EFI Fuel Pump Upgrade

[gregs78cam]

Website version with assembly pictures at:
http://www.gearhead-efi.com/gm-ecm-pcm-conversion/in-tank-fuel-pump-conversion.html

If you have a vehicle that came with some type of EFI then this may only be a slight upgrade, but if you are doing a conversion then this is really the only way to go in my opinion.

Through looking for part numbers, I found that there are many different height units. It very well may be possible to find a module that fits your tank height with out modification. But I would recommend only using one that has the siphon jet, be sure to check as some don't.

I have done this to both my '78 Camaro and my '74 K10 Truck. They both work great. Enjoy. Sorry I had to .zip them, it was the only way to fit them on the forum.

Part 1 Module modification
Part 2 Tank modification

[EagleMark]

Nice work Greg! :thumbsup:

Thanks for sharing!

[gregs78cam]

Thanks, I am just glad to be able to contribute.

[93V8S10]

Nice Work!!

[EagleMark]

Remind me after the game to unzip this and I will build an HTML webpage for the writeup. We will use it for a link from the BCCFind webpages... it's such a sweet deal it should be in web format, I can then post it here in forums to so it can be read and still download the files.

[gregs78cam]

Thanks.

Run with it Mark.

[EagleMark]

Giants would doing the running right now! Woo Hoo!

[gregs78cam]

Some background first. One issue I found when I swapped the old carbed 350 out for a TBI 350, was while driving my truck, I noticed that after using about 13 gallons out of a 20 gallon tank, if I stopped too hard the fuel would slosh forward away from the pump pick-up and the truck would stall. This got annoying but served as a low fuel warning, which was helpful because my fuel level gauge wasn't working at the time.

After that swap, I was in the process of planning the Dual TBI swap on the Camaro, and decided to integrate this mod. One thing that I had read many times was that when doing an EFI upgrade to a second generation Camaro, most guys that just stuck the EFI pump in the stock tank would constantly have to keep the tank more than a ¼ full or it would stall while cornering. Some have added elaborate baffles, some add sumps to the tank, but I wanted to do some thing better. Something like the factory would have done today, using today's technology.

The results? After doing the swap on the Camaro, which included this mod, I was able to drive the car to the gas station (which is up a pretty good hill and has both right and left hand turns going up this hill), with the gauge reading empty the entire way, (about 2 gallons in a 19 gallon tank). So I know this pump works very well.

I can say without a doubt that this pump will support up to 400hp at TBI pressures (~13psi), but may only support up to around 200hp at MPFI pressure (~43+psi). However if you are running an MPFI setup, and expect to make substantial power, there is the option of going to www.racetronix.com (http://www.racetronix.com/) and getting their FPA-016, this is a pump that would support 400hp at up to 58psi. Or for more power get the FPA-001 capable of 600hp at 58psi. Now I have not tried either of these options, so I can't say definitively if they will drop right in the housing, but they look like they should and will keep the siphon jet functional. If I do go MultiPort this winter one of these Racetronix pumps will be what I try to use.

Now for the pump.
In the mid 90's GM started putting these fuel modules in vehicles instead of putting the square baffles on the bottom of the tanks. These work by using the pressure from the pump to operate a small siphon jet that keeps the bucket full regardless of the level in the tank. The return from the engine drops right back into the bucket via one of the 1/4” stainless tubes that support the bucket. These pumps do normally run at MPFI pressures, but so far the one in the Camaro feeds two 350TBIs just fine at 13psi. I currently have this pump installed and running in my '74 Chevy truck with a single 350 TBI and have had no problems with too much or lack of fuel flow.

Start with two fuel pump modules, they don't have to be identical, as there are a couple of different styles that incorporate the bucket and siphon jet. I chose identical ones so I would have spare parts. These came from '95-'98 Pontiac Sunfire. There are other styles but they all work about the same and most of the steps here would work for them as well. Basically I will be extending the 1/4” stainless tubes that hold the bucket in place. If your tank is similar in height to the tank you get this module out of, you probably won't need to do any modifications to the module.

