jdperk-86elco

Hi All,

I need some help. I did an LS1 sway back in 2005 and everything was great except for the last 3 months. The motor is dying when I come to a stop randomly. It has happened about 4 times and the last one the worst. The first time I was driving back from work on a really hot day and I was below a half of a tank; as I came to a stop light slightly on a slightly inclined hill the engine stumbled and died. It would not re-start. Everyone behind me was mad but there was nothing I could do about it. Anyway I tried restarting but it would not. I sat there for 3 to 5 minutes then it started and ran fine. I was thinking (guessing) it was low fuel and the intank electric fuel pump overheated and stopped. This same thing happened about two weeks later with low fuel. It then happened with over a half a tank. So far waiting about 5 or 10 minutes it will restart and I have been embarrased but able to drive home.

Yesterday I am working on a work project about 1.5 hours out of town and coming back I am below 1/4 tank and take an off ramp that is uphill to get gas. I am inline and the car stumbles and is partially running way below idle and doesn't have any power to move the car. It dies and will not restart. I wait the 10 minutes and it will not start. I was cruising at about 75mph passing most before I took the off ramp. It is another hot day and I know my fuel is low but it isn't empty. I end up calling a tow truck which takes about an hour to get there but before the end of the hour I try it again and it starts up. I drive it the 1/2 block to the gas station and fill up. It starts and drives fine now and I thank the tow truck driver for coming and he goes on.

I have a new aftermarket FI tank for my Elco with an original new 1986 GM sender and a aftermarket high pressure electric intank fuel pump. When I routed the fuel line I used the existing fuel line mounted on the passenger frame rail and added an extension tube at the firewall line up and over the transmission joint between the transmission and the engine and out centered and behind the engine intake. I then go with a flexible hose to the drivers side fuel rail connection. All this time I have had no problems until randomly these past few months. The fuel line is clamped to the body transmission hump so I know it is not laying on the tranny or engine. I have the Corvette fuel filter near the tank so the fuel return exits the filter back to the tank and I have 1 main line to the 2000 LS1 motor.

So is my electric fuel pump going bad? Is it overheating, electrically opening an internal thermal switch, then resetting? The electric fuel pump has wined loud since day one after install that I can hear it before I start the car.

Am I experiencing Vapor Lock? If so why now after all these few years?

I don't have a fuel pressure gauge to help diagnose the problem but if I get one which one do I get to mount inside the car on the winshield pillar and where do I connect it on the fuel rail?

I would appreciate the help. Oh I am still having trouble with filling this aftermarket tank due to its venting problem. If I have to drop the tank to change the fuel pump I will weld in a vent line as suggested by G-Body.

I have EFILive and I have no trouble codes or anything I can see wrong.

James

ls1nova71

iTrader: (4)

I think I would start by checking the fuel pressure like you said, but you would have to wait for it to screw up again. Does it do this on a regular basis, or is it more random, by that I mean can you make it do it (by driving on the hiway for extended period of time or something)? BTW what part of KC are you in? I don't recall ever seeing your car, or if I have the hood wasn't up. I have a pressure guage, and I'm in Independence.

jdperk-86elco

I am in Kansas City, well a KC address but I live near or just North of Raytown.

I can not duplicate the problem. It appears or is just a coincidence during hot days. Hence my thought of hot days and hot motor causing a vapor lock due to my fuel line routing. It could be that my fuel pump is starting to fail; however usually anything electrical fails completely and not intermitently.

G-Body

iTrader: (4)

IIRC you have EFI Live 7 right? Try scanning the car and checking the injector duty cycles, if they seem way to high you are probably low on fuel pressure. If you are low on pressure it might not be the pump, I had the 2" long piece of fuel line between the pump and sending unit split on me......

