327_TPI_77_Maro

iTrader: (8)

I have a '165 6E mask TPI swap running well and I can burn chips for it but I am finding one minor issue...every time I remove the fuel cap I have a TON of vapor pressure coming out. I am guessing that my purge valve is not working (I purchased a used TPI charcoal can and wired it up when I repinned my TBI harness to TPI). My plan of action is the following:

1. test that when voltage is applied the canister purge valve is actually passing vacuum (I have quite a few spare TPI canisters and valves if it's bad)

2. make sure I actually have continuity from the ecm pin for CCP to one of the pins @ the canister

3. make sure the pink/black lead at the other canister pin actually has IGN on power




Aside from checking those things, when can I expect to see the ECM sending a ground to the canister to purge it, so I can check it? Will it purge at startup or some other known condition that I will be able to check easily just to idiot proof this setup?

Thanks

Steve

RBob

iTrader: (1)

The CCP vapor control valve opens at a little under 1 psi (5 KPa). The tank pressure will build to that level before the fumes are sent tot he canister.

So it is normal for the tank to build up a lot of air/fumes, more so the more empty the tank is.

The canister is open to air, and air is pulled through when the ECM opens the purge solenoid.

RBob.

327_TPI_77_Maro

iTrader: (8)

Is this CCP vapor control valve the electric one on the canister or is it somewhere else? The vehicle in question was swapped (by me) so I wonder if I left something out towards the tank end?

RBob

iTrader: (1)

See this thread:

https://www.thirdgen.org/forums/tbi/...ter-lines.html

The round piece with the three lines is the vapor control valve. The CCP line at the tank has a small restriction in it. Found another reference that states it opens at 6 KPa. So it will open in the 5 to 6 KPa range...

There is a rollover valve on the tank sender, but I don't know if that is on the CCP line or the tank pressure/vacuum vent line.

RBob.

327_TPI_77_Maro

iTrader: (8)

Got it, yeah I used that valve and appear to have plumbed it correctly. Do you know under what conditions the ECM applies signal to the solenoid itself?

RBob

iTrader: (1)

Usually once in closed loop, not at idle, and the foot is on the TPS. They even purge at WOT.

The purge DC% can be scaled back if the BLM drops too low.

RBob.

Saar

i don't know if this applies to the TPI motors(it's been far too long since i've had one in a road worthy vehicle), but on certain motors, where the CCP solenoid's tubing meets the throttle body, the throttle plate has to actually open so far(around 5% on a FWD3.1) before the port for the CCP is actually exposed to vacuum, otherwise, the vapors are only exposed to atmospheric pressure.

RBob

iTrader: (1)

They are probably all that way, called ported vacuum. Usually has a restriction in that port.

The other thing to check is whether the solenoid is NO or NC. GM used both for a real mix-and-match. The calibration usually has an option flag for which solenoid is used.

RBob.

Saar

the port in the FWD 3.1 was just a tiny hole, maybe 1/8" diameter at most.

strangely enough, when GM went from the 3.1 to the 3100, they moved the port from the TB to a couple of inches behind it and integrated it with the PCV "suction" half. i guess they were more trusting of the electronics at that point? or it may be due to the all 3.1s using normally open solenoids and all 3100s using normally closed.