TBI stall with FSJ coffin?

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rherndon
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Location: Houston, TX

TBI stall with FSJ coffin?

Post by rherndon »

Anyone had issues with the TBI not getting enough fuel when running at low fuel levels??

Spoke to a local mechanic that just installed a TBI on an FSJ and he warned me that I may have to modify the tank or the sending unit. The issue was fuel starving at low fuel levels when turning corners and such. With a carb I guess there is enough fuel in the bowl to "bridge the gap" long enough for the flat coffin tank to level out again and get fuel back to Send Unit. Said they lengthened the sending unit arm/sock so that it laid flat on bottom, but still having issues below 1/4 tank.

I have not heard of this before. Anyone have any issues like this? I can see how it could happen.

I am replacing steel coffin with MTS but am going to keep steel in case we need to modify with some sort of sump or baffle.

Thanks,
Rogers
'76 Wagoneer w/401; Restoration in progress

cmaje72
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Location: Western NY

Re: TBI stall with FSJ coffin?

Post by cmaje72 »

I have a LT1 in my wag with external pump and the pickup lying on the bottom of the coffin tank. I can run it down below 1/4 tank but I do get some fuel starvation issues on hard stops not so much on turns. I don't wheel my wag but I can see how it can become a big issue heading down steep inclines.
The lack of fuel also shortens the fuel pump's life. I always carry a spare since I have been left on the side of the road in the past with a dead pump. I go through one a year or so. In contrast the in tank pump in my cj has been going strong for over 10 years.

I would go with one of the EFI tanks that fit between the rear frame rails that you see on the threads around here. I have not gotten to it yet but I have a S10 blazer tank sitting in the shed for when I switch over to a 5.3. There is also a thread over on the other site where a guy built a fuel system with a reservoir (using a big inline fuel filter) for his efi install. That is a possible solution.
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will e
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Re: TBI stall with FSJ coffin?

Post by will e »

When I had a TBI I didn't have too much issue with normal driving but going down hill with a lower fuel level it would cut out on me. I switched to a Holley TA but before doing so I looked at various secondary can options.
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Topic author
rherndon
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Location: Houston, TX

Re: TBI stall with FSJ coffin?

Post by rherndon »

I was not aware of the secondary tank option. That is a great idea. I will look into that. If anyone has a product/vendor that they recommend, please share.

I will search prior threads and other sites.


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shimniok
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Re: TBI stall with FSJ coffin?

Post by shimniok »

Haven't run into starvation yet. Usually run mine down to 2+ gal before fill.

I can't promise the pump isn't getting starved and dying too soon. I already went thru one pump in a couple years, so maybe.

I saw on some senders there is a little bucket around the pickup presumably to help with this problem. I would imagine the bucket has little holes at the bottom to let gas seep in. But angles should not be a problem.

Or, tiny inline reserve tank.



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360, TBI, 4" Skyjacker, 33" BFG MTs, WT D44+ARB, WT AMC20 + LockRight, CB 2m 6m 70cm, K0FSJ
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Topic author
rherndon
Posts: 142
Joined: Mon Aug 11, 2014 5:25 pm
Location: Houston, TX

Re: TBI stall with FSJ coffin?

Post by rherndon »

I wanted to share this article , specifically the discussion on surge tanks. Apparently this is a very common issue.

Image

Full article. Good read for a noob like me.

http://www.rowand.net/Shop/Tech/EFIBasics.htm

I do like shiminioks idea of a shallow tub placed underneath the sock of sending unit with some small perforations. Sort of a baffle with a temporary holding pond.

For the MTS plastic tanks, I think this could be designed with some PVC or quality plastic container and epoxied to bottom. Have to be small enough to fit through hole.






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Topic author
rherndon
Posts: 142
Joined: Mon Aug 11, 2014 5:25 pm
Location: Houston, TX

Re: TBI stall with FSJ coffin?

Post by rherndon »

And another option. Foam baffle. Any experience? Very simple.

http://www.ksrfoam.com/site/9857bee9129 ... m.php#2675


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FSJ Guy
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Re: TBI stall with FSJ coffin?

Post by FSJ Guy »

The 2 door S10 Blazer tanks have a baffle built into them to prevent starvation issues. Aside from the spare tire and hose size issuea, it might be the best solution.
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shimniok
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Re: TBI stall with FSJ coffin?

Post by shimniok »

Take a look at maybe GM sending units? Or apparently edelbrock has something:

Image

Keep us posted and if I find anything I'll post up. I'd like to do something about this too, but without having to swap in an S10 tank. I want to install a 25 gal Blazer aux tank in back for extra capacity instead. So, I'd rather just do something with the senders or use a surge tank.
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'86 GW "Troubled Child" tc.wagoneer.org
360, TBI, 4" Skyjacker, 33" BFG MTs, WT D44+ARB, WT AMC20 + LockRight, CB 2m 6m 70cm, K0FSJ
The world's first Robotic Full Size Jeep!

FSJ Guy
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Re: TBI stall with FSJ coffin?

Post by FSJ Guy »

If you want the extra capacity, use the S10 Blazer tank as your main tank. Have a low pressure electric tank automatically come on when the S10 sender reads low. Turn off the pump when it gets close to full. You know, make it autonomous. ;- )

Now you have extra capacity and a baffle in your main tank.
Ethan Brady

http://www.bigscaryjeep.com

Jeepless, but I still have a lots of old parts in my garage!
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