tbi fuel psi - The 1947 - Present Chevrolet & GMC Truck Message Board Network

salrod00 · 05-11-2008, 06:52 PM

i got a 89 tbi motor that im dropping in my short bed. what is the psi on the fuel. i want to put a outside electric fuel pump on it .

LONGHAIR · 05-11-2008, 08:31 PM

I think it's about 15-18 psi., but I would make sure you have some way to regulate it and a guage to know exactly where you are.

72freak · 05-11-2008, 08:36 PM

The above is correct.........dont go fancy with all the special fuel pumps...just get a stock TBI in line pump and you will be fine.

ChevyTech · 05-12-2008, 02:03 AM

The TBI fuel pressure specification for small block Chevy’s is 9 – 13 PSI with the truck running.

salrod00 · 05-12-2008, 03:11 AM

ok so dont get a expensive one or what. i got a MSD pump but i was told that it was a high output... but i got one of a friend and it says max 8psi. its relatively small compared to the MSD pump. also it looks like a off brand but it was on a tbi motor . no regulator. also '72freak' where do i find a stock tbi inline pump.. what do you mean

ChevyTech · 05-12-2008, 04:30 AM

8 PSI is not enough.

The model 220 TBI unit used on Chevy V8s has a fuel pressure regulator built into it.

You must have a return line to the tank from the TBI unit.

Here are some links to photos/ illustrations.

http://chevythunder.com/tbi_regulator.jpg

http://www.goingfaster.com/spo/tbidiagrams2.html

http://www.snflupigus.com/Partspics/image054.jpg

http://www.goingfaster.com/spo/TBIdiagram.html

rfmaster · 05-12-2008, 07:38 AM

I apply a simple rule of 20-30PSI when fuel pump is dead headed. It also must deliver adequate fuel volume to satisfy HP requirements. Do not go crazy with high volume pumps - bypassed fuel will be returned back to gas tank, and fuel temperature will be increased due to excessive circulation!
Stock TBI engines do not need anything over 40GPH. Additional pressure (over 15 PSI) is needed to overcome fuel filter restriction. Also avoid pulse pumps since fuel pulsation may interfere with injector firings. Generally, you want a laminar flow in EFI system. Carter or Delco made pumps are the best to be had.

//RF

salrod00 · 05-12-2008, 06:55 AM

well i got the tank and lines off the suburban that i got the motor from. i have the return line,gas line and what looks like the breather that goes to the canister... could i just use this instead of buying a inline pump.

bigtruck81 · 05-12-2008, 07:50 AM

use a Z28 TPI pump (Delco #EP-241) it will give you more than enough pressure, and give you some room to move up if you decide to do some upgrades to the motor. many stock motors like pressure higher than the 13psi recomended high pressure.

89 crew · 05-12-2008, 09:26 AM

Quote:

Originally Posted by bigtruck81

use a Z28 TPI pump (Delco #EP-241) it will give you more than enough pressure, and give you some room to move up if you decide to do some upgrades to the motor. many stock motors like pressure higher than the 13psi recomended high pressure.

Yes they do like higher pressure, but the pump doesn't. we were given a pump for a port injected 454 to put on a tbi 427. The pump lived for 4 hours of run time!

LONGHAIR · 05-12-2008, 04:58 PM

Quote:

Yes they do like higher pressure, but the pump doesn't. we were given a pump for a port injected 454 to put on a tbi 427. The pump lived for 4 hours of run time!

TPI pumps are signifigantly higer pressure, roughly double, but that really shouldn't have killed it. It may have been on it's way out anyway?

rfmaster is right about the "over-circulation". It gets even worse if you run with the tank low on fuel.

salrod00 · 05-12-2008, 09:21 AM

thanks guys . i almost put the MSD pump. now i can return it and get the right one.. off what year is the Z28 pump come off. also what autopart store can it be purchased.i will keep yall posted on how the sounds when turned on

Walts_restoration · 05-12-2008, 07:58 PM

TPI pumps are 45psi, get one out of a 454 truck if you want volume, they used TBI too.

salrod00 · 05-14-2008, 05:23 AM

i ran into another problem. i connected the stock suburban lines and gas tank and it seems that the truck doesnt want to crank. it turns over but doesnt fire up. i ran the pump direct and i can hear it on. any ideas yall..... i did notice that when i put gas in the intake it fires up but then dies a couple of seconds later.. i did blow a big fuse that is hanging on the firewall. i cant find out what it is but am sure that it might be why. the relay is connected to a harness that sits on the passenger side of the motor next to the ac..

