EZ EFI in a mid 80s truck?

[piecesparts]

Anyone here put and EZ EFI system in their mid 80s truck? I want a better fuel band for my stroker engine and the issue would be how I should set up the fuel pump. I have a set of dual tanks, but I figure the install would have to be off of one tank and use the other as a reserve tank to fill the on-line tank. I am trying to see if I would have to drop the tank and install a fuel pump from an 87 truck (TBI truck) or can I use the supplied external pump to feed the EFI unit. The boys at FAST/Cpmp Cams have been no help. Any thoughts?

[KQQL IT]

Tbi trucks are 13-17 psi typically. What fuel presure is needed
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[Firebirdjones]

I run an external electric pump on my pickup (dual tanks). I mounted it right in front of the tank switch where the 2 lines merge, so I can use the dual tanks as they are intended, the pump sucks from either.

If it helps, I did an LS swap on my blazer (which requires ~55 psi) and I also used an external pump on that swap which works fine. Not exactly what I want as ultimately it will be a custom tank and in-tank-pump setup, but it works for now.

[wilkin250r]

I think you can get a combination of tanks/sending units to work just fine with the external fuel pump.

The sending units used with mechanical fuel pumps are just basic pickup tubes, obviously, but the 3-outlet has a return line. Pair it with the 6-port fuel selector valve that switches not only the fuel line, but also the return line, and you would have the proper setup to switch both the pickup and return fuel lines to each tank. That should work very well with the external fuel pump, yes?

[chebyshortbox65]

You have to watch fuel rail pressure I did an ls swap with a duel tank setup with the newer switching valve for a tbi truck and the return line is to small it put the rail pressure at 90 best bet would be to run which tank you want run a 87 r10 tank and sending unit and an a/c delco ep385 fuel pump it was under 250 from napa for new tank sender and pump then use a tbi sender and pump from the junkyard on the other tank and wire it to a toggle switch to transfer fuel to th the primary tank that's how i did it and worked great
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[piecesparts]

Originally Posted by chebyshortbox65

You have to watch fuel rail pressure I did an ls swap with a duel tank setup with the newer switching valve for a tbi truck and the return line is to small it put the rail pressure at 90 best bet would be to run which tank you want run a 87 r10 tank and sending unit and an a/c delco ep385 fuel pump it was under 250 from napa for new tank sender and pump then use a tbi sender and pump from the junkyard on the other tank and wire it to a toggle switch to transfer fuel to th the primary tank that's how i did it and worked great
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This is where i figured I would have to go. My thoughts were to either try the external pumnp to the EZ setup and then just align the left-hand tank fro use and set up the right hand tank as a feeder to the left-hand one. As for installing an in-tank pump, I would believe that the top of the tanks would be the same, so a fuel senfing unit and pump assembly from GM in the factory 84 tank and upgrade the pump to the pressure caoability that I need. FAST sells those on their web.

This is all to support what I have already built and am running under the hood of the truck

[chebyshortbox65]

The 87 tbi inj sender will drop right into your tank but at 1/4 you will hqve problems with the fuel starvation while hard throttle and braking also I ran an Msd fuel pump and it ran good but anytime over 90 degrees outside while sitting for more then a couple minutes the pump woulf stator overheating and whine and I live where 115-120 is the norm for summer and don't want to be stranded.
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[chebyshortbox65]

Nice looking engine in running a 5.3 and in the process of dropping a e rod 6.2 crate motor in a 88 caprice cop car for a buddy
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[piecesparts]

I have a 2000 LS-1 out of a Trans Am hanging on an engine stand, but it is destined to go into a 68 Chevy truck project. I have had this stroker engine going for awhile, but I need a better solution to fuel and power. With a 650 carb it is very streetable, but limited on max power. With a 750 carb it is sluggish in city traffic, but runs out great at higher RPMs.

[76stepsidechevy]

the ez efi needs 43 lbs so a stock tbi pump wont work here. I'm getting ready to install the same setup in my 76 and also thinking about adding a second tank. So far it seems like using a transfer pump from the aux tank to the main would be the easiest route. Also thought about welding in some bungs for a balance tube between the two but it would have to be down low to work.

[Firebirdjones]

Should be able to dial in a 750 on a stroker engine (I assume 383?) relatively easily to perform well in traffic and highway.

Used to do it for a living. Tuning with a wideband, playing with air bleeds, power valves and power valve orifices you can make a carb perform pretty sweet with excellent throttle response and good fuel mileage returns.

I've run 750's on engines as small as 327's that perform nicely (my 69 Z and it's little 302 has a 780 from the factory). I used to run a 355 in my blazer with a 750 holley, and with a little trickery it performed nice as a daily driver and gave me 13 mpg city and 16 mpg highway (no overdrive and 33" tires pushing a 3.07 gear).

