May get rid of EFI

[swatman260]

I currently have a FAST EZ-EFI system on by bucket that I am having problems with. I purchased the efi to make my car more reliable, and I'm having the opposite experience. After spending way too many hours on the phone with their tech support, I have decided that I may pull the system and go with a carb. So, my question is this...I have built the whole vehicle to opperate off this EFI. I built the fuel cell with an in tank fuel pump with a return system. The FAST fuel regulator regulates the fuel pressure as it EXITS the carb, on the return line. Would I be able to re-plumb this regulator and have it control the fuel going into the carb, and just eliminate the return line? I realize I would have to rewire the power to the fuel pump, but keeping the existing regulator would be the simplest solution, because it's mounted to my firewall, and I don't want holes there if I remove it.

 

[railroad]

Some regulators will not operate properly, dead headed and the carb will probably not move enough fuel to maintain the pressure level required. You are looking at going from 30-60 to 4 to 7 lbs. That is quite the drop for one specific regulator. Don't know how frustrated you are with the EZ, but I will bet there is someone that can get it right. Nothing against carbs, I like them for their simplicity and nostalgic look.

 

[swatman260]

Ultimately, I don't believe its the FAST system quite as much as it is the application. I have a set of open lakester headers that are pretty short. As a result, the O2 sensor is both too close to the exhaust ports and too close to the end of the pipes, which result in some sketchy O2 readings. I'm tryig to let the sytem "learn" through this, but the car is not really driveable once the readings go haywire. As I'm not willing to put a different exhaust on the car, I may have to sacrifice the EFI.
Now, when you say the regulator may not work "deadheaded", what do you mean?

 

[Hotrod46]

Aeromotive sells a regulator that can be set up for EFI or carb. It comes with 2 springs to allow you select the pressure range that it delivers. The FAST regulator may not have enough adjustment to get to the low pressure needed for a carb.

You will still need the return line. The in-tank pump needs a constant flow of fuel to keep it cool. Using it in a "dead head" set up will cause it to overheat and fail. Dead head simply means no return line. Even the so-called returnless EFI setups like the LS Corvettes actually have a regulator and return line at the filter under the car.

The only true returnless systems are the "Pulse Width Modulated" pump drives that basically speed up and slow down the pump to regulate pressure. These signals are controlled by the computer.

 

[swatman260]

So how would I run a return line from a carb?

 

[Hotrod46]

Here is a link to diagram. It shows EFI, but it will work exactly the same for a carb. Just substitute carb for fuel rails. The regulator can stay on where it is now or could even be moved to anywhere in the supply line.

http://www.tanksinc.com/img/efiregbefore.jpg

 

[fordsbyjay]

Does the FAST system have a way to turn off the self learning. It will never work right with the exhaust that short so it will need to be manually tuned.

Hotrod46 nailed it with the diagram.

 

[swatman260]

There is no way to turn off the self learning at this point. I guess thats the drawback of a system that is smarter than I am. If the system were able to learn long enough to build an effective map, I could disconnect the O2 sensor and run the efi as a closed loop system, that would no longer self learn, however at this point, it doesn't learn long enough to do that, and the system is not running where I want it to, full time.
I'm going to give it a few more weeks of tinkering and trying, but if that doesn't pan out, I'll have a really good system for sale, for those of you with longer exhausts.

 

[one finger john]

Nice, crisp, shiny, color photos would be nice. Both of the EFI system and its components in place.
And, of course, your car. That 1 picture = 1000 words thing.

John

 

[PotvinGuy]

Oh, my, Swatsman, don't give up yet. I have the FAST EZ-EFI and love it. Put on a set of conventional T headers, put the O2 sensor just ahead of the muffler and let the system learn for a few days. Then you can disconnect the sensor and put your pipes back on. That's what I do when I put on my open pipes:

The system runs fine without the sensor once it's had time to build the fuel map.

 

[swatman260]

I'm hoping I can come up with something that I can do to get a map built without having to buy a whole new exhaust system. I'm gonna try building a baffle system for inside the lakester header that may keep air from flowing in as freely, but I guess as a temporary fix, perhaps I could weld an adaptor that would allow me to put a regular muffler onto the lakester pipe to run for a couple of weeks. It would look silky as heck, but if it gets me past this hurdle, it would be worth it.

 

[one finger john]

Before Mike passed, there was talk of a set of roadster headers that would be swapped among members in order to break in engines without harming their headers finish.

Maybe PotvinGuy would loan you his headers to set a fuel map in your car if you paid the shipping???
Maybe include a couple of six packs of sumtin sumtin to grease the wheels of progress.

John

P.S. This is pending on you both having the same type of engine.

If you send us pictures we would know instantly if this were possible. Or might be able to scare up an appropriate substitute.

 

[swatman260]

While I love the idea, I'm running a BBC 454, and I know PotvinGuy is running some kind of crazy NASA inspired engine.

 

[one finger john]

Its' a 383 Chev small block, IIRC

Advertise for "1 set 454 Chev roaster headers, chrome or painted, can have surface rust, not so good chrome, marginal paint. Classic or sprint style. Send pics. Wont spend over $100.00 plus shipping."

If your headers have augers & caps it will be nothing to add a glass pack to the end cap.

Where is that picture of your headers?

John

I CAN HAVE AN ANSWER FOR EVERY "YEAH, BUT ...... " YOU GOT.

Used stock manifolds with a length of tubing and a muffler (for each side).

 

[swatman260]

I can't, for the life of me, figure out how to post photos on here anymore. I finally have a completed t bucket that I've been building for 3 years, and I can't post a photo of it. Lol. I'm trying to figure out this photo bucket thing.

 

[swatman260]

http://i1382.photobucket.com/albums/ah246/Swatman260/Mobile Uploads/20151120_130229_zpsfpz15cqo.jpg

 

[Indycars]

Your are not the only one, I have not been able to post pics
since the new ownership. I have asked for help in the Computer
section to no avail.
T-Bucket Forums


Very, very nice car you have built and have plenty to be proud
of for persevering over many many months or possibly years.

 

[choppedtop]

 

[Hotrod46]

After looking at the pic, I would do as One Finger suggested. A couple of bends, flanges and some straight pipe would extend the headers back to the rear axle. That should allow the ECU to get a consistent O2 reading long enough to write a table. I would try that before I ditched a very expensive EFI unit.

BTW - That's a nice looking car. I'm a fan of the long radius rods (hairpins). They flow better visually than the shorter parts, IMO.

 

[PotvinGuy]

Hmmm...the pic thing still works for me. Once you have the pic on your screen, right-click and select "copy image URL." Then in your post, click the little landscape icon next to the happy face on the top line, and paste.

Yep, still works.