Swapping in TBI tank and pump

[Mastiff]

My tank sprung a leak, so now I'm thinking about what it would take to switch to a TBI tank and in-tank pump to support my EFI conversion (83 K5). Right now I have an in-line fuel pump.

First, do most people agree that the in-tank pump is better? In a way, I like the in-line pump because I can carry a spare and it's easy to replace. I haven't yet experienced any issue with sloshing or anything.

If I decide to go with the in-tank pump, I was looking at this tank:

http://www.autopn.com/store/pc/viewprd.asp?idProduct=7467

It's polyethylene instead of steel, which seems good in rust country. Any opinions?

Would an 89-91 sending unit be correct (pic below)? I'm not sure I understand what the big pipe is for, any ideas? I understand I need fuel out, fuel return, and vent. What else?

Also, will my existing lines connect to this sending unit as is, or will I need to splice in some hose or something? At present I feed off the rigid lines halfway up the frame, then go with rubber hose to the TBI.

 

[JUNIOR-K5]

I have a sending unit with working pump for 31 gal. tank out of a 90 suburban if your intrested. Your existing lines will not work if they dont have threaded ends. I did the same swap in my k5.

 

[ChickenRammit]

the big pipe is the air vent for your filler neck. you'll see where it goes when you drop your old tank. as for your fuel lines, you'll need new ones. you should be able to get the lines from an '87 and up blazer, suburban, or k10. you can also have hoses made by a hydraulic hose company, but they usually have to use AN fittings and then you have to use saginaw adapters to connect to the GM sending unit. i personally prefer the in tank pump because most people say the inline pumps are unreliable and that they are kind of loud.

 

[dyeager535]

4th for that sender is EVAP. Your truck will already have that of course, if it's still there.

If you can get a polyethylene tank with baffles, that would be fine I think. I assume they would handle all sorts of vibration and shock (not directly to the tank of course) or they wouldn't be sold. Metal should be good too, but how long did the stock one last on your truck? That would be my benchmark. Paint if you want to add a bit more life to it I guess. The aftermarket tank I got was obviously galvanized or whatever on the outside as well as inside.

 

[Mastiff]

the big pipe is the air vent for your filler neck. you'll see where it goes when you drop your old tank. as for your fuel lines, you'll need new ones. you should be able to get the lines from an '87 and up blazer, suburban, or k10. you can also have hoses made by a hydraulic hose company, but they usually have to use AN fittings and then you have to use saginaw adapters to connect to the GM sending unit. i personally prefer the in tank pump because most people say the inline pumps are unreliable and that they are kind of loud.

Yeah, I understand what that big pipe is for now. I should have remembered from when I replaced my K30 tank.

Anyone else have opinions on in-tank vs in-line pump? Maybe I should post a poll.

 

[JEBSR]

In my experience I would say the in-tank pump have more possitives than negs. Can not get hit on the trail, Don't get wet when in water, no corrosion and no impact.
As for the tank you need to have a good shield for the tank so it doesn't get punctured. Also poly tanks eventually do dryrot and start to crack, but that would be years down the road.
Don't know if you know, but if you can get an older tank (and you want a used one) You can use a tank off of a carberated model as well. You just have to switch the sending unit, pump housing. I am running a 77 tank in my 87

 

[Mastiff]

In my experience I would say the inline pump have more possitives than negs. Can not get hit on the trail, Don't get wet when in water, no corrosion and no impact.

You mean in-tank? My in-line is on the frame rail. It's almost impossible to get hit, but it will get wet and possibly corroded. The one I'm using is from a Ford truck application.

As for the tank you need to have a good shield for the tank so it doesn't get punctured. Also poly tanks eventually do dryrot and start to crack, but that would be years down the road.

Don't the OEM's all use poly tanks these days. My Jeep tank is plastic.

Don't know if you know, but if you can get an older tank (and you want a used one) You can use a tank off of a carberated model as well. You just have to switch the sending unit, pump housing. I am running a 77 tank in my 87

The old tanks don't have the baffling though, right?

 

[JEBSR]

Yea I meant in-tank. I have had wires snatched out of the inline setup as well when going over tall brush.

Not all oem's use poly tanks. They are not bad tanks, but they do have a tendency to crack after years of expanding and contracting. But like I said earlier it would years.

I have not had any problems with mine as far as the baffling goes. I've had it on some very steep inclines with 1/4 tank and no problems. I had it stumble once when taking a 90* turn. However I was headed to the gas station and added just over 30 gallons of gas to it so I believe it would have done it anyway (baffled or not). Just my oppinion though.