Just remember this pump is capable of much higher pressure than the factory TBI pump. Always use EFI rated Fuel hose, and clamps. I am not responsible for any damages caused by following these instructions.



This is what they look like. Also be sure to get the flange from the tank. I use a screwdriver to punch into the tank and tin snips to cut the piece oversize so I can trim to a nice edge as shown here.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1719&d=1330076983


This is the stock shape of the float arm. This sender happened to be a 0-90 ohm one so it should work with the older gauges.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1720&d=1330076983


I bent this float arm to be slightly more accurate, which won't be a whole lot since I am adding quite a bit of height to the unit. It is not hard to put a different wire into this sender and make it read accurately for any tank. The wire is 0.128” so 1/8” stainless TIG rod would work great. Near the end you will see how I made the arm longer for better accuracy. In this pic you can also see I have removed the black cushion/spacer from the bottom of the module. Once you do this the sender slides right off.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1721&d=1330076983


I thought I would throw this tip in at this point because soon you may be needing to remove the wires from the connector on the bottom of the lid. What I have found is that 0.025” MIG wire works great for removing pins from the metri-pack 150 connectors. Simply insert the wire into the small notch in each socket, while pushing in on the insulated wire from the other side. Then just pull the insulated wire out of the plug.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1722&d=1330076983


Now push in the two tabs at the top of the bucket and remove the pump from the bucket. You kind of have to manhandle the thing to get the inner screen out, but don't worry, the small line to the siphon jet is very durable. You will need to do this for both units eventually.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1723&d=1330078179


On the DONOR unit you will be cutting the three stainless tubes at the top where they meet the lid. I used this clip I had laying around to hold the spring back.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1724&d=1330078224


So what you end up is this.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1725&d=1330078341


And after careful measuring to figure out how much added height you need, you will cut the other unit to look like this. The module was right at 10” in the extended position. My tank is 11” deep, So to get 11” compressed I need 12” extended. That is 2” longer that stock. So 2” minus the 5/16” that the couplers add between the tubes that left me with 1-11/16” of tube that I need to leave on the module that is going into the tank.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1726&d=1330078386


On to assembly. Put a long tube through the pump holder and slide a spring over it. Then using a clamp/vicegrip to hold the spring back install a 1/4” tube coupler. Do the other two tubes and this part is done.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1727&d=1330078485


One issue I ran into with this module that I didn't have with the Camaro was due to the amount of height I was adding, the fuel pump wanted to pull up out of the plastic holder. So to fix this I drilled a small hole through one the locating blocks just above where the rubber lug on the pump sleeve sits, and I installed a stainless pin to hold the pump down. There is no need to bend the other end because as this slides down into the bucket, the wall of the bucket will hold the pin in place.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1728&d=1330078536


On the Camaro I only added about 1” in overall height so the wires to the pump and sending unit were long enough. However on this one I had to extend them. Another good reason to get two complete assemblies. Easier to make one splice per wire than to make two.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1729&d=1330078598


And the finished product, with 2” of compression available.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1730&d=1330078631

[gregs78cam]

Part 2, Tank modification.

This is the new flange that will hold the module and the o-ring that seals the unit. Trimmed to size and hammered flat. To mount the flange to the tank, I like to use a gasket sandwiched between the tank and the flange. On the Camaro I had a friend plasma cut a stainless ring that went inside the tank to add some rigidity and used riv-nut inserts to hold the ring to the tank and to provide a thread for the 12 bolts that squeeze the gasket.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1731&d=1330079435


I made a drawing with AutoCad to help with placement of the 18 bolts holding this flange to the tank. This was later changed 24 bolts.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1732&d=1330079469


Here is the top of the fuel tank that I am adding this pump to. I used a chisel to remove the old lock ring retainer from around the hole.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1733&d=1330079527


