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2007 Shelby GT500
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Discussion Starter · #1 ·
Hi All, please dont beat me up too bad if this has been covered already (or do beat the shit outa me, whatever lol) I am just now dipping my toes into true first world problems and could use your collective advise, smartass comments and personal experiences. Car is setup as follows:
2007 13,XXX miles
VMP 800hp Kit
VMP Gen II 2.3L TVS
2.8" Pulley
JLT Intake
JLT Throttle Body Twin 67mm
JLT Oil Separator
170⁰ Thermostat
Dual Fan Triple Pass HE w/3x Capacity tank
90mm Idler
08 Balancer
Kooks Long Tubes
Kooks O/R Mid Pipe
Borla Atak Cat Back
McLeod RXT Clutch
MGW Gen II Short Throw
Eibach Sportline Springs
MM Caster Camber
MM Bumpsteer Kit
BMR Adjustable Panhard Bar
BMR Lower CA
All Reservoirs replaced with powder coated Canton tanks
NGK plugs
1000cc FIC Injectors
KB BAP
91 Oct tune


Just bought the car last week. During the test drive, it was mentioned and ultimately mistakenly understood the tune (Shaun at AED in Sac) had built in a failsafe mode for the car if the coolant temp was below 165*. So long as it wasnt romped on prior to coming to temp, the failsafe never came on and when it did it only flash the light and gave the tone..never retarding the motor.

While driving it home, the FSM did come on and during moderate pulls in 3rd and 4th the car would stutter and choke itself in the classic FSM performance. Our first thoughts were either tune related or Kenne Bell BAP related. AED confirmed not tune related. We were able to hook a laptop up to it and take it out and recreated the issue. The car is definitely leaning out under load. There is a thread that showed the power distro box having 3 fuses needing to be replaced, 41, 66 and F6. I noticed that according to the post my fuses were not correct and still factory configuration... but the fuses werent blown so I do not believe that is the issue. Checked all the connections for the BAP and everything seems good.

I am leaning towards this being a fuel pump issue. This is the first vehicle I have owned that has duel pumps. It is my understanding that if one goes, the other will be able to support "normal" driving, but under load with not be able to keep up, lean the car out and send it into FSM. I'm also under the understanding the KB BAP are "notorious" for killing fuel pumps. While the car only has 13,XXX miles on it, the pumps are still 15 years old. I have ordered DeatschWerks DW300m pumps so I will have them once I have the time to properly diagnose the pumps. So my questions are;

1.) Has anyone else ran into this?
2.) Is this common behavior for a failing fuel pump(s)
3.) How do I verify fuel pressure at the rails? I dont see a valve I can tap into like the SN95s
4.) Is it normal for there to be 300 miles of FSM driving with no CEL or codes? Also important to note that it was choking the entire time, maybe a second or less during diagnostic pulls (less than 5)
5.) The car is getting tuned Monday the 10th for change in elevation from 20' to 4600'. I am expecting an up to 4psi boost loss. What will I need to do to keep the car performing, yet not kill me if I drive to lower elevation (1000') I live in Reno (4600') and plan to regularly take the car to Vegas (2,000')

My dream ride and our new GT500 for your thanks!

215209
 

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KEN (#1) 2008 Metalic Vista Blue Convertible Stripe Delete w/some Stripes
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OKAY... it may help to post a picture of your car ! .....the ride looks nice!

I have a lot of the same mods as yours, most ALL VMP, including their Dual Pump Boosters, and TUNE... I would be a bit less than comfortable to have such a 'mix' of components and along with some 'others' Tune.
Hopefully your Tuner knows these cars as well if not better than VMP or BJ... may have some doubts. You probably know, do not go to boost on a Lean Tune... keep your foot out of it, regardless of what 'protections' you believe are there!
The tuner can make or brake it, literally ! I have three tunes in my device and can re-flash for differing conditions... I previously lived at altitude in Colorado, but now retired to Arizona, differing locations also came with different grades of fuel 90 to 93, it makes a difference in the engine sensors... Have faith in your tuners ability's, ok. I am not a 'tuner' and put my faith in those that are experts with these vehicles, Joe Goodnough (?) spelling VMP, or BJ of Venomous are the absolute best. Good luck in getting the answers you are looking for, maybe @Catmonkey could jump in and help you.

Welcome to the Forum. Sorry I may not be much help, but perhaps point you in the right direction... Just Please don't push that engine while LEAN... I will not like that.
 

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2007 Shelby GT500
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Discussion Starter · #3 · (Edited)
No worries, thanks for the reply. Yes I keep my foot out of it for sure.

As far as the current tune I have been told by multiple people the Shaun at AED is one of the top 5 in the country for coyote and GT500 tuning, although I am not familiar with him myself. The car previously had a VMP tune on it. I do know its a pretty conservative tune. Could definitley push harder than what it is.