ChevyTech · 05-14-2008, 05:52 AM

Quote:

Originally Posted by salrod00

i ran into another problem. i connected the stock suburban lines and gas tank and it seems that the truck doesnt want to crank. it turns over but doesnt fire up. i ran the pump direct and i can hear it on. any ideas yall..... i did notice that when i put gas in the intake it fires up but then dies a couple of seconds later.. i did blow a big fuse that is hanging on the firewall. i cant find out what it is but am sure that it might be why. the relay is connected to a harness that sits on the passenger side of the motor next to the ac..

Sounds like the fuel pump fuse and fuel pump relay.

What year of truck is this on? 1989?

Can you post a photo?

salrod00 · 05-14-2008, 11:05 AM

yes they are on the 89 motor . im dropping this motor on the 85 shortbed truck. where are this fuses located at. on the fuse box in the cab? i will post some pics today

ChevyTech · 05-14-2008, 05:33 PM

Quote:

i did blow a big fuse that is hanging on the firewall. i cant find out what it is but am sure that it might be why. the relay is connected to a harness that sits on the passenger side of the motor next to the ac..

Here is a photo of the fuel pump inline fuse and fuel pump relay on a TBI truck.

rfmaster · 05-14-2008, 09:21 PM

Quote:

Originally Posted by ChevyTech

Here is a photo of the fuel pump inline fuse and fuel pump relay on a TBI truck.

You may want to check how much current that new (TPI???) pump is drawing. High pressure pumps may draw more current than old TBI pump used to draw.

Can you hear fuel pump come on for about 2 seconds when you cycle ign key from off to run position? Also, do you see SES light turn on - blink off - turn back on? This is POST executed by ECM.

During cranking ECM (engine speed <400 RPM) monitors Fuel Pump voltage on ECM connector B2. Make sure that you are getting 12 volts during cranking on that pin. Also, Pin A5 Ignition Fuse should be +12 during cranking - it is all too common to screw this one during swap! Pin B1 (orange) should always be hot - this circuit is connected to battery via that FP fuse.

If above is OK - check trouble codes by shorting pins A & B on ALDL connector together. If all is well you should only see Code 12.

//RF

salrod00 · 05-15-2008, 01:57 AM

when i did the swap i took everything from the suburban and put it in the truck. i used the motor and tranny intact, steering column,rearend, evap canister, and even the whole fuse box and wires. basically i stripped the inside out and re-ran all the wires again. i did this for i wouldnt have to cut and splice any wires. dont get me wrong i did splice some wires but it was just a few. so my fuse box is the suburban and all the wires and computer are as well. im also using the fuel lines and tank from the suburban. i ran the pump directly and yes it does turn on and pumps up the fuel. when you say the pin A1 and B5 those are on the fuse box right... thanks alot guys for walking me threw this. its my first swap and its harder than i thought... thanks again

rfmaster · 05-15-2008, 06:31 AM

Pin A1 and B5 are not located in the fuse box!

Take a look at ECM (it should be above just beyond glove box, under dash ) ECM has two connectors gray (2x 16 pins,C1-C16; D1-D16 ) and blue (2x 12pins A1-A12; B1-B12). You can see pin numbers and reference designators in the photo below:

Larger view

You can back probe with a sharp DVM test lead or in its absence a paper clip should suffice. FP relay should be controlled by ECM - its a safety issue, plus ECM power on self test (POST) routine expects to see FP voltage being cycled, OFF-ON-OFF.

//RF

salrod00 · 07-23-2008, 05:54 AM

I checked to see if i get current to those pins.. B1 gets 12volts at all times. A5 and B2 get no current at all. where did i mess up and what can i do to fix this issue

rfmaster · 07-24-2008, 12:51 AM

Salrod00

Pin B2 is called fuel pump voltage signal - Gray wire. This is used by ECM to monitor fuel pump voltage and it used by ECM for voltage compensation routines. Check Fuel pump relay connections and oil pressure switch.