Too bad you aren't close by, I'd give you a hand at dialing it in.

[piecesparts]

Originally Posted by Firebirdjones

Should be able to dial in a 750 on a stroker engine (I assume 383?) relatively easily to perform well in traffic and highway.

Used to do it for a living. Tuning with a wideband, playing with air bleeds, power valves and power valve orifices you can make a carb perform pretty sweet with excellent throttle response and good fuel mileage returns.

I've run 750's on engines as small as 327's that perform nicely (my 69 Z and it's little 302 has a 780 from the factory). I used to run a 355 in my blazer with a 750 holley, and with a little trickery it performed nice as a daily driver and gave me 13 mpg city and 16 mpg highway (no overdrive and 33" tires pushing a 3.07 gear).

Too bad you aren't close by, I'd give you a hand at dialing it in.

I had a 750 on the engine and all the while I had to fight to slobbering at the lights. It may have had something to do with the type of carb--It was NOT a spreadbore carb. It also could have been the torque converter that I had, I can not remember if it was before or after I had the 2300 stall converter installed. With the 650 carb installed and adjusted to a good performance level, I get around 15 MPG with a stroker engine, 2300 stall converter, 700 R4 W/O a lockup converter, and 3.73 rear end gears pushing a 28" tall tire. My limit is the ability to accelerate when the RPMs reach the upper end of the scale. The 750 allowed so much more air and fuel at the top end, than the 650 does.

ALSO, It is my perception that the FAST guys sell a replacement pump for the internal setups. That way you could update what you have inside the tank and not have to add an external to piggyback the lower pressure pump.

http://www.compperformancegroupstore...stemEZIEFIKits

[Firebirdjones]

Originally Posted by piecesparts

I had a 750 on the engine and all the while I had to fight to slobbering at the lights. It may have had something to do with the type of carb--It was NOT a spreadbore carb. It also could have been the torque converter that I had, I can not remember if it was before or after I had the 2300 stall converter installed. With the 650 carb installed and adjusted to a good performance level, I get around 15 MPG with a stroker engine, 2300 stall converter, 700 R4 W/O a lockup converter, and 3.73 rear end gears pushing a 28" tall tire. My limit is the ability to accelerate when the RPMs reach the upper end of the scale. The 750 allowed so much more air and fuel at the top end, than the 650 does.

ALSO, It is my perception that the FAST guys sell a replacement pump for the internal setups. That way you could update what you have inside the tank and not have to add an external to piggyback the lower pressure pump.

http://www.compperformancegroupstore...stemEZIEFIKits

Yeah that sounds like a tuning issue. A 750 shouldn't be slobbering all over itself while idling. The idle circuits aren't that rich in the 750 vacuum secondaries, and only slightly richer on a double pumper (don't know which you had). Not a ton of difference in idle circuitry between a 650 and 750 either.

I should think better mpg are to be found as well. 15 mpg although may be acceptable, I don't see it as steller for the combo you run (.70 overdrive/28" tire/3.73 gear) There is more to be found there, keep tinkering.
I'd check the idle circuits in the 750 metering blocks and make sure they haven't been drilled. Stock size should be more than enough for a 383, and should be able to lean the mixture to ~14-15 afr easily. Then drive with the wideband and shoot for a lean AFR at part throttle by coming down on jet size (primary). About 72 is stock but I'd start with 68 and work from there. At wide open throttle shooting for an AFR of 12.8 you can drill the back meter plate or change jets if you have a rear block. On the front side keeping the jets lean will provide good part throttle response and MPG. To pick up more fuel on the front side without affecting mpg, drill the power valve orifice to compensate so the power valve drops more fuel when below a certain vacuum reading (aka: wide open throttle). That's a quick and dirty overview but it would get you on the right track.

[piecesparts]

Originally Posted by Firebirdjones

Yeah that sounds like a tuning issue. A 750 shouldn't be slobbering all over itself while idling. The idle circuits aren't that rich in the 750 vacuum secondaries, and only slightly richer on a double pumper (don't know which you had). Not a ton of difference in idle circuitry between a 650 and 750 either.

