HELP! HELP! HELP! HELP! HELP!

Ok Guys, I have been dealing with Fuel Pressure issues foe a while now!! My car is a 383 with D1SC and Automatic. I drive my car on the streets so its not a track car only! I do like to take it to the track when everything is ok!

It all started when I decided to go to a 3.71 Pulley instead of the 3.85 I had, so I knew I was probably going to need more fuel! ! When I was running the 3.85 Pulley, I had a Racetronix Intank Pump, with a Kenne Bell Boost-A-Pump and car made 625RWHP with a perfect Air Fuel........I then purchased a 3.71 Pulley and since I knew I was going to need more fuel I purchased an ECS Fuel Kit, so the ECS Kit was installed with the 3.71 Pulley and then we went to the Dyno and all hell broke loose! Fuel pressure at idle was at 58-60 but when we hit 5000RPM fuel started to drop below 40 Lbs. Corey (Tuner) try everything to get more fuel but we had no luck, so I called Doug at ECS and he told me that therer was some issues with the way the external pump was mounted by the exhaust because of the heat, so he sent me the upgrade kit to move the pump inside the rear fender and also replaced the 6AN lines from the tank to the external pump, since the car went back to the shop I decided to replace the Racetronix Pump with a New LPE just in case the intank pump was bad, so we head back to the Dyno and again we are having issues with fuel pressure dropping below 40 Lbs. so at the Dyno I called Doug and since he knows I have been having this issues, he had us draw a diagram of the way the system was installed, after he review it, he said everything was ok..........My question is, has anyone running this kit ever had issues with fuel pressure dropping! ! Guys, this is not a thread about bashing anyone, so please do not post if you can't help! This is a matter of trying to figure this Fuel issue out! I know ECS has a great reputation and by no means do I intend to harm them, they have been great to me everytime I call them for parts or technical support!

I have talked to few members on the forum and some have told me that they run the External Pump all the time, otheres run it on a Switch by the pedal to only activate it when car is at full throttle!

Once Again, Please only input any available help/options you guys may have!

Also, if anyone has modified this system to improve it, please input what you have done!

 

Hey Mike,

You know how mine is setup.

For what it's worth, I had the biggest, baddest Aeromotive fuel pump on my convertible at one point. It moves enough fuel to support something like 1600hp NA (so, a LARGE amount of fuel). It would fully fuel the car with no issues for about an hour -- and then after around an hour, it would lose fuel pressure, and if you ran the car long enough, it couldn't even idle!

Why?

This is what happens when you are oversized on your pump -- especially in a tropical/hot climate. The fuel will eventually get so hot it will boil and you'll end up with air in your rails which results in lost fuel pressure. I can almost guarantee this is happening to you. You are heating the fuel by compressing it (same reason we run intercoolers for our compressed air, compressing a liquid or gas makes it hotter!), you are adding heat by the fuel soaking heat from the fuel rails, and that heat is eventually going back into your gas tank and your fuel pump. In an ideal world, your fuel system would ONLY deliver as much fuel to the rails as your motor needs to consume. This prevents unecessary heating of fuel and fuel components.

It will take an hour of labor TOPS to set your aux pump to run with a nitrous pedal switch only. Assuming your car still runs off your OEM fuel pump and nothing is wrong with it, this will more than likely solve your issue.



Oh, what time of year did you change your pulley? Was it starting to warm up outside around that time?

Also, may I ask why you haven't tried the nitrous pedal switch approach yet? I figured after we spent so much time on the phone on Saturday you'd at least give it a shot?

 

Tony:

That is defently an option Im looking at since I have not called Doug to see what he had in mind! I will be calling Doug tomorrow, he was going to talk to few guys that are running the same set up!
Arnold was going to put my car on his lift tonight and go from there! ! I like the idea of not having the external pump running all the time and just run the external pump when its full throttle! ! Im also checking on prices to on all the lines and fittings I will be needing for this project!

 

I don't think heat is an issue, unless this is a return style fuel system, and you are returning fuel after it has been in the rails. If it is set up this way you might have a problem

I know this sounds dumb, but check all the fuel filters. If it works fine at idle, and part way under boost, when the demand for fuel increases, it can't pump enough through a cloged filter. I have had that happen a couple times. I would put money on a bad filter, or an obstruction somewhere before i would blame heat.

 

ECS Fuel Kit has about 200 Miles on it (including Filters), LPE Intank Pump has less that 50 miles...........By the way, I do have a return line going back to the tank!

 

This may be a stupid question, but have you verified your F/P sending unit is in 100% working order?

There have been quite a few guys here that have actually started to have the sending unit on their autometer guage go out. This would give them "False" low fuel pressure readings.

 

I take it that you did not make a boat load more power after the ECS switch over before running into FP issues?


