Throttle body issue?

[crazyhorse]

I have an 05 gt 5 speed with about 58,000 miles on it. I installed the Jlt series 3 cai, gt 500 throttle body, and got it dyno tuned. After taking off from a cold start the car sometimes jerks off the line. Feels like it's "skipping over a bumpy road." Happens most of the time after cold start but has done it after the car was turned off for an hour and still warm. Is it a throttle body issue?

 

[stkjock]

Sounds like the tune needs refinement.

 

[crazyhorse]

I just got a new tune from Brenspeed and the car jerks/ jumps when taking off from a stop. My old tune from a local shop did this to so was hoping a new tune would fix it. Brenspeed suggested I get the Ford racing twin 62 mm throttle body (the polished one). Would this throttle body be better for my set up?

 

[Dino Dino Bambino]

Unless you've upgraded the heads, cams, and intake manifold, the stock TB flows more than enough air for the engine's needs. There's no need to plonk $600 on a Ford Racing 62mm unit unless it's burning a hole in your pocket.

 

[Silverhorse.s197]

I'm having the same issue with my GT500 throttle body on my DOB supercharger . My tuner is now reviewing a 20 minute datalog . One thing i did notice when it stumbles and jumps , my wideband jumps lean . After i run the car a while its fine , Just does is from the initial start up , reguardless if the car is warm or not . Did you have to swap out tps and motor off the stock throttle body ? I did and i always wonder is i dicked up something . Hopefully its a tune issue and it gets resolved.

 

[o2sys]

Did you try the idle relearn?

 

[crazyhorse]

I did not have to switch out the tps and motor to the gt 500.



How do you do the idle relearn?

 

[Silverhorse.s197]

I left the battery unhooked over night , then started it and let it idle for atleast 10 mins . Then some easy driving on some back roads . I may try it again just to take that out of the picture.

Sub'd for a solution ....

 

[o2sys]

It's letting it idle for 10min then with AC on full blast for another 2 min or something like that. I would disconnect the battery first to start fresh.

I have the GT500 with BBR plate and JLT 3 as well and don't have those issues cold or hot.

 

[07 Boss]

Bigger is not always better. Bigger throttle body takes finer adjustments to produce the same results as a smaller one. Just needs some fine tuning. It's like trying to tune a motor with too big of injectors.

Sounds like open loop tuning needs to be adjusted. Even if your engine is warm it will run in open loop until the O2 sensors are hot enough. So if it only does it cold or after the motor has cooled a bit, it is going to be a tuning issue.

What other mods do you have besides the CAI and TB? Why the bigger throttle body?

 

[06 T-RED S/C GT]

I left the battery unhooked over night , then started it and let it idle for atleast 10 mins . Then some easy driving on some back roads . I may try it again just to take that out of the picture.

Sub'd for a solution ....

The issue your having is most definitely tune related.. I had the same problem with my car sputtering at part throttle until my engine warmed up and I still use the stock throttle body..

When I switched my tunes to Brenspeed, the cold start issues stopped immediately and haven't encountered any sputtering issues since..

If you suspect that your GT500 throttle body is causing your cold start issues , try re-installing your stock throttle body if you still have it and if that stops the sputtering, then you'll know the GT500 throttle body is responsible and will require a tune revision..

 

[crazyhorse]

I have the basic bolt ons. Intake, throttle body, X pipe and bassani mufflers. I thought I read somewhere that with the Jlt series 3 the throttle body needed to be upgraded as well which is why I purchased it along with the adapter plate for the throttle body. I do have my stock throttle body still so I can give that a try. Would I need to call Brenspeed to have them adjust the tune again for the stock throttle body?

 

[06 T-RED S/C GT]

I have the basic bolt ons. Intake, throttle body, X pipe and bassani mufflers. I thought I read somewhere that with the Jlt series 3 the throttle body needed to be upgraded as well which is why I purchased it along with the adapter plate for the throttle body. I do have my stock throttle body still so I can give that a try. Would I need to call Brenspeed to have them adjust the tune again for the stock throttle body?

You do not need to upgrade your throttle body to run the JLT III CAI.. They're designed to be fully compatible with the stock throttle body..

If Brenspeed tuned your car for just the cold air intake prior to upgrading your throttle body ? You can just re-load that tune back into your ECM along with the stock throttle body.. Otherwise you will need to call them and have them e-mail you a revised tune file before re-installing your stock throttle body..

 

[crazyhorse]

Last night I replaced the gt 500 throttle body with the stock throttle body and haven't had any issues yet. Will see how the next few days go while driving.

 

[06 T-RED S/C GT]

So did Brenspeed e-mail you a revised tune file for your stock throttle body or did you reload your old file before upgrading to the GT500 throttle body ?

 

[crazyhorse]

I emailed them and they said I didn't need to retune it for the stock throttle body.

 

[Kylar]

I have the same issues with a gt500 tbody on a DOB setup. I've tried to have my tuner tune it out, but its still there. Its only for the first 5 mins of driving while its still in open loop i believe. After the car warms up and im out of open loop i have no issues.

I've also have an issue with aggressive shifting, if i shift fast (as in racing) sometimes i get a "hiccup" where it almost feels like i hit fuel cut, or a rev limiter. Only happens for a split second. Tried to have that tuned out to no avail.

I guess im just going to have to live with it...lol

 

[06 T-RED S/C GT]

I emailed them and they said I didn't need to retune it for the stock throttle body.

I'm glad everything worked out and that your no longer having any sputtering issues

I have the same issues with a gt500 tbody on a DOB setup. I've tried to have my tuner tune it out, but its still there. Its only for the first 5 mins of driving while its still in open loop i believe. After the car warms up and im out of open loop i have no issues.

I've also have an issue with aggressive shifting, if i shift fast (as in racing) sometimes i get a "hiccup" where it almost feels like i hit fuel cut, or a rev limiter. Only happens for a split second. Tried to have that tuned out to no avail.

I guess im just going to have to live with it...lol

If your current tuning vendor is unable to correct your issues while still in open loop, I'd consider looking for another tuner such as Lito or look into having your car custom dyno tuned instead..

But you don't have to live with it, unless it's by choice...

 

[Pentalab]

Unless you've upgraded the heads, cams, and intake manifold, the stock TB flows more than enough air for the engine's needs. There's no need to plonk $600 on a Ford Racing 62mm unit unless it's burning a hole in your pocket.

Agreed. The GT-500 twin 60mm is a waste of effort on a NA eng as well. The oem twin 55mm is ample for NA use. The GT-500 twin 60mm is good for 650 rwhp per VMP..and he doesn't even have 1/2 of that. The polished Ford twin 62mm made zero difference on my 2010..and that's with a Roush M90 blower with 5.8 psi boost.

I'm surprised Brenspeed would even suggest the twin 62. The real issue is the Brenspeed tune. If they can't tune the twin 60, what makes u think they can tune the twin 62.
Ditto with the twin 65 and the twin 67.

 

[sman247]

I currently have a 62mm ford racing on my whipple with no issues but for an n/a car its a waste and causes problems than good. besides the nice whistle it gives you, you wont gain more than 5hp to the wheels