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(1) Does the Vette itself drop off in power or "Fall Hard" when you get on it when it is warmed up?
Or
Is it that the Fuel Pressure only "Falls Hard"? like you said.
No there is no power it leans out bad feels like I'm getting drug back when fuel pressure drops. I can see it drop and I can feel the car saying F you and basically no getting fuel to the rails. I know for a fact it's from the rear side not anything to do with my current setup. This was doing this BEFORE I even went to this setup. It was doing it with the stock setup. It's only does it when getting into boost. Other than that the car runs and drives fine if I'm out of boost and fp stays in the 60 range cruising.
(2) Can you please, and you are gonna hate me for this, also add you additional system (secondary setup) to the drawing or do one with it drawn in too?
No problem I can do that and add a video like I did above but it won't be until tonight. My phone doesn't take pics it's a work phone and the camera is disabled for security reasons..
(3) What fuel pressure gauge and sender are you using? - I ask for a reason! A good one too!
Prosport. And I have had 2 sending units installed and they read the same. I also used a autometer to verify I wasn't having issues with the prosport. It's dead nuts. Also my fpr mirrors my prosport when I increase or decrease base pressure on the fpr. Those are solid..I even was going to take the hood off and add another mechanical and tape it to the window but 2 sending units and another brand all say fuel pressure is dropping . When cruising it's fine when cool it's fine and boost hell even the bap works and raised pressure. Once it's hot then all hell breaks loose. The bap is disconnected at the moment it's not part of the system.
Thanks,Matt
I should be on break hopefully in the next hour to call.
I talked with Matt and a few others and we are on agreement that the issue is coming from the tank area. Matt brought up something I never would of thought of. The convoluted tube inside the tank may be compromised. The tube is usually held on by a gm clamp I bypassed that when I was yanking on the tube and put a worm clamp on it. He said the pressure build up may be getting past that worm clamp and into the system causing my issue and I possible cracked that line somewhere so I will pressure test it tonight. I will pull the pump tonight and see what i find..
edit: Part ordered from lingenfelter...4 dollar part..8 dollars for shipping....12 bucks total. I will get the oetiker clamps in town
I talked with Matt and a few others and we are on agreement that the issue is coming from the tank area. Matt brought up something I never would of thought of. The convoluted tube inside the tank may be compromised. The tube is usually held on by a gm clamp I bypassed that when I was yanking on the tube and put a worm clamp on it. He said the pressure build up may be getting past that worm clamp and into the system causing my issue and I possible cracked that line somewhere so I will pressure test it tonight. I will pull the pump tonight and see what i find..
edit: Part ordered from lingenfelter...4 dollar part..8 dollars for shipping....12 bucks total. I will get the oetiker clamps in town
Awesome! Keep us posted on the findings - I hope we nailed it down and that is the fix!
Here is where we can "ALL" get the fuel tubing from:
I talked with Matt and a few others and we are on agreement that the issue is coming from the tank area. Matt brought up something I never would of thought of. The convoluted tube inside the tank may be compromised. The tube is usually held on by a gm clamp I bypassed that when I was yanking on the tube and put a worm clamp on it. He said the pressure build up may be getting past that worm clamp and into the system causing my issue and I possible cracked that line somewhere so I will pressure test it tonight. I will pull the pump tonight and see what i find..
edit: Part ordered from lingenfelter...4 dollar part..8 dollars for shipping....12 bucks total. I will get the oetiker clamps in town
^^^Very much plausible, I've seen a few aftermarket pumps that leaked internally causing this same issue. Although hot/cold really shouldn't play that big of a roll with that.
I asked about you're only running a single pump, are you sure you're not just outrunning the one pump? That's why we created the secondary system, because generally with too much boost you outrun what the single pump can handle.
^^^Very much plausible, I've seen a few aftermarket pumps that leaked internally causing this same issue. Although hot/cold really shouldn't play that big of a roll with that.
I asked about you're only running a single pump, are you sure you're not just outrunning the one pump? That's why we created the secondary system, because generally with too much boost you outrun what the single pump can handle.
