Throttle unresponsive revisited

dubbsfaris

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Well, it did it to me again today. I was leaving my brother's house, and killed it trying to back up on the street. Started it back up and it did it again. At this point I was worried because I haven't stalled my car in a really long time. I decided to coast down the street and flip a u turn at the col-de-sac. By the time I got to the bottom, I realized what was going on, and just held my accelerator to the floor. After another 10 seconds or so, my throttle returned, but slowly, as if I was doing normal take off. I was going to my next stop, park the car, get back in and start it, and go to drive. Same damn thing. Turned off the car here, back on, same thing. So I considered the previous experience, and mashed the go pedal. I sat there maybe 30 seconds, then all of a sudden, throttle came back to life and I came on home. I wanted to write about this while it was still very fresh in my mind. Here are my conclusions-

Restarting the car 3 times had no effect. It needed to idle about 45 seconds for it to engage the throttle. Pumping the gas, leaving accelerator engaged, none of that really mattered. It was definitely a computer lag issue. Perhaps a bug in their PCM programming. If it continues like this on my car, I will leave it as is and do some data logging to chase this issue down. Need to get with my friendly local shop and Dr. Lund to see if they can figure this out. But my point is to let people know my "out on the street" solution is to let it idle and warm up before you take off.
 

steeltoe

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Factory throttle body? If not did it start after the change? As far as Ford related hardware it could be the throttle body TPS or APP. I don't think it's an air filter blockage because that would be more of an on/off type feel. This sounds like one if those issues where you need a meter and the IDS.
 

2011 gtcs

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I wounder if it's a issue with the factory TB, I have the CJ TB and never have had a issue
 

Lethalchem

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Well, it did it to me again today. I was leaving my brother's house, and killed it trying to back up on the street. Started it back up and it did it again. At this point I was worried because I haven't stalled my car in a really long time. I decided to coast down the street and flip a u turn at the col-de-sac. By the time I got to the bottom, I realized what was going on, and just held my accelerator to the floor. After another 10 seconds or so, my throttle returned, but slowly, as if I was doing normal take off. I was going to my next stop, park the car, get back in and start it, and go to drive. Same damn thing. Turned off the car here, back on, same thing. So I considered the previous experience, and mashed the go pedal. I sat there maybe 30 seconds, then all of a sudden, throttle came back to life and I came on home. I wanted to write about this while it was still very fresh in my mind. Here are my conclusions-

Restarting the car 3 times had no effect. It needed to idle about 45 seconds for it to engage the throttle. Pumping the gas, leaving accelerator engaged, none of that really mattered. It was definitely a computer lag issue. Perhaps a bug in their PCM programming. If it continues like this on my car, I will leave it as is and do some data logging to chase this issue down. Need to get with my friendly local shop and Dr. Lund to see if they can figure this out. But my point is to let people know my "out on the street" solution is to let it idle and warm up before you take off.

This has only happened to me once and I was hoping it would be an isolated issue after reading so many other people say it's only happened one time to them as well. Hearing it has happened more than once to you and a couple other people has solidified my feelings about leaving the tune alone (and warranty fully intact) until some answers can be given. You're modded aren't you?
 

Lethalchem

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Factory throttle body? If not did it start after the change? As far as Ford related hardware it could be the throttle body TPS or APP. I don't think it's an air filter blockage because that would be more of an on/off type feel. This sounds like one if those issues where you need a meter and the IDS.

I wounder if it's a issue with the factory TB, I have the CJ TB and never have had a issue

Though I can't speak for the OP, I know myself and a couple other COMPLETELY stock guys who have had this same event occur.
 

steeltoe

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Ford had a problem a few years ago with the throttle body striping the teeth off the gears in the throttle body but as far as I know Ford switched to metal gears to prevent that again.
 

dubbsfaris

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Hmm. Frank, you are right. I am running the FRPP twin 65 TB. Now that you bring it up, it hasn't happened until I swapped the TB. I will discuss this with Van. Thanks for the insight. I wasnt thinking it could be the TB, but Ive already had to swap one of these out.
 

5.8 Venom

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Let me ask you this, do you have an oiled air filter?

I had problems in the past when I had an oiled K&N air filter where the oil would collect on the MAF wire and the car would do exactly what you are describing.

