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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
Here are a few pictures of the fuel pump taken out of the 02 Pontiac Trans Am plastic fuel tank. I want to use the fuel pressure regulator that is on the LT1 engine. That means I need to remove or bypass the FPR in the fuel pump assembly. How do I go about doing this?
Here are a few pictures of the fuel pump taken out of the 02 Pontiac Trans Am plastic fuel tank. I want to use the fuel pressure regulator that is on the LT1 engine. That means I need to remove or bypass the FPR in the fuel pump assembly. How do I go about doing this?
Is this the FPR?
That is it. The metal piece in the LH side of that clamp is the piece to remove. It is a very small regulator. You can just basically remove it. If you do it that way though a significant amount of returning fuel is going outside of the bucket and not cooling the pump. I machined a piece that replaced it and kept all the fuel going to the bucket when I swapped in my 4th-gen tank many years ago. You might be able to just gut the regulator and re-install. I machined a piece 'cause I like to over-engineer things way to often.
That is it. The metal piece in the LH side of that clamp is the piece to remove. It is a very small regulator. You can just basically remove it. If you do it that way though a significant amount of returning fuel is going outside of the bucket and not cooling the pump. I machined a piece that replaced it and kept all the fuel going to the bucket when I swapped in my 4th-gen tank many years ago. You might be able to just gut the regulator and re-install. I machined a piece 'cause I like to over-engineer things way to often.
M
I'd love to see a picture of your modification, but I know that is not possible. Thanks so much for the reply. I plan on buying a new pump assembly as this one is an original. Hummmmm is there another fuel pump assembly that doesn't have a FPR that will fit in the plastic tank?
Actually it is quite possible. I remember seeing a couple of months back the little ziploc baggie containing the removed regulator, some other bits, and a copy of the drawing I made. At my store room a couple of blocks from my house. There is also a good chance I still have the CAD file on my computer at work. I usually copy all my working directories to a storage sub-directory when I upgrade computers every three or four years. It might be a couple of days till I go digging at my store room or digging thru subs on my work computer.
Possibly better yet, from what I understand the V6 pump for the plastic tanked later 4th-gens doesn't have a regulator in it. I believe I read that in this forum but I have absolutely no idea what pressure and volume the pump is good for if it is true. You will possibly have to do some searching and reading if interested.
Actually it is quite possible. I remember seeing a couple of months back the little ziploc baggie containing the removed regulator, some other bits, and a copy of the drawing I made. At my store room a couple of blocks from my house. There is also a good chance I still have the CAD file on my computer at work. I usually copy all my working directories to a storage sub-directory when I upgrade computers every three or four years. It might be a couple of days till I go digging at my store room or digging thru subs on my work computer.
Possibly better yet, from what I understand the V6 pump for the plastic tanked later 4th-gens doesn't have a regulator in it. I believe I read that in this forum but I have absolutely no idea what pressure and volume the pump is good for if it is true. You will possibly have to do some searching and reading if interested.
M
Thanks for looking in advance. I appreciate it.
Right now I'm working on making the "trap door" so I can get at the fuel pump easier in the future. Also, after a practice fit of the tank into the body, I'm also working on the filler neck. This might take a little ingenuity.
I had a thought about using the FPR in the pump assembly, but then I'd have to remove the FPR on the LT1 fuel rail. That might be a problem so right now I'll go with removing the FPR on the fuel pump assembly. The V6 fuel pump assembly only has 19 g/s where the V8 has 30.2 g/s flow rate. The V6 pump assembly doesn't have a FPR on it. Any other ideas out there? These pump assemblies are expensive.
Found the file. Dated 2007! I believe it is sized for a 2-117 Viton o-ring.
M
I printed out your drawing of the piece. I take it that this is just a passage way for the fuel to run back to the canister. Here is a picture or two of my regulator taken apart:
I assume that the return fuel comes in at the top of the black plastic piece that holds your modified piece and runs to the pipe which goes down into the baffling canister where the pump is. If so, can I remove the piece holding your replacement of the FPR and go directly to the pipe going down to the pump? Let me try this again.
The return fuel comes in at the top through the white nipple (see photo). Once in the black plastic piece that holds the FPR, the fuel then goes to the pipe which goes down to the pump inside the baffle. Is this right?
My little bit completely o-ring seals the return cavity where the regulator "was" so that ALL fuel gets routed down the tube into the receiving are of the pump bucket. As if a leak was an issue! I found these today and imagined it might be possible to simply buy and just cut the little tit off the end of it and use it like the piece I made, just without a sealing o-ring: http://www.lingenfelter.com/mm5/merc...2#.Vblf4vlVhBc
BTW your description of routing I believe is as 100% as my memory from eight years ago remembers it as. I cannot remember where the down tube dumps...