The car started running crummy and was a harder to start, then one day it was running really bad and when I left work it died out and would not restart. I was passing the shop that my uncle works at and coasted in. I could not get it to restart so I was going to wait for him to get off work and tow me home. when he got off work I tried restarting it and it ran, but didn`t have a lot of power. I limped it home and by the time I made it home if I pushed on the gas pedal at all it wanted to die. It would be something to check as its pretty easy to drop the tank on an EC

1996firebirdformula

iTrader: (3)

Sounds like fuel pump. It would bog down With A/C on from stop if tryed to get up and go quick. Mine died on Hot Day after i came home was leaving died in driveway. After it cooled it would start and run.

jdperk-86elco

Well, I bought a fuel pressure gauge and connected it to the fuel rail. Static pressure with the 2 second pump run with the key in the on position only has 30psi. After starting is goes to 40psi and drops 10psi on throttle increase before it recovers back to 40psi.

Now since it is suppose to be 58psi I would suspect the electric fuel pump in the tank; however, could it be my Corvette fuel filter? I have the fuel filter mounted near the tank where the return line goes back to the tank.

The fuel pump has always been noisy with a high pitch whine. I wonder if it wasn't working well from the beginning and now it is just lower pressure and the car can't run when it gets hot. The pressure relief line on the fuel pressure gauge showed air bubbles instead of just a solid flow of fuel, so I am thinking I am experiencing vapor lock with the fuel boiling in the line. I probably should re-route my fuel line from behind the intake and put it on the drivers side frame rail to keep it away from heat better.

I would appreciate some thoughts before I go out and purchase a new electric fuel pump and drop the tank. Well this would let me add that fuel vent line so I can fill the tank fast.

G-Body, did you weld on a bung on the tank and filler neck or what did you do there to add the vent line? Should I add it at the very top of the tank or upper side of the tank? Should I make it a hard line or jut nipples and use a rubber hose between them?

I will look over the whole fuel line to the tank to inspect everything so see if I am missing anything.

ls1nova71

iTrader: (4)

I've had this happen in the past too. Does it hold fuel pressure when the engine is off (or after turning key on to prime) if it falls off quickly, I would check that hose. Mine had a hole so small you couldn't see it, but under pressure it shot out of the hose, and wouldn't make pressure at the rail.

jdperk-86elco

After the 2 second prime to 30psi it will hold that pressure and will not fall off. When I start the car the pressure increases to 40psi and drops off 10psi when I bump the throttle.

I will crawl under the car and check out all the fuel lines and fittings before I drop the tank.

I don't smell gas or see any signs of a fuel leak on the ground.

LiT1_up

iTrader: (16)

Is your tank vented now?

ls1nova71

iTrader: (4)

Well now that's starting to sound like the filter to me. But don't hold me to it, but that's where I would start. I always try to start with the easy to change parts first, and if the filter dosen't fix it, you've got one for another swap, or for when yours does need to be changed.

jdperk-86elco

I've always said to try the simple stuff first. The Corvette filter is the regulator also and I was just thinking it could be the problem. I did mount the filter/reg just ahead of the tank for easy changing and used quick disconnect fittings just for that purpose.

The pump is running so good idea, I will try the Corvette filter/reg first. I need to find the part number. Does anyone have the part number for the Corvette fuel filter regulator?

G-Body

iTrader: (4)

I have actually done it both ways. Heres what I have learned, rubber hose sux cause its very difficult to find in 1/2" and fuel resistant. You also don`t want to put it in the very top portion of the tank because it fills too high then and you will smell fuel because it will seem out of the o-ring around the sending unit. Now I put it in as a single piece out of 1/2" steel tube. It works much better, but I wish I had drilled the hole a little higher in the side of the tank so that it would have filled higher. The tubing that I used is 1/2" OD that I bought from mc master carr. They have benders available for 1/2" OD tubing but they are expensive, I was able to bend it with a 1/2" thin wall electrical pipe bender. It is a sloppy fit, but worked out great.