Here I cut along the marked line in the previous pic and hammered the entire area flat to remove the drain groove from the area where the gasket will sit.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1734&d=1330079577


This is the stainless ring that I had plasma cut for this tank. It was a bit of work getting this ring to sit flat because the heat from the plasma cutter had turned it into sort of a belleville washer. So with some heat to help it relax, and some hammering around the outer edge to stretch it a bit, it sat flat enough to split one side in order to spiral it into the tank. At this point I have also drilled all of the holes out to the required size for the riv-nuts. This ring could be replaced with appropriately sized washers to reinforce the edge and take up the difference between the tank thickness and the minimum thickness the riv-nuts can be mounted in.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1735&d=1330079651


Here are the riv-nuts installed with a small amount of loc-tite under the head to help with sealing. Also the new flange with 9/64” holes drilled to the same layout of the tank.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1737&d=1330079752


Here you see the tank, flange, and gasket cut from 3/16” rubber. To make nice neat bolt holes in the gasket, I used one of the stainless tubes that were left over and filed the end, stuck in the cordless drill and cut the hole easily.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1738&d=1330079818



Here is the new longer float arm made form 1/8” brass brazing rod to make the sender more accurate.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1736&d=1330079701


And here is the entire unit installed with stainless screws and loc-tite to ensure no leaks.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1739&d=1330079964

With these modules the hard plastic hoses are metric, however, 3/8” on the feed line, and 5/16” on the return and vent lines works just fine after removing the plastic lines. I hope this helps for your next EFI conversion.


Gregs78cam

[PJG1173]

wow very inventive. another thing to add to my "to do list"

[EagleMark]

Nice work Greg! Looks way beater than just an attachment! :thumbsup:

[woody80z28]

Something I will need to do with the Camaro as well. I need a new tank though anyway...so I can just weld the ring on rather than doing a gasket with rivnuts. I also thought about leaving my stock sending unit in place for the gauge and adding the pump in a new hole.

[EagleMark]

And you are now an officially published Internet Author of fuel injection conversion write ups! :thumbsup:

http://www.gearhead-efi.com/gm-ecm-pcm-conversion/in-tank-fuel-pump-conversion.html

[gregs78cam]

Thanks guys, I have been meaning to get the thing layed out in the thread for a while.


Something I will need to do with the Camaro as well. I need a new tank though anyway...so I can just weld the ring on rather than doing a gasket with rivnuts. I also thought about leaving my stock sending unit in place for the gauge and adding the pump in a new hole.

I have a friend that is going to put one in his mustang and he is planning on welding the ring to the tank. Also if you need the newer sending unit ohm range, there are modules that have them, that way you only have one hole. The racetronix module mentioned has the newer sending unit. I think if you get one out of a '93-'95 S10 it should have the newer sending unit.

[woody80z28]

IIRC the stock '80 sending unit is 0-90ohms, I'm not sure what the newer ones are...but my main reason to keep the stock sending unit would be the accuracy without modifying the float. Is there a stop on it to see full float and full drop (0ohm and 90ohm positions) to modify it to work correctly at the new tank depth?

[gregs78cam]

yup the arm only travels so far. In the second to last pic you can see the stop at the top of the travel.

[bing98]

Outstanding work Greg. I'm putting an L67 into my 72 Nova and would like to us this setup, but my tank is only 7 3/8 deep. How small does this set up get when compressed?

Also, I found a similar setup here http://vetteworksonline.net/ls1_conversion_fuel.htm using an LS1 F-body pump. According to them this pump has a built in regulator which allows them to do the following to eliminate the need for a return line. This is ideal as it will save me money and time running the extra line.

http://vetteworksonline.net/LS1%20conversion/fuelpics/F-Body-fue-pump.gif

Another suggestion to eliminate the need for a return line was to use a 99 and up Vette filter/regulator at the tank.
http://image.chevyhiperformance.com/f/30719946+w750+st0/0911chp_13_z+1972_chevy_nova_lsx_engine_swap+fuel_ return_line.jpg










What did you do for a filter/regulator?

