243

Howdy. I installed a '95 S10 Blazer fuel tank and module in my '78 Cherokee to run the Junkyard TBI on the 360, both are only two years old and it appears the 5.3 Flex stock pump is running 45-50 psi based on what I found on Youtube.

The Blazer pump specs are 25 gph, static pressure 80-130 psi and maximum pressure is 60 psi.

I have no plans in the new future to modify the engine, is the flow sufficient for the 5.3?


Here are a few pictures of the Heep, the 5.3 on arrival and progress on a second rolling chassis I am building up for the swap.

ijimmy

You need 58 lbs of fuel pressure , 255 walbro is popular , and corvette regulator

lowchevytrucks8503

iTrader: (1)

This is what I did for my '85 C10^. I used a K5 blazer tank & sending unit. I attached the Walbro 255 pump to the sending unit and dropped them into the tank. My fuel rails were the returnless style so the return line runs from the sending unit to the Corvette filter/regulator. The feed line runs to the filter/regulator then out of the filter/regulator to the rails.

ls1nova71

iTrader: (4)

I would replace the pump. You would basically be maxing out that TBI pump all the time which will shorten its life and you'll be replacing it anyway. Easier to do it now than when the whole truck is together. It looks like your engine has a return line so the Corvette filter isn't necessary, just a regular EFI rated filter will be fine, probably what you had with the TBI.

243

I need to keep the tank as there are very few options for a tank that fits an FSJ in the spare tire location. I got Airtex on the horn and tech reported there was not an option to replace the Blazer pump with another pump using the existing sump but I bet it's possible. I don't recall what it looks like down in the sump so I may go to the parts store and look at a new pump.



I used an inline pump on my CJ with the stock tank and that cost me about 5 gallons of usable fuel capacity since it didn't have a sump, the Blazer tank is only 19 gallon so I can't afford to lose capacity so that is my reasoning to keeping and modifying the fuel fuel pump module.

If ya'll have workaround for this let me know.

gagliano7

You should be able to just replace the pump and still use your bucket. On my 1992 Chevy pickup the pump I bought fit right in place of the original one.

243

Thanks, I will look at replacing the pump in the S10 module once I pull the body, it will be a while since rebuilding the 4L60 this winter is my next project.

33willys

iTrader: (1)

On my '39 build I used an 03 Trailblazer pump which fit in the TANKS tank nicely. You can look at different options on Rock Auto but most of the GM assemblies will fit the hole you have in your tank. Just a case of how deep tank is and how the pump will fit depth wise. My tank was 8.5 inches deep. Found and old used unit, scrapped everything except the cover and made an in tank Walbro unit as a backup. Cost of an over the counter replacement is high but Rock Auto can be much cheaper and a home made backup pump means you won't be at the mercy of the local parts store.

reedld

iTrader: (7)

When I put the 4th gen f body LS1 bucket in my 2nd gen tank, I replaced the factory pump because it came from a junk yard and I wasn't sure how many miles were on it. It was easy to disassemble the bucket. I did need to cut the tube that went to the pump, it was ridgid/stiff...wouldn't simply pull off.
Factory fbody bucket has a built in regulator for the LS1, not sure if the S10 bucket has this or if it is adjustable. So you could change to a 58 psi pump but still not have correct pressure.

Plenty of 5.3 truck buckets in the yards...could you adapt IT to work in the S10 tank?

243

That is a good point, in the short time I have been reading the forum I have seen a lot of guy's hack-fab some awesome solutions.

Here is the 04 Yukon Flex module, it does not have a vent or a return (not sure which) but if a new pump won't fit directly on the S10 module it may be easy enough to graft the S10 upper to a Yukon or other lower.




A '99 Yukon 5.3 pump looks more similar to the S10.



When I get a chance I will stop by the parts store and take a look at some modules.


I am looking at some 25+ gallon tanks but it may be a lot of effort for little return, and even 15 mpg would get me as far as my 2500HD, a gas sucking pig getting 12 mpg with a 24 gallon tank.


.

reedld

iTrader: (7)

The 04 Yukon bucket has fuel out and return. The vent must be somewhere else on the tank. The return always goes back into bucket. The idea is to keep pump submersed in fuel, and when you goning around a corner and fuel moves, the submersed pump always has fuel to deliver to engine (no tank baffle needed). Air is an enemy and shortens pump life. There are a series of check ***** in bucket that help prevent air being sucked.

The earlier 99 5.3 module (if it fits) would eliminate any uncertainty. Since you are early in the swap, buy a correct ohm reading fuel guage for the modern fuel bucket. I wish mine was that way. I'm using the 1978 0-90 ohm sender. The new ones are better in my opinion.

Project GatTagO

iTrader: (7)

Be careful with the buckets that you have pictured above. They are quite sophisticated. See the MAP sensor that is built in? This is for a true closed loop returnees fuel system. The ECU monitors fuel pressure at the pump and adjusts settings (presumably through PWM) to alter the output of the pump.

Andrew

243

Andrew, I think that is a tank pressure sensor on the '97 Blazer, I did not connect it for the TBI and ran the vent to the charcoal canister.

243

Leon, I had already purchased an AM fuel gauge before researching the tank swap and it read backwards, I formed a new rod to get it to work but it has never read correctly.

I plan to use Speedhut and I believe the fuel gauges are programmable.