Fuel tank & pump questions for a mpfi motor in an 86 K30

[j20m715]

I'm putting a mpfi 350 in a previous 6.2 diesel 86 k30.
Fuel tank & pump are where I'm at a stand still.
I would like to run (at least for now) a stock 20 gal tank in the original location. What fuel pump & hoses are yall running in this swap ?

 

[AV8TER]

I have an 84 K5 gas engine. Here's my setup. I have an MPI system off a Merc 502 Mag. It runs on about 45 psi and has the regulator up on the fuel rail. I took the fuel line out of the tank and ran it to my pumps which are mounted just in front of the fuel tank. From there it runs up to the fuel rail and the bypass fuel from the regulator goes back to the tank via the stock return line. Works just fine. No in-tank pump.

 

[j20m715]

I have an 84 K5 gas engine. Here's my setup. I have an MPI system off a Merc 502 Mag. It runs on about 45 psi and has the regulator up on the fuel rail. I took the fuel line out of the tank and ran it to my pumps which are mounted just in front of the fuel tank. From there it runs up to the fuel rail and the bypass fuel from the regulator goes back to the tank via the stock return line. Works just fine. No in-tank pump.

What pumps are you running ?
You don't have any issues with using your stock fuel tank ?

Thanks

 

[AV8TER]

What pumps are you running ?
You don't have any issues with using your stock fuel tank ?

Thanks

I'm just using marine EFI pumps. I have a low pressure lift pump and a high pressure EFI pump. The high pressure pumps don't have much suction so they run an old school Carter carb type electric pump to feed the high pressure pump. With the high pressure pump at the same height as the tank it may not need a lift pump. I had both so I used them. I know a lot of Mercruiser engines only run the high pressure so maybe.

The stock tank works great. You just have to have a return line for the regulator to return back to the tank. I don't know how the plumbing on the diesel tanks work.

 

[dyeager535]

So get a tank, pump, and sender from any truck that was TBI and used the same size tank. That would be '87 for sure, perhaps crew cabs up to 1991, old body style of course, but you'd need to know if the tanks were all the same.

Going to guess, perhaps $300 in parts...tank, sender, and TPI fuel pump if 43.5PSI is enough for your application. Of course, that doesn't count tank straps, hoses, or anything else you might need due to age, damage, etc.

 

[j20m715]

So get a tank, pump, and sender from any truck that was TBI and used the same size tank. That would be '87 for sure, perhaps crew cabs up to 1991, old body style of course, but you'd need to know if the tanks were all the same.

Going to guess, perhaps $300 in parts...tank, sender, and TPI fuel pump if 43.5PSI is enough for your application. Of course, that doesn't count tank straps, hoses, or anything else you might need due to age, damage, etc.

Yes, that's my plan if possible.
I have a new 20 gal tank (tbi style)
Looking to see if I can put a newer (higher psi) pump in a tbi sending unit.

OR If someone had a better idea or setup.

 

[dyeager535]

Done all the time. TPI pump from Corvette/Camaro is pretty much a direct fit (outlet diameter on the pump is a bit smaller on the TPI pump IIRC, but the hose will fit) as long as they put out enough pressure for your setup.

How much fuel pressure do you need? TPI was 43.5, but no idea how much they will actually push if you try and adjust the regulator.

 

[j20m715]

Done all the time. TPI pump from Corvette/Camaro is pretty much a direct fit (outlet diameter on the pump is a bit smaller on the TPI pump IIRC, but the hose will fit) as long as they put out enough pressure for your setup.

How much fuel pressure do you need? TPI was 43.5, but no idea how much they will actually push if you try and adjust the regulator.

I need 60-66 psi with key on not running, 55-58psi running at idle.

 

[dyeager535]

Someone here probably knows, but in the absence of them posting, I'd google "TPI fuel pump replacement high pressure" and see if you can find any recommended replacements. To my knowledge there was nothing factory that ran that high that will fit directly in place of the TBI pump (although there was one high pressure TBI application, I can't recall what it's pressure was).

I'm sure Walbro and the like make higher pressure pumps that replace the TPI one.

Depending on what you are going with, obviously you have to re-do the fuel lines, are you going with a returnless system using the fuel filter with built in regulator? That would seem the hot ticket if you have to run new lines anway, and it's pressure is good for your application.

 

[j20m715]

Someone here probably knows, but in the absence of them posting, I'd google "TPI fuel pump replacement high pressure" and see if you can find any recommended replacements. To my knowledge there was nothing factory that ran that high that will fit directly in place of the TBI pump (although there was one high pressure TBI application, I can't recall what it's pressure was).

I'm sure Walbro and the like make higher pressure pumps that replace the TPI one.

Depending on what you are going with, obviously you have to re-do the fuel lines, are you going with a returnless system using the fuel filter with built in regulator? That would seem the hot ticket if you have to run new lines anway, and it's pressure is good for your application.

Thanks for your help, I am hoping someone who has done this will chime in.
I am running a return line back to the tank, (I have the complete truck the motor came from & plan on using most of its fuel lines & such).
Motor is entirely stock (for now) & I just need to get it running & dependable 1st.

