Re: David's GT500 Troubleshooting Thread

by Papi 4/5/2011, 12:24 am

That's cool with me. Well try to get Bill from Unique next door to come by. He has a really nice looking Saleen, He's not open on the weekends.

by Shelby10' 4/6/2011, 1:28 am

Hey David...some more ideas after research

1)Boost bypass set correctly? Set correctly in the tune to allow for the increased boost?

2)Vaccum lines not blown off or split?

3)Any gaps between the blower and lower?

4)Also check the vacuum line that comes off of the front of the lower intake manifold up to the passenger side fuel rail. Make sure it is attached but also make sure it flows freely and isn't occluded. If that line is off or closed up that can cause all sorts of problems and they come off sometimes.

5)check out how many amp's your alternator is putting out. As far as Volts go... It has a 14.2 regulator in it. That is controlled by the PCM. So at an idle it should have 14.2 with nothing on. But you really need to see how many amps it has when its loaded. Ive found a few cars with blown diodes and they still had 14.2. But only put out 60 to 70 amp's. Causing the everything in the system to run slow. Including the charge cooler pump. Then it will start to pull timing. With one hard pull.

6) Belt slip...the OEM belts have a tendency to slip then glaze over

7) Quote from another forum: "Could be boost leak. you can make or buy an intake boost leak tester. that's the easiest way to find a leak. i had boost problems and used my tester. sprayed some soapy water and found a 2" crack on my steeda cf intake. the crack was on the inside, but the vacuum from the blower was enough pressure to force a leak through intake tube."

8)Another Quote: "I'd venture to guess that it is a leak in the system as well. Weather it be a bypass valve hanging open or lines or mating surfaces."

Here is what the Terminator guys do to test their Bypass Valve. Dont know if its similar to ours though:

"you can check to see if your boost bypass is working by revving the motor at the tb. With the car idling you should see the stop arm swung very far back towards the firewall. While revving it quickly at the tb you should see the stop arm swing back forward until it bottoms out on the set screw. If it isnt bottoming out you may have a vacuum leak. If it does bottom out it may need adjusting like stated before. The set screw can be adjusted down farther into the blower allow that swing arm to go farther, thus allowing the bypass valve to fully close."

"Another way to test the bypass is to pull off the top line and pull the swing arm back, use your finger to block off the top port. if the swing arm stays in the up possition it is ok."

9) Quote: This guy was way down on boost....only showing 4psi His advice to another member having the same problem was to "Check all of your vacuum lines. I had a similar problem when my car was on the dyno and found out one of the vacuum lines had melted onto the EGR pipe. I found it by pulling them off and holding a finger on one end and blowing in the other."

Thought this was a good read about the Bypass valve on the Terminator...might relate to ours.

http://www.svtperformance.com/forums/how-230/611497-how-eliminate-boost-drop-off-eliminate-boost-solenoid.html

by 07Shelby500 4/6/2011, 7:51 am

I will check tonight. Still waiting to see what Justin says about the data log files.

by Shelby10' 4/6/2011, 12:28 pm

10-4....good luck sir

by 07Shelby500 4/6/2011, 1:37 pm

It's really driving me nuts. Thanks for the help.

by Shelby10' 4/6/2011, 5:55 pm

Resetting your KAM:

"KAM is the Keep Alive Memory.

It is simple to reset.

To reset it, disconnect the Negative (-) battery cable from the terminal. Leave it disconnected for ~1/2 hour (*I* say 1/2 hr. to be safe, most will tll you 10-15 mins).

I take this part one step further and I advise everyone else to do this too.

I take the DISCONNECTED end of the Negative (-) batt. cable and touch it to the Positive (+) batt. terminal and CABLE end. What that does is releases any built up charge in the PCM's capacitors (i.e. condensors, and you are just grounding them by touching the cables together).

After disconnecting the batt. cable and touching them to each other, go have a doughnut and a cup of coffee. Again, I give it at least 1/2 hour with the power disconnected.

Afer ~1/2 hour, connect the Negative (-) batt. cable to the Negative (-) batt. terminal. At this point, make sure the terminals are clean. It's a good time to clean them off.

Now get in the car and don't touch ANYTHING. Turn the ignition key to the "ON" position. Watch your gauges. Allow all of the gauge needles to "set". They will rise and then fall to their "natural state".

Now turn the key OFF.

And again, I go one more step further.

Do not touch ANYTHING in the car except the clutch pedal and the igntion key. Be sure the transmission is in Neutral. Depress the clutch pedal, reach up and start the car and let it idle. Again, and this is important...DO NOT TOUCH ANYTHING. Do not touch the gas pedal, the steering wheel, the shifter knob...NOTHING.

Let the car sit and idle for about 10 minutes. You usually (you may or may not) hear the engine idle speed change up and down and eventually it will settle in to "curb idle speed".

