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How to TBI
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Author:  runvs_826 [ Wed Nov 21, 2007 5:16 pm ]
Post subject:  How to TBI
Ok so this isn't excatly a professional guide or even that expirenced, but it has worked for me and I know I didn't break a grand on the entire project. I'm not going to list this in exact order of how we did the project, but more into the sense of how I would've done it in step. First, we did locate a MegaSquirt v2 on ebay for I want to say around $200 with wiring, pretty good steal. Now I don't expect everyone to be able to get this steal, I hate readin about Freebies or "Good Deals", however, this doesn't mean you can't be savy. This project like many can save time by rounding up the parts needed before you take apart your car. I will post a list at the end cause I'm still not sure what all I will need. So after acquiring a Megasquirt, breeze through the manual to get a grasp of what will happen. YOU WILL BE OVERWHELEMED, it's ok, just know where to go when you have a question about tuning the acceleration wizard. So after getting the megasquirt and wiring I tore out the gas tank, I've read it is easier to take it to a radiator shop and get it flushed, you can also have them hot tanked. We set up an electrolisis tank made out of a kiddie pool for the project. , simply rinse it out. Next you will get a battery charger and connect the red lead to the dirty piece, and the ground lead to the "sacrifical" piece of sheet metal. After cleaning it all out I coated the inside of it with "Rust Doctor" or "Rust Mort."
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We made a plate about 8in in diameter, and drilled holes to attatch to the tank. The circle pattern made the most sense at it will form a tight seal, bisecting with a ruler will give you nice lines and run another circle, punck center holes. I choose the top instead of the side being as that is how my sending unit worked best. We also made a backing plate to have the piece bolt to the gas tank, I believe we used a 1/4in plate in a circle with a slot and grooved it in like installing piston rings, this will give you something to bolt the plate too. The bottom was also cut at the time so we could weld it in. We cut the bottom and made a sunk box where the fuel pumps hose drops into, this runs parallel with the sending unit. The electric fuel pump is off a big block chevy we ordered from federal. This wraps up the fuel tank modifications, by sealing off the old hookups.
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This is where we cut into my trunk, I was very hesitant, but unfortunately we had to as that is where the fuel pump and sender unit came up. On my duster we cut through a bracing piece and had to renforce it again. After the fuel tanks was installed we wired the pump and sender, than simply made a metal box that was a "hat", riveted it in with silicone. This is the back end summary, and the biggest headache if you ask me.
Author:  runvs_826 [ Wed Nov 21, 2007 5:33 pm ]
Post subject: 
Next was to re-do all the fuel lines. We bought 3/8in fuel line and ran it from the tank to the engine and back. The return line was simply a 90degree back into the tank. We bought a large roll of the line, I would advise against it, because you have to straighten it out again, and it is not worth it. I thought the section I bought of 6ft straight looked a lot better. Overall I used 30ft, and it was very frustrating! Stick with it, it's worth it to know you did it right. I than used metal tabs I made from sheet metal to wrap around the line and bolt with self tapping bolts into holes I drilled usually near the stock ones. If you haven't installed sub-frame connectors I would advise it I used 2x2 tubing and a cutting torch to fit and weld it in. If you look under your car you will see two tubes that look like they should be frames but going up into the car. Than you can connect the lines to the connectors which makes life easier, and help strengthen your car. My roof actually had ripples in it from the years where it started to accordian (sp?), now you could only see it in the body primer stage but still scary stuff.

