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In line fuel tank pressure sensor for LS swap

K30Blazer

K30Blazer

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I need a fuel tank pressure sensor for my evap on my LS swap and my sending unit doesn't have a port. I hear that some GMs came with an in line sensor on the return line but I can't find anything. I see Bosch made something but I can't find a part number either.

Last piece of the puzzle. Anyone got any ideas. Is drilling the tank a feasible option?
 
4wheelinfury said:
I need a fuel tank pressure sensor for my evap on my LS swap and my sending unit doesn't have a port. I hear that some GMs came with an in line sensor on the return line but I can't find anything. I see Bosch made something but I can't find a part number either.

Last piece of the puzzle. Anyone got any ideas. Is drilling the tank a feasible option?
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I've never actually heard of someone installing a fuel tank pressure sensor for a swap before. Gotta love Cali...

I bet you could install a bulkhead fitting on the top of the tank and thread the sensor into it.
 
the evap sensor you need to install most likely is NOT to have fuel run over it . as in the return line.

its for the upper bubble/bladder area of the tank position .

little splash now/then o.k. but not full contact of fuel .

possible to just remove sender and drill hole in top of tank and install factory bushing/rubber and then sensor .

now some might have installed the sensor in the filler neck maybe . :dunno:

but ya from what I have read cali if newer drive line swap = all emmisions stuff from same donor year vehicle . . . . got to love it . :doah:

don't forget gas cap swap out to non vented . and closed system evap not like out old system stuff.
 
yea, it is a PITA. I have two years May 2017 until my smog is due so I have some time to get all this stuff sorted, but I want to at least have a game plan.

I was pretty sure there were some sensors that were placed in line. That would be the easiest as I am running return lines off the filter right now.
 
4wheelinfury said:
yea, it is a PITA. I have two years May 2017 until my smog is due so I have some time to get all this stuff sorted, but I want to at least have a game plan.

I was pretty sure there were some sensors that were placed in line. That would be the easiest as I am running return lines off the filter right now.
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It needs to see tank pressure.

Drill a hole in the tank or sending unit and install the sensor.
 
yep that sensor is for checking the evap / charcoal can system is working and flowing threw the can . and not leaking in to the outside world.
 
I'm guessing that since this is a California registered vehicle you will need all of the emissions stuff from the "donor" vehicle to be used. This means you need to find out (maybe you do know already) what your engine came out of and install everything that was part of that vehicle, exactly as it was in that vehicle. (I'm not 100% on the cali laws for engine swaps but I think you have to match the emissions to the year and model of vehicle you engine came from)

I believe that GM has been using the closed vent less fuel tanks for several years and you can get the evap/charcoal canister from just about any late model GM vehicle.

I'm guessing that you have EGR, evap/charcoal canister, several sets of O2 sensors, catalytic converter. I can't think of what else would be used but there are probably several things I'm forgetting.
 
Yea I got everything else. It came out of a 2005 escalade ESV. This is the last piece of the puzzle.
 
I'm in the same boat planning out my CA compliant LS swap and have seen a couple ways of doing it. One is using the newer sending that has the sensor built in to it which requires an adapter for the locking ring and a little modification to the sending unit to make it the right height (I can post a link if you want it's easier than it sounds). The other way was hooking up a short piece of hose to one of the existing outlets on the older style sending unit and sticking the pressure sensor in the end. From what I understand just drilling a hole in the sending unit or tank won't work because the metal isn't thick enough for it to seal properly. Using a bulk head fitting might work except the FPS is a goofy plastic push in fitting with no good way of threading it in. Or at least that's how the one on my donor is and I'm not sure if other styles are compatible.

FYI one other issue you'll most likely run in to is the fuel level sensor. The PCM needs to know how much fuel is in the tank so it knows when to run the evap monitor and purge (or something along those lines). Some guys on another forum tried to trick the PCM to just do a constant cycle but the smog ref found it when they hooked up to the OBDII port and put everything in to test mode. They were failed and sent back to the drawing boards lol. I was just going to modify a newer sending unit to fit in my tank since it has everything the PCM needs to see for the evap system.
 
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There are ways to legally get around the stupid california smog thing. If I remember correctly, it's Sierra County, or Butte County, I can never remember, that requires no smog, at all. Get a post office box there, register your truck with that address, and have your mail forwarded to your home address, where ever that may be. Then carry on with your swap how ever you please, without having any worries about smog or emissions. My truck is titled as an '84 diesel, so I have no worries anyways, but for those without the diesel title, that's the best way to do it.
 
KidJethro said:
There are ways to legally get around the stupid california smog thing. If I remember correctly, it's Sierra County, or Butte County, I can never remember, that requires no smog, at all. Get a post office box there, register your truck with that address, and have your mail forwarded to your home address, where ever that may be. Then carry on with your swap how ever you please, without having any worries about smog or emissions. My truck is titled as an '84 diesel, so I have no worries anyways, but for those without the diesel title, that's the best way to do it.
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Pretty sure using a PO box to lie about what county you live in isn't exactly a legal way to get around the smog laws lol. Plus that only works until those counties eventually decide to follow suit (or are forced to) like a bunch have already started doing. Personally I'd rather take the extra hour or two to install/modify something and have it working correctly instead of dealing with PO boxes and hoping the smog requirements don't change for the life of the vehicle. Having a diesel title is definitely the easiest way to go but getting a swap through the smog ref isn't as bad as a lot of people make it out to be either.
 