Thanks

[gregs78cam]

Thanks, as far a compressed height, I will have to measure one. There are a couple of different style buckets with different compressed heights, but just from memory 7 3/8 may not be enough room.

Yea I looked at the VetteWorks stuff, but it was out of the budget, so I made due with what I could find.

For a filter I am using an Earls -6AN inline filter and a SummitRacing deadhead regulator that I modified to be a bypass type after the throttle bodies.

With an MPFI setup, the line pressure with deadhead plumbing is high enough that there is really no 'lag' between injectors going wide open and the regulator closing off bypass flow way back at the pump, but with TBI pressures the regulator NEEDS to be near the engine.

[EagleMark]

I couldn't get one to work when I did that shallow long tank from an IH truck. IIRC it had 9 inches to work with and was close, but still no go after cutting the spring loaded posts down. Unless you can find a shorter bucket?

The pumps without a return line that come on newer rigs ar PWM and have PCM controls. Would be a sweet setup if that one did have a regulator in pump.

But if it's not designed to be returnless it's got to be a heavy burdon on pump designed to flow freely, without flow it would built up heat and without flow not cool?

[bing98]

I hear that on the cost. VetteWorks wants $60 for this simple retaining ring set up........

http://vetteworksonline.net/LS1%20conversion/fuelpics/fbodypumpadapter3.gif

http://www.vetteworksonline.net/catalog/images/fbody-fuel-pump-adapters.gif

I understand they need to make a profit, but we're talking 2 steel rings and 4 tiny studs and nuts. If I can get the retaining ring off of the tank the pump comes out of I can just tack it to mine. I spoke to someone else about the height of that setup and I think you are right, it's to tall. I'm simply going to fabricate a small, approx 3", square well on the bottom of my tank for the pump to sit in. That should be the simplest and most cost effective way of doing this.

Could you please explain what deadhead plumbing is? Is that what was pictured in my original post from VetteWorks?

[gregs78cam]

Yes deadhead would be just like your first post, where the fuel line runs to the injectors/rails and just stops, no return, similar to a carb - (the evil four letter word, I know, sorry). In that pic the regulator is in the return line after it goes back into the tank.

[gregs78cam]

My friend that was putting one in his mustang, got this used one from somewhere, ended up not using it, needed one even smaller, I don't know what it came out of, but here it is compressed......

3965

[69crewcab]

My friend that was putting one in his mustang, got this used one from somewhere, ended up not using it, needed one even smaller, I don't know what it came out of, but here it is compressed......

3965
Greg
any chance you can ask your buddy what that pump came out of?? thats the size i need.

[gregs78cam]

I will give him a call, and find out and get back to you. As far as the mounting ring, I can draw up an .dxf or .dwg of any dimensions you might need. The first one I made for the Camaro was pretty small, the one for the truck was larger and easier to work with. Were you going to have it cut, or just want some guidelines on size?

I found the larger one. For some reason I can't post .dxf or .dwg, but that is not a problem. These are just for the reinforcing ring that I put INSIDE the tank:
OD 7.5"
ID 5.5"
24 holes on 6.5" bolt circle.

[69crewcab]

I will give him a call, and find out and get back to you. As far as the mounting ring, I can draw up an .dxf or .dwg of any dimensions you might need. The first one I made for the Camaro was pretty small, the one for the truck was larger and easier to work with. Were you going to have it cut, or just want some guidelines on size?

I found the larger one. For some reason I can't post .dxf or .dwg, but that is not a problem. These are just for the reinforcing ring that I put INSIDE the tank:
OD 7.5"
ID 5.5"
24 holes on 6.5" bolt circle.

Ok thanks let me know what you find out.
i was going to plasma one out. Is the inside ring welded in or how? Or I need to go read more lol

[jaros44sr]

hey gregs, great writeup, and followed your instructions, sorta! heres the problem, i lost one of the springs on the support rods, would you happen to have an extra spring

ill post pics later, but thanks for the great write up, it was almost painless

[ony]

I HAVENT DONE ANY COVERTING, but 92 plymoth,dodge mini vans have a 40 psi pump assemble that lay kindof flat you might look at a pic of one could be a possible alturnitive.