A5 is service check light - it is a floating line until ECM pulls down when SES light is on.

//RF

05-11-2008, 06:52 PM	#1
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	tbi fuel psi i got a 89 tbi motor that im dropping in my short bed. what is the psi on the fuel. i want to put a outside electric fuel pump on it .

05-11-2008, 08:31 PM	#2
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: tbi fuel psi I think it's about 15-18 psi., but I would make sure you have some way to regulate it and a guage to know exactly where you are. Last edited by LONGHAIR; 05-11-2008 at 08:32 PM.

05-11-2008, 08:36 PM	#3
72freak Rottenwood Garage Member Join Date: May 2005 Location: Marietta, Georgia Posts: 4,321	Re: tbi fuel psi The above is correct.........dont go fancy with all the special fuel pumps...just get a stock TBI in line pump and you will be fine. __________________ 2004 Chevrolet Suburban C1500 2001 Chevrolet 2500HD Crew 6.0 1999 Harley Davidson Electra Glide 1972 Chevrolet C-20 Custom Camper "Dump Truck" 1972 Chevrolet C-20 Suburban "Big Green" 1969 Chevrolet C-50 Wedge Hauler "Leonidis" 1966 C-10 2x4 short fleet 327 4 speed "Race Truck" 1952 Plymouth Cranbrook "Rican" (my grandfathers) 1931 Ford Model A Coupe "Black Beauty" 1930 Ford Model A truck "Club Cab" 4x4 Rottenwood Garage and Speed Shop.....where everything must be racy! *It's not just a hobby..It's a LIFESTYLE!!!* Thanks for nothing Barrett-Jackson You cant fix stupid or teach accountability! Time wasters, looky Lous and tire kickers are everywhere!

05-12-2008, 02:03 AM	#4
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,621	Re: tbi fuel psi The TBI fuel pressure specification for small block Chevy’s is 9 – 13 PSI with the truck running.

05-12-2008, 03:11 AM	#5
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	Re: tbi fuel psi ok so dont get a expensive one or what. i got a MSD pump but i was told that it was a high output... but i got one of a friend and it says max 8psi. its relatively small compared to the MSD pump. also it looks like a off brand but it was on a tbi motor . no regulator. also '72freak' where do i find a stock tbi inline pump.. what do you mean Last edited by salrod00; 05-12-2008 at 03:13 AM.

05-12-2008, 04:30 AM	#6
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,621	Re: tbi fuel psi 8 PSI is not enough. The model 220 TBI unit used on Chevy V8s has a fuel pressure regulator built into it. You must have a return line to the tank from the TBI unit. Here are some links to photos/ illustrations. http://chevythunder.com/tbi_regulator.jpg http://www.goingfaster.com/spo/tbidiagrams2.html http://www.snflupigus.com/Partspics/image054.jpg http://www.goingfaster.com/spo/TBIdiagram.html

05-12-2008, 07:38 AM	#7
rfmaster Registered User Join Date: Oct 2003 Location: OC CA Posts: 1,374	Re: tbi fuel psi I apply a simple rule of 20-30PSI when fuel pump is dead headed. It also must deliver adequate fuel volume to satisfy HP requirements. Do not go crazy with high volume pumps - bypassed fuel will be returned back to gas tank, and fuel temperature will be increased due to excessive circulation! Stock TBI engines do not need anything over 40GPH. Additional pressure (over 15 PSI) is needed to overcome fuel filter restriction. Also avoid pulse pumps since fuel pulsation may interfere with injector firings. Generally, you want a laminar flow in EFI system. Carter or Delco made pumps are the best to be had. //RF __________________ "The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)

05-12-2008, 06:55 AM	#8
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	Re: tbi fuel psi well i got the tank and lines off the suburban that i got the motor from. i have the return line,gas line and what looks like the breather that goes to the canister... could i just use this instead of buying a inline pump.

