My car was converted to electronic fuel injection two years ago with a new tank, and electric in-tank fuel pump. Normally when I put gas in it I only fill the tank to about 3/4 full and don't let it get below 1/4 full. However, the other day for some reason I decided to be different (dumb?) and pretty much topped it off, releasing the pump handle when I felt like the tank would be about full. The normal sequence I follow to start the engine is I put the key in, turn it to run, the fuel pump runs for about five seconds and stops, then I crank the engine till it fires. Going to leave the gas station, the pump ran a little slower than normal, but it started fine. The car got driven about 3 or 4 more times after that, and everything worked normally. However, Thursday morning I went to start it up. I followed the sequence and the engine runs for about three seconds and dies. Turning the key off and putting it back to run yields no fuel pump noise. The car is currently in the shop waiting for one of the techs to pull the old fuel pump so I know exactly what to order to replace it. So the question is, could overfilling the tank have killed the pump? I've always heard it's bad to run fuel pumps in a near empty tank, and it's bad for emissions systems to overfill the tank, but I don't recall ever hearing anything bad happening to a fuel pump by overfilling the tank. A fluke maybe? Curious if anybody knows of anything else that might kill the pump that I didn't talk about here.
Never heard of that. I have owned multiple turbo Buicks which have the pump in the tanks, and never worried about filling the tank. The pump is submerged in the fuel.
No. The pump started going, that's how they often do. Hiccups, slow, surges, dead, then work again, then leave you stuck on the side of the road.
Nick, Sorry, but I don't know details of your build. What's the EFI conversion, and more importantly, tell me about the tank and pump...and maybe most importantly, for this EFI is venting the tank still part of the design/original intent? Devon
Ok I dont really all the fundamentals on Gas EFI or duel fuel lines on a gas motor...... Now diesel that I know more about but still old school mechanical... Start motor cold fuel is drawn from tank into the injection pump.. Unneeded fuel is returned to the tank... As time goes by with this fuel going in&out of the tank the fuel in the gets warmer..... Thats all I really got to say... I dont like seeing my tank get below half.
I fill my GN and TTA to the brim every time. Was your tank cleaned when the conversion was done? Are you using alcohol free fuel with Sta-Bil? BTW, when you turn you ignition off count to ten before you turn it back on, if you do it right away it will not run. Put a pressure gauge on the fuel rail and see what you have, should be 35 to 43. Do you have an adjustable fuel pressure regulator, if so, turn it up to see how far it goes, if you hit 50 it's probably OK.
FiTech EFI, easy street 600 hp TBI setup. There is a supply and return line at the throttle body. I don't have a record of what tank and pump were installed since the shop that did the conversion ordered all the parts for me. If I had to deduce what they are it would be this tank (mine has the notched corners like this one): https://www.tanksinc.com/index.cfm/..._id=587/category_id=102/mode=prod/prd587.html and this pump: https://www.summitracing.com/parts/tnk-gpa-4 Don't know what the venting situation is on my tank.
Does FiTech EFI require any tank venting? I was thinking of an easy try, but not very safe with the original design w/cap at the rear on a full tank...I was thinking of cracking the cap open just a bit to vent, leaving it that way, then another try. But I was only thinking about it. Vented cap would be a better try. Devon
When it first died, I tried something similar. I took the cap off for a moment to equalize the pressure in the tank to atmospheric pressure, then put the cap back on. Tried to crank it again and still nothing from the fuel pump. Don't know what FiTech requires for venting but the shop that put the system in has done many FiTech installs before so I presume they know what they're doing. Plenty of other reasons though why I don't want to go back there. Jim Weise knows all about my fun with that place.
Reading through the FI install instructions, some kind of tank vent IS required. If it turns out I have no such thing, could filling the tank kill the pump? My fill cap is an original style non vented one I believe.
I replied earlier from my phone and my olde eyes had trouble reading the entire post, so I read it again) I have FiTech on both 64 and 68 Skylarks. The 64 has a 2x4 and the 68 is a single. Both have Spectra Premium tanks and their "bundled" pump/sender unit. (I have read several reports about the pumps going bad) Does your tank have the rubber connector sleeve or is it a single piece soldered tube from tank to the filler cap? The 64 pump started giving me fits and had "soft" failures a few times before I changed it. First event was at cruise about 85MPH on the interstate after about 1.5 hours of driving, and engine simply cutoff fuel for a second and came back, just enough to drop about 3 MPH, like pedaling at the big end of a run. No other trouble for several months, then within a few weeks time, the pump stopped dead and the engine quit, and both times I opened the trunk and whacked on the bottom of the trunk over the sender/pump well and it started up and drove fine. Again about a month, and in another period of weeks, it did it again. All of those events happened when I was in town and pulled up to traffic light to stop, and car "stalled" and would not start. Then a few days later as I was on the highway driving home, just nice cruise about 75 and pump stopped, engine stalled (manual) tried pedaling and got the "wah wah" of blades opening but zero power, so I pushed to neutral and tried cranking a few times, then pulled over. On highway I could not tell if the pump was running with key on (prime) and did not think to pop the hood and put the phone on record pointed at the pressure gauge and try. A guy and his family pulled up behind me and I showed him the key and went back to the tank to listen and heard nothing when he keyed on. Whacked the floor again, nothing, so I swapped relays (I was running dual relays/circuit for failover) and that seemed to work, or the pump cooled down. Drove home, ordered an Aeromotive PWM pump, swapped it and set the pump control off the FiTech and abandoned my relays. Been driving for over a year now and no issues at all. The 68 still has the Spectra pump (I think it is a Walbro, and what was in the 64 as well). It was connected to the FiTech control from the beginning and has never been a problem. I can see in the log files, the PWM functions as intended. Both were dead head with an Aeromotive high bypass regulator direct return to the tank, (and the normal vent line), but I changed the 64 to a return, because I was not sure if the fuel was too hot with a short return (1 foot) to the tank vs the loss of heat over the 18 feet of return line with time and heat exchange of the line. And I wanted to see if there was any noticeable difference with anything EFI related with return vs deadhead. There was none, not even an adjustment to the regulator. I still run the 68 as a deadhead, and both cars otherwise have exact same components and routing of the fuel delivery. (I like to keep things the same as a pattern if they work.) Both cars have new everything for the fuel systems, tank, regulator, 10 micron filter, 3/8 hard line, and AN8 fittings and braided steel PTFE lines in the "soft" spots at the engine side. (exception is Push lock 3/8 return on the 64). Both regulators are set to 60psi at the rail at the FiTech, and it regulates to 58, so I figure with the deadhead, 2 PSI delta is not a problem, and I have eyeballed the gauge and it never moves above or below the 60PSI under any condition. (the Areomotive regulators are dead on and rock steady on both cars). Hope this helps. (you, or someone else that may have questions). If you have any questions, that I might be able to answer, ask.