 

[dyeager535]

What setup are you dealing with? LS? Plastic fuel lines or metal? With that much pressure, I don't think you'll hear many claim clamped rubber is a good idea with that much pressure. Retrofitting fuel lines is a real pain that normally doesn't work well. If you have to cut, splice and create fuel lines, converting to returnless if possible, may save some work and hassle, if that option is available to you. I've never checked into the returnless setups, but it's a fairly new way of doing things.

I ran the TPI Camaro lines on my truck, and that was a nightmare trying to just somewhat straighten them up so I could run them along the truck frame, and it looks terrible and IMO is iffy in terms of safety. When I re-do the frame I will be buying the proper tools to make my own fuel lines.

 

[j20m715]

What setup are you dealing with? LS? Plastic fuel lines or metal? With that much pressure, I don't think you'll hear many claim clamped rubber is a good idea with that much pressure. Retrofitting fuel lines is a real pain that normally doesn't work well. If you have to cut, splice and create fuel lines, converting to returnless if possible, may save some work and hassle, if that option is available to you. I've never checked into the returnless setups, but it's a fairly new way of doing things.

I ran the TPI Camaro lines on my truck, and that was a nightmare trying to just somewhat straighten them up so I could run them along the truck frame, and it looks terrible and IMO is iffy in terms of safety. When I re-do the frame I will be buying the proper tools to make my own fuel lines.

97-98 mpfi (steel lines).
This setup has supply & return lines coming off the back of the motor, down trans to frame.
Since this is a rev cab truck & I plan on running the tank in the factory location, the fuel lines will be pretty short.
I guess my newer plan is to install an external pump on the frame near the tank, then a stock style fuel filter.
Lines will either be steel or steel braided hoses.

I will look into the returnless systems.

 

[Larry]

I need 60-66 psi with key on not running, 55-58psi running at idle.

In that case you need an AC Delco EP381 for the higher pressures of sequential port fuel injection. The 8.1Ls in my K10 and Suburban use TBI fuel tanks, TBI sending units with the EP381 pumps (1996 5.0,5.7 and 7.4L pump). When I initially ran my 8.1L in the K10 in an MEFI-4 ECM (Marine and RamJet) it required lower pressure of 43 psi like an old TPI engine so I ran a EP241 to run that (EP241 is what was used to run TPI cars). From experience I can assure you an EP241 will not have enough nut to run a sequential port injected engine properly as it is only good for about 55psi while the EP381 will run up to 80 psi (and possibly higher). Both of my 8.1Ls run at 65 psi. They just seem happy at higher pressures.

Here is an EP381 mounted to the ’89 Suburban TBI sending unit.

 

[j20m715]

In that case you need an AC Delco EP381 for the higher pressures of sequential port fuel injection. The 8.1Ls in my K10 and Suburban use TBI fuel tanks, TBI sending units with the EP381 pumps (1996 5.0,5.7 and 7.4L pump). When I initially ran my 8.1L in the K10 in an MEFI-4 ECM (Marine and RamJet) it required lower pressure of 43 psi like an old TPI engine so I ran a EP241 to run that (EP241 is what was used to run TPI cars). From experience I can assure you an EP241 will not have enough nut to run a sequential port injected engine properly as it is only good for about 55psi while the EP381 will run up to 80 psi (and possibly higher). Both of my 8.1Ls run at 65 psi. They just seem happy at higher pressures.

Here is an EP381 mounted to the ’89 Suburban TBI sending unit.

Larry Thank you Thank you Thank you.

NOW my next question is

Will that suburban sending unit fit in a truck saddle tank ?

 

[Larry]

Larry Thank you Thank you Thank you.

NOW my next question is

Will that suburban sending unit fit in a truck saddle tank ?

Probably not. Just use a TBI truck side saddle sending unit if you’re doing a side saddle truck. I must have confused you by mentioning a Suburban. My K10 runs a TBI side saddle tank sending unit while the Suburban runs a Suburban TBI sending unit. Makes sense, no?


Here are part numbers for you


Looks like the Napa part numbers for Specta Premium sending units for an 1987 TBI pick up are as follows: 16 and 20 gal use the same sending unit.

FG05M – Driver’s side
FG05N – Passenger’s side

TBI Fuel tanks:
GM1C 20 gal – fits RH or LH
GM11C 16 gal – fits LH or RH

These Specta Premium tanks and sending units are cats meow. They are Canadian made (and very well made at that) unlike the China’s finest garbage from LMC. Although, when it comes to fuel pumps I only use AC Delco. Also, don't mess with an external frame mounted pump. Their loud, get hot and just suck in every way. If your going to do it, do it right

 

[j20m715]

Probably not. Just use a TBI truck side saddle sending unit if you’re doing a side saddle truck. I must have confused you by mentioning a Suburban. My K10 runs a TBI side saddle tank sending unit while the Suburban runs a Suburban TBI sending unit. Makes sense, no?

