end of your post, this is my son's car, I was a Master tech but I left the business about 20 years ago, totally, the best thing I ever did, when on business by myself on something totally unrelated, I have some knowledge but this new cars are kicking my behind.
I don't get offended real easy, specially when I need help, so don't worry about that.
I don't have a tuner per se, he, my son took the car to a tuner a while back, we don't know what was done because the car was left there, The battery when bad because the car seat for a while and we replaced, so battery has been disconnected. The car has different cama installed by the previous owner and on 5 gear has no power so when the heads were replaced we went with OEM cama, the car was tuned to the old cama, so at this point I don't know if the tune done by the tuner still there after the battery replacement.
 

8RedGT

Member
Aug 29, 2018
6
1
13
24
Florida
Hi John, than you for your response.
I'm going to start by the end of your post, this is my son's car, I was a Master tech but I left the business about 20 years ago, totally, the best thing I ever did, when on business by myself on something totally unrelated, I have some knowledge but this new cars are kicking my behind.
I don't get offended real easy, specially when I need help, so don't worry about that.
I don't have a tuner per se, he, my son took the car to a tuner a while back, we don't know what was done because the car was left there, The battery when bad because the car seat for a while and we replaced, so battery has been disconnected. The car has different cama installed by the previous owner and on 5 gear has no power so when the heads were replaced we went with OEM cama, the car was tuned to the old cama, so at this point I don't know if the tune done by the tuner still there after the battery replacement.
I have been doing some searching trying to get back on track on new cars.
A tune was done a while back with a different set of cams, we replaced the cams with OEMs. I think the car ran good for a while until the ECM relearned after disconnecting the battery and kept the settings of the previous cams.
Could that be a possibility?
Is there a way to return the ECM to oem Specs?
I'm waiting on a scanner that I ordered and a 16 mm adapter for the compression test
 

08GT500

Active Member
Jul 12, 2018
184
23
28
Massachusetts
Hi, The only way to get your Car back to a VIN# and CPU ID “Stock” Tune is by going to a Ford Dealership and having it Reflashed by them. Make sure all the Parts- even a Cool Air Intake can make it run too lean on a Stock Tune, and may run awful. If you want to add performance parts once you have a Stock Tune back- I’d suggest you go to AM or JEG’s and get an SCTX4 WIFI Tuner, with the “free Tunes for life” option. BAMA will send you upgraded Tunes via WIFI, you need only fill out an online form each time that you list any Part or Parts added, and you will receive the updated Tune(s) in 48Hrs Max. You will get one lower Octane Tune (or a bit less radical), the other- is more “all out” but not beyond your engines capabilities.
The OEM Stock Tune will be stored on the Tuner, and you connect it to your Computer as a backup, so you’ll always have it, never be in the same predicament again, and it can be converted back to Stock anytime you desire. Each Time q you want created (really is no limit) you can talk to a Tuner and get it the way you desire, I.e., Rev limiter upped to 6,500, Speed limiter removed, adjustments for calibrating Speedometer with new Tire sizes,etc...
Only way you can get the Original Tune back is by locating the 1st Tuner, and he may still have it in his Computer. It’s sloppy on their end not to keep it saved for the next person or possible reason it’s needed.
The ECU should retain a Tune if it’s Flashed correctly, the adaptive Strategy or relearning process should only make the Vehicle react a bit different and a little less powerful according to the type of driving it’s exposed to. You could also ask the last atuner if HE is in possession of your Stock Tune. If he uses HPTuner’s Software, he should be able to re-create one, but ask a Dealer how much they’ll charge, first. Too many “backyard” Tuner’s out there not using PRO Software, only standard versions, and they’re out for $$. Any more info, please don’t hesitate to text! Good luck! John
 

08GT500

Active Member
Jul 12, 2018
184
23
28
Massachusetts
Thanks, John, will look in to it and get back
Sounds good, good luck! I’m on here usually once a day, feel free to drop me a line. If you have an old Friend at Ford you may have worked with, that’s who I’d seek out. I’ve heard of prices from 100$ to 400$ for a Stock reflash. Cheers!