Well, draining the gas tanks isn't going as well as I had hoped.
I pulled off the -6 fuel line going into the input of the Aeromotive pump, as this is the line coming from the output of the stock in-tank fuel pump. At least it is supposed to be based on how I assume the plumbing is hooked up. For reference, this fuel line comes off of the bottom tube on the stock fuel pump.
Anyway, I hooked up HPTuners, stuck the hose end into the 5 gallon gas can and turned on the fuel pump via HPTuners. I didn't know what to expect, so I had Connie help me by holding the hose in place in case the gasoline would come out under pressure. Heck, we could hear the pump running, but the gasoline was just coming out at a dribble. We let it run that way, maybe for a half hour, and in that time it looks like just barely a gallon has come out. I thought perhaps there was a vacuum being created in the gastank, so I took off the gas cap, but that didn't make any difference at all. I took a video of what I have now, and as you can see, virtually NOTHING is coming out of that hose, and it actually sounds like the pump is sucking air.
Rather that run the risk of burning up the pump, I just shut it down. So that's where I am right now. This didn't go even CLOSE to how I had thought it would go. What the heck am I doing wrong? Why isn't that pump pulling gasoline out of my gastanks like I think it should?
Well, today I figured I would hook the Aeromotive pump back up and see if that would pull gasoline out of the tanks, but no go. Dammit. Still just drips of gasoline going into the gas can. What the heck am I doing wrong? Power is going to both pumps and I simply dropped a fuel line down from the output of the Aeromotive pump into a gas can. I opened up the gas cap in case there was a vacuum in the tanks. What am I overlooking?
I don't want to find out after dropping down the gas tank and cracking open the fuel pump mounting that I overlooked some really stupid minor little thing to make the EASY way work. Heck, with the stock fuel pump apparently dead, I couldn't even run the car to burn up the gasoline if I wanted to do it that way.
But on the plus side, at least I have a 2002 model that doesn't require pulling the fuel tank (and dropping the cradle, I've read) in order to get the fuel pump out. Of course, I don't know how LONG that fuel pump is that goes into the back of the fuel tank, and whether I'm going to have problems getting it around the lower control arm. Not THAT would piss me off to have to take apart that suspension again after just putting it back together.
In any event, Connie is going out to visit her sister tomorrow, so this gets put off till Sunday at the earliest. I don't want to tackle the fuel tank thing alone in case I need another hand or two. No, this just couldn't be done the EASY way, now could it?
Looks like it was a good thing I picked up one of the bad boys when Amazon had them at a good price.
Going to come in handy with the fuel tank, I guess.
Well the replacement rotors came in today and look fine, so maybe I'll fiddle with that stuff tomorrow.
Just for giggles, I hooked the fuel plumbing back the way it was when I brought it home. Stock pump feeding the Aeromotive external pump, and from there going to the fuel rails. I wanted to see what would happen when I tried to start the car, not really expecting much, as I thought for certain that the stock fuel pump had given up the ghost.
I turned the key and watched the fuel pressure gauge, and was surprised that it even got to 20 psi. Took a little while, since all the fuel lines were pretty much emptied. And I was VERY surprised to see the pressure continue to climb, albeit slowly. Just for chuckles I tried to start the engine. Cranked over but obviously the fuel rails just weren't able to deliver fuel to the injectors. Then I got a "REDUCED ENGINE MODE" on the DIC. (Mike, yeah, I thought of you at that moment..) Then "SERVICE ABS" and "SERVICE TRACTION CONTROL" messages started rotating through the DIC as well. Aw hell.... Now I did it. I turned the key off a couple of times since the stock pump was only running for two second intervals and I figured maybe that would help speed up building the fuel pressure. Well eventually the car started and surprisingly enough continued to run with the fuel pressure right up close to 60 psi (probably 58, as it is supposed to be). The error messages all went away, and the car was idling smoothly. I'm thinking that maybe putting in new rear hubs with the new sensors might have confused the system momentarily causing those ABS errors. And probably the low fuel pressure triggered the reduced power mode. So I just let it idle for a while. Revved it up slightly and fuel pressure didn't waver. So I just let it run until it stopped spitting water out of the tail pipes and shut it down quite perplexed.
So, obviously I was doing something wrong trying to drain the fuel tanks like I was doing. But what? Why couldn't the stock fuel pump by itself pump out the fuel when I put the outlet hose into a catch can? Why wouldn't the Aeromotive pump do any better drawing through that stock pump? What in the world am I missing here? Obviously I am missing something important about this.
But in any event, I'm not going to have to drop down that fuel tank and worry about it cracking at the top where the filler hose and crossover hose connects. I bought a small fuel filter that replaces the 90 degree -8AN fitting on the output side of the Aeromotive pump, so tomorrow I'm slapping that guy in there and will just run the engine till it drains the fuel tanks that way. I'll just keep an eye on it to make sure it doesn't over heat, and will shut it down when it looks as close to being empty as it can get. I'll probably do it in stages to give the pumps a chance to cool down inbetween runs, though, as it may take a while.
Anyway, this is just crazy stuff. I doubt those fuel pumps work by magic, but they certainly weren't following any logic I tried to apply to make them do what I wanted them to do.
No one seems to know why I can't drain the fuel tanks using the fuel pump. So heck, maybe it IS all done by magic.....