Well, suit yourself I suppose. :dunno:

But here's the thing. People have been doing it for years. As long as laws regarding engine swaps have been a thing in this state. No other state has laws like this. So many laws (guns laws for example) in this state ALONE, make zero sense at all, and have no precedent among other states. Living in cali, you should know that. The DMV computer that sends your smog papers and registration to you, doesn't give two ****s what address it sends your paperwork to. There is no oversight on the matter, and no way for it to ever become an issue. NO way for them to enforce anything. The emissions requirements are a lame, pointless and stupid requirement that has zero effect on the very issues the laws were worded to fix. We breath the same air as Nevada, Oregon, washington etc. But we have people like Dianne Fienstien and Barbara Boxer etc telling us how we should live and what we should do. If you wish to toe the line of those retarded fools, then that is certainly your choice....You could save your self a LOT of time, effort and not to mention money, by doing it the same way the rest of the world does things.

And it is Sierra County, I had to make a call to confirm.

The diesel title thing is waaay more sketchy than the other method. There ARE ways for the DMV system to flag such things, and send you some sort of notice or if the dmv person or smog tech is savy enough, and anal enough...you're focked.
 
Don't get me wrong I'm not sticking up for the retarded smog laws or anything like that all I'm saying is that laws keep changing in this state and more often than not they wind up screwing people like us. We used to live in Sonoma County 20 or so years ago and I still remember my dad freaking out when they told him he had to get rid of the long tubes on his '85 Burb and the same thing has happened to other people in my family that live in some of the more rural counties around the state. Having a PO box somewhere else might work right now but with how things keep changing in this state, I wouldn't count on it being a permanent solution. If you have the donor (or all of the components from it) then hooking up the evap system isn't really that hard or expensive. Yeah it adds to the difficulty factor a little bit but then it's done right and you don't have to worry about it again. Out of curiosity, what's sketchy about the diesel title? I've never heard of anyone having any issues except for the people with the 98+ trucks that now have to get smogged...
 
The diesel title route is sketchier than registering out of county, because the DMV has the ability to oversee that, via employees that pay attention and a computer system that can do the same. What happens when that same VIN shows up in the computer, for two different, concurrent registrations, with two different people, separated by hundreds of miles?

The DMV is not connected to anything that happens outside of it's own systems. They are only concerned that you comply with whatever is on the paperwork they send you. And what they send is based on the county your vehicle is registered in. It is all automated, no human oversight. After that registration/smog etc letter goes out, that's it. They have no hand in it anymore. It's up to you to comply with what they say. So....get them to send you a letter that says you don't have to smog your truck, and your done.

And basing decisions now, on something that may or may not happen in the future, like Sierra County changing it's policy's, is lame. As Garth said in the movie Waynes World..."Live in the now man." And even if that happens, you said it yourself, it only takes a couple hours extra to hook up the emissions stuff.

And please excuse my blunt way of speaking and explaining things. It is not personal or meant to be insulting to you.
 
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Gotcha so it sounds like you're using a diesel title/VIN from another truck then? I was thinking your truck was originally a diesel rig that had the engine swapped out at some point since that's what I've seen some of my buddies do. They get their registration renewal in the mail but never have to smog it or do anything else that would raise a flag about what engine they actually have in it.

I see what you're saying about trying not to worry about things changing until they do and if they hadn't been steadily eliminating exempt counties for the last couple decades then I'd agree with you. I've just seen way too much crap change over the years to risk going that route.

Sorry about the sidebar OP. To answer your question, there's a couple of ways to get that sensor working if you want to go that route and ways to get around needing it if you want as well.
 
rjfguitar said:
No, his truck is titled as originally a diesel, which it sounds like it was. Nothing wrong or illegal there.
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Actually...Anthony is correct. My VIN plate does not match my title. The VIN plate says it's what it looks like. The title says its an 84 2wd with a 6.2. This is why that method is more risky than registering in Sierra County. Too many things left to chance, or out of my direct control.

I'm not worried about the outcome anyways, if there ever were any problems I'd just tell'em to stuff it up their arse and piss off, take a day trip up the sierra county, through some of the most beautiful parts of the state, and take care of business up there.

Also, still have georgia plates and georgia title. gigglesnorrrt
 
Ha ha. I love where this went. I had considered the diesel frame vin idea but with an 87 the vin is stamped on the frame too. I am gonna see what the easiest route to go is. I have heard the inline return sender can work. Just need to track one down.

Oh yea don't talk to me about stupid Cali gun laws.
 
yes ecm commands test at over 1/4 tank up to 3/4 tank .

if other tests have passed it will try and run this one.

good trick to remember if you can have 1 monitor / test not run and still pass is the evap test is last and WONT run if under 1/4 tank and over 3/4 tank full. . . . .:whistle:
 
I would place the sensor as high up as you can, into the filler neck if possible like mentioned. This is just to keep the full from splashing on it before it tests.

Are you documenting your swap? Very interested.
 
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