05-12-2008, 07:50 AM	#9
bigtruck81 Registered User Join Date: Feb 2004 Location: northern, in Posts: 350	Re: tbi fuel psi use a Z28 TPI pump (Delco #EP-241) it will give you more than enough pressure, and give you some room to move up if you decide to do some upgrades to the motor. many stock motors like pressure higher than the 13psi recomended high pressure.

05-12-2008, 09:21 AM	#12
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	Re: tbi fuel psi thanks guys . i almost put the MSD pump. now i can return it and get the right one.. off what year is the Z28 pump come off. also what autopart store can it be purchased.i will keep yall posted on how the sounds when turned on Last edited by salrod00; 05-12-2008 at 09:28 AM.

05-12-2008, 07:58 PM	#13
Walts_restoration Real Projects never die Join Date: Jan 2007 Location: Lawrence, kansas Posts: 1,508	Re: tbi fuel psi TPI pumps are 45psi, get one out of a 454 truck if you want volume, they used TBI too. __________________ Ill put it this way, ive got a few lawn ornaments My name tag says Ryan KansasTwister On other forums Last edited by Walts_restoration; 05-12-2008 at 07:58 PM.

05-14-2008, 05:23 AM	#14
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	Re: tbi fuel psi i ran into another problem. i connected the stock suburban lines and gas tank and it seems that the truck doesnt want to crank. it turns over but doesnt fire up. i ran the pump direct and i can hear it on. any ideas yall..... i did notice that when i put gas in the intake it fires up but then dies a couple of seconds later.. i did blow a big fuse that is hanging on the firewall. i cant find out what it is but am sure that it might be why. the relay is connected to a harness that sits on the passenger side of the motor next to the ac..

05-14-2008, 11:05 AM	#16
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	Re: tbi fuel psi yes they are on the 89 motor . im dropping this motor on the 85 shortbed truck. where are this fuses located at. on the fuse box in the cab? i will post some pics today

05-15-2008, 01:57 AM	#19
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	Re: tbi fuel psi when i did the swap i took everything from the suburban and put it in the truck. i used the motor and tranny intact, steering column,rearend, evap canister, and even the whole fuse box and wires. basically i stripped the inside out and re-ran all the wires again. i did this for i wouldnt have to cut and splice any wires. dont get me wrong i did splice some wires but it was just a few. so my fuse box is the suburban and all the wires and computer are as well. im also using the fuel lines and tank from the suburban. i ran the pump directly and yes it does turn on and pumps up the fuel. when you say the pin A1 and B5 those are on the fuse box right... thanks alot guys for walking me threw this. its my first swap and its harder than i thought... thanks again

05-15-2008, 06:31 AM	#20
rfmaster Registered User Join Date: Oct 2003 Location: OC CA Posts: 1,374	Re: tbi fuel psi Pin A1 and B5 are not located in the fuse box! Take a look at ECM (it should be above just beyond glove box, under dash ) ECM has two connectors gray (2x 16 pins,C1-C16; D1-D16 ) and blue (2x 12pins A1-A12; B1-B12). You can see pin numbers and reference designators in the photo below: Larger view You can back probe with a sharp DVM test lead or in its absence a paper clip should suffice. FP relay should be controlled by ECM - its a safety issue, plus ECM power on self test (POST) routine expects to see FP voltage being cycled, OFF-ON-OFF. //RF __________________ "The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)



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07-23-2008, 05:54 AM	#21
salrod00 Registered User Join Date: Dec 2007 Location: tyler texas Posts: 165	Re: tbi fuel psi I checked to see if i get current to those pins.. B1 gets 12volts at all times. A5 and B2 get no current at all. where did i mess up and what can i do to fix this issue

07-24-2008, 12:51 AM	#22
rfmaster Registered User Join Date: Oct 2003 Location: OC CA Posts: 1,374	Re: tbi fuel psi Salrod00 Pin B2 is called fuel pump voltage signal - Gray wire. This is used by ECM to monitor fuel pump voltage and it used by ECM for voltage compensation routines. Check Fuel pump relay connections and oil pressure switch. A5 is service check light - it is a floating line until ECM pulls down when SES light is on. //RF __________________ "The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)

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