CK
Yes I am sure I am not over running the pump. I could see if I was rowing gears and being wot and see pressure falling. But this issue happens as soon as I get into boost maybe around 2-3psi and it falls faster then you can blink a eye when the car has been ran awhile and temps in the 200 range. I'm not talking 5-10 psi drop I'm talking all teh way to zero if I let it and that secondary won't help at that moment. I need to fix this issue before I add teh secondary...At 2-3 psi I'm probably around 300-400 wheel so it falling like that tells me it's another problem and not that I am running out of pump. That aem 320 combined with the bap, hotwire kit and bigger lines with 60lbs is plenty of fuel. If it wasn't we would of seen it on the dyno right away after making 16 pulls. Mind you none of them were back to back they all had cool down periods and the dyno room was nice and cool... Also it doing it with the stock pump at the same exact time confirms this I can tell you it's definately something I did but I'm just retracing all my steps now. If this new hose and clamp dont work I will check the voltage at the pump under boost and I will make a video showing how it runs when it's cool vs what happens when it's hot..
CK, can you also pm me a price shipped to 87124 on a new walbro pump that comes with your kit. I bussed the terminal on mine so it's no bueno.
I have the pump out and I was hoping to find a crack in the tube but no cracks it's just kinda orange/brown like all them are from the gas. I put some compressed air in and blow on it and hate to say even sucked the crap out of it and I couldn't get air to come out or in through where the worm clamp is clamped to. I had both bottom plugs on the fuel pump blocked off and no air was escaping from where the worm clamp is attached. I just hope that it wasn't enough pressure that's why I'm not seeing anything trying to blow or suck through it. I only put a few psi through it with the compressor. Voltage was solid as I have checked quite a few times maybe .1-.5v drop from battery to the pump harness. Like I said after the new parts arrive if it still happens I will check voltage while under boost driving..
I ordered a new walbro pump for my secondary since I busted the prong off that should be here Monday. I got the new convoluted hose in and just installed it on the pump assembly. I put TWO oetiker clamps on each end so it has a total of 4. They are so tight the tube can't even turn. Even from the factory you can turn the tube on the pump outlet. Even the Hulk couldnt turn these or pull these off if he tried. They are sealed without a doubt!!!. I will intsall the assembly here in a few once I'm done running around
No difference I also tried it without the harness no difference. Tommorow ill check voltage then once the new pump comes in ill use that as primary and see if I have the same issue. If I do then I know the fuel is getting to hot and well I don't know what to do...if not then I know its the pump even though I have tried a different one.....its either voltage or fuel is getting to hot...
Man kudos for keeping your head in this struggle. There aren't any kinks in your fuel hat output line. The line that goes from the fuel hat and y's to the pass tank and fuel filter? Just curious.
(1) No difference I also tried it without the harness no difference.
(2) Tommorow ill check voltage then once the new pump comes in ill use that as primary and see if I have the same issue.
(3) If I do then I know the fuel is getting to hot and well I don't know what to do...if not then I know its the pump even though I have tried a different one.....its either voltage or fuel is getting to hot...
1. So you saying then you went direct to the factory wiring instead bypassing all other wiring?
2. Are you going to be able to "LOG" voltage? HP Tuners or something just to make sure?
3. I don't think the fuel is getting too hot.
Do me a favor and humor me for a minute, (and man do I wish you lived closer):
A. Are you positive there is no obstruction from the "RETURN" off the regulator to the tank (or where you connected into the factory return line?)
B. Is it possible that your FPR is bypassing by itself?
What I mean is it cannot hold pressure and just dumps the fuel or opens wide up and allows free flow back to the tank.
C. Can you or do you have a friend who can "LOAN" you their FPR for a minute in order to test and eliminate the possibility of yours being dead or bypassing?
D. Does your fuel level or fuel gauge work properly?
E. I also wonder if this is something of a tuning possibility, maybe your fuel "CUTOFF" is skewed at a low RPM for one reason or another -
Is there any way you can have the tuner look at your tune and see where the or at what RPM the fuel "CUTOFF" is set at? My Gawd this is a high possibility and would explain a lot!
Could you imagine for a moment if this was the case that "ALL" is good "BUT" your FPR is what is bad! or Fuel "CUTOFF" is set low!!!
It is a possibility, that it is still (what I will call) a "MECHANICAL" problem and "NOT" a voltage problem!
These are the very things that I thrive on and enjoy finding the solution too and love helping out with. So Please be patient with me, and yourself and we "WILL" find the problemo!
Thanks,Matt
Last edited by madmatt9471; 07-26-2014 at 11:33 AM.
Man kudos for keeping your head in this struggle. There aren't any kinks in your fuel hat output line. The line that goes from the fuel hat and y's to the pass tank and fuel filter? Just curious.
Thanks it's just a matter of time before I find the issue once I intsall the extrenal walbro and use that as my primary I will have a better ubderstanding of what's going on...No kinks they are hard lines and plug and play. I looked at them yesterday and no issues.