Although I amstill a student with all of the tuning, I dont want to get caught in the endless "its the tuner" or "this guy is better than this guy" debate (not saying that is what you are doing at all). I dont believe the current issue I have is with the tune as the car performed flawlessy for two years after the tune prior to this issue. The reason for switching to a different tuner for the upcoming tune is the ease of tuning at actual elevation and local conditions. I dont plan to drag it, track it or make youtube videos with the car so I am not wanting aggressive tuning at all. Something reliable that makes fun HP on the way to dinner. I wouldnt care if the car made 500rwhp or what it currenlty puts down, 642.
 

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2012/2013 Hybrid
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I'm not sure where to start on this one. What do you know about the car? You just purchased it running like crap? Do you know whether the tune ever worked on this car and how well it ran prior to this? Do you know the sequence of mods and if there are any mods not accommodated in the tune? You mentioned hooking up a laptop. Did you data log the car? If you're data logging, does it have a wideband? How are you coming to the conclusion it's leaning out under load? What's the a/f ratio you're seeing under load? Have the checked the fuses in the boost-a-pump? Are you sure it's hooked up properly? Have you changed the fuel filter? Have you performed a compression check to make sure you're not working with a damaged engine?

If it were me, I'd call Shaun and ask him what he can tell you about the tune and the mods and whether he's aware of any mechanical issues the car has. Find out if he did a dyno tune or a mail order tune and how long ago he tuned it.
 

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2007 Shelby GT500
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Discussion Starter · #5 ·
I'm not sure where to start on this one. What do you know about the car? I have a pretty good history of the car, all of the receipts, documentation, email correspondence between the previous and original owner, etc. You just purchased it running like crap? I went and looked at the car, rode with the previous owner and test drove it myself. The previous owner did do a few strong pulls with it while I was in the car without issue. 5 Days later I returned and purchased the car. If you werent trying to pull it, you really wouldnt know there is any issue. The issue started on the way home with it. Do you know whether the tune ever worked on this car and how well it ran prior to this? Yes, the car ran fine aftere a while the tune for quit. Do you know the sequence of mods and if there are any mods not accommodated in the tune? Yes, the 800hp kit from VMP was the start of the mods and had a tune from VMP through the SCT XCal4. It originally had a 2.4" Pulley. It was swapped for a 2.8", plugs were changed to NGK and FIC injectors were added. Headers, BAP and O/R X Pipe added and then retuned by Shaud at AED. You mentioned hooking up a laptop. Did you data log the car? If you're data logging, does it have a wideband? How are you coming to the conclusion it's leaning out under load? What's the a/f ratio you're seeing under load? Alex at Muscle Motors will be doing the new tuning. He hooked his laptop up and got some data logged, yes. It was through this we determined the car was leaning out. Have the checked the fuses in the boost-a-pump? Are you sure it's hooked up properly? Yes, fuses, connections and wiring have been checked. Have you changed the fuel filter? No, I have not. Wanted to start with a check of the pumps. Have you performed a compression check to make sure you're not working with a damaged engine? No, I have not..yet.

If it were me, I'd call Shaun and ask him what he can tell you about the tune and the mods and whether he's aware of any mechanical issues the car has. Find out if he did a dyno tune or a mail order tune and how long ago he tuned it. I have corresponded with Shaun via email in a chain with the previous owner. Car was physically tuned on a dyno Nov 8, 2019. Obviously without doing a compression check, saying the motor is "healthy" is unverified, but I really dont have reason to believe its NOT simply a fuel pump issue. No other mechanical issues.
I know theres a lot to unpack there. The easiest way to respond to the individual questions is by replying to each one up top. I have highlighted my responses in underlined italisized font. Let me know if there are follow up questions I may be able to answer.
 

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Congrats on your new ride! Sorry you are dealing with these issues. Also, based on your forum name, thank you for your service.
You have an impressive list of mods. If you look back over the 15 years of threads, you will see VMP and BJ (once worked for VMP) have been extremely reliable in the GT500 world. I’ve read countless threads here from members who have a GT500 tuned by some other person or company, Bama always comes up, where someone is having an issue. I can’t say who is the best. But, what I can say is I haven’t heard complaints about BJ or VMP. In fact always the opposite, exceptional customer service. They have been providing the right products and building powerful and RELIABLE tunes since the GT500 came out back in 2007. Your running a VMP TVS, I’d stick with the people that helped design it.
I too own a 2007 with a TVS. If I need anything I reach out to BJ or VMP. I’m not saying they are the best for all GT500s. If I had a KB under the hood, I would go to Lund. But, because you have a TVS, BJ or VMP would absolutely be the only ones we would use. You’re already making a change to the tune for elevation, take the guess work out of it and reach out to BJ at Venomous Tuning or VMP.

