well i've got most of the motor sorted out, and i got the exhaust manifolds to fit and the wiring is being done right now. but i'm kinda stumped on a couple things.

first is the one and only vacuum line that came with the motor. its clipped to a bracket near the AC compressor and goes around to some funky thing near the rear passenger side that has the hose fitting on it as well as an electrical connector. i cant figure out where this one goes on the other end. i know i'm being vague, but i'll try to get pics and other info.

the bigger problem i have is there are 3 lines coming from my fuel tank. a pressure, a return and an evap line. i know the pressure and return go to the 2 lines up top tho i dont know which is which. one is larger and has a shrader valve on it, am i correct in guessing this is the pressure line? once i figure out the order i have those 2 covered, but where does the evap line connect to? i cant find a fitting for it anywhere, and since i dont really know WTF its for i'm kinda clueless where to start. thanks guys.

BTW its a 98 4.3 vortec SMPI from a 1/2 ton pickup.

Dallas

The evap would go to the charcoal canister, if you are using one. I think you can block it off if you don't have a canister.

well i have the stock charcoal canister off my 2.6, but where in the hell does it connect to the 4.3?

Dallas

What vehicle you installing this in? S10- 2.8 to 4.3? On a stock 4.3 s10, the three lines are pressure, return, and evap. The evap goes to the charcoal canister in the front of the engine. There is then a line from the canister to the throttle body to suck off the fumes into the engine. That is how it works on a TBI engine, I don't know about CPI. If it is an s10 swap, go over to the s10.org bulletin board, they can get you a lot more info.

its not an S10 swap its goin into an isuzu amigo, and its not CPI its SMPI. thanks for the info tho.

Dallas

I installed a 92 4.3 CPI in my CJ7... The evap canister connected to a fitting on the bottom of the intake on the front of the engine.
There was a single vacum line off the back of the intake (near the distributor) that was used for power brakes AND a vacum connection to the evap canister.

Don't know how much different the SMPI are.. but this might provifde a clue or two...

i'll have to look over the front of my motor better, but when i was lookin for that vacuum line i couldnt' find anything up there. also the brake booster has its own fitting, i had to order it from GM so i know it isn't shared by the canister.

Can anyone explain exactly how and why this system works for me so i'll have a bit more of a clue what i'm doing. On my 2.6 there was a line from the tank to the canister and 2 coming off it, but i cant remember where they went, just that i had to pull em off everytime i changed the starter to get space. thanks again.

Dallas

The front line is NOT a vacum line. Its the evap purge line...
Purges the vapors from the canistor by drawing them back into the motor.

The evap has 3 lines:

1) from the tank routing vapor to the canister.
2) a vacum line from engine (I think when there is enough vacum a valve opens...)
3) the purge line from the canister to the intake...

The purge line on the CPI was kind of buried.. I'll take a picture tonight and attach it...

You might go looking for a haynes or similar for the donor to get more info for your swap...

Lots more information about my paricular swap on my website....
Follow link in sig.

As I recall, my 98 vortec evap system did not have an engine vacuum line to it. I think it operated via electronic controls.

Shoulda said mine is a 94 CPI and the evap lines on it are as follows...

:rasta:

go ahead and ask over at www.s10-4x4.org

Just cause it ain't an S10 doesn't mean we won't know the answers to your questions. I haven't had to mess with the engine you have, so I can't answer it for you. Go over there and ask Mark. Bad Bowtie.