This "extra step" allows the Adaptable Strategy parameters to be reset. The PCM is basically going to each sensor, checking it and using the (now, new) reading to be used as its "baseline" setting. By touching anything within this period you are giving the PCM a false baseline to work from. On a brand new car where there is very little wear on the engine and/or sensors, this is not nearly as important as on a older car with wear on it.

After about 10 minutes (ususlly a little less) you can either shut the engine down and go do what ya wanna do, or go drive it.

You're done."

Wouldnt hurt to try?

by cobradoc 4/6/2011, 8:51 pm

Do you have your time slips from your best to worst runs?If so,post them.You can tell from those how the car has changed and where it is laying down.60 ft 330, 1/8 and 1/4 times and speed.I lurk here often and see you guys use a lot of box tunes.They are fine,but I can tell you from experience dyno tunes are a must for GT 500's.I have done several of these cars and none of them have the exact same tunes,even with the exact same mods.I had one a year ago with a box tune andCAI that was so lean it would pop and fall on it's ass.I am in no means knocking anyones tune just telling you what I have personally seen after modding several.You should probably log your short term trims and see what the correction is.Do you recall how much boost you made during the run?What plugs,what gap?

by cobradoc 4/6/2011, 8:55 pm

Another thought,how are you prepping the car between runs?Heatsoak kills!High downsteam temps=retarded timing.

by 07Shelby500 4/6/2011, 9:27 pm

-Car sat for two hours before run. No heat soak

-Plugs are NGK TR6 gapped at 35 thousandths

-Tune is from Justin at VMP (very reputable gt500 tuner) not canned type tune from SCT.

- Car was down on ET and mph at 330 1000 and 1320' marks. Down all over the range. 60' times were a spinning 2.1 on BFG DR's.

- I have noticed that my boost gauge is only showing 10 lbs of boost (4th gear from 3K roll then hammered) in lower gears it only goes to maybe 11 lbs in cool temps. I should be getting a solid 12 lbs with the 2.59" pulley. I may have a faulty boost bypass valve? This would explain the lack of performance. If I'm losing 2-3 lbs of boost through the bypass that might be upwards of 80rwhp?

I've checked every vacuum line and connection around the car. All are good. I data logged two files which I have sent to my tuner. Waiting to see if there is anything obvious from those that might point me in a different direction.

The car runs and drives great other than not having the power it should with my mods. No clutch slip, no misfires, stumbles, etc. Nothing that would lead me to believe I have a mechanical issue. Right now the boost bypass is my best guess. However I'll wait to do anything until I hear back from the tuner. If he sees nothing then it's going on a dyno to get sorted out.

by ARMORINE 4/6/2011, 9:47 pm

not to knock on any one but if its not on a dyno in front of the tuner its still basically a boxed tune. tuner still has never seen the car in person. dont care how much experience a person has. still not as accurate on a tune as having the instruments in front of you and reading what the cars doing in real time.

now that i've said my peice im going to retire back to cramming history books into my head before my test tomorrow morning....... samuri

by 07Shelby500 4/6/2011, 10:10 pm

Ok. Here's the deal. If youve tuned a few hundred of the same car on a dyno with good success you pretty well know what works and what doesn't. You can establish a good tune and adjust accordingly for location and octanes etc. Data logging allows the end user to have the tune tweaked as necessary remotely. The way your making it out is as if I'm running a canned SCT tune?

by cobradoc 4/6/2011, 11:43 pm

I know of Justin,he is a great tuner.My take is with the car on the dyno with the tuner in the same place at the same time you can see real time the issues.I am not knocking anybody or any tune.What you are doing is fine but it's going to take time and patience to get right.It is hard to see everything through a few datalogs.Usually when you have poor sixty foot times and a lot of wheel spin MPH will generally come up but ET will suffer.10 to 11 psi sounds way low to me for that combo.I would expect somewhere around 14 depending upon humidity and temp.520 to 540 is generally what I see out of that combo.He can turn the boost bypass off in the tune,but if it's leaking....you will experience low boost.Coolant temp at beginning of run?

by 07Shelby500 4/6/2011, 11:50 pm

I don't know what the coolant temps were when I ran. When I data logged they were normal.

When I ran the car I drove it from 116th st N In Owasso to the track. About 8 miles. The car sat for at least 2 hours before running.

by cobradoc 4/6/2011, 11:53 pm

Just asking to see if it went closed loop and wasn't adding fuel for cold temps.

by 07Shelby500 4/6/2011, 11:58 pm

Don't know. I'd say the coolant was around 170-180* ?

by cobradoc 4/7/2011, 12:02 am

07Shelby500 wrote:Don't know. I'd say the coolant was around 170-180* ?

