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Uuughhh, I free'd up the fast idle linkage(was stuck and kinda rusty) and adjusted the choke to center and now the car just fast idles all the time and will die if I sit at stop lights in gear for too long. I'm over this ****. Going to order the TBI adapter plate and fuel pump and ****.
I'm thinking DIY MS2 unless someone can convince me otherwise.
Sounds like a good plan to me, although I'm surprised someone with your skill isn't just making the plate.
Yeah, I mean it's probably monetarily worth it to make the plate, but the time investment doesn't make sense for $38. If it fits poorly I'll send it back and make one from aluminum
So my summit order looks like this: TRD-2210TBI Adapter, 3-Bolt TBI to Square Bore Carbureted Manifold ADO-219-607Throttle Body Repair Kit (I'm not 100% sure this is the right kit, but it seems like it) ATX-E8094Fuel Pump - 17PSI and 50 GPH, should be fine without a regulator and includes mounting brackets and hose barbs SUM-390561Fuel Injection Hose Clamps CEL-65152Fuel Injection Hose KNN-PF-1300Fuel Filter (I'm only going to put one pre pump) PRO-302-290Fuel Pump Block-off Plate (I'm sure there are cheaper ones, but this one called out the it's compatible with the 390FE) VPE-17193P-Clamps for the fuel line
Given how fast summit is at shipping things, I'm sure I'll still be hemming and hawing about which MS to get by the time it all arrives.
Ok, so my **** is going to get a little weird because I have a dual tank setup, but I want to run this by you "people" before I get too far down the rabbit hole.
This is a super generalized "flow" diagram of how the factory system is setup on my truck:
There is no regulator, and everything is gravity fed from the tanks in the rear all the way up to the engine mounted mechanical fuel pump. Simple as dirt, right?
(73 & 74 are "special" in that the dual tank models included a brass tank selector valve that is mounted to the floor next to the drivers seat. If one tank runs dry, you reach down and turn the handle to select the next tank.)
So with the TBI there is a pressure regulator mounted inside the TBI unit itself, right before the injectors, and there is a return line that I will need to add. Because I've got dual tanks this complicates things immensely. I can't just return to one tank because it then becomes a transfer pump, and eventually I'm going to overfill the tank with the return and start pumping fuel out the vapor vent in whatever tank I'm returning to. I don't have the mental bandwidth to remember to "use main tank first" or whatever. I really don't want to complicate my setup by adding 2 more ridiculously long fuel lines and another tank valve, so I've been having a think about this.
I've read "on the internet" (everything you read on the internet being true and all) that all you need to do is add a T on the suction side of the TBI pump and run your return line into the T. Because the engine is always using some amount of fuel, it shouldn't build any pressure in the return and you are good to go. This sounded too good to be true, so I started doing some reading. It turns out this may or may not be the way to do things, so I'm slightly nervous about setting it up this way.
After thinking about it for a while, I've come up with this:
Perhaps "accumulator" is the wrong word for this, but its what I stuck on the drawing. My main concern would be getting a bunch of air trapped in the "accumulator" and building pressure that would keep fuel from gravity feeding from the tanks. I could put an atmospheric vent in the "accumulator" that would allow it to vent, but it would need a check valve to prevent the pump from just sucking air. The line for that vent would have to go up higher than the highest point in the fuel system (lest it gravity drain) and due to the height of the engine, we are now talking a fuel line that runs up past the top of the hood. Plus this adds stupid complication that I don't want to deal with. Maybe the "accumulator" doesn't need a vent? Maybe it just needs to be purged of air occasionally?
I'm very curious to get some input on this from the brain trust.
Also, before you all go batshit insane, I know Ford made a reservoir/tank switch assembly that they used on 1980's dual tank F250/F350s that would take care of this problem. The part number is F1UZ-9B263-B and unfortunately they are quite expensive new:
And I've never seen a dual tank anything in the junkyard. Anecdotal evidence (again, the internet) also says they tend to be quite failure prone. It feels like a bad idea to design a system around a somewhat rare and possibly failure prone part. K.I.S.S. and all.
I'm unaware as to how other manufacturers do this, but I'm open to suggestions.
I tuned one of those microsquirt setups you linked above. Until the crap wiring job the owner did set that unit on fire. Literally
It was basic and really easy to work with
Clearly you need an arduino monitoring the level senders in both tanks and controlling a valve that directs the return flow into the appropriate one. You could replace the manual feed valve with an electronic one while you're at it.
I tuned one of those microsquirt setups you linked above. Until the crap wiring job the owner did set that unit on fire. Literally
It was basic and really easy to work with
So... bonus points for the Microsquirt, just don't be an asshat with the wiring?
Actually, while we are here, does @18psi want to tune these things? Fuel only, you'll have no control over the timing. Should be fun, right?
Originally Posted by codrus
Clearly you need an arduino monitoring the level senders in both tanks and controlling a valve that directs the return flow into the appropriate one. You could replace the manual feed valve with an electronic one while you're at it.
--Ian
No, because:
Originally Posted by EO2K
K.I.S.S.
Originally Posted by sixshooter
A second brass valve that selects return to each tank mounted next to the other valve. Whenever you switch one you switch both.
While your dual valve thing would work, I'd prefer not to do this because:
Originally Posted by EO2K
I really don't want to complicate my setup by adding 2 more ridiculously long fuel lines and another tank valve,
The real problem with running individual returns back to the tanks is that I really have no desire to drill the tanks for a return nipple. Getting to the tops of the tanks might actually require bed removal, and I don't have the space or tools to do that. If at all possible, it's something I'd really like to avoid.
To me, the "accumulator" idea seems like the simplest solution. If you guys don't think it'll work, I'd love to hear why.
Most fuel tanks have a vent tube up in the filler neck not too far from the fuel cap. If you use that location for your return you will likely do okay.
10-23-2017, 01:54 PM
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