LT1CST

thanks for your guys help with my last post
Now after i.start it up the rpms just race sky high. To thw point i have busted two push rods. One source told me a possible vacumm leak if so which hose? can anyone share some insight?
chris

zcardriver22

If it is a vacuum leak you will just have to check all of the vacuum ports on the intake manifold. Make sure they are all connected and that none of the hoses are in poor shape. You should be able to hear the leak and just feel around with your hand on the intake manifold. Once you find the leak the engine should start to settle down almost immediately. Good luck.

LT1CST

Now that think about. i.might have pinched my vacumm hose on the fuel pressure regulator. i accidently bolted it down underneath the intake during install. i had to cut it and i placed the remaining on. its kinda streched out. could that be an issue?

ACE1252

Do you mean the thing goes wide open on start up and holds that RPM?

Injuneer

If its idleing fast enough to break pushrods, sounds like it would be getting air from a source much larger than the vacuum line to the fuel pressure regulator.

Who built the engine?

LT1CST

Fred. I built the motor. This is my second build. The first time I made I made bunch of mistakes with the rotating assembly, main caps were not in the right place, And I had rods not in the right clynders. This time around I took my time and made sure that stuff was button up corrrectly. Now with the opti on my last post being off a tooth or so. Also when I crank the motor I hear alot of pulsing air somewhere.
Chris

LT1CST

ACE yes right when I start it the engine rpms go up fast and it holds around 2500 or so sometimes 3k. It doesnt drop at all.
CHris

LT1CST

ANy ideas guys? injeneer i.checked all hose and everything seems to be hooked correcty. No sign of any vacuum leak. The only thing that i can think of is maybe a bad opti spark? Also during cranking imhearing this air pulsing noises coming from the intake. I wonder if thats the intake valves opening.
chris

ACE1252

I think Injuneer is right, it has to be sucking air from somewhere.....could the IAC valve be stuck all the way open?

Also, can you take a vacuum gauge and check the vacuum level on the engine?

ACE1252

I'm not sure that is normal.....

LT1CST

How do I varify a IAC that may be stuck open? What do I look for?
Chris

Injuneer

Did you put the gasket in between the throttle body and the intake manifold, and tighten the TB bolts? Do you have the EGR valve, or at least a blocking plate on the hole for the EGR valve? Have you verified the large vacuum line to the power brake booster is not leaking? Have you verified that the throttle blades are fully closed?

LT1CST

Fred,
I have varified everything you stated. I checked the TB blades which are closed, Teh EGR port in the back of the intake has been blocked off, The brake booster line that leads to the intake. I pulled that off placed my thumb on one end and blew on the other. No LEAKS. TB bolts are secure and the gasket is in present in between the TB and the Intake.
Just in FYI, all of the componets on my motor were used during my last build with the exception of a used PCM, used OPTI (Still have old OPTI in garage) and a used MAF.
Chris

LT1CST

Theres something else that bugs me as well Injuneer, And thats when Im cranking the motor I hear this sucking type noises that has a pulsing type sound to it. I dont recall every hearing that type of sound before. Oh and I have new Roller Rockers.
Chris

LT1CST

UPdate 9/1/08
Found out the problem with my high idol. Intake gaskets were shot to hell. I swapped out the gaskets and walla!!! It idoled. I also got a tune too. After going through all of that I started putting trans fluid in the trans and now I think my trans is shot. LOL Never ending for me. Anyway I bought this transmission from a wrecked LT1. It had tranny fluid in it allready when I did the install. After putting in a couple of qaurts adding to what was in there I tried putting the car in gear to see if it would engage. NOthing. I placed more transmission fluid in there and still nothing. So right now im thinking I have a bad tranny. I know trans need alot of fluid so will see. I gotta leak in the back of my intake I think theres oil coming from under the rear seal area, wasnt doing that before the new gaskets. Thanks for your help people
Chris