BowtieBeliever

I just bought a 95 Silverado with a 2000 ls1 out of a 2000 corvette! I have a few questions after looking under the hood.

First, there's a brass fitting at the front of the intake manifold (driverside) right behind the tb.. What attaches there? It's some kind of vacuum I'm guessing

Second, there's a plastic tube coming out of the back of the driver side valve cover and its broken after about 3 inches.. Idk what it is or where it goes

And lastly, the o2 sensors aren't hooked up, I found the plug from the harness on each side, but idk if they are front or rear. They are square femails with 4 male pins inside, the wires are purple, pink, tan, and black?

And just curious, my maf is unplugged as well as the o2's being disconnected.. Is this bad? The other day at idle I plugged the maf in and it started to kill the engine before I unplugged it again.. Idk I don't know fuel injected very well. Just carbed engines really..

punisherls6

Throw a couple of pics up may help in diag .. the plastic tube on rear of valve cover I be love is for the PVC valve pit up a couple of pics and I can see what were talking about

BowtieBeliever

BowtieBeliever

Top pic is the fitting that idk what attaches to it.. Bottom is the broken line. And I need to replace my pcv line as you can see in this one

bww3588

iTrader: (49)

The brass fitting goes to the evaporation soleinoid which appears to be missing. That is A decent vacuum leak.

The plastic fitting goes to the pcv system. Hook it up with the line running to your pcv valve. The pcv valve is directly below your throttle cable in the last pic.

For the evaporation fitting, just cap it off if you don't have the equipment.

After that, hook up your o2's and maf and see how it runs. More than likely, someone unhooked the maf and o2's to force it into open loop to overcome the vacuum leak.

bww3588

iTrader: (49)

Oh, and after zooming in on the last pic, your pcv valve is broken as well. That is another vacuum leak.

BowtieBeliever

Vacuum leak after vacuum leak lol.. So cap the brass fitting, and replace the pcv line. Do they make 1 entire replacement pcv line?

bww3588

iTrader: (49)

I believe so. But it's gonna cost you. You can easily piece it together with some 3/8 fuel line, a t fitting and some hose clamps. Just make sure you route everything correctly. Connect both rear valve cover nipples to either end of the t fitting and run a line from the t fitting to the intake where the pcv valve is. Then connect the passengers side front valve cover nipple to the fresh air fitting on the throttle body.

Just cap the evap nipple on the intake unless you still have the evap system on the truck.

BowtieBeliever

I'll just cap it the evap then.

So is there a nipple on the back of the passenger side valve cover also?

codyvette

iTrader: (24)

Yes there is a nipple on rear of the passenger side valve cover. There is a stickey in how to archives on how to cheaply and easily fix this problem. Good luck to you.

bww3588

iTrader: (49)

It's going to be on the top of the valve cover pointing toward the rear of the engine. You'll see it.

BowtieBeliever

Fixed it! Tell me if it looks okay!

BowtieBeliever

Now, what is this in the picture? I know my maf is on the left but what is on the right?

Mattyfresh89

looks like the intake air temperature sensor..usually sits in the air intake Lid, but you do not have one shown here..just an open element filter.

My6speedZ

iTrader: (18)

That IAT might be like that because if that corvette motor is using the 5 pin MAF the IAT is integrated in the mass air flow housing. Count the wires on the connector. That might be left over from the truck harness or something. If not you can easily just put a grommet in the piping and install it.

If you want to redo your pcv hoses I helped a guy with it in another thread and it has the correct part number for the pcv valve and some pictures here:

https://ls1tech.com/forums/generatio...over-hose.html

TyCZ28

Thats IAT (inlet air temperature) sensor... just make a hole somewhere before the MAF and shove it in. you can put it in the boot on the filter if you need to

Jovozx12

iTrader: (6)

You can plug it in anywhere between the throttle body and the MAF like TyCZ28 said. Some MAF's had them all in one.

Jovozx12

iTrader: (6)

The line you fixed out of the valve cover just catches blow by. It defenitly needs to be hooked up through the PCV or you will have the bad vacuum leak.

BowtieBeliever

So did I fix this problem? I connected both lines from the valve covers to a T which then routes the air through the pcv and into the intake.

Thanks everyone for the quick and accurate responses! Can anyone point me towards where in the harness I might find the plugs for the front o2 sensors? I found the rears, unfortunately it's the fronts I need

bww3588

iTrader: (49)

There should be plugs for both the front and rear o2's. 4 total. If you can only find 2, someone may have pulled the rears from the harness and you may only have the fronts. Which is fine. Peel back the loom and look at the wire colors and match that to a wiring diagram for the Corvette and see which they are

Your pcv routing is fine. Now get your o2's figured out, plug that maf and ait sensor in and let's see if this thing runs.