But also not having one of those Lingenfelter pieces in front of me so I can measure, it might just work exactly as it is with no modding...
M
Thank you kind sir. I'll order one and see if it fits. I have a choice of the blue one or the red one. I wonder if they have the same dimensions? I better call first. Do you think I could just make a flat plate to cover or seal the open end of the black plastic piece?
Thank you kind sir. I'll order one and see if it fits. I have a choice of the blue one or the red one. I wonder if they have the same dimensions? I better call first. Do you think I could just make a flat plate to cover or seal the open end of the black plastic piece?
There appears to be more than just a color difference. They look physically different. One is for the driver's side tank and the other the passenger's. I have only vague knowledge of Vette. If you can get contact with L* ask them if either of those two pieces will fit the 4th-gen F-body pump.
Yes you could probably just make a flat plastic plate and retain with the factory clamp piece. I am sure leakage is not really an issue seeing as the pressure will be regulated elsewhere and this is just the final dump back to the bucket.
There appears to be more than just a color difference. They look physically different. One is for the driver's side tank and the other the passenger's. I have only vague knowledge of Vette. If you can get contact with L* ask them if either of those two pieces will fit the 4th-gen F-body pump.
Yes you could probably just make a flat plastic plate and retain with the factory clamp piece. I am sure leakage is not really an issue seeing as the pressure will be regulated elsewhere and this is just the final dump back to the bucket.
M
I've been trying to register at Ling... so I can post the question. I guess it just takes time. So, I'll call. Is there a way to dis-assemble the fuel pump assembly / module? BTW, thanks for staying with me on this.
Okay, I called and they think this plug is Corvette only for stopping the fuel balancing between the tanks. The plug might stop the flow of fuel completely and in our case that is not what we want to do. So, I'm going to fabricate a plate to cover the piece that held the FPR. This way the fuel will run directly from the return line through the black plastic "cup" that held the FPR and right into the pipe going to the baffle canister. Wish me luck.
Is there a way to dis-assemble the fuel pump assembly / module? BTW, thanks for staying with me on this.
Okay, I called and they think this plug is Corvette only for stopping the fuel balancing between the tanks. The plug might stop the flow of fuel completely and in our case that is not what we want to do. So, I'm going to fabricate a plate to cover the piece that held the FPR. This way the fuel will run directly from the return line through the black plastic "cup" that held the FPR and right into the pipe going to the baffle canister. Wish me luck.
Never taken one apart except for removing the regulator from a brand new Carter brand one and putting my blank thingy in. When I finally install the LS that has resided in a far corner of my garage for five years now I will be doing this fuel pump upgrade:
For curiosities sake I am tempted to buy those L* brand blanks and see if they do fit even if they must be modded to allow fuel flow. Will be much easier for folks than getting one machined per my drawing.
Never taken one apart except for removing the regulator from a brand new Carter brand one and putting my blank thingy in. When I finally install the LS that has resided in a far corner of my garage for five years now I will be doing this fuel pump upgrade: Racetronix Fuel Pump Install - 99-02 F-body Fuel Sender - FPA-001A - YouTube
For curiosities sake I am tempted to buy those L* brand blanks and see if they do fit even if they must be modded to allow fuel flow. Will be much easier for folks than getting one machined per my drawing.
HTH,
M
I watched the video and it's just what I needed. Thanks again. If you ever get up to Charlotte, let me know and I'll buy you a drink or two.
Did a little work on the project. We cut out an access hole so we could service the new electric fuel pump out of our 2002 Trans Am gas tank. Here are a few pictures of the job:
shows the size of the hole
This shows the cover
This shows the over lap of the cover
I used black silicone covered with wax paper then pressed the cover down to form a gasket
We welded bolts from the bottom up so we could remove the cover when needed
We did a little more work on the project. We prepared the underside and sprayed it with Lizard Skin. Now we can install the tank once I figure out where all the connections and fuel lines go. Few pix:
This is the product we used. We also bought the spray gun kit. We like the product so far.
IF YOU MADE THE TRIP FROM THE OTHER POST, START HERE
Next on the project is installing the gas tank. I'm going to try and post some pictures of the 2002 trans am plastic tank with questions about each fuel and wiring connections. And again no luck on the pictures. Did the forum change lately? I was able to post 4 days ago. One more try: nothing
BTW, if you want to see the whole tank go to post #194.
finally got the photos to work again.
Last edited by Strick1; 09-09-2015 at 07:44 AM.
