Thanks Sandy. Is there a way to get an in-tank pump into a stock A body fuel tank? This is a really ignorant question, as I have no idea how big those pumps are. Do you know if anybody sells a tank that will go in an A body that will take an internal fuel pump? I always thought the internal pump was a real PITA to change, so felt the eternal one was superior in many ways. Do you know what the brand of the pump is that you can still hear through open pipes. I certainly want to avoid that brand. I have one like that already. As you can tell, I am looking for clues about which electric pump to purchase here. There is a mechanical pump advertized for GM EFI. They say it is dead quiet, and delivers 90 PSI in the stock location. It is fairly expensive at $299, but that sounds like it solves alot of problems. The thing is, until I get a good report from someone, this old pump stays on, and the car, more or less, stays at home. Bob, to answer your question, the AF ratio goes steady and lean. It just acts like the computer has a new formula for the injector opening pulse width.

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69 Dart Swinger, 230 ci slant, t-5 five speed, intercooled turbo, 4 wheel disk brakes, tubular upper control arms.

Vader,
Does it lean out at cruise, acceleration, idle, all of the above?
Bob D

Use a surge tank. Basically you have the stock mechanical fuel pump pull the gas from the tank and fill the surge tank. Your EFI pump will then feed from the surge tank to your injectors. Most surge tank designs require a return line back to the fuel tank. The SDS EFI site was plans on how to build one, so does this site: http://www.oatsoda.com/fuel_injection/

Kesteb, that was very interesting. I don;t have much space for a surge tank left under the hood with all the turbo plumbing. I wonder if the volume of the stock mechanical pump would keep up with the turbo volume demand. I guess I could put a high volume, low pressure electric pump to the surge tank, and then the high pressure pump to the fuel rail. I wonder what brand of Bosch knock off this gent is using. My Accel pump looks just like the Bosch unit, and I assumed that it was made by Bosch. Maybe the Bosch unit would be better.

Oh yeah, Bob, it goes lean accross the board.

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69 Dart Swinger, 230 ci slant, t-5 five speed, intercooled turbo, 4 wheel disk brakes, tubular upper control arms.

I was going to suggest that your lean problem might be caused be the 5/16 feed line that you're using. I don't think that is big enough for a turbo application. But, if it is occuring at idle and cruise, then I don't think that the basic problem is due to the feed line or the pump. My guess is that it's a sensor/computer issue.
Bob D

I use the stock pump to fill my surge tank which is about 0.8 liters in volume and have never had a problem with starvation. See details at the bottom under Fuel System here if interested.
http://www.projectplato.com/cars/efi.html

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Cheers!
Al T

Vader,

Have you done any datalogging yet? This would tell you what the problem is right away. Could be feedback issue, or many other things.

Do you have a spreadsheet program like MS Excel? Your work should have a copy. Read about it on MegaSquirt and we'll talk...

Also, have you tried changing the fuel pressure as Bob/Sandy suggested? Have to recalib VE table (use "Scale all values"). This might help with noise too.

Lou

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