[gregs78cam]

hey gregs, great writeup, and followed your instructions, sorta! heres the problem, i lost one of the springs on the support rods, would you happen to have an extra spring

ill post pics later, but thanks for the great write up, it was almost painless

Hi, thanks for the feedback, sorry I have not replied back sooner, I have been EXTREMELY busy for a few weeks. Yes I have a few of the springs, if you still need some let me know, I can throw them in an envelope and send them out.

[oldfoop]

Greg, terrific write-up. I was looking for tank/pump for my truck, found this, and knowing very little about TBI or fuel pumps. I wonder if the tanks you modified had had fuel in them? I have been guessing how you kept from getting blown up - I decided maybe dry ice-carbon dioxide is heavier than air.

I have an old tank form what I think was an early '80s Olds. Has 3 5/8 dia sender in it,and only 8" deep. I wonder if modifying that tank and looking for module that short - I see springs on the tubes, so assume they have some slide adjustability,

Or, should I lok for newer tank with 4 1/8 dia sender opening, and find sender module to fit it, and match my 0-90 ohm guage curve. Can the resistance be changed easily on one of these modules?

Write-up seems to say the additional fuel pressure won't hurt the TBI or regulator.

also, I assume the fittings and electrical connectors won't match the original harness and the fuel fittings may be new to me too.

Hope this isn't too far backwards.

Thanks again for your write-up and I am really glad to find this forum.

[gregs78cam]

Hi, yes all three tanks that I modified have had fuel in them. Fuel in liquid form will not burn, it is the fuel vapors that ignite easily. Two of the tanks were done without any welding. On the latest one though, we drained the fuel out, then blew compressed air through the tank around all the crevices to make sure there was no liquid left in there ANYWHERE. When I didn't see any more fuel and only a slight smell remained I then turned on the shopvac and blew air through it for another 5 minutes or so. Then welded the flange on.

8" might be a bit on the shallow side for these senders. These have about 1 to 1.5" inches of compression built in to them so they always stay pressed against the bottom of a tank. My best suggestion is to just go to your local Pull-a-Part, and drop a few tanks and check out what is there.

The pressure shouldn't be any problem at all, it works just fine for TBI.
Fittings and plugs will be different, but not hard to sort out.
The level senders I used in the write up came with both ohm ranges for different applications, then later they changed style to the one pictured in post 22. These, I believe, were only available in the newer ohm range.

I hope this works for you.

[oldfoop]

Thanks Greg,

I found Spectra Premium makes replacement tanks and senders etc. I looked for anything that would fit space I have, then for sender to match. Hard part is, any tank that fit, I found all have the small sender opening, even though I found some for fuel injection. One has a "sump" in the bottom to prevent dry-run in tight turn or steep uphill run. I think I may wind up trying one of them.

I live in NH, and we don't have pull a part here, they dismantle, and keep what they think will yield the most $, and scrap/recycle the rest -called green yards. Its too bad, because the few yards that have cars out bacl, are being forced to get rid of them. Lots of nice old iron gone for ever.

I wondered about the high pressure of the sender that matches the tanks I think will fit - min press 72.5, and max 130.5#. Too high for TBI? The tanks were in '94 - '96 Blazers and Jimmys, and I think were well after TBI, so much higher pressure. If pressure isn't a problem, these will work well, because they are 0 - 95 ohms sender curve, and my guages are 0 - 90. Close enough. Can you buy replacement resistance cards for senders?

By the way, what is dual TBI? I'm old, but guess I missed this.

Thanks again for your help.

[EagleMark]

Greg has two 2 barrel TBI units on a special made adapter.

Those high pressures will work, what is not used is returned to tank via the return line. In your case I'd run 3/8th return line as well as feed.

