I recently did an intake swap on my Z28. I had the battery undone for about a month or so while I was waiting on some spare parts. Tonight I finally got everything back together and ran into some big problems.

Put the key in the ignition and turn on the electrics, but NOT the car yet. Hear a little clicking noise. Check the throttle cable and it is kind of twitching. I jump back in and pump the gas once. twitching goes away. I figured it must have been a little loose and I go ahead and try to start it. Soon as the engine turns over the car immediately trys to redline. Revs just go all the way up. It scared the hell out of me the first time so I turned the car off. I figured "ok, I'll try one more time." same thing. I tried blipping the throttle and it just comes right down and starts climbing again.

Anybody have an ideas? it's almost like the throttle is sticking?

 

mine did that except rpms only went to 3500......it happens when car sits for a while with no power


but try to look under the hood and make sure the tb is closed......

 

Did you do anything to get it to go away?

 

nope just let it sit

 

Just check out what your throttle body is doing. Might need someone elses help too

Mine did this, except just the gauge redlined and not the engine, still havent figured out why but it is pissing me off

 

I would leave the battery connected and pull the computer fuse..leave it out for a while, and then try things again. Make sure the throttle cable is routed correctly and that the TB is closing completely. The TB doesn't have to open all the way for the engine to reach redline when the tranny is disengaged.

 

Check all the intake and TB bolts...make sure all the bolts are torqued properly....you could have a seal blown...maybe your intake is cracked...also check that any wires in the rear of the intake aren't pinched...making the intake not sealed...one last thing..make sure the butterfly has tension.


Good luck

 

Maybe the computer needs to relearn?? Maybe let it idle for 5-10min.

 

any updates on the ssituation?

 

I let it sit overnight and tried it this morning and the same thing happened. I'm going to go through everything tonight and make sure every nut, bolt and wire is secured.

The only place I can think of there being something wrong is with all those tiny vacumn lines in the back. I had the hardest time getting them to stay on while I wiggled the intake back into place. Seems like there is no room to fit your hand back there while you are putting things together. Anyone know if this might be the culprit?

The only problem with letting it idle for awhile is that I have a borla and it is on wide-open. I don't think my neighbors would love hearing that for 5 to 10 mins.

Thanks for all the help so far guys...

 

Your battery may have gone dead. Try recharging it.

Awhile ago my battery went dead at work. So I had to jump start it to get home. The rpms imediately shot up to 3500 revs. Then after removing the cables from the host vehicle, the car idled as if a teenager was blipping the throttle. On the way home everytime I pushed in the clutch it would rev wildly out of control. Even in the parking lot, I had to stand on the brake to keep it from launching.

I replaced the battery the next day. After I connected the negative cable to the battery, I started it up with absolutely no running or idle problems what so ever.

What I think happens, but I could be wrong, is the CPU needs a minimum amount of power to run. If the battery is too weak, the engine will increase the output of the alternator to make up the difference. resulting in a high and eratic idle.

Its possible that a month of sitting discharged your battery and the engine is trying to supply the lost amperage with a high idle. Check your battery to see if its good. It probably needs a charge or replacing.

Good luck. Let us know how it turns out.

 

Happened to me once after EGR mod. The cable was not sitting in the groove properly.
Put it back, no problem.

 

If it's redlining...it's got nothing to do with the computer...redlining is a huge issue...check your intake install, check everything.

Good luck man

 

it could defintly be those vacuum lines

 

no way a vacuum leak can cause an engine to red line, it needs way more air than a vacuum line can give, i would put money on the "drive by wire unit" or cables. on the LS1's 1 cable runs from the gas pedal to this untit, then 2 cables run from it to the throttle body, 1 for cruise, the other for normal driving. first check the cables. next i believe that the computer may have some control on this unit,i think the way it works is that your foot pulls the cable, that sends a signal to the computer or this unit, then this unit opens and closes the throttle body. i know its not directly connected system between your foot and the throttle body. i hope this info helps and keep us updated