I’m eager to find out what you come up with and look forward to what insane numbers those mods are putting to the wheels.
Good luck!
 
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Is your Muscle Motor contact just a tuner or does he perform diagnostics? Is he telling you the log appear to show the fuel pumps are not making enough fuel pressure? The fuel filter is underneath the driver foot well. I'd replace it before pulling the pumps. For all you know it's original equipment. You should be able to log the fuel pump duty cycle. If you do replace the pumps take a good look inside the tank and the fuel socks for signs of sediment or other contaminants. Pumps can and do fail, and if they are incapable of supplying enough pressure to the injector, it will go lean. If you wanted to install a fuel pressure gauge, you can get an adapter that goes on the fuel rail at the rail pressure sensor. Most aftermarket fuel rails have plugs that allow you to add an fuel line for a gauge. The Aeroforce gauge taps into the OBD port and may display pump duty cycle. It does on my 2012, but I'm not familiar with the earlier models.

Once you get it running right, that 2.8" pulley is never going to make a great deal of power.
 

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'08 GT500 Condor - Ebony Black, White Stripes
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Not sure if it would be the actual issue, but I'd make sure you have a power wire upgrade ran from the battery to the BAP. Stock power wire to the FPDMs are insufficient for the BAP, and many people skip this simple step. Not to mention it should get you even more FPDC headroom. Doubting the fuel pumps would go bad on their own at the mileage particularly, so if one is dead, there's likely another issue going on that needs solved. Fuel filter is easy and should be done first. Triple check all the connections around the FPDMs/BAP. If it was soldered then there's a chance it broke somewhere and has intermittent bad connection, I prefer crimping with heat shrink. Check engine codes via a tuner; you don't need to have a check engine light for there to be codes stored in the system. If there are codes, that can help with troubleshooting. If they didn't change the fuses then that is a huge red flag. That tells me they weren't following very simple instructions on the BAP install, and their wiring may not be up to snuff/correct either. Or the previous fuses blew, and they replaced with factory rated. And now there's a mechanical issue from a prior "event". My money is on the BAP/wiring at or near the FPDM. And if it is a dead pump, it can likely be because of a heat/wiring issue.

Edit: the injectors could eventually be another thing to check are working properly, but I wouldn't say that's as likely. Do the receipts show they were purchased new? If used, there's a red flag.
 

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2007 Shelby GT500
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Discussion Starter · #9 ·
Thanks everyone for the feedback! My work schedule has had me bogged for the last few days, so I havent been able to do anything but look at the car on my way through the garage. Im going to go through the basics again to start, fuel filter, etc. Also going to check the plugs to see how they look just for good measure. I'm sure its something simple, but want to hear from you guys about your experiences. The power wire upgrade is a good point, will also check that. No codes currently to check. I have a read a few other places that their GT500s are going into FSM without ever throwing a code as well. I'm using the SCT XCal4 to check for stored codes as well. Agreed on the red flag for the fuses. My original theory was the BAP not working appropriatley. I reached out to KB for a guide on how to properly perform a function test on a BAP, still waiting to hear back.

The tuner at MM is both diag and tuner, but want to ge tthe problem solved or at least max out my diagnostic ability before I send it to someone. I have heard nothing but good things about BJ and the team at VMP. I've started a conversation with VMP about the elevation and performance changes.

Like I said above, I really do not want anymore power. Just want reliable, fun power so the 2.8" is fine by me.

I really appreciate everyones input! Will keep everyone post as I will get my first chance to really devote time to it tomorrow.

Cheers!
 

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2013 Shelby GT500 performance white
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Thanks everyone for the feedback! My work schedule has had me bogged for the last few days, so I havent been able to do anything but look at the car on my way through the garage. Im going to go through the basics again to start, fuel filter, etc. Also going to check the plugs to see how they look just for good measure. I'm sure its something simple, but want to hear from you guys about your experiences. The power wire upgrade is a good point, will also check that. No codes currently to check. I have a read a few other places that their GT500s are going into FSM without ever throwing a code as well. I'm using the SCT XCal4 to check for stored codes as well. Agreed on the red flag for the fuses. My original theory was the BAP not working appropriatley. I reached out to KB for a guide on how to properly perform a function test on a BAP, still waiting to hear back.

The tuner at MM is both diag and tuner, but want to ge tthe problem solved or at least max out my diagnostic ability before I send it to someone. I have heard nothing but good things about BJ and the team at VMP. I've started a conversation with VMP about the elevation and performance changes.

Like I said above, I really do not want anymore power. Just want reliable, fun power so the 2.8" is fine by me.

