New owner of 5.3 swap...few questions about Vortec Voodo (1 Viewer)
- Thread starter AKFJ80
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
workingdog
GOLD Star
I am running a similar rig (done by Georg/Orange45) and can tell you you shouldn't have those problems. The FIRST thing I would do is wire an OBDII port to the cab and get a gauge/scan tool for the cab. The one I like best is ScanGauge. They ahve some issues as a compnay, but the unit is good and comiplte. You can check and clear codes and monitor every gauge in the computer - which can be real handy. Codes on a modern engine are really handy - if will tell you if the MAF is going bad. You live and die by the MAF (and the 02 sensors) on these engines.
Also, the EVAP cansiter function is important to get right. The 5.3 computer needs a GM sending unit in the tank to operate the evap cannister, which can be tricky if you want to continue to run the stock fuel gauge.
Peter
Also, the EVAP cansiter function is important to get right. The 5.3 computer needs a GM sending unit in the tank to operate the evap cannister, which can be tricky if you want to continue to run the stock fuel gauge.
Peter
rover67
SILVER Star
Nice work on the MAF sensor. You diagnosed it properly. Code is probably still stored, so you'll need some device to clear it (autozone will let you use their scanner for free) if the smog folks check that stuff.
Weird about the evap stuff. I'd re-plumb it as mentioned above and make sure it is right.
I don't have a fuel level sensor and my swap works OK, but I do get some pressure variations in the tank I bet would be solved by the level sensor. I actually never knew it gave an input that affected the evap solenoid.
Weird about the evap stuff. I'd re-plumb it as mentioned above and make sure it is right.
I don't have a fuel level sensor and my swap works OK, but I do get some pressure variations in the tank I bet would be solved by the level sensor. I actually never knew it gave an input that affected the evap solenoid.
I would not screw with the evap stuff unless you have to pass emissions testing....but since I don't own a 5.3 not sure if feasable to disable or if it impacts driveablity issues. If you want to make all of that work..then you might as well go shoping in the junkyard or you'll have to hit the GM dealer for parts...most of the emissions stuff is GM only. Rock Auto is a good place for GM parts on teh stuff they carry.
while my swap is different.... 5.7 engine. I simply run an external fuel pump and have replace the hoses that feed and return from teh tank to the engine. I made no mods to the yota evap stuff in the passenger side storage area fender well, and I removed the yota charocal canister and I just vent from the hard line at the fire-wall that use to connect to the charcoal canister. Did away with the GM evap stuff and I never plugged in or enabled the gas tank pressure sensor. (1999 ver of 5.7 vortec)
So basically I'm technically emissions "free" ...I would have no chance in hell of passing sniffer or other testing.
trouble codes ....once set are maintained in the PCM memory until cleared as rover noted above. If you plan to keep the truck ...you might as well get a decet engine scanner, make sure to get one that reads live data as I noted previously.
while my swap is different.... 5.7 engine. I simply run an external fuel pump and have replace the hoses that feed and return from teh tank to the engine. I made no mods to the yota evap stuff in the passenger side storage area fender well, and I removed the yota charocal canister and I just vent from the hard line at the fire-wall that use to connect to the charcoal canister. Did away with the GM evap stuff and I never plugged in or enabled the gas tank pressure sensor. (1999 ver of 5.7 vortec)
So basically I'm technically emissions "free" ...I would have no chance in hell of passing sniffer or other testing.
trouble codes ....once set are maintained in the PCM memory until cleared as rover noted above. If you plan to keep the truck ...you might as well get a decet engine scanner, make sure to get one that reads live data as I noted previously.
Were does your tank vent?
The PO of my rig desmogged and installed a Weber... the tank was vented to atmosphere and it STUNK TO HIGH HEAVEN of gasoline everywhere I went.
Nice and clean now, no fumes to speak of
- Thread starter
- #26
DBleon THANK you for that diagram. And others as well for the help.
I am home right now taking pictures and tearing into this "mess" haha.
I have no way of contacting the guy who did the swap...apparently he is out of the game these days so I only have clues from his earlier posts as to how he routes things. The guy I bought the truck from "V8TUFF" does not return e mails or calls so I am SOL there too. Thats okay I can figure this out and you guys are awesome help!
I have found that he cut a hole above the gas tank next to the stock sending unit as you did in your setup. I do not know if this is an in tank GM sending unit however it makes sense it it is. Does this unit have an atmostpere vent? I dont know...and he used RTV to seal the hole shut with some aluminum....odd but I guess that works? Looks like someone was in a hurry back there.
So.... mystery hole next to stock sending unit....
the 4 small tubes that are no longer needed were open to the atmosphere...you read that correctly,..when I picked up some fuel I had a nice suprise of gas dumping all over the place above half a tank. Sweet.
I will cap those off.