I should think better mpg are to be found as well. 15 mpg although may be acceptable, I don't see it as steller for the combo you run (.70 overdrive/28" tire/3.73 gear) There is more to be found there, keep tinkering.
I'd check the idle circuits in the 750 metering blocks and make sure they haven't been drilled. Stock size should be more than enough for a 383, and should be able to lean the mixture to ~14-15 afr easily. Then drive with the wideband and shoot for a lean AFR at part throttle by coming down on jet size (primary). About 72 is stock but I'd start with 68 and work from there. At wide open throttle shooting for an AFR of 12.8 you can drill the back meter plate or change jets if you have a rear block. On the front side keeping the jets lean will provide good part throttle response and MPG. To pick up more fuel on the front side without affecting mpg, drill the power valve orifice to compensate so the power valve drops more fuel when below a certain vacuum reading (aka: wide open throttle). That's a quick and dirty overview but it would get you on the right track.

The carb was an Edelbrock 750, which eliminated the vacuum secondaries. This truck runs at 2500 RPM at 75 MPH and the mileage is actually pretty good for a 4000 lb brick. Many are getting less with smaller setups and carbs.

[Firebirdjones]

Oh, not too hip on the edelbrock design for a few reasons. Popular carb though, I'll work on them if I have to.


That's not bad mileage though, but I think there is more.

I ran a 750 holley on my built 355 (mild cam and heads) 350 turbo (no overdrive) in my 4x4 72 blazer that weighs 4,650 lbs and knocked down 16 mpg highway cruising at 26-2700 rpms.
I've since switched it to a 6.0 LS/4L60E setup and now knock down 22 mpg. That overdrive is a wonderfull thing, and being able to tweak the fuel tables a little more intricately helps. Still alot of untapped potential in a carb if setup right though.

My 79 1 ton pickup with a GM 502/400 turbo and 3.73's (no overdrive) will get 14 mpg highway if I keep the rpms at 2800 or less. It weighs 5400 lbs. Not horrible considering what it is.

I think carb tuning is a dying trade or lost art. I have other old classics muscle cars here that are respectable on gas as well.

I see some of the newer trucks and what they get (father has one) and it's not all that impressive considering the advancements. So your 15 mpg is nothing to sneeze at.
Hopefully your fuel injection swap will make things simpler and you'll find what you are looking for.

[piecesparts]

Originally Posted by Firebirdjones

Oh, not too hip on the edelbrock design for a few reasons. Popular carb though, I'll work on them if I have to.


That's not bad mileage though, but I think there is more.

I ran a 750 holley on my built 355 (mild cam and heads) 350 turbo (no overdrive) in my 4x4 72 blazer that weighs 4,650 lbs and knocked down 16 mpg highway cruising at 26-2700 rpms.
I've since switched it to a 6.0 LS/4L60E setup and now knock down 22 mpg. That overdrive is a wonderfull thing, and being able to tweak the fuel tables a little more intricately helps. Still alot of untapped potential in a carb if setup right though.

My 79 1 ton pickup with a GM 502/400 turbo and 3.73's (no overdrive) will get 14 mpg highway if I keep the rpms at 2800 or less. It weighs 5400 lbs. Not horrible considering what it is.

I think carb tuning is a dying trade or lost art. I have other old classics muscle cars here that are respectable on gas as well.

I see some of the newer trucks and what they get (father has one) and it's not all that impressive considering the advancements. So your 15 mpg is nothing to sneeze at.
Hopefully your fuel injection swap will make things simpler and you'll find what you are looking for.

This engine has a Comp Cams roller setup that is a 264HR grind with a 212 intake and 218 Exhaust lift, working a set of Dart Sportsmen heads. I had to put the larger stall in the truck to keep it from pushing the truck through the intersection at a stop light. After the install of the converter, I can now idle at 700 RPM with it in gear, again. The timing is set at a 35 degree max and it runs a little rich, but not enough to foul plugs or turn them black.

I just sold my daily driver (5.7, TBI, with a 700 R4 and 3.42 gears) that got 19 to 20 MPG religiously for many years of ownership, so I can see that there could be some gain, but not without giving up something in performance.

[Firebirdjones]

I could keep the performance you desire and still get you mpg if you wish. Trying to walk you through it on the internet is tough, wish you were closer. That's a very tame camshaft that doesn't have any overlap to speak of, very easy one to tune. Probably ground on a 110 lsa with 4 degrees of advance. Good cam for a heavy truck that should give you snappy throttle and decent torque down low.

[piecesparts]

Originally Posted by Firebirdjones

I could keep the performance you desire and still get you mpg if you wish. Trying to walk you through it on the internet is tough, wish you were closer. That's a very tame camshaft that doesn't have any overlap to speak of, very easy one to tune. Probably ground on a 110 lsa with 4 degrees of advance. Good cam for a heavy truck that should give you snappy throttle and decent torque down low.

I believe that I got what I wanted with the cam. The idle has a decent lope to it and the truck is still driveable on the street. I will turn the tires and eat up little pony cars quite easily.