My son has a 94 Z28. An exhaust manifold bolt broke causing us to pull the intake and driver's side head for stud removable. The car has 110,000 miles on it and the removed head needed a valve job. So we pulled the right side head as well. The real and front mains were leaking some so we pulled the engine as well. Block looked good as did the crank.

Rebuild includes the following: Stock crank, new bearings and seals, stock size forged pistons & rods, stock exhaust valves, increased from 1.94 to 2.0 intake valves. New Comp cam (07-502-8) intake 218, exhaust 224 . Upgraded from 1.5 stamped rockers to 1.6 rollers. New oil pump, water pump.
Hooker short tube headers with cat back exhaust from hooker as well. He also rodded out the cat. New O2 sensors.

Had trouble adjusting the valves but finally have that. Now there's no throttle response. Engine just idles. Comp said the cam would work with the computer and stock torque converter. The also said yesterday it may require a chip upgrade.

Anyone been here before ? Does the throttle positon sensor require offsetting? If so how to ? Or is this taken care of in the computer ? Any other required mods for this set up ? Desire is to keep streetable.
Also trying to operate without the electric air pump. Could this be causing problem ? Check engine light is not on so I'm thinking we're not setting any diag. codes. Could I be wrong ?

 

sounds like valve adjustment problems. the car should run "okay" even with a stock tune on a small cam like that one.

the converter shouldnt be an issue either.

how much past zero lash did you go when setting the rockers and what lifters are you running?

 

Lifters are stock. They are hyd. Tried to set between 1/4 to 1/2 turn past zero lash. Trouble is feeling zero lash. We orig. set twisting the push rods but this didn't work and we ended up with no compression, no run. I then adjusted by moving push rods up/down to feel for zero lash. This made big difference and allowed engine to run. It would only barely idle at around 500 rpm and would not go over if throttle was pressed, even at full throttle no increase in rpm's.

 

Love the name.. lol..

How are you adjusting the valves besides 1/4 turn or so? are you turning the crank 180 degrees to adjust the other valves after you have reached TDC for number one and adjusted the valves accordingly?

 

I'm also going with the "valves not set right" theory. You don't need a chip upgrade, TPS sensor tinkering, or any of that other accessories baloney to get an engine to rev by simply opening up the TB.

Why'd you reuse the stock lifters? Yuk. Reused stock springs and all that, too?

Mike

 

So you hit the pedal and nothing happens, correct? if so i would make sure the throttle cable is actually hooked up and opening the TB. If it is then i would make sure the TPS is hooked up. I dunno if the car will run with it unplugged. You shouldn't have to readjust the TPS at all.

 

No all new valve springs.
Yes, we started at toc and with #6 on compress stroke. Adjusted both then rotated 90 deg. and followed firing order making sure both intake & exhaust were shut. Is it possible the lifters are not fully pumped up with the engine off and once the engine starts and they fully expand, they not adjusted right?
It shouldn't be this hard to do. But then again, this valve adjustment question shows up a lot on this board.

 

See if it revs when you manually open the TB from under the hood.

Mike

 

Well, we finally got it. It was the opti. Had a friend hook up his computer. No codes set. But we did notice the timing was staying at zero when we opened the throttle. Also went back over the valves again. Made sure they were not too tight. Installed the opti and bang, started 1st time. Running and sounding great. Thanks to all for their help.......