Fuel Delivery Advise

[twangismythang]

Recently acquired my 87 V-10 which was converted from TBI to carb. The truck runs terrible as if there's bad gas or the carb is gunked up.

The drivers side fuel tank is inop and the 1 on the passenger side is the only 1 used.

Question is if the truck was TBI would the tanks have fuel pumps in them instead of the mechanical one on the block?

And if so would some sort of regulator have to be used to slow the fuel delivery to the carb?

I am thinking about dropping the tanks and cleaning them out. I figure that would be the best place to start. I don't know if the tanks are metal of not and hopefully wont be to terrible of a job to remove them and clean them out.

I would like to just use the drivers side tank and just run a new line to the fuel pump.

Any advise would be welcomed..

[Just call me Sean]

Yes each tank would have an electric pump. They are a lower pressure pump, but I would think you would still need an adjustable regulator to use them for carbed.

[twangismythang]

Originally Posted by Just call me Sean

Yes each tank would have an electric pump. They are a lower pressure pump, but I would think you would still need an adjustable regulator to use them for carbed.

I was wondering if that's why the truck wont run right, I will have to get under it and see if anythings been added to regulate the pressure.

Maybe just buy a replacement tank for an earlier year and run a new fuel line?

[Just call me Sean]

Personally, I would put the fuel injection back on. If I were to make it right for carbed, I would put a mechanical pump on and switch the tank pickup to a carbed one. Tanks should work, pretty sure the only difference is baffles inside to keep fuel around the pump. Lines should be fine with some modification, they've probably already been modified some.

[twangismythang]

Originally Posted by Just call me Sean

Personally, I would put the fuel injection back on. If I were to make it right for carbed, I would put a mechanical pump on and switch the tank pickup to a carbed one. Tanks should work, pretty sure the only difference is baffles inside to keep fuel around the pump. Lines should be fine with some modification, they've probably already been modified some.

I would like to convert back to TBI at some point but for now its cheaper I think to get what I have working so I can have 4X4 for the winter.

Maybe during the cold months I can stock up on TBI parts.

Thanks for the info, you have been very helpful.

[Corts60]

Is there a regular mechanical HEI distributor installed in the engine or did they leave the electronically controlled one in place?

[twangismythang]

Originally Posted by Corts60

Is there a regular mechanical HEI distributor installed in the engine or did they leave the electronically controlled one in place?

best I can tell, its a regular mechanical HEI distributor, havent had a chance to look at it closer I have to hang with the wife today since I played outside yesterday.

[kalbert]

Being converted, god only knows what is actually on it now. I'd say pull the tank down and look inside, if it has a pump in it take it out. Swap the whole sending unit for a non-EFI one, they are cheap. That Edelbrock and single plane intake aren't doing you any favors though. The intake is almost certainly killing power and making low speed driveability awkward and sloppy. The carb could be anywhere from tuned wrong to way oversize. You've got your work cut out for you for sure, but fear not, we can steer you in the right direction!

[twangismythang]

Originally Posted by kalbert

Being converted, god only knows what is actually on it now. I'd say pull the tank down and look inside, if it has a pump in it take it out. Swap the whole sending unit for a non-EFI one, they are cheap. That Edelbrock and single plane intake aren't doing you any favors though. The intake is almost certainly killing power and making low speed driveability awkward and sloppy. The carb could be anywhere from tuned wrong to way oversize. You've got your work cut out for you for sure, but fear not, we can steer you in the right direction!

Good advise, I thought that looked like a single plane guess I need to see what CFM the carb is probably gonna have to switch em both out.

[csdineley]

Looks to me that it's not a converted tbi engine. But the entire engine was swapped for an earlier one. Also your fuel line to the carb is running down toward the front passenger side. Which to me seems like it already has a mech fuel pump. The Tbi fuel lines run up the back of the block. Now the electric pumps might still be in the tanks. If it is using the electric pumps, they put out around 13 psi and your carb only want's about half that. So a regulator would be required in that case.

[biggsteve97]

With out the computer the tbi electric pumps will not run with out some real enginuity so more than likely they are creating a restriction. I second that the engine is not a converted tbi engine and the entire thing has been swapped to an older engine with mechanical pump. Iwould start by checking fuel flow and filter, plugs, and timing.

[twangismythang]

Originally Posted by csdineley

Looks to me that it's not a converted tbi engine. But the entire engine was swapped for an earlier one. Also your fuel line to the carb is running down toward the front passenger side. Which to me seems like it already has a mech fuel pump. The Tbi fuel lines run up the back of the block. Now the electric pumps might still be in the tanks. If it is using the electric pumps, they put out around 13 psi and your carb only want's about half that. So a regulator would be required in that case.

Right you are appears to be an earlier engine it has mech. pump up front. I have to get the numbers off the block sooner or later.

I am betting that the tanks need to be dropped to see if they were set up to run a carb.......I hope to get started on it this weekend.

[twangismythang]

Originally Posted by biggsteve97

With out the computer the tbi electric pumps will not run with out some real enginuity so more than likely they are creating a restriction. I second that the engine is not a converted tbi engine and the entire thing has been swapped to an older engine with mechanical pump. Iwould start by checking fuel flow and filter, plugs, and timing.

Thanks 4 the input.....

[twangismythang]

A bit more investigating revealed that the 700R is now a turbo 350 so going back to TBI may cause some issues with the difference in transmissions.

Think its just going to be a carb truck for now, the intake manifold is an ole school edelbrock streetmaster. I have read mixed reviews regarding performance, think im just going to get a newer designed dual plane one. The carb is either a 600 or 650 CFM I forget which one.

So the plan is to change the intake manifold and drop the tanks and make sure everything is right with them to work with a carb.

[Just call me Sean]

The '87 EFI computer doesn't care what transmission is in it.

[biggsteve97]

Originally Posted by twangismythang

A bit more investigating revealed that the 700R is now a turbo 350 so going back to TBI may cause some issues with the difference in transmissions.

Think its just going to be a carb truck for now, the intake manifold is an ole school edelbrock streetmaster. I have read mixed reviews regarding performance, think im just going to get a newer designed dual plane one. The carb is either a 600 or 650 CFM I forget which one.

So the plan is to change the intake manifold and drop the tanks and make sure everything is right with them to work with a carb.

I blew up the 700r4 in my 87 silvy 7 years ago and swapped in a th350 for about a year and a half until i could gather up all the necessary parts to do an NV4500HD 5 speed manual swap and the th350 was great. The computer never knew that the 700r4 was gone. For that matter the computer never realised the automatic was gone when i swapped to the manual. Truck ran great the whole time i had the th350 installed.

[twangismythang]

Thanks for the info, at least now I know I have options as long as I can afford them. A 5 speed would be fun 4 sure.........