Reason: fixed
I got this to work. So, here is the questions about this photo: What is item "A"? Is it an over pressure valve? The line coming out of it just runs to an open end.. Can I just leave it alone? (the white paper is just to isolate the lines for clarity)
research tells me that this is an over pressure relief valve. I just leave it as is.
Last edited by Strick1; 09-09-2015 at 07:43 AM.
Reason: clarification
What is item "B"? The line starts at the fuel pump assembly and connects to the line coming out of "B" and then runs to the EVAP canister.
This line comes out of the canister and has a quick connect on it. Where does it go? Back up to the engine for maybe vacuum?
After researching all about EVAP systems, you tube, helms service manuals, etc, the line coming out of the canister (blue line on it) goes to the fuel canister purge valve solenoid located on the intake of the LT1 engine. "B" and the yellow lines are for guiding the vapors into the fuel canister. These stay as is.
Last edited by Strick1; 09-09-2015 at 07:47 AM.
Reason: Research answered this question
Items "C" and "D" are these the fuel purge solenoid and fuel purge solenoid control? Will my 95 Chevy Caprice PCM control it by utilizing the two wires coming out of "D"?
After further research, the picture shows the fuel canister vent valve solenoid ("C" and "D"). The fuel canister purge valve solenoid is located on the intake of the LT1 motor and dumps into the throttle body. The vent valve is normally open and only closed (in OBDII systems) during testing and monitoring by the PCM. So, I just leave it alone. Wiring not needed.
Last edited by Strick1; 09-09-2015 at 07:33 AM.
Reason: Further research added
These are the two plugs that connects the tank assembly to the car. They control the fuel pump, fuel gauge, and (I assume) the EVAP system. Got any ideas where I might find the other ends of these plugs? I can guess that the green plug carries the fuel pump assembly items and the orange plug is the EVAP wiring.
Again, after further research, I just have to run wires from the fuel pump and fuel level. So, I can use a simple 4 wire weather type plug.
These are the plugs that connect to the fuel pump assembly. These plugs and the ones going into the EVAP make up the harness that goes to the two larger plugs shown previously.
After further research, I don't need the 3 wire plug or the pressure sensor in the 95 EVAP system.
This shows the fuel level rheostat out of the 2002 fuel pump assembly. From what I have read, this will not work with the 3rd gen fuel gauge. They say I need a 0-90 ohm rheostat which I have no idea where to get.
Here I'm trying to show where the in tank FPR is located. As you can see, I have removed it as I will be using the FPR on the rails of the LT1. My plan is to fabricate a cover for the place where the FPR came out so that the fuel from the return line will flow directly to the fuel bucket through that pipe coming out of the fuel pump regulator housing.
notice the rust. Must be from the ethanol in the gas.
This is a little out of order, but it shows the plugs for the fuel pump and fuel level sending unit. There are 7 wires coming out of them. I understand two wires are for the fuel pump and two wires are for the fuel sending unit. What are the other 3 wires for?
The black plug seems to be some kind of electronic sensor as that black unit looks like it just pops out. It has 3 wires going into it but nothing comes out the other side. Is this the "shut off" if it goes upside down?
The wiring has been resolved and I only need the 4 wire plug to run the fuel pump and fuel level.
Disregard the black plug. I don't need it. It's a tank pressure sensor used in OBDII EVAC systems which wasn't in the 95 EVAC system.
Last edited by Strick1; 09-09-2015 at 07:22 AM.
Reason: resolved info
So many question about the fuel tank installation. If you can help out I'd appreciate it. I can figure out the fuel lines to the fuel rails, the return and pressure lines. The power to the fuel pump seems simple enough except for the fuel pump relay and the oil pressure circuits that are connected to the PCM. The PCM energizes the fuel pump relay when there is RPM. I also learned that the oil pressure switch is not for saving the engine should oil pressure drop. It's just a back up to the fuel pump relay should it fail. What about the fuel cut off circuit that turns the pump off when the car is in a crash or turned upside down? Then there is the EVAP system. I just need to know if the 95 PCM can be programmed to run the solenoid and can I run the line coming out of the Canister to the engine for vacuum. What about filling the gas tank? There must be a way for the pressure to escape when the tank is being filled. Looks to me like it might be in the EVAP system. I promise that if I find all the answers to these questions I will post a detailed tutorial on how to install a gen 4 tank w/EVAP into a gen 3 car. SO, please give me a hand.
This paragraph shows the questions I had before my seemingly college level research of how the EVAC systems (OBDI and OBDII) work. I'm sure others have had the same questions about this EVAC system. Look below for my plan.