I really appreciate everyones input! Will keep everyone post as I will get my first chance to really devote time to it tomorrow.

Cheers!
BJ is no longer with VMP. He has his own business. Venomous tuning.
 

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Discussion Starter · #12 ·
Ok, Deatschwerks DW300's were installed tonight and I replaced the fuel filter. Still going into FSM.
 

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I think you will find that the elevation change is the problem 20’ to 4600’ is a large gap.
 

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Discussion Starter · #14 ·
I would agree, but noticed the issue on the way home, no more than a hundred or so feet elevation
 

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'08 GT500 Condor - Ebony Black, White Stripes
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Yeah going to need to datalog the fuel system. Fuel Pump Duty Cycle(if this is maxing out at .50=100% then you have a wiring issue as the stock pumps and upgraded shouldn't be having issues at your power level/the rpm it happens at unless the tuning is way off, which it isn't if AED did it...), FP voltage actual, FP voltage from table (compare actual and from table under WOT to see how good the tune is in general terms and also if the pump is getting what it needs power wise, could help see wiring issues), injector duty cycle(shouldn't be maxing injectors but if you have some debris clogging issues could show up here maybe?), pressure drop across injectors (if there is any issue with the pumps all the way up to the injectors causing a physical drop in pressure under WOT load the amount of drop will be seen here, if somehow there is no drop here then you likely aren't even going lean and there's some weird wiring/ECU/tune thing going on tripping the fail safe mode); but if it is going lean you can see exactly what rpm the drop happens, and compare that rpm with the other parameters listed here to start making connections on what is happening, and battery voltage (this one is obvious but even if you're not getting enough voltage drop from the alternator to throw a light, I'm pretty sure you could be getting enough to start messing with your whole system causing a lean condition, and OEM alternators on these cars suck as is) would be a good place to start.
 

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You can also go lean due to vacuum leaks, MAF issues, exhaust leaks at the head/manifold, etc. Cleaning your MAF is also a good idea, especially if you have an oiled air filter. I'm doubting the vacuum leak or exhaust leaks though as those should trip a check engine light or a stored code at a minimum. I'm surprised the car has gone lean that many times testing it and still no stored codes....
 

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Discussion Starter · #17 ·
Yes, going to be data logging once I talk to Shaun again. Spoke to a local shop who specializes in Cobras and Shelbys, both new and old and he is lending a troubleshooting hand as well.

I do have a few questions for the group;

-Given I have a triple pass, dual fan Heat Exchanger and a 3X coolant tank, what range should my IAT's be reading at say 70* outside temp? Same for Coolant temp. I have a 170* thermostat installed.

-There is an AeroForce gauge that plugs into the OBDII port. It has a ton of parameters that it will display, one of which is Rail Press. My understanding is, without a T tapped into the factory rail feed line, I wouldnt be able to check pressure at the rail without data logging. The readings I am getting o nthat gauge are from between 21 at Idle and max 29 at 80 mph, typically 23-24. Theres no way my car would be running normal at 80 mile per hour at that low of pressure, right? I dont know what the correct range is, but I would assume it has to be in the 40's. Thoughts?
 

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2010 Shelby GT500 Kona Blue/Silver stripes
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Lots of good advise here that I won’t repeat or even comment about. Real silly question, but have you really looked closely at the rubber sleeve that seals around the CAI and throttle body inlet? Many times we’ve had people do work on TB, fuel injectors, or even just an engine cleaning, and they either over-tightened the clamps, which cracked the CAI tube letting air in after the MAF, or they didn’t get everything lined up correctly and snug, which also lets unmetered air into the TB. These both would cause a lean condition.
 
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Discussion Starter · #19 ·
Lots of good advise here that I won’t repeat or even comment about. Real silly question, but have you really looked closely at the rubber sleeve that seals around the CAI and throttle body inlet? Many times we’ve had people do work on TB, fuel injectors, or even just an engine cleaning, and they either over-tightened the clamps, which cracked the CAI tube letting air in after the MAF, or they didn’t get everything lined up correctly and snug, which also lets unmetered air into the TB. These both would cause a lean condition.
Yep, I did check it. I've tried eliminating all the simple mechanic issues that could be present regardless of mods. I just sent Shaun an email asking what specific things he'd like me to data log for him. Waiting to hear back.
 

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As far as the Aeroforce, it would help if you knew what firmware version you had to look up the right set of instructions and related parameters. Something back there in the recesses of my mind recall something about doubling the values because of the dual pumps on the GT500. I'll have to look at mine tomorrow, but I know it's different platform than the 2007-2009 in terms of gauge parameters. I think the firmware data is on the back of the gauge. Aeroforce has all the manuals available for download on their website. Live Link will probably be a better alternative if you data log.
 
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