ACONLP

the part number on the filter reg. is the brand WIX 33737

Old Geezer

iTrader: (3)

What vent setup is on the tank, now? Has the smog system been retained? If not, and the smog lines, [ie: cannister] have been plugged, a sealed cap is used, you have no vent.
If that's the case, as you run the fuel level down, there's a vac pulled on the pump inlet. This will cause cavitation.
A pump operating in cavitation will be noisy, overheat, and ultimately go "tango uniform".
If you have a sealed cap, adding the vent line, will help w/ filling, but have no positive effect on the tank's ability to "breathe".
Also, check the voltage at the pump, vs the alt output.

jdperk-86elco

I retained the charcole canister and original vent line. The tank refilling issue seems to be with the aftermarket tank design.

Anyway here is what I have diagnosed. I read in a manual that if one caps the return line of the fuel filter/regulator that the pump pressure should climb to the pumps output capability. I capped the return line and the pump still only put out 30psi with the 2 second on time. I went ahead and ordered a new fuel filter/reg and changed it and got the same low pressures.

I put a T in the charcole canister ventline and ran it to open air in the hopes that it would cure my tank filling issue but that didn't work so I am sure the vent line is not clogged.

Monday I will talk with the guys where I bought the walbro fuel pump and get a new one.

QUESTION Gbody on the pictures is this the way you have found to be the best solution as in tubing size and position of the line on the tank and filler tube?

G-Body

iTrader: (4)

The 1/2" tubing works perfectly. The tank fills up as fast as the gas pump will pump it in, and has never splashed back out the end of the fill tube on the first kick-off of the pump. The placement on the fill tube is perfect. On the tank side I would probably raise it up a little higher. I put it in so that the 1/2" vent line was about level with the center of the fill tube. If I had to do it again I would put the 1/2" vent tube into the side of the tank level with the top of the fill tube or even a little higher, it doesn`t really hurt anything to have it a little low like I have mine, but an extra gallon or 2 of fuel capacity would be there if I had put it in higher.

ssvolvo

Is the sock on the pump in good shape? Any tears? I would replace the pump, sock AND filter. If you have EFIlive you've probably been tuning aroung this isssue for awhile. Might need to redo your VE.

jdperk-86elco

Ok, just dropped the tank and removed all the gas out of it plus rinsed it out with water.

The fuel pump was working so I used it to pump out most of the gas into a gas jug. The pump is a Walbro F20000169 which appears to be a new style. The new pump I am going to replace it with is the Walbro GSS340.

Ok now I need to weld on the tank to add a vent line. How can I do this safely without blowing my head off? I am going to use a leaf blower to dry the tank out and get the water out of it but I was thinking of getting some welding gas like nitrogen and fill the tank up with it to displace the air.

Any safe methods I should use?

G-Body

iTrader: (4)

Well theres a few ways.

I usually just drain the gas, blow it dry with a leaf blower for a couple hours, fire up the oxy/acetylene torch with a 3` flame, wave it around the openings and then into the sending unit opening to check for fumes and start welding.

Some guys will wash it out with soap and water too.

Others will fill the tank with an inert gas such as carbon dioxide

Other people say that the safest way is to have the tank boiled out by a radiator repair shop.

I have also heard of people hooking the exhaust pipe of another car to the tank and leaving the car running while they weld so that the tank is full of exhaust fumes and therefore should not have enough oxygen to combust

jdperk-86elco

Well I decided to go get a bottle of inert gas and put that in the tank so I can weld on the vent lines to the filler neck.

I decided to blow through the vent line from the tank to the charcoal canister and it appears to be slightly clogged. What I mean by that is I get a lot of back pressure but I can get a little air through the line. I have it disconnected at the cannister and it is a straight tube so I am expecting little resistance but that is not what I am getting. So I think I have found a contributing factor with the fuel pump going bad. So I will go and get some rubber hose and run it the full length of the car for a new vent line. I will see if that helps this new pump.

I don't know how that line could even get clogged?