Last edited by Strick1; 09-10-2015 at 06:54 AM.
Reason: more explanations
This is the gutted FPR. Just need to plug the nipple so fuel will run down to the fuel bucket. Any ideas how to do that? I don't think JB Weld would work in a gas environment or that a rubber plug would hold up under the light amount of pressure.
BTW, the FPR had a torn diaphragm which made it inoperative.
Had to use the new FPR in the new fuel pump assembly. (see below)
Last edited by Strick1; 09-11-2015 at 06:54 PM.
Reason: added text
I ordered a new fuel pump assembly. I'll remove the FPR from it and replace it with the gutted FPR from the old assembly. I also ordered a FPR for the fuel rail. I hope this works.
This is the gutted FPR. Just need to plug the nipple so fuel will run down to the fuel bucket. Any ideas how to do that? I don't think JB Weld would work in a gas environment or that a rubber plug would hold up under the light amount of pressure.
JB Weld laughs at gasoline. I had to use it once in the past to seal NPT threads that would not stop leaking on an additional in-line fuel filter that I added. Held up for over for over seven years till I removed the extra filter assy completely.
JB Weld laughs at gasoline. I had to use it once in the past to seal NPT threads that would not stop leaking on an additional in-line fuel filter that I added. Held up for over for over seven years till I removed the extra filter assy completely.
M
I just looked at all the different JB Weld glues. Which one to use is the question. Looks like the original is the leading candidate. Then there is the Marine JB Weld.
????
Don't need it. I used a 1/4" pop rivet with a washer to plug the hole in the new FPR which had a hole instead of a nipple.
Last edited by Strick1; 09-11-2015 at 06:56 PM.
Reason: clarity
After a lot of research both on you tube and my Helms service manuals, The 95 PCM and it's EVAP system is different than the 2002 Trans Am EVAP system. The 95 system uses a pressure control valve with internal orifice, the canister, the solenoid valve, and the lines that connect them. That's all there is to it. When the pressure in the tank gets high enough, it opens the pressure control valve (not electrically) and the vapors go into the canister where it is stored. The solenoid valve is controlled by the PCM to open at certain times; not at idle, above 2mph, throttle position sensor not closed and the engine at operating temps. Not much to it. The purge valve solenoid is located on the engine and two lines come into it; one from the canister and the other goes to the throttle body. Maybe the 95 PCM EVAP tab (D10) will control both the vent valve and purge valve if I put them in series. I just won't have all the monitoring of the OBDII system.
Things that are different with the 2002 system is the addition of a vent valve, tank pressure sensor, fuel quantity sensor input, and a bunch of system checks and monitoring. The PCM controls the vent valve and purge valve solenoids and goes through several system checks (I guess for the emissions testing) i.e. tank pressure monitoring, valve monitoring etc.
This is where I'm at. Any discussion? Help me out.
As it stands right now, I can ignore the tank pressure sensor on top of the 2002 fuel pump assembly. What do you think?
All of this is answered further on in this thread. I'm leaving this here to show my questions on this swap.
Last edited by Strick1; 09-09-2015 at 07:58 AM.
Reason: added text
Default state of the LS1 fuel tank is vent open. If you don't have to worry about emission checks, then just hook up the fuel pump and go. The charcoal canister helps lower the "old car stink" of a vented fuel tank.
Default state of the LS1 fuel tank is vent open. If you don't have to worry about emission checks, then just hook up the fuel pump and go. The charcoal canister helps lower the "old car stink" of a vented fuel tank.
Thanks for the reply. Do you think I could just run the purge valve solenoid from my 95 PCM and ignore the vent valve solenoid since it's open anyway? I'd like to run the EVAP as best as possible.
Look below for my plan.
Last edited by Strick1; 09-09-2015 at 08:00 AM.
Reason: added text
I think I have a plan. (as far as the EVAP system goes) The fuel pressure line and the return line is easy. Just run the lines to the fuel rail. Now to the 2002 fuel tank connections. The wiring harness first. I won't need the fuel tank pressure sensor as the 95 system doesn't utilize one. That's 3 wires gone from the harness. I also won't need the 2 wires going to the fuel canister vent valve solenoid as it is open (the 2002 system closes it under certain conditions for testing/monitoring). So, the only wires I'll need are for the fuel pump and fuel level. Next is the fuel lines: The 2 running to the fuel rails are a no brainer, just have to put a fuel filter in the pressure line. The other line coming out of the canister runs up to the fuel canister purge valve solenoid that is on the intake of the LT1 which is wired to the 95 PCM.