Here is where it is interesting. The Neck filer vent is routed to a T fitting with one end going to the tank vent as it should, and the other routed to the Delpi evap canister adjascent to the filer neck.
So...We have a good vac source from engine manifold routed all the way back to second nipple down on delphi can...then below that is the line coming off the t fitting that is also routed to tank and filler neck then the top fitting on delphi can is going to the sensor thing (sorry still learning)
Clear as mud? Lets hpe these pics shed light.
Question though: I am plugging the open holes in the tank
And then routing the tank vent to the filler neck... where then wil I get my fumes for the evap sensor to sniff?
You see the evap box was pulling a vac as it should and FILLING itslelf with fuel and causing the truck to stall and no longer run.
It is acceptable to have the tank vent/filler neck be used as a vent source for the Delphi canister? Is it a simple plumbing issue?
I am trying to figure out if those open lines were causing siphining effect.
I am rambling forgive me.
I am home right now taking pictures and tearing into this "mess" haha.
I have no way of contacting the guy who did the swap...apparently he is out of the game these days so I only have clues from his earlier posts as to how he routes things. The guy I bought the truck from "V8TUFF" does not return e mails or calls so I am SOL there too. Thats okay I can figure this out and you guys are awesome help!
I have found that he cut a hole above the gas tank next to the stock sending unit as you did in your setup. I do not know if this is an in tank GM sending unit however it makes sense it it is. Does this unit have an atmostpere vent? I dont know...and he used RTV to seal the hole shut with some aluminum....odd but I guess that works? Looks like someone was in a hurry back there.
So.... mystery hole next to stock sending unit....
the 4 small tubes that are no longer needed were open to the atmosphere...you read that correctly,..when I picked up some fuel I had a nice suprise of gas dumping all over the place above half a tank. Sweet.
I will cap those off.
Here is where it is interesting. The Neck filer vent is routed to a T fitting with one end going to the tank vent as it should, and the other routed to the Delpi evap canister adjascent to the filer neck.
So...We have a good vac source from engine manifold routed all the way back to second nipple down on delphi can...then below that is the line coming off the t fitting that is also routed to tank and filler neck then the top fitting on delphi can is going to the sensor thing (sorry still learning)
Clear as mud? Lets hpe these pics shed light.
Question though: I am plugging the open holes in the tank
And then routing the tank vent to the filler neck... where then wil I get my fumes for the evap sensor to sniff?
You see the evap box was pulling a vac as it should and FILLING itslelf with fuel and causing the truck to stall and no longer run.
It is acceptable to have the tank vent/filler neck be used as a vent source for the Delphi canister? Is it a simple plumbing issue?
I am trying to figure out if those open lines were causing siphining effect.
I am rambling forgive me.
- Thread starter
- #27
Suspect t fitting. This would FILL with fuel and subsequently the evap box above it.
Were does your tank vent?
The PO of my rig desmogged and installed a Weber... the tank was vented to atmosphere and it STUNK TO HIGH HEAVEN of gasoline everywhere I went.
Nice and clean now, no fumes to speak of
The hardline at the firewall that use to feed the charcoal canister under the hood is now connected to a rubber hose that runs over to the driver side fender well. I've never smelled gas fumes. WE never disconnected any other hoses that feed over to the evap stuff in teh rear fender well. Only replaced/re-worked the engine supply and return.
I have purchased a vent "valve" to put on teh noted hose but so far have not gotten around to doing that, so the hose is just open at the end.
once again...our modifications had nothing to do with the hoses and parts in the passenger side rear fender well...
Last edited:
- Thread starter
- #29
I forgot to mention. There is a fairly larger MSD external pump mounted upstream to the frame rail. I do not know if this is a "lifer" pump is you would see in a diesel application or the primary pump for the system. I do know that it does prime itself with ignition switched on and no other sounds coming from the tank that I can hear.
It looks as if my issue is the vacume sourse drawing fuel our of the filler neck and into the evap box.
Now for a solution.
PS: this truck is Oregon registered and I do not need it to be smog legal, however I do believe things should be done correctly and safely in the world of fuel vapors!
It looks as if my issue is the vacume sourse drawing fuel our of the filler neck and into the evap box.
Now for a solution.
PS: this truck is Oregon registered and I do not need it to be smog legal, however I do believe things should be done correctly and safely in the world of fuel vapors!
orangefj45
Supporting Vendor
I don't like what I'm seeing. Not at all. Your canister is in the passenger compartment and so is the vent solenoid. Gas fumes in the driver compartment. Bad.
The canister should be mounted in the engine compartment or under the truck. I mount them in the engine bay. Even on stock road driven gm trucks the vent solenoids plug up. So I keep them up front so they don't suffer that faite.
I would re-install the factory vent canister and then run the vent line from it to the gm canister. it works.