Originally Posted by madmatt9471
1. So you saying then you went direct to the factory wiring instead bypassing all other wiring?
yes
2. Are you going to be able to "LOG" voltage? HP Tuners or something just to make sure?
no I asked a few people and they said it can't be logged I only had access to efi live. So what I did was took a Fluke multimeter and tesed it on another source to insure nothing was wrong with the meter..So I tapped into the stock wire(Grey wire at the end of the plug if you look directlt at it) and grounded it to the frame. Started the car and voltage was right around 11.5-12.0..I had Ivan(Chassed on this forum) with me to watch the voltage. The first time I laid into it we didn't get a reading think I freaked Ivan out because he had his hand out towards the dash and staring at the road I told him watch the meter I'll watch the road. ..Anyways a few pulls(temps in the 180's, 190's oil temp ~200) car ran solid fuel pressure stayed at 60psi and voltage around 11.5 ~12.0..Did this several times voltage was consistant. Got up to around 215-225 coolant temps and oil temps ~20 degree higher and did some more pulls and finally the fuel pressure dropped. I would say it was a good 20-30 mins of driving before it happened. Fuel pressure dropped into the 40's then 30's..With each pull it got worst..Then finally dipped into the teens. I stopped because I didn't want to mely anything(This whole time I have teh meth maxed out to help me with the test) You could feel the car loose power because well no fuel..ANd voltage did NOT drop. I was hoping to see it drop from 11.5 to like 8,7,6.. but nope it was consistant and even went up to 12.1. So I can without a doubt rule out voltage...
3. I don't think the fuel is getting too hot.
I ran with the hood off and no difference same drop my rails are -8 my lines are -6 not sure why I did that.....
Do me a favor and humor me for a minute, (and man do I wish you lived closer):
A. Are you positive there is no obstruction from the "RETURN" off the regulator to the tank (or where you connected into the factory return line?)
100%..That rubber line goes above the tunnel plate with a few zip ties that's it..zipties arent that tight...ALso it did this with teh factory setup also in the fuel filter/regulator combo that's by the rear of the tank..
B. Is it possible that your FPR is bypassing by itself?
What I mean is it cannot hold pressure and just dumps the fuel or opens wide up and allows free flow back to the tank.
It's not even after I shut the car off I can watch it bleed off and it takes awhile while it returns to the tank before the gauge starts going down. I mean 10-20 minutes??. Ill be honest I thought it was supposed to go to zero when the car was off so I guess it's doing it's job..
C. Can you or do you have a friend who can "LOAN" you their FPR for a minute in order to test and eliminate the possibility of yours being dead or bypassing?
Yes and no...So yes but not until Wednesday but it's not dead or bypassing because when it was down last week I lent it to a friend that makes 662 and it worked fine for him he used it for a few days. Also remeber this same issue happened with the stock fuel filter/regulator combo and at that time I even took the new one back because I thought it was defective and got another new one.It has had 3 new regulators in it..same issue
D. Does your fuel level or fuel gauge work properly?
like a champ..It's a brand new AC delco
E. I also wonder if this is something of a tuning possibility, maybe your fuel "CUTOFF" is skewed at a low RPM for one reason or another -
Is there any way you can have the tuner look at your tune and see where the or at what RPM the fuel "CUTOFF" is set at? My Gawd this is a high possibility and would explain a lot!
I can BUT let me ask you this when the tune is set it's set it wouldn't let me run fine and rev to the moon and boost and fuel pressure hold then decide it wants to cut fuel off. Once the parameters are set that's it they are set. I will have him look at this thread maybe he can chime in not sure if he has a account here but I am also going to ask him to log it and see what he sees anything. I think with 3 brand new regulators one of them working flawless on a 662 Subaru it's safe to say the regulator is good...
Could you imagine for a moment if this was the case that "ALL" is good "BUT" your FPR is what is bad! or Fuel "CUTOFF" is set low!!!
It is a possibility, that it is still (what I will call) a "MECHANICAL" problem and "NOT" a voltage problem!
I believe it is a mechanical/operator issue. I will drop the tank again because I know this is probably self induced and because I have changed pumps 3 times and regulators in the rear twice..I also have dropped the tank 2-3 times. Maybe I did something to a line? I mean nothing is leaking but what if there is a hairline crack or the pushlock is worn out and not sealing letting air in but not fuel out. Of course you would think if air could get in fuel would get out??