NH would be a horrible place to live with those laws on junk yards! :yikes:

[oldfoop]

Thanks EagleMark, sounds like modified twin 4 barrel manifold - better set up than multipoint? Would sure look good.

Right now NH is a little tough in winter too, and junkyard laws are speeling the end here. I bet northern Idaho is miserable in winter too.

Thanks again.

[EagleMark]

I bet northern Idaho is miserable in winter too.Nah! Our Junk Yards are still open and we have plenty of old cars laying around. :happy:

[User Nameless]

This thread fascinates me. I started my L67 swap based on the many sources of info posted on all related forums. I overlooked the fuel pump aspect because I misread some info stating the OEM pump will work fine for an unmodded L67 setup. I did not see much about the fuel pump in the process of grazing through the best threads on the subject. Now, it is a problem that must be solved. I have a steel tank with a lock ring and pressure sensor on the top of the module. I have a donor module from a 1997 Regal s/c with a venturi type module. Based on this thread here, I should be able to adapt my OEM module to use the venturi swirl bucket and pump. The unknown part is the EVAP canister and pressure sensor. It is a shame the salvage yards in Las Vegas empty the car of all fluids and catalytic converters before they are available for the public to get perts from. This means no good fuel tanks, they all have at least 2 holes punched in the bottom. Trans pan had a hole punched through it straight into the filter too. All the single piece exhaust systems have the cat converters cut out, and not cleanly I must say. Another thing I have noticed is nearly every GM vehicle has the MAF sensor removed too. The employees claim they are not the ones removing the MAF sensor, so someone is either trying the shotgun approach to diagnosing their own car or they are making money on the parts as they are small enough to pocket and walk away without paying.

[User Nameless]

To my understanding, the Impala 9c1 Police Package has the NA 3800 engine, but the fuel pump and module assembly used in the L67 cars. Thanks for posting your FP mod Greg! Here is my contribution. In theory, this should work for my L67 swap - I suppose I will find out in the next few days.

UPDATE: My L67 swap project is nearly complete. First start of engine went without any problems. 28 sec. video here:
https://www.youtube.com/watch?v=yf7R4gOU4-c

The fuel pump mod worked great. The first and only test drive so far was around a residential neighborhood. The transmission shifted into all gears and the engine sounded and felt great! Just before I turned the corner to the house, I goosed the throttle to about 1/3 and the front end of the car lifted and put me back in the seat. That felt great! I pulled the car into the garage, revved the engine 2 times and as the RPM level came to idle, it fell below idle and engine died. I now have a crank but no start situation and the car has not started up since. I am waiting on a fuel pressure gauge for further diagnostics as ignition spark is present. One thing I have not replaced during the swap is the fuel pressure regulator. I have a feeling what happened is when I goosed the throttle, the high-speed fuel pump relay kicked in and blew the hose off the fuel pump or at the other end where it connects to the module. I will edit or update this post when the problem is identified.

The other thing I wanted to add to this project is about the rubber feet on the module. They are there to prevent the spring pressure from flattening the fuel sock between the module base and the fuel tank. The used module I pulled from the junk yard had only 2 of the 3 feet. That module was from a steel tank which uses the thick rubber O-ring type seal along with the large snap ring lock. The plastic fuel tank I have uses a steel rotating lock ring with a wide rubber seal. The rubber feet at the bottom of the module interlock with the plastic bucket through 2 holes. Unfortunately, the only 2 rubber feet I had were removed... in pieces... Old and dry...

The solution I used was cutting three pieces of the unneeded rubber O-ring seal from the steel tank design about an inch long. Folding a section in half, squeeze it into the hole for the original rubber foot and allow the return spring tension of that piece to hold itself in place in the oval shaped hole. With the spring pressure from the module itself pushing down on the new feet, I highly doubt they will find a way to work themselves loose from the assembly. I did not take pictures of this. If I need to remove the assembly for repair, I will be sure to take some pics then.