justbrad

we finally got heads back on car the maggie bolted on and everything buttoned up now no throttle the car idles fine throttle works once or twice then just idle we took tb off and cleaned it no change anybody know if i have to buy another can i put a bigger one on ?if so how big what would you do

NITRO UK

Hi
Maybe check all the connections to the t/b ,seems odd if it was working before strip down . Could check the accelerator pedal as well.

You can put a larger t/b on ,LS2 is popular but you need to have your supercharger front snout modified to 90mm and a tune.

Also see if you have any fault codes .

highpockets

Any throttle/TPS related trouble codes ? ANY interference or binding of TB when installed will default to idle only,if commanded and actual TPS varies by just a bit,system fails to idle. Have seen MAF bolted next to TB,TB hitting a NOS nozzle,several strange things.Double check all. Good luck.

BLOWNBLUEZ06

If it's pissed, it should show a Reduced Engine Power message on the DIC. Anything electrically or physically wrong and it'll go into REP. You can reset it by entering diagnostics mode. Reset all messages on the DIC and then press and hold button 4. Hit button 1 4 times. Then go into manual mode by hitting 3 or 4. Go to your PCM codes and press and hold 6 (Reset) and it will clear them. You might want to document what codes they were before clearing them.

justbrad

well its pissed throttle goes to 87% and car goes into reduced power thinking it could be throttle sensor or pedal how do I test them

JoeyG

With a clear view of the throttle blade, key on to run position. The throttle blade should move and basically its verifying pisition. With the key still on you can move the accelerator pedal and the throttle blade should follow. This is the easiest way ive used without having a scanner close by. The throttle blade on key on should move from the "0" or "parked" position to the idle position which is around 10-13% open. Triple check all connections going to the throttle body, especially if using an adapter harness

justbrad

we have done that when the pedal is almost to floor it goes into reduced engine power my local corvette shop wants $500 for a used one saying gm discontinued them local stealership says still available $360 so with what we have done does that sound like the problem?does it have anything to do with my boost

JoeyG

Could be the TAC module, TB, or pedal. So before new heads it worked correctly, now unable to idle or drive? If it faults when almost going wide open is the throttle blade hitting anything? If you take the throttle bodyoff and hold it in your hand will flooring the pedal open the TB all the way without a fault code setting? Are you able to monitor throttle % and pedal pisition at all?

justbrad

swapped tb for another known good one no change with tb off and plugged in nothing obstructs car ran fine before heads broke up a little under wot how do i test tac and pedal

justbrad

we are able to idle and drive but once pedal hits 87% it goes to rep so now we think it could be tac or pedal i just don't want to keep throwing parts at it we bought hp tuners pro but are a little scared of it right now

BLOWNBLUEZ06

Where are you located?
There are people out there that can properly troubleshoot this for you. Throwing parts at it until the problem goes away can get expensive quickly and doesn't always work.

justbrad

tampa fl

JoeyG

In that case how far away is your tuner? If you can idle and drive it up until that 87% throttle level then the predicted airflow table for the throttle % is prob in need of adjustment. Or higher Bret to vacation in FL for a few days.

justbrad

wheres bret and does he know we are in the 80s here
drove the car for a little it started running a little hot 230 whats next been waiting 2 weeks to be put in line for tune

JoeyG

Bret's outta Texas, I do believe. Have you looked all over FL? Theres alot of shops down in FL, should be able to find someone that'll give you a comfortable schedule.

BLOWNBLUEZ06@RKT Performance

I'm in Forney Texas.

We could get you a HPTuners module and I could help you remotely. You purchase the module from me and I'll include 30 minutes tutorial time to help you with setup, config creation for logging or wideband addition and calibration or whatever else you need.
We can log pedal position, commanded ETC position, actual yielded position, TPS 1 and 2 voltages and many other things to help diagnose this issue.
Bad grounds can cause this issue too. The ground for your TAC module and PCM is on the frame, under the battery, under a 10mm nut. I would recommend cleaning and re-torquing your ground.

justbrad

where were you friday when we bought hp tuners?guess I need to get to know you guys and what you do.actually I bought hpt pro with 20 gm credits on it used from my brother in laws neighbor he lost his speed shop in teen last month and is having a fire sale with his cars tools everything,none of his cars run worth a **** so Im not asking for help.I finally have a tuner calling me back it will go in after the holiday.I did clean that ground and every other one i could find.I have to walk away from it Im so disappointed that I can't stand it. I want to thank you all for your help I hope I can report back in a week or so with good news if not does anyone have a trailer so I can get it to texas

BLOWNBLUEZ06@RKT Performance

Helping is my pleasure.

I do quite a bit of remote tuning if you want to try that. The price varies on the work that needs to be done. I try to come up with pricing that's fair to us both and do work that makes customers remember why they started this journey in the first place. :-)

highpockets

If you cannot get local help,I would not hesitate for a min to give Bret a call.The man is a fountain of corvette knowledge and will get you on the path to enjoying your car ASAP,and you can be sure the pricing will reflect the work and advice received ! Good luck with your project,I wish you the best.