These Specta Premium tanks and sending units are cats meow. They are Canadian made (and very well made at that) unlike the China’s finest garbage from LMC. Although, when it comes to fuel pumps I only use AC Delco. Also, don't mess with an external frame mounted pump. Their loud, get hot and just suck in every way. If your going to do it, do it right

Larry Thank you again

No confusion on burb vs saddle tank.

The reason I ask about the burn sending unit is because burbs & blazers use the flare fitting with o-ring where all the tbi trucks use clamp on rubber hoses.
I have no idea why.
I am referring to the square body style (R & V).

So with your help today I SHOULD have it started & running this weekend

So I guess the best way to do this is tbi tank, tbi sender with ep381 pump

 

[Larry]

Larry Thank you again

No confusion on burb vs saddle tank.

The reason I ask about the burn sending unit is because burbs & blazers use the flare fitting with o-ring where all the tbi trucks use clamp on rubber hoses.
I have no idea why.
I am referring to the square body style (R & V).

So with your help today I SHOULD have it started & running this weekend

So I guess the best way to do this is tbi tank, tbi sender with ep241 pump

Oh, yeah….I get you now. I forgot about the line connections at the sending unit. It is odd they are different.

I wouldn’t be too worried about using rubber EFI hose to plumb the fuel lines. I’ve been running rubber EFI hose (black hose with a blue internal liner) on the K10 for 7 years with no issues. To be safe I added Hi-Tac sealant inside the hose before I slid them on then double clamped them (I do the same thing when building A/C lines). The K10 has rubber from the sending unit to the fuel filter then from the filter to the fuel rail I’m using OEM Workhorse Chassis braded fuel lines. The return side is the same except I made a piece with a quick connect on one end and a barbed clamp fitting on the other. I take the truck on a long off-road trip every spring and usually run about 2,000 miles in 10 days. It gets a big shake down before we leave and I always double check those lines. So far they have worked great.

Now this tank is the LH tank in the K10 that is an ’87 TBI fuel tank, ’87 TBI sending unit with an EP381 pump inside. If you’re running a 96-00 L31 5.7L sequential injected engines (MPFI as you called it) you’ll need the same pump I am using, not a EP241….or is the engine you will be using something different than a L31? The fuel pressures you gave sound like an L31 5.7L. The fuel tank in this picture is actually cheap Chinese LMC piece of crap as I didn’t know any better at the time. Funny thing is this turd cost more from LMC than a good Spectra Premium from Napa. Live and learn!

Now this RH tank is the high quality Canadian built Specta Premium from Napa. It is heavily aluminized….and built like a tank (hehe, nice play on words, eh...hoser ) where as the LMC tank above is just painted garbage. These Spectra tanks can be procured through other sources besides Napa as well. I've seen them on EBay and Amazon too

 

[j20m715]

Oh, yeah….I get you now. I forgot about the line connections at the sending unit. It is odd they are different.

I wouldn’t be too worried about using rubber EFI hose to plumb the fuel lines. I’ve been running rubber EFI hose (black hose with a blue internal liner) on the K10 for 7 years with no issues. To be safe I added Hi-Tac sealant inside the hose before I slid them on then double clamped them (I do the same thing when building A/C lines). The K10 has rubber from the sending unit to the fuel filter then from the filter to the fuel rail I’m using OEM Workhorse Chassis braded fuel lines. The return side is the same except I made a piece with a quick connect on one end and a barbed clamp fitting on the other.

Now this tank is the LH tank in the K10 that is an ’87 TBI fuel tank, ’87 TBI sending unit with an EP381 pump inside. If you’re running a 96-00 L31 5.7L sequential injected engines (MPFI as you called it) you’ll need the same pump I am using, not a EP241….or is the engine you will be using something different than a L31? The fuel pressures you gave sound like an L31 5.7L.

Now this RH tank is the high quality Canadian built Specta Premium from Napa. It is heavily aluminized….and built like a tank (hehe, nice play on words, eh...hoser )

Larry Again THANK YOU for all your help. I'm really glad to talk to someone that has "been there & done that"

I will try the efi fuel hose, since you have had such good luck with it.

Yes this a 96 L31 350/4l80e

The project is an 86M1028, L31 350, 4l80e, np 205, 60 w/ls, 14 bolt w/Detroit, 4.56's, 6in lift on 37's.

Once that is all dialed in & working correctly, the 205 will be replaced with an np203/lomax 205 doubler setup.

Hope to have it running this weekend.

I'll keep yall posted.

 

[dyeager535]

Pretty sure the difference between threaded and non-threaded fitting is due to the K5/Burb setups having the tank under the passenger compartment, trucks not. So safety insurance of some sort.

Only thing I could think of that made sense.

Does the Vortec stuff use the same saginaw fittings that the TBI setups did?

 

[j20m715]

Pretty sure the difference between threaded and non-threaded fitting is due to the K5/Burb setups having the tank under the passenger compartment, trucks not. So safety insurance of some sort.

Only thing I could think of that made sense.

Does the Vortec stuff use the same saginaw fittings that the TBI setups did?

Parts are ordered

Dyeager535
I didn't think about the passenger compartment issues but the saddle tanks are under the cab also.
I do think you are correct though.

Unsure if the vortec stuff is the same as the tbi stuff.