Following the fuel lines is the injector unit. I have read arguements about which is best and such, however, chevy has made some good stuff over the years and it was cheap! So my unit of choice was adapting a 350 tbi unit to a one barrell manifold. We used a plate of 3/8 and epoxied it to the manifold we butchered. I would use an offy and adapt it next time (I had bought and offy, however, the one barrell was free what did I have to lose?) as it would look cleaner and align the unit more 90degrees from the engine., the single barrel put it at a wierd angle to fit it correctly.
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Wiring was very quick for me, but I've grown a talent for it. In the process of rebuilding the car I installed a Painless kit along with 2 others, so a stock harness might be a little more difficult, involving cutting a hole to allow access to the senders and sensors. The wiring is not as difficult as one might fear it mostly involves some relays and wiring to each of the sensors. My uncle sent me a LM1 innovate o2 sensor, and we also wired in the GM Hei system. The Megasquirt was installed into the heater box semi hidden. This was efi in a nutshell, now to tuning.
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Author:  Sam Powell [ Thu Nov 22, 2007 3:48 pm ]
Post subject: 
Thanks Man! That was a pretty cool job! It will probably work great once you get it tuned. Have you started it yet? Is that car a Duster? It is hard to tell from the photos. I really like what you did with the fuel tank. The lack of baffles could be a problem, as fuel might slosh away from the pick up under cornering or acceleration. Be on the alert for sudden lean conditions when you drive it. I am still open to putting in a good fuel injection style tank in my car. That is in the future.

Good Luck and keep us posted.

Sam
Author:  runvs_826 [ Thu Nov 22, 2007 3:55 pm ]
Post subject: 
yeah it runs and drives, I've been playing with lots of diffrent settings and such. I think I'm going back to twin 85lb injectors cause the the 45lb just doesn't cut it. we don't have a picture of the problem, but there is essentially a sunk bottom that fuel always sits and that is where the pump pickup is located. So... unless I pull a couple g's I think I'm safe, however, there is no foul proof plan I guess. The megasquirt has been a challenge, I think I'm going to start over with the new High Resolution program. DON'T CHANGE MORE THAN ONE VARIABLE AT A TIME! I essentially have to start over cause I lost track of what worked and what didn't. Oh well.
Author:  sandy in BC [ Thu Nov 22, 2007 4:42 pm ]
Post subject: 
Cool!...Im doing the same thing with an Offy.

The 85 lb injectors are way to big.....Id use 55lb
Author:  SlantSixDan [ Thu Nov 22, 2007 5:21 pm ]
Post subject: 
I agree, 85 lb injectors are way too big.

What's your fuel pressure regulated to?
Author:  tommj55 [ Fri Nov 23, 2007 9:45 am ]
Post subject: 
Congrats on your acheivement!

You're post couldn't have come at a better time. Recently, I've decided to swap out my carb with an EFI from a 1990 D150 with a 318 and use a MegaSquirt-II ECU. I have a Clifford 4-bl manifold with a 2-bbl adapter.
Author:  runvs_826 [ Fri Nov 23, 2007 12:07 pm ]
Post subject: 
Ok so there was some confusion with the injectors. We intially pulled the TBI unit off a 80's camaro 350. The injectors are set at 55lbs for 15psi in the fuel lines. We jacked it up to 30psi, which according to the calcs put us at 2 x ~80lb injectors. Dad and I agreed that must be way to much! So he then ran a single 2.4L injector which we thought was off a 4.3L v6. So we scrapped all that and put the 55lbs back in at 14psi. This is a little more than we need however need but not by much. We might try to play with staged injecting again which was primo with the 80lbs. So with starting over I had mega make me a ve table, is anyone has one I could look at it would be great cause I don't trust their table quite yet, been playing with it though.
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Author:  Joshie225 [ Fri Nov 23, 2007 5:47 pm ]
Post subject: 
I don't think I'd use staged injection unless all the air and fuel were entering in the same place. You have two holes in that throttle body so the air enters in 2 places even though they are close together. I worry that the mixture distribution will be poor. If it will idle well with both injectors I'd run them both full time.