I have a similar issue. I have the ECS Fuel system and the FP is good until about 850 rwhp or 6000 RPM and I drop to 25 PSI. But I'm told in my case it is because the standard pump shipped with the ECS kit is good for about 1000 fwhp, which I'm hitting. In defense of ECS the purpose of the using the non-AirCraft grade pump is because Vette owners do not like the loud noise of that the pump makes. It also requires 6AN fuel feed line to be installed and of course the pump relocation hardware will be going in.

Keep us posted of the outcome and root cause

 

Ok I am here in texas as well with the ECS system as well. In the beginning I had major fp drop issues like you had. I eventually found part of my problem and it was my fault. It seems that when I put the transmission and drivetrain back in the car after the install I crimped the factory metal line by bumping it with the trans. I remedied this by removing all of the factory feed and return with -6 stainless. In hindsight I wish I would have gone with -8, but it worked fine. It fixed almost all of my problems aside from the heating fuel and cavatation noises the pump would make. I still had about 58psi at idle and when coming up on 6500 rpm my fp would still drop to around 52ish on my gauge....I could live with that little drop and it was tuned that way. About 2 weeks ago I took a fp sending unit off of a customers car (with his permission of course) and tried it on my autometer gauge and what do you know....58psi idle and 56-58 psi at redline. No more drop in fp. I am not saying that this is your problem, but I to had a bad sending unit. I later header wrapped part of my drivers side header and the rear hump part of my exhaust that goes over the axle. In addition I got the flame retardent high heat hose wrap and covered every inch of the line...feed and return. This helped alot, but still hasn't fixed all of the problem, but it is noticeably better. I am in the process of relocating the pump with their retrofit kit today and I will let you know what happens later with that. I am also in the process of trying to do a vacuum pressure gauge, but after 2 attempts with two different switches (neither of them working) I am on my third attempt with another brand and it should be here today or tommorow. Call me if you would like to talk about it 903-705-2886.

 

LPE just sold you the exact same pump you had in the tank from Racetronix. We also had a similar issue with my D1SC, and we moved upto the Bosch 420 pump (p/n ending in 044) Are you running a stock return style system, after market regulator ?

 

Good suggestion on the filters, might as well check them. They are probably the cheapest fix at this point.

BTW, the ECS system does return from the front of the car and/or rails depending on how you set it up.

 

Oh, also -- I do have data to back up what I said about fuel system components and heat. Running the pump all the time most certainly does create additional heat in the fuel that you don't need. In fact I measured about 50 degrees difference -- 165F after a couple of hours with the pump running all the time, 115F under the same conditions without the pump running all the time.

http://forums.corvetteforum.com/show....php?t=1415268

 

I don't doubt what your saying, but the fuel won't get hot unless it is being circulated through the motor to heat up. As long as you return it back before it gets hot, you shouldn't have a problem

 

I know, but this is a moot point: he and I are running the same fuel system, and unless he plumbed his drastically different... he is subject to the same heat. Also note, the fuel pump itself creates heat regardless of where the fuel is returned. Fuel rail heat is only part of the equation.

Also, I think *most* guys on this board with a return system have the regulator up front near the rails somewhere to help keep rail pressure most consistent. So I think this issue will affect more guys on this board than not.

Finally, when Mike and I spoke, he said the car would run fine and hold pressure for about an hour and then lose its ability to hold pressure. This particularly sounds like a heating issue.

 

Set up the pump to run at only WOT and/or under boost. Try the WOT switch and a Hobbs switch. Good chance heat build up is your issue.

Before I had mine set up like that I would notice a dip in pressure when the pump got hot. Nothing close to what you have though.

 

Mike have you tried to pm Road Rebel? Doesn't he have some setup where he runs the LS2 rails, some relay off a Pontiac GTP and a intank pump no return line? He has some customers over 800 rwhp, i mean Earl H has 402 TTix and auto? I've tried Pm'ing him but I don't think he like's me enough to respond back-maybe you'll have better luck?

 

Mike told me today they may have found the problem, if so I will let him post, he and Gotjuice? have been all over this since last week to get to the bottom of this, I hope they got it as Mike wants to get to the track and into the nines with his setup

 

Well guys, Im hoping that we have a solution to this, Arnold has the car on his lift and will get to it! ! What happens was that when we pulled the Racetronix pump from the intank and installed the LPE, I never knew that the polarity was backwards, so that might be a problem, the intank is not doing the work that is supposed to do! ! I have got on my knees and pray that this is the problem....in the other hand, Im looking into a Hobbs switch/Pedal Switch to ony run the external pump when the car is under boost or full throttle. Also will be runnig a check valve! !


So guys, keep mikes99corvette on your prayers tonight because my car has been collecting dust at Arnolds in the last 6 months and summer is comming up and I want to enjoy the car! ! !



Also I want to thank everyone that has giving me their ideas/opinions to try to solve this issue! ! Great guys on this forum! !

 

Good luck. Polarity would be a simple problem with a simple solution.

 

Good Luck Bro

 

results??? so what happend last night?