2002 fuel tank
As of right now, this is my plan. I'll let you know if it works later in the swap. If you see any flaws in my plan or theory, please let me know. Thanks guys
Here is the 95 Fuel canister purge valve solenoid. The shorter line goes to the throttle body and the longer line goes to the canister on the tank. It mounts on the intake manifold near the throttle body. Just so you know, the two pins in the purge valve are power and the other is gnd. The PCM works with the gnd to complete the circuit and open the valve when the parameters are met. Should this plan all work, if there is a demand, I'll do a tech tip explaining how to replace the fuel tank in a 3rd gen with a LS or plastic tank.
Last edited by Strick1; 09-10-2015 at 07:07 AM.
Reason: correction
Next on my research is the fuel pump circuit. Where to put the relay and the proper wiring utilizing the PCM and oil pressure switch. I wish my scanner worked as I have a circuit diagram in my 95 Caprice Helms service manual that shows how it all works.
One of the reasons this thread is so long is that I hope to cover the little things that most other threads skip over and assume you know what needs to be done on certain systems. You know like those TV shows that take 30 minutes to a project like this.
I could almost write a book on this engine swap. If I did it would have to be online complete with videos. We'll see. Maybe only a few other guys are interested in these LT1 to 3rd gen swaps and it wouldn't be worth it.
I got my new fuel pump assembly today and immediately removed the FPR and had to gut it as there are small differences in the sizes of the FPR so I couldn't use the older one I gutted.
FPR gutted. Notice the end of the FPR, I used a 1/4" rivet and a washer to fill the hole at the end of the FPR. Not perfectly leakproof but it does the job.
What brand is that FP and what part number is it and application is it for?
M
The brand is Spectra Premium and Part # SP3368M from RockAuto and it is for a 2002 Pontiac Firebird Trans Am. There were other pumps available but this was the most reasonable. I didn't want to put a $350 assembly in and not work. Later, I might replace it with a quality pump assembly and it will be easy with my trap door. There might be a fuel pump assembly out there without the FPR in it, I just couldn't find it. There was one for the V6, but the pumps smaller. I'm happy with this one for now.
To continue our lesson on the EVAP system, here are a few shots of the 95 Caprice EVAP system. This is a typical OBDI set up:
Shows all of the system, except the fuel canister purge valve solenoid.
This is the pressure valve that opens when there is pressure in the tank and allows vapors to go into the canister.
This shows the line that I will run from the canister on my 2002 gas tank to the canister fuel purge valve solenoid on the intake. It's the long one and it is nylon.
This shows the top of the Caprice canister. 3 hoses. 1 is the air intake from the car's air cleaner, 1 is coming in from the pressure valve, and 1 goes to the throttle body.
I will be using the 95 Caprice fuel canister purge valve solenoid and the rest from the 2002 system. I'll just have the vent valve de energized (unplugged) and the tank sensor de energized as it is not needed. This will be a OBDI set up and since the car and engine are controlled by OBDI computer, I think it would pass. At least there won't be any gas vapors floating around smelling bad.
Got an important step done today. We installed the 2002 plastic gas tank complete with all the connection ready to be used. At first the tank didn't seem to fit as the straps from the 83 Camaro seemed too short. But after moving it around and shaking it, It finally slipped into place. Putting in the filler tube was a problem. After trimming about an 1 or maybe 1 1/2" off the filler tube (just like a radiator hose) the tube finally slipped into place. There is a bracket on the metal part of the filler tube that I secured to the frame with a bolt. Pretty secure. Even the 3rd gen gas door assembly fits. We're happy with this installation.
We also finished spraying the Lizard Skin material.
Next will be the rear end. We have to assemble the disc brake assemblies and re install the suspension. Then we can put some rubber on the ground.
Anybody there?
Shows a normal gas door after the plastic tank install
The filler tube fits nicely and secure
This view is from inside the drivers side rear wheel well looking up at the filler tube. There is a plastic panel that had to be removed so you can get access to the filler tube. Here you can see the bracket and my spacer which is an old pilot bearing.
I just ran a bolt just on the other side of that rim that the bearing is sitting on.
The tank installed
The fuel lines and EVAP line
Finished with Lizard Skin
In case we forgot, if we get another fuel pump we'll remember.
On the header question, I still only know of one place to get a set of headers, Dyno Dons. I found out that to have a set made just for my application would be way too much$$$$. I should be able to order the headers next month (Oct). It's always something.
07-28-2015, 12:17 PM
I found these today and imagined it might be possible to simply buy and just cut the little tit off the end of it and use it like the piece I made, just without a sealing o-ring: http://www.lingenfelter.com/mm5/merc...2#.Vblf4vlVhBc