If the 225 is stock the VE will fall off quickly over 4000 RPM so you'll need less fuel there. As a matter of fact VE falls off on either side of the torque peak which is 2400 RPM if you believe the book. The VE table actually looks like a pretty good start. Might be a bit rich at light throttle above idle, but that's just a guess. Even the advance table doesn't look too bad if a bit conservative. I'd bring in full advance by 3000 RPM though.
Author:  SlantSixDan [ Fri Nov 23, 2007 6:13 pm ]
Post subject: 
I'm curious: Why use a pump unit that required cutting the trunk, rather than an external in-line pump?
Author:  runvs_826 [ Fri Nov 23, 2007 7:32 pm ]
Post subject: 
Exterior pumps I was under the impression required replacing or such if driven everyday especially in Oregon's 9 month winter. The pumps don't cool as well, and are probably going to be pretty noisy. I really like to do things that are proactive, so a little more work now, not having to work on it later idea.
The engine isn't very stock... I ported and polished the head, went with the 1.44/1.7 valves, the cam was done by OregonCams with 270 duration and .48 lift. The injectors seem to be working a lot better today at twin 55lbs (15PSI in the lines). I changed the VE table, but kept the timing the same, I got it running well except for the hood wouldn't close. It was on my list to replace the hinges, guess it was time.
Author:  Joshie225 [ Fri Nov 23, 2007 8:20 pm ]
Post subject: 
External pumps aren't that loud and don't fail that often. Ford used thousands of external EFI pumps. Since you don't need 3 bar fuel pressure an external pump would have been fine.

OK, since the engine isn't stock the VE table looks better, but I'd still bring in the timing faster.
Author:  SlantSixDan [ Fri Nov 23, 2007 9:47 pm ]
Post subject: 
Quote:
Exterior pumps I was under the impression required replacing or such if driven everyday especially in Oregon's 9 month winter.
Huh? No. Where'd this come from?
Quote:
The pumps don't cool as well, and are probably going to be pretty noisy.
Neither of these is true, unless you select the pump thoughtlessly and mount it improperly.

Gazillions of '70s-'90s Volvos racked up many, many miles with their external fuel pumps operating silently and without trouble.
Author:  Sam Powell [ Sat Nov 24, 2007 5:18 am ]
Post subject: 
I hated my external fuel pump when mounted to the rear frame rail. It sounded like Godzilla coming out of the ocean. I tried several different manufacturers, and they were all loud. Not only that, even though they were mounted below the tank level, there were intermitant times when the pick up would go dry, and the car would stumble. When I put the same pump up front with a surge tank fed by the stock mechanical pump, I could no longer hear it, and the dry falter was gone. The drawback is, the pump and surge tank take up alot of space under the hood.

It is incovenient to pull the tank to change the puel pump. I have always hated that part of modern auto construction. But, the pump does cool better there in the fuel, and it is much quieter. So it is a trade off. If you are a gear head, and the car is strictly race, then more noise is better. So go for the simpler set up if possible. If you are trying to present a polished, OEM style set up, then in the tank is the style that does that the most convincingly. neither is wrong. If I were doing it over, I would do it in the tank.

You can use more timing between 1300 and 3000 in the low KPA numbers. In stock trim your vacuum advance pot would be working there, and pulling in as much as 18 more degrees. They are usually set to gradually drop timing out between 12 and 8 inches of mercury, and I think that is around 40 KPA. You better check that conversion though. I should put the chart on my wall. Thanks fro publishing your timing and fuel maps. Keep them coming along with reports on the drivability/performance.

Sam
Author:  runvs_826 [ Sun Nov 25, 2007 5:28 pm ]
Post subject: 
Ok, well after a loooong weekend we finally got the car running on all cylinders sort of speak. We wasted a day as I had the newer megatune and the other computer had the old version. We essentially got the constants set, a good spark table, than generated a table from megasquirt. We got the idle set to 17.5 at vaccum. Than I started running it, plug it into megatune re-work the table and repeat. I did this about three times and now it runs great. We still need to set the accel wizard. All in all I'm impressed by how much it brought it alive from the two barrell set-up. Here's my newest spark and VE table, changed a lot!
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