Another thing I discovered that seems kind of insane has to do with the special wrenches they sell for AN fittings. Now these sound kind of handy as they are made of aluminum, rather wide at the jaws so they get a lot of surface area at work against the fitting, are short handled so you don't tend to apply too much torque against the fittings and distort them, and are coated so as to greatly reduce the marring of the fittings that can happen if you use your regular old crescent wrench. Sounds great, eh? But what they DON'T tell you is that if you order the wrong kind of set, you really need to have TWO sets to do anything with them.
Look at this set:
Looks nice, doesn't it? But wait a minute, you want to loosen or tighten up that AN fitting on the hose you are working on and grab the correctly sized wrench for the job. Hmm... Well darn. Look at that....
How the heck are you going to do THAT with only one wrench? Well, quite bluntly, you CAN'T. You either need TWO AN wrench sets to have TWO of each size, or else you can buy a set that seems to have thought this through properly....
How did I figure out this? Well, GUESS......... I had to buy an extra -8 wrench since that was the size I plan on having to work with the most.
Oh yeah, try to get a set that has two different angles on the ends as well, as that will come in REAL handy if you are in tight quarters trying to work on a fitting. Sometimes a straight ended wrench just won't cut it, but one at a 60 or 90 degree angle will make all the difference.
Rich, that last photo of the fuel line looks like it melted?, or is dissolving?...I have never see anything like that before?
Beats me. The fitting on the other side of the Aeromotive pump looked fine. And from what I recall trying to relocate that crossover line at the front of the fuel rails, they were OK as well.
I sent these pics to the guy that the fuel injectors came from (Jon at FuelInjectorConnection.com) and he asked me to send those injectors to him for inspection, free of charge. A clogged fuel injector can cause a lean cylinder which would be VERY bad news under boost.
I guess I've got to learn how to take out and install fuel injectors now...
Well, everything I tried to do to drain the fuel tanks using the internal and/or external Aeromotive pump failed. I checked the service manual and they make it sound simple enough.
First three steps are the usual about getting the car prepared for the procedure.
Attach a length of flexible fuel hose to an air operated pump device. (Now what in the world are they talking about here?)
More stuff about positioning a drain container and putting shop towels to sop up spilled gasoline....
Disconnect the fuel feed rear pipe (#4 in the diagram which is the lowest of the three tubes - which is the one I have been using).....
Attach the flexible fuel hose from the pump device to the fuel feed pipe nipple (#5 in the diagram) using a screw type clamp.
Drain the left fuel tank until no fuel comes out.
This is all on page 6-955 of the 2002 service manual, btw..
Man, that sounds SO easy, doesn't it? I had a hand operated pump sitting in a cabinet so I broke that out and hooked it up to that pipe they indicated. Worked the plunger like mad and all I got was a few dribbles of gasoline. Beats the heck out of me what I am doing wrong, but this just isn't doing the job.
So I put the inline fuel filter on the outlet of the Aeromotive pump, and after finally getting the fuel pressure high enough (seemed to take longer today than yesterday), I just let the car run for about an hour to burn up some of the gasoline in the tanks. Honestly, this was probably the first time I ever cursed the relative fuel efficiency of these Corvette engines. After an hour, the gas gauge didn't move much at all. I kept tabs on the coolant temperature, and it never got above 190 degrees. At that point the fans kicked in and dropped the temp down to 185. At one point I did get into the car and revved it up just a little but, but heard some exhaust popping and let off of it. And the engine died, of course. Seems to have a lot of trouble maintaining idle after coming off of throttle movements. But hopefully a decent tune will take care of that.
Anyway, it's going to take several stretches of running the car at idle to burn off the remaining gasoline. Which brings a question to mind that maybe someone can answer for me. When the gas gauge says "half full" what exactly does that mean in relation to how much gasoline is actually in each of the two tanks? Is one tank empty or mostly so, or are both tanks actually half empty together? In other words, does one tank empty before the other, or do they both empty at an equal rate while the engine is running?
Oh, during that hour of running the car, I got kind of bored. So I broke out the video camera and just walked around the car taking various angles of video. So if you want, you can get bored right along with me.....
And another btw.... I bought one of those handy dandy fuel line disconnect tools and this was the first time I ever tried to use it....
Darn if I could figure out how to make it work. I finally was able to get that fuel line off of the tube coming from the fuel pump, but seems to me I didn't use the tool at all. Just squeezed on that plastic piece coming out of the end and tugging on the fitting with a decent helping of curse words, of course. How is that thing SUPPOSED to work?
Oh yeah, I had my other camera over in the garage as well. Here's a pic of that fuel filter I installed on the Aeromotive pump.
And I forgot to mention that I installed the brake stuff on the rear of the car earlier in the day, so the rear end stuff is now done. Half shafts are in, and new rotors and pads are in. Oh yeah, I've still got to put those braided brake lines in. Still got the fronts to do, but I'll have time to do them while waiting on the modded fuel pump to get done when I get that out of the car. But here's a few pics of how those new rotors look.
Why not just get a cheap hand siphon pump and pump the gas out from the filler opening?
Back in the days when I was still in Maryland, and before I decided to heat my garage, I used to use a kerosene heater to take the chill off in the garage. I used a battery operated hand held siphon pump to pump the kerosene out of the can and into the heater. They were not terribly expensive and moved the kerosene pretty quickly. Here is a link to one I found that was like the one I used. Pretty cheap to eliminate the aggravation that you are going through.
I had to buy an extra -8 wrench since that was the size I plan on having to work with the most.
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