alien_rx7

Sorry for the long post in advance, just trying to put in everything I've done with results so far.

I swapped in a running engine out of a rusted '82 into a nice '83 body. I drained the '83 gas tank since I was unsure of how long it had sat before I got it and put in fresh gas. Car would start but only run as long as I had left it off between starts, acting like it used up its gas supply in the line and then dying. I swapped fuel pumps with the one from my '82 and got same results. Swapped fuel filter and it seemed alright and even made it to warm up idle but it was real low. Next day I tried starting it and it started doing the same thing and the pump sounded real noisy. Changed it back to the other one and noticed the filter was clogged again. Changed filter again. Car start acting the same as original again. Jacked it up and took the fuel pickup line and dropped it into a fuel container full of fuel. Ran fine and warmed up to idle fine. Hmm, gas tank must be really dirty. Swapped tanks from the '82 (that I had previously swapped in a different tank before doing the engine swap and the '82 had run just fine). Car starts up and goes to warm idle which is good. I drive it around the driveway to make sure it isn't going to stall out or anything (had tried a test drive before and died half a block from the drive) and it seemed to run ok. I take it out onto the street and it starts going pretty good and then when I hit 3rd midrange it starts to sputter like it is running out of gas and loses power then dies. I get it restarted but it only runs a little and dies again. End up having to push it to turn it around and actually get it start rolling back to the house, still run into the same problem on the way back before I get to the drive. I get it restarted and just feather the gas a little bit to just keep a little power in 1st and shift it into 2nd to just move along at a steady pace and it seems to run ok that way. I get back and lift the car, fuel filter dirty again. So I figure with all the swapping this gas tank had been through maybe I knocked a good bit of crude loose so I take the spare up to the local shop and get it cleaned (btw, the tank was dirty! ) I bring it back along with a new filter and install it. Fill it up with about 4.5 gallons. I put on the fuel pump again from the '82 and it has a hard time even starting and the pump sounds very noisy and doesn't sound like it is sucking gas at all so I change it back to the other one and it sounds just fine, pulling gas and all and the car starts right up and then....dies. It continues to do this like it was originally doing, just starting long enough to run the gas out in the line is what it seems. So needless to say this really sucks since now I've replaced just about every part of the fuel system (including the check valve and cutoff valve) and the fuel filter shows no sign of dirt like the others did after starting.

I'm going to do a flow test and pressure check as soon as I can but does anyone have any ideas? Can the car get too much gas but still start up and still get too much gas which basically floods it and makes it stall? Too much pressure (generic aftermarket fuel pump)? Really odd since this engine was running just fine in the other car and now I have most of the fuel system from the other car on this car now too plus a clean tank and filter. Oh, and looking down in the tank (the clean one and the dirty one) it looks like there is something on the pickup tube that looks like a filter connect between the pickup tub and the bottom of the tank with no way to get to it. What is it? The guy at the shop said he wouldn't be able to seal the tank without blocking that thing up and then I wouldn't get gas at all.

Sterling

There's a plastic assembly back by the tank that is a rollover check valve. It's a tangle of hoses, and all these rubber hoses get gummy from fuel or oil contact.
Your steel fuel lines might even be clogged with rust or crap.

I suggest you unhook the fuel pump hose and the carb inlet hose, and flush the steel line with fuel. Catch it in a basin at the pump end, and see what comes out.

As long as you're now used to popping tanks in and out, you might as well yank it out again, remove the plumbing unit, and flush out the tank.

jeremy

iTrader: (1)

agreed. i had to replace my hardline due to rust and gas gumming it up. even if the hoses by the tank aren't gummed up, they will be cracked and will eventually leak. might as well replace those. look in the tank and make sure there isn't rust. otherwise it will be a never ending battle. i suggest taking it to a radiator shop that can flush, clean, and re-line. should run around 70-100 depending on they're equipment and your location.

somewhere in the chaos of threads is my experience of this with my old 79 last spring. just in case you want to follow my adventures in 1st gen fuel delivery.

alien_rx7

I think I've found the problem. I took the tank to the local shop and it was practically filled with rust and goop! Only thing is that they would not reline it because they said there is some type of strainer on the bottom at the fuel pickup line. When I look down in there, there sure is something there. They are afraid that relining the tank will seal that part up and I'll never get anything pumped out of it. I told them that is fine and I'll just keep it close to full as much as possible with the ever increasing gas prices around here. Sure am glad this thing eats low octane

Anyways, that seems to be only part of the problem. I finally went out and purchased a fuel pressure gauge. Slapped it on and I'm only getting out about 3.1 psi. Hayes book recommends minimum of 3.7 psi to 4.7 psi. Kind of short on that one! Also ran a flow test according to the Hayes manual and only flowed about 28oz as compared to a needed minimum of 37.6oz.

Looks like the pump, so I'll most likely finally just pick up a Holley Red and fuel pressure regulator to tune it in. Local holley dist. is quoting 169.99 for the pump and 40.99 for the regulator.