Need Vortec Evap advice - SoCal (1 Viewer)

[JohnCapoccia]

I'm looking for advice on my Evap system charcoal canister. First some background: This is for a Gen III vortec in an FJ62, and it has to pass Cali smog. I committed to using my FJ62 in-tank pump. In restrospect it may have been better to modify the tank to accept the GM unit. My harness has already been configured, so I'm not turning back. It seems everyone has done it differently, whether it be an FJ60, non-smog, custom fuel tank, GM pump unit or any combination of above.

So my basic questions are where to mount the charcoal canister, where to install the pressure sensor, and where to place the vent valve.

I was hoping to avoid dropping the fuel tank, but it looks like I'm going to have to do it. I guess I could avoid it by just cutting and capping three of the four lines, and splicing in a new line for the canister on the fourth line using a barbed connector to plumb it to the evap canister.

So where is the best place to mount the canister, in front of the fuel tank, in the engine bay, or in the right rear quarter panel? My understanding is that I do not need the fuel separator in the quarter panel, and it looks like the can might fit nicely right there. It seems like an advantage of this location is that it's higher than the fuel tank, so there's no chance of it being fouled with gasoline. I saw in AKFJ80's post, that the recommendation was to get it out of there because he was smelling gas, but how is that possible, it is a sealed unit? Or was the concern with the vent valve? I now have plenty of room in the engine bay on the passenger side, but I really just don't want it there just because. I've seen others put it in front of the fuel tank, but wouldn't it be better to mount it higher?

For the fuel pressure sensor, I was originally thinking of mounting it in the fuel sender plate, but it's a tight fit, and I don't think it would be a good idea to just insert the rubber nipple that's on the sensor into a hole in the plate. It seems that it should have a bushing so that the rubber nipple makes a good seal. I could machine a precise bushing (my son has a lathe), but as much as I like to think I'm pretty skilled with this stuff, there's a chance I could f- it up then I have to find a new sending unit. It seems that the best thing would be to use one of the three unused bungs in the side of the fuel tank that are no longer needed for the fuel separator, but then there's a chance that liquid gas could get into it - is that even a problem?

For the vent valve, I could use the existing plumbing that was used for the FJ62 charcoal canister and mount it in the engine bay, which would be my preference, but the existing plumbing is a smaller diameter. I can't see why it should matter, but there's probably a reason the GM engineers decided on a 3/8 tube instead of a smaller diameter.

Any thoughts???

Thanks,

John

 

[megolfer]

Im interested in this also.

 

[MANUCHAO]

John, for the canister I say put it in front of the tank or at the engine bay....

for the FPR as you seen on the GM pump it is pressed in.. so I imagine it would be the same for the stock tank or on the sender as these are non moving parts...
The PCM must register a fuel level in order for EVAP to run some tests. EVAP tests won't complete without a valid fuel level signal.

You should talk to Brendan Patten at lt1swap@centurytel.net
He is knows this stuff and could explained all this in more detail.....
As far as it coming into contact with fuel.. I think that would be a non issue, so as long as it does not stay submerged in fuel for longer periods of time. Hose size should not matter either so as long as you your the EEC stuff.

Frank

 

[JohnCapoccia]

John, for the canister I say put it in front of the tank or at the engine bay....

for the FPR as you seen on the GM pump it is pressed in.. so I imagine it would be the same for the stock tank or on the sender as these are non moving parts...
The PCM must register a fuel level in order for EVAP to run some tests. EVAP tests won't complete without a valid fuel level signal.

You should talk to Brendan Patten at lt1swap@centurytel.net
He is knows this stuff and could explained all this in more detail.....
As far as it coming into contact with fuel.. I think that would be a non issue, so as long as it does not stay submerged in fuel for longer periods of time. Hose size should not matter either so as long as you your the EEC stuff.