That should do it.

by 07Shelby500 4/7/2011, 12:06 am

So if I'm losing 2-4 lbs of boost what are the possible causes?

by cobradoc 4/7/2011, 12:16 am

Bypass leaking which I really don't see much of.Belt slip,downstream leak.I know your gonna think I'm crazy but I have seen gains and losses as much as 20 horse in CAI.JLT is by far the best from what I have seen.Is the throttle going 100 open.Postive displacement blowers do not like upstream restrictions.I am located in Owasso,be glad to look the car over if you would like.

by 07Shelby500 4/7/2011, 12:22 am

Checked the tb opening it does go 100% open. The C&L is about as least restrictive as I could imagine. From what I've seen online the C&L and JLT put out about the same numbers. Don't think the belt is slipping. I'm really stuck on the BP valve being a possible cause. Not sure what Justin has commanded in the tune for it.

by Shelby10' 4/7/2011, 12:27 am

Im running the same exact tune as david from Justin (Not sure if Justin changes anything for the 2010 MY).....Never had any of the issues David is experiencing.

We ran the same night, same temps, same drag radials, have similar mods...etc

I netted 120-121mph traps compared to his 108ish results.

I took the car out last night and video'd my 3rd gear and 4th gear quick pulls to see what I was registering for boost and the results were a consistent 13psi...Ive seen 14psi in colder weather.

I would agree with some of the statements that a dynotune is the best way to get the most out of the car....BUT you also have to have a reputable tuner that knows and understands what hes doing, Especially when dealing with boost. Sometimes a remote tune from a reputable tuner can net better results than Joe smoe with a dyno and tuning software.

Cobradoc you seem to know your stuff....what experience do you have with tuning? Someone elses opinion on what is happening is always welcome as the datalog numbers give me a headache and I am definitely not able to desypher what is going on by looking at them.

by cobradoc 4/7/2011, 12:29 am

I would imagine your running A auxiliary idler.You remember what length belt your using?I would imagine Justin would get back with you soon.

by 07Shelby500 4/7/2011, 12:32 am

Stock length belt 90mm idler

by cobradoc 4/7/2011, 12:49 am

See what Justin has to say.If he doesn't find anything,PM me and I'll loan you a 100mm idler.That combined with a new belt will rule out belt slip.I like the 100 with a stock belt is makes tighter than snot.
Jarrod,I am a power junky from way back.I work with a tuner here in town whom some love and some not so much.We have great relationship and between us have a pretty vast knowledge.I am fortunate enough to be able to do what I love for a living.

by Shelby10' 4/7/2011, 12:53 am

cobradoc wrote:See what Justin has to say.If he doesn't find anything,PM me and I'll loan you a 100mm idler.That combined with a new belt will rule out belt slip.I like the 100 with a stock belt is makes tighter than snot.
Jarrod,I am a power junky from way back.I work with a tuner here in town whom some love and some not so much.We have great relationship and between us have a pretty vast knowledge.I am fortunate enough to be able to do what I love for a living.

They say if you do what you love for a living....you never work a day in your life. I hope to be in your shoes someday.

I believe I have met you before...had a very nice silver centri powered SN95?

Thank you for your help as it is much appreciated sir.

by cobradoc 4/7/2011, 12:59 am

I have a DSG 03 Cobra.Don't get out much,too busy fix in other peoples stuff.May have met at the Shelby meet.Hopin to make TNT this year,trying to get my stock blower in the 11.50's.

by Shelby10' 4/7/2011, 1:02 am

cobradoc wrote:I have a DSG 03 Cobra.Don't get out much,too busy fix in other peoples stuff. May have met at the Shelby meet.Hopin to make TNT this year,trying to get my stock blower in the 11.50's.

Love the DSG Cobras. I hope to have an 03/04 cobra in the garage someday, very much the cobra fan. Definitely let us know when your going to TNT, would love to see that ride of yours and meet you. Always good to be surrounded by fellow car enthusiasts.

Was actually helping out a fellow BMMC member tonight with one....has an 03 sonic blue Cobra that we believe is having coil pack issues. At least that is the code he through. Its going into ford tomorrow morning to run some diagnostics to isolate which coil is bad.

by cobradoc 4/7/2011, 1:05 am

Jerry? Mr D's old car?

by cobradoc 4/7/2011, 1:07 am

What was the code?

by Shelby10' 4/7/2011, 1:18 am

cobradoc wrote:Jerry? Mr D's old car?

You are correct sir. Mikes old SB cobra.

Not sure the specific codes that were thrown....Jerry would have to chime in.

Something about bad coil pack A and the other code referenced too much boost? Car is stumbling and running rough. Happened after pulling out into traffic and giving the gas pedal a spirited push.

by cobradoc 4/7/2011, 1:22 am

Sounds like a coil is toast.I can scan it for him if he doesn't have an in at Ford.

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