Cleaned that thin wire and changed the filter, no more problem.
 

steeltoe

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Hmm. Frank, you are right. I am running the FRPP twin 65 TB. Now that you bring it up, it hasn't happened until I swapped the TB. I will discuss this with Van. Thanks for the insight. I wasnt thinking it could be the TB, but Ive already had to swap one of these out.


Your problem has very limited caused and is most likely electrical because the TPS and throttle body have been one piece since 04/05 when Ford started using ETC.
 

gassman

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this has happened to me several times and Van jus told me its an air filter or connection issue, but I went through it several times and it still happens.....I'll live w it till I decide to take it all off and go back to stock
 
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dubbsfaris

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Let me ask you this, do you have an oiled air filter?

I had problems in the past when I had an oiled K&N air filter where the oil would collect on the MAF wire and the car would do exactly what you are describing.

Cleaned that thin wire and changed the filter, no more problem.

I do have the K&N. im thinking of jerking the whole section, filter to TB. I think Im going CJ route with Jim. Its an upgrade over the twin 65 which hasn't been real good to me, and Im not a big fan of the carbon fiber tubing anyway.:shrug:

We will see how that pans out.:pop:
 

steeltoe

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I do have the K&N. im thinking of jerking the whole section, filter to TB. I think Im going CJ route with Jim. Its an upgrade over the twin 65 which hasn't been real good to me, and Im not a big fan of the carbon fiber tubing anyway.:shrug:



We will see how that pans out.:pop:


You have to really oil down a filter coat the hot wire in a MAF and that is a lot harder to do with a slot MAF. If your filter is a pinkish purple your fine if it's a reddish purple you have way to much oil.
 

dfroehli

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The throttle body voltage should be set at 1.7V. Easiest way to check would be to use the SCT and look at TPS sensor voltage at idle. Just go into the diagnostic menu in the SCT.

This could be an issue.
 

steeltoe

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The throttle body voltage should be set at 1.7V. Easiest way to check would be to use the SCT and look at TPS sensor voltage at idle. Just go into the diagnostic menu in the SCT.



This could be an issue.


But you need a laptop and the software to do that.
 

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Before you go throwing money at the problem by replacing things that don't need to be replaced let's look at the isolation of your issue and that of a few other people that are modified, modestly.

Going with a larger MAF will do absolutely nothing to the the throttle calibration.

With that said you are the only customer for whom I had to do a FRPP Dual 65MM Throttle Warranty Swap. Yes, the only one.

Jon Lund and I both worked on that throttle and corrected the TPS voltage, it didn't make a difference.

Here is what we do know. Your's is an isolated incidence with the twin 65.

At this point what I would like to do is have you re-flash the car to stock. Download the SCT Device Updater Software and do a firmware update to the SCT device.

If you do not have the latest and greatest tune you were sent I will help you and get it sent.

What we do know:

13/14 GT500's are VERY sensitive to throttle position voltage
SCT Firmware Updates are necessary in some instances and I recommend everybody do this
Changing your MAF will do absolutely nothing and reporting the issue to Lund Racing and doing some datalogging can probably reveal the issue.

Van
 

dubbsfaris

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Van called me today and we have a game plan. Let me just say this- I wasnt suggesting going with the JDM CJ as a fix. I just think it looks damn sexy, and its certainly no downgrade. But my first priority is to chase down this issue before I go changing anything out. But, that aside, I will share our findings as we run this issue down!

As I told Van, its not a problem if I have 30-45 seconds for the throttle to engage at startup.
 

Snoopy49

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Van,
Can the throttle response curve be changed? It would be nice to dial down the sensitivity from idle to about 1/4 throttle.
 
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steeltoe

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an,

Can the throttle response curve be changed? It would be nice to dial down the sensitivity from idle to about 1/4 throttle.


You can change the % of throttle blade open to APP input.

For example from the factory my old Raptor(5.4) at WOT was only 80% until over 5200 and then opened to 100%.

But the problem is these cars make a lot of power and have a very long stroke(longer than most big blocks). I used to idle my car out of my parking spot and only had to give throttle input when I started up the ramp to street level.
 

Sherrodmustang

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I had this issue today.. was doing some data logging for Lund. Did a WOT pull in third to about 5000 rpm when I had to slow down due to traffic. I came off the interstate on the off ramp. Went to pull out and had no throttle reponse for a couple pushes of the throttle and then it came back. Also had this happen from a traffic light just pulling out, foot on the pedal and nothing.. then all of sudden I had the throttle back.
 

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