Georg
The canister should be mounted in the engine compartment or under the truck. I mount them in the engine bay. Even on stock road driven gm trucks the vent solenoids plug up. So I keep them up front so they don't suffer that faite.
I would re-install the factory vent canister and then run the vent line from it to the gm canister. it works.
Georg
here is a pic of the way GM sets up the canister....
Yes please move that canister and vent out from where is at.....
The MDS pump is probably the external inline fuel pump that feeds gas to the engine...
Scary n sad some one sold you a rig in this condition...
Yes please move that canister and vent out from where is at.....
The MDS pump is probably the external inline fuel pump that feeds gas to the engine...
Scary n sad some one sold you a rig in this condition...
- Thread starter
- #32
Thanks manch And Georg.
Yes. It is very ghetto to say the least which begs the question about the rest of the swap.
I'll be re routing things tomorrow at daybreak.
I will keep you posted.
Yes. It is very ghetto to say the least which begs the question about the rest of the swap.
I'll be re routing things tomorrow at daybreak.
I will keep you posted.
WOW... I guess I should move mine then!!
It's in the same location.
The thing is, I get absolutely no fumes in the cab whatsoever.
rover67
SILVER Star
That's what I did.
I hooked up my charcoal canister from the GM up to the vent line and kept it all under the hood. FWIW, I never smell fuel coming out of it, but I do hear it cycling sometimes.
Ya the sound is annoying to me. Rover, does your click repeatedly? Mine clicks like 3x per second and its really bothering me since it's inside the cab in the rear quarter.
- Thread starter
- #36
Here is what I am not understanding. If the engine pulls a vacuume to the canister how is it not pulling fuel up into the can on your swaps? Mine is and it is quite frustrating. I assume the canister must be above tank level to prevent this?
Today I am going to pull the carpet back and see what this guy did for the tank sending unit or pump. Hopefully there is a factor vent as shown in the pic I can use for the canister. I think I will locate the canister fwd of the tank or under the hood like Georg does.
Today I am going to pull the carpet back and see what this guy did for the tank sending unit or pump. Hopefully there is a factor vent as shown in the pic I can use for the canister. I think I will locate the canister fwd of the tank or under the hood like Georg does.
Without looking at the FSM...
My assumption is that the fuel tank vents to the large plastic chamber in the pasenger side fenderwell, which then vents to the charcoal canister under the hood (metal hardline at the firwall, then rubber hose to canister on OEM Yota setp).
I think its part of the emissions rules that you don't have a so-called direct vent to atmoshere from the fuel tank. Where gas fumes can escape...obviously you have to allow air into the tank so that fuel can flow and the task does not become a vaccum device.
Maybe my logic is flawed? I would follow Georg and Rover's advice.
My assumption is that the fuel tank vents to the large plastic chamber in the pasenger side fenderwell, which then vents to the charcoal canister under the hood (metal hardline at the firwall, then rubber hose to canister on OEM Yota setp).
I think its part of the emissions rules that you don't have a so-called direct vent to atmoshere from the fuel tank. Where gas fumes can escape...obviously you have to allow air into the tank so that fuel can flow and the task does not become a vaccum device.
Maybe my logic is flawed? I would follow Georg and Rover's advice.
FWIW...Most gas caps are one-way vent valves. Letting air in to prevent vacuum, but not letting fuel vapors out.
orangefj45
Supporting Vendor
Correct.
The factory vent canister is designed to collect the fumes from all four corners of the tank without letting any fuel thru. That's why it's mounted up high in the fendewell and why I keep telling you to re-install it......
The gm canister works in conjunction with two solenoids. There's a vent solenoid and a purge solenoid. One of the solenoids is on top of the intake and when powered up allows vacuum to flow. The solenoid at the canister allows venting to the atmosphere. The gm computer actuates the solenoids when need be.
If both these canisters and the two solenoids are installep, plumbed and wired properly then there's no way for raw fuel to get into the charcoal canister.
Done.
Georg
The factory vent canister is designed to collect the fumes from all four corners of the tank without letting any fuel thru. That's why it's mounted up high in the fendewell and why I keep telling you to re-install it......
The gm canister works in conjunction with two solenoids. There's a vent solenoid and a purge solenoid. One of the solenoids is on top of the intake and when powered up allows vacuum to flow. The solenoid at the canister allows venting to the atmosphere. The gm computer actuates the solenoids when need be.
If both these canisters and the two solenoids are installep, plumbed and wired properly then there's no way for raw fuel to get into the charcoal canister.
Done.
Georg
Georg, can you please clarify some things?
After the fumes travel through charcoal canister they are condensed and pulled into the intake..correct?
So the vent solenoid (at canister) should only vent clean air (ie. not fuel vapors).. correct?
I imagine the vent solenoid is only to prevent pressure buildup in the tank/system...
I wish I knew a GM engineer.
Thanks