These are the very things that I thrive on and enjoy finding the solution too and love helping out with. So Please be patient with me, and yourself and we "WILL" find the problemo!
Thanks,Matt
I appreciate all the help and ideas. Ill do whatever it takes so keep the ideas coming. I'm pretty patient on this whole thing it's been a few months and I haven't cracked nor will I. It's all part of the game when modding and I actually enjoy it. Hope Laguna and Disney Land are treating you well this weekend..
WHat about the wiring INSIDE the tank you know the one that clicks into the pump would that matter? That is stock,,,,? I know Troy makes big power and he has the stock wiring inside the pump. I mean the connector that connects to the actual pump itself that clicks in. I don't know how to upgrade that since the pins on the end are so small to go into the harness to plug into the hat you can't get much bigger..
Next step is the external fp that I will run without the factory pump. If the walbro does the same thing then we need to look at cavitating(like we have said I doubt it) if the pump works then we know we have a issue going from the tank to the rail...Some how some way something is not letting the fuel get to the rails albeit pump, line, crack, etc etc. I have to get differnt fittings I will get those tommorow. And my next day off is Wednesday so that's when I'll drive it and check with the extrenal..it's all hooked up just need to add the 2 fitting and power ground everything else is ready
E. I also wonder if this is something of a tuning possibility, maybe your fuel "CUTOFF" is skewed at a low RPM for one reason or another -
Hello I'm Chicago1's tuner. Here is a screen shot of his CUTOFF tables.
Just a FYI fuel CUTOFF has nothing to do with the fuel pump. It has to do with when the computer shuts the injectors off to control RPM but I figured I'd post a screen shot anyway to eliminate this as a issue.
ETC CUTOFF is "Electronic Throttle Body Cutoff". You can see that the tab to the left says disabled but the values are set at 9k to make sure it doesn't interfere with Rev limit.
I ask because I've installed a sock wrong before (non vette) and it stuck above the fuel in the tank after it reached 1/2. So then it would suck air from the top of the strainer instead of fuel. Kinda like a scuba snorkel.
I have had it full with and without the sock. At the moment I have it without the sock..My fittings should be here in a day or two and then I will just run the walbro as my promary. Also Troy is going to come by and we are gonna put the go pro in a few places and see if the lines underneath are doing anything or that thick crossover tube that goes on that blue part of the tank is collapsing..Here is teh part I am talking about..It's the big hose that connects to this blue part..
also maybe I cracked that hard line and air is getting in? but like I said you figure I would smell fuell or it would leak..If I get the same results then I may have no choice to take it to a shop which sucks because I want to find the issue and that's my drag radial money..
I still want to know where this sensor is on my car..
Something else I read...It's worth me looking into..
locate the filler neck for the fuel tank somewhere in that area you will see a rubber hose coming of the gas tank with a plastic valve attached to the end. If that valve is dirty and not opening then the vapors can not get out of the gas tank and then forcing air into the fuel line. Just pull of the valve and clean it out really well..
Not sure if we have one in the fill neck area or maybe that hard line is clogged? And as it gets heated it forces air into the lines? This was just stuff I was goggling. I don't even know if we have one or not. I have taken out the a.i.r system pump and all the lines and have had the egr turned off. I had the a.i.r system off when it was N/A though...The evap is intact and never been touched.
No worries matt I'm chipping away at it. Hopefully I will have those fittings today or tommorow. I think that will tell me alot when I run just the walbro
No worries matt I'm chipping away at it. Hopefully I will have those fittings today or tommorow. I think that will tell me alot when I run just the walbro
Sounds good, looking forward to some results to this saga!
Well I have news and its odd. I posting this from my phone so ill make it quick. So I ran the secondary system as my primary meaning 6an feed 6an return. And power source straight from battery on a relay. Guess what....same exact issue...so I ran them both at the same time....guess what same exact issue. I even had troy with me and he was like wtf even on the secondly. I even took it to a friends shop they couldn't figure it out. I talked to few other people and we believe its a vacuum issue inside the tank. Don't know what's causing it or how but its keeping the pumps from pumping fuel to the motor. I could add 5 more pumps it would do the same exact thing. I made a video I will have it up Monday. The tank is out now nothing seems out of place. Crazy that the secondary on its own line and own power that's external does this. Some type of pressure or vacuum is causing havoc. When I undo the gas cap I do not get a whoosh sound so I'm lost again. Ill be back on Monday
07-21-2014, 12:22 PM
and we "WILL" find the problemo! 
