EFI Fuel Pump Upgrade

[gregs78cam]

hey gregs, great writeup, and followed your instructions, sorta! heres the problem, i lost one of the springs on the support rods, would you happen to have an extra spring

ill post pics later, but thanks for the great write up, it was almost painless

Hi, thanks for the feedback, sorry I have not replied back sooner, I have been EXTREMELY busy for a few weeks. Yes I have a few of the springs, if you still need some let me know, I can throw them in an envelope and send them out.

[oldfoop]

Greg, terrific write-up. I was looking for tank/pump for my truck, found this, and knowing very little about TBI or fuel pumps. I wonder if the tanks you modified had had fuel in them? I have been guessing how you kept from getting blown up - I decided maybe dry ice-carbon dioxide is heavier than air.

I have an old tank form what I think was an early '80s Olds. Has 3 5/8 dia sender in it,and only 8" deep. I wonder if modifying that tank and looking for module that short - I see springs on the tubes, so assume they have some slide adjustability,

Or, should I lok for newer tank with 4 1/8 dia sender opening, and find sender module to fit it, and match my 0-90 ohm guage curve. Can the resistance be changed easily on one of these modules?

Write-up seems to say the additional fuel pressure won't hurt the TBI or regulator.

also, I assume the fittings and electrical connectors won't match the original harness and the fuel fittings may be new to me too.

Hope this isn't too far backwards.

Thanks again for your write-up and I am really glad to find this forum.

[gregs78cam]

Hi, yes all three tanks that I modified have had fuel in them. Fuel in liquid form will not burn, it is the fuel vapors that ignite easily. Two of the tanks were done without any welding. On the latest one though, we drained the fuel out, then blew compressed air through the tank around all the crevices to make sure there was no liquid left in there ANYWHERE. When I didn't see any more fuel and only a slight smell remained I then turned on the shopvac and blew air through it for another 5 minutes or so. Then welded the flange on.

8" might be a bit on the shallow side for these senders. These have about 1 to 1.5" inches of compression built in to them so they always stay pressed against the bottom of a tank. My best suggestion is to just go to your local Pull-a-Part, and drop a few tanks and check out what is there.

The pressure shouldn't be any problem at all, it works just fine for TBI.
Fittings and plugs will be different, but not hard to sort out.
The level senders I used in the write up came with both ohm ranges for different applications, then later they changed style to the one pictured in post 22. These, I believe, were only available in the newer ohm range.

I hope this works for you.

[oldfoop]

Thanks Greg,

I found Spectra Premium makes replacement tanks and senders etc. I looked for anything that would fit space I have, then for sender to match. Hard part is, any tank that fit, I found all have the small sender opening, even though I found some for fuel injection. One has a "sump" in the bottom to prevent dry-run in tight turn or steep uphill run. I think I may wind up trying one of them.

I live in NH, and we don't have pull a part here, they dismantle, and keep what they think will yield the most $, and scrap/recycle the rest -called green yards. Its too bad, because the few yards that have cars out bacl, are being forced to get rid of them. Lots of nice old iron gone for ever.

I wondered about the high pressure of the sender that matches the tanks I think will fit - min press 72.5, and max 130.5#. Too high for TBI? The tanks were in '94 - '96 Blazers and Jimmys, and I think were well after TBI, so much higher pressure. If pressure isn't a problem, these will work well, because they are 0 - 95 ohms sender curve, and my guages are 0 - 90. Close enough. Can you buy replacement resistance cards for senders?

By the way, what is dual TBI? I'm old, but guess I missed this.

Thanks again for your help.

[EagleMark]

Greg has two 2 barrel TBI units on a special made adapter.

Those high pressures will work, what is not used is returned to tank via the return line. In your case I'd run 3/8th return line as well as feed.

NH would be a horrible place to live with those laws on junk yards!

[oldfoop]

Thanks EagleMark, sounds like modified twin 4 barrel manifold - better set up than multipoint? Would sure look good.

Right now NH is a little tough in winter too, and junkyard laws are speeling the end here. I bet northern Idaho is miserable in winter too.

Thanks again.

[EagleMark]

I bet northern Idaho is miserable in winter too.

Nah! Our Junk Yards are still open and we have plenty of old cars laying around.