Thanks Frank,

I also read another description that says the fuel level must be between 1/4 and 3/4 for the system to run the evap test. But what can I do? Pacific Fabrication says they've built hundreds of these harnesses for California and they say that cars with their harnesses pass. So I'm going to go for it, and if I have problems then at least I'll have something specific from the referee to go back with to Pacific so that I can ask for a fix.

So what's the downside of putting the canister in the quarter panel? I know it's not good to put the vent valve there but it looks like a convenient location for the canister.

I guess it's a consensus that the stock FJ60/62 separator is useless and it's OK to cap off the corresponding tank connections? The question is whether I should drop the tank and cap at the tank or just cut the hoses and plug them.

Another way to put it, What's the best way to cap unneeded connections on a gas tank?

 

[MANUCHAO]

The connections at the tank you could hook them to each other with a 12" fuel hose.
What you want to do is mimic the GM fuel pluming as much as possible.

The canister on the quarter panel is a health/fire/explosion risk if you ask me....
It should not leak, but if it does... it could hurt yah....

Regarding what PF says about their harness is true, but there are othe steps involved on the pluming of the EVAP system.
Yes, do as plan and if anything your PCM will alert yah with DTC's (engine ligh comes on).
You will also be able to read with a scanner what systems go on ready mode which ones do not....

Sounds complicated, but it really is not.. dont worry about this until you get there.... I say

 

[JohnCapoccia]

The connections at the tank you could hook them to each other with a 12" fuel hose.
What you want to do is mimic the GM fuel pluming as much as possible.

The canister on the quarter panel is a health/fire/explosion risk if you ask me....
It should not leak, but if it does... it could hurt yah....

Regarding what PF says about their harness is true, but there are othe steps involved on the pluming of the EVAP system.
Yes, do as plan and if anything your PCM will alert yah with DTC's (engine ligh comes on).
You will also be able to read with a scanner what systems go on ready mode which ones do not....

Sounds complicated, but it really is not.. dont worry about this until you get there.... I say

OK, I'll eliminate the quarter panel. I'm going to try to do this without dropping the tank.

 

[daytonadogie]

Have you read this thread?New owner of 5.3 swap...few questions about Vortec Voodo

 

[cruiser enthuiser]

It took some fiddling, I had to make an odd shaped bracket, but here's where I put my evap canister on the fire wall:

 

[cruiser enthuiser]

FYI, I originally ran the vent from my evap canister straight to the gas tank. I had problems with fuel backing up into the line especially in hot weather or after a fill up and it would cause the occasional engine stumble. This is probably because I had deleted the stock fuel/vapor separator and welded shut the extra holes closed on the tank.

So now I run the evap canister vent back to this aftermarket tank in the rear quarter...

From this tank I vent it back to the fuel tank (black line in the below pic). It serves basically the same purpose as my old stock fuel vapor separator.

Works like a charm!

GL

-Ed

 

[JohnCapoccia]

Ed, Looks good. That won't work for me because my engine is further back. I don't have room between the engine and firewall.

@daytonadogie: Frank had sent me that link before but I read it again. From what I can deduce from that thread, and also from Ed's post, is that the fuel separator is useful to keep the GM canister from flooding with fuel.

It sounds like the first problem with AKFJ60's rig was that the canister flooded with fuel, and the second problem is that the vent valve was in the quarter panel, which resulted in fumes. But, after reading Georg's comments, I see an advantage of placing the cannister in the engine bay. If I'm understanding Georg correctly he's recommending that we keep the existing separator and plumbing to the gas tank as shown here

Then connect this port on the cannister

To this pipe on the firewall

That would be consistent with connection #8 on this diagram

Am I understanding Georg's remarks correctly?

I can shoot him a PM, but I know he's busy running a business so I don't want to bother him if I don't need to. I think this will work really well for me, the plumbing is easy, exept for reducing the 5/8" port on the cannister to the 1/4" pipe on the firewall. I've got plenty of room on the passenger side fender well, and as Georg and Frank have said, the vent valve is less likely to get clogged if in the engine bay rather than under the truck.

Thoughts???

John