A full tank is absolutely nothing to worry about. Easy enough to diagnose, check for power and ground or beat on the tank with a rubber mallet while cranking. The 60 psi mark reminds me of the 90s vortec powered blazers and trucks. The pump failure rate was nearly 100%.. I must have replaced 100s of them. Only the Delphi pumps lasted more than a year and were nearly 600 bucks. The jobber pumps were less than half but only lasted a few months. I hate to say it, but I would not have high hopes for anything with the spectra name...
The Spectra tank is a decent tank. If I were installing a new EFI tank, I would swap for a good quality pump before installing. (Aeromotive stealth) I dug out the original pump from the 64 and pulled of the rubber isolator, it has Spectra's numbers on it, so I think it is China crap. (not as some people have claimed it is a Walbro, on the innerwebz)
I don't have the car here to check it, if it was made by Tanks Inc then I think it will have the rubber coupler. What is the need for a PWM pump? The Tanks, Inc instructions for their GPA series of pumps state that if it is to be used with a FiTech system that you have to turn PWM off.
They have you turn the PWM off because the pump is likely not PWM rated, and it will damage the pump. PWM allows a motor to operate by rapid pulse, rather than continuous current and the result is longer life and more efficient operation by only doing enough "work" for the "demand". So, less running during low fuel requirement, idling, coasting, low RPM, low speed driving. A motor that is not designed to use PWM, will be damaged by the constant "on/off" switching effect. Electromagnetic coil style relays will also be damaged, and even a PWM motor if enabled by a mechanical switched relay will likely result in damage to the relay and the motor. I am using FiTech PWM control on both the Spectra pump and the Aeromotive Stealth pump. Since the Spectra pump is not the greatest quality piece, if it dies, I already have the Aeromotive to replace it.
What is the Aeromotive pump you're using? What I would like to do right now is just get an identical replacement for whatever pump I have now to just get the car running again. Then, I'd like to figure out a better combination of parts to use longer term. I want a reliable system that I don't have to replace the pump on every two years. Tanks Inc claims to use Walbro pump motors (which I've heard good things about) for their in-tank pumps but mine only lasted two years. I've also heard good things about Aeromotive. If I can swap the in-tank pump motor for an Aeromotive unit if I can find a known reliable one that works with the FiTech setup I'm open to that. Also I'm thinking if I did that, even though I have a return system, it might be a good idea to add another pressure regulator before the throttle body as a means of redundancy and to prevent wear/overuse on the regulator in the throttle body since I have no idea of it's reliability or how much of an ordeal it would be to replace. Alternatively, I want something with a pump that is more easily swappable on the side of the road somewhere (external as opposed to in-tank). Is it true that external pumps require hookups at the bottom of the tank so they are gravity fed? That means I would have to modify my tank.
Aeromotive 11569 340 LPH Stealth Aeromotive 13301 Regulator I have the regulator at the tank and bypassed back to the tank from the regulator, about 1 foot of line. Regulator set to 60 psi from there to the Fitech, and the FiTech regulates to 58 psi. This is a rock steady setup without a return from the FiTech for both my Nalhead with 2x4s and the BBB @ about 540 hp and 510 ft torque so both can turn the fuel gauge into a fuel flow meter at WOT. (it does not waiver off 60 psi over any throttle demand) (I did change the nailhead to a return line to the tank, thinking that might help lower fuel temp when I first started having trouble with the pump, but the FiTech works fine on both cars with a deadhead setup.) External needs to be as close to the tank and below the bottom level as these pumps are "pushers" and not designed to be "suckers", you can cavitate a pump on suction and there is a lot of formulae for calculating all that which Uncle Sam made me learn for hydraulic and engine fuel systems, but it's boring and not necessary. People do run pickup tubes in the top mount style tanks, but even with a check valve, if the line loses the fuel, and the pump loses the prime, you can have problems, so it is why it is recommended to pick up from a free flow gravity rush to the pump from the bottom of the tank, and not a siphon. Just place an properly calculated pump from the requirements using the math provided below. https://help.summitracing.com/app/answers/detail/a_id/5245/~/what-size-fuel-pump-do-i-need? My system works well for me, and is what a lot will call "overkill", but I lost my father to a dragster fuel fire and dealt with enough aircraft fuel fires to put in extra effort. ("Overkill" was one of my call signs...) Others will have good info and input, but I will be happy to provide any information and opinion that you or anyone would like.
