O.K., I mildly looked for a thread on this, and didn't see one. What is the recommended fuel pressure at idle, and setting (5.0 SEFI, 24# injectors...info in my sig). Where should I set the AFPR and so on? Thanks.
around 40 41 with the vacuum disconnected is a good start
Thanks. I'll install the AFPR asap and set it where I need it. I THINK it was set to 42 with my 19# injectors. I'll keep it at the stock numbers for the 24's.
when I ran 24's I bumped it a little higher .......... but all I want to do is go fast lol
Fast is fine, but I don't want it to be running too rich. What should the gauge show with the vacuum line hooked up after it's set with the hose off?
rated flow is 43.5 psi, but I believe the computer expects 40 psi.
Around 35
With the current FPR it was reading about 22 at idle with the vacuum hose hooked up.
to low set it to 33 ish
what pump do you have
Haystacks is correct most all injectors are rated at 43.5 PSI for flow at rated output. And an injector should never be operated past 80% DC. I would set the regulator at or around 44 LBS NO VACUUM. 22 lbs is ABSOLUTELY NG even for a stock setup. Better find out why your fuel pressure is so low before jumping in to new injectors or a regulator. Your car must run terrible if this is the fuel pressure you are running. And you could very well have leaned the motor out drastically. Better check that out real fast. Good luck
It has a 255lph pump. I have been wondering if it's pumping the fuel that it should be. I have had 24# injectors on the car for some time, and was running my Kirban adjustable fuel pressure regulator. When we were installing new rings and bearings, and had everything apart, I misplaced my Kirban and installed a factory FPR that I had in my desk drawer in the garage. I have since found the Kirban, but haven't installed it yet.
So, should I install the Kirban, check the pressure and go from there?
put it on and see what happens if you try to crank the pressure and it wont go you probably have a week pump or clogged filter
I'll get after it tomorrow. I'll start with the FPR, then, if necessary, the filter and if I have to, I'll order a pump. I appreciate you guys. If there are any more comments, or lessons, or whatever, keep it coming.
you can check to see if the stock regulator is bad if there is any fuel in the vacuum line
No fuel in the vacuum line. I've had that off a short time ago when I was swapping the valve covers and had removed the upper intake.
read up on the fuel pressure vinny, I remember reading that the stock pressure at 39 psi is what the computer expects, I also think the computer will trim the injector pulse to compensate for the higher pressure. Your already fooling the EEC with doctored readings from the mass air meter.. messing with the FP is just going to throw it off more.
I want to keep the pressure that the computer wants.....I also want the pressure to be what it needs to be. I'm not trying to turn it up high and get crazy. I just want it to work as it needs to. I've been thinking that the engine may not be getting the fuel it needs.
At 22 lbs at the rail it most definitely is not getting enough FUEL. I cant believe it even runs correctly. Question is your gauge accurate???
I can only hope that it's accurate. The gauge is brand new (and yes, I know that doesn't mean that it works right.). The car runs fine, but feels weak when you hit the skinny pedal. I have felt a little low end struggle. At times, strong. Other times....not so much. I've questioned a fuel issue for a while. I'll swap the filter first, and see if that helps. Wondering if I need a pump the more I think about it. Filter first, though. First thing in the morning.
Yea 22 pounds is way low it would run like a dog
Going to grab a filter shortly.
do what i do to check the fuel pump,, works real well with an aod tranny and im sure the same on a stick.
buy the extender hose on your fuel presure tester
duct tape the guage to the windshield with the tester connected
drive the car and observe the guage
as the rpms go upwards in between gears, the fuel presure reading will decrease
you need to take a mental note of where it averaged out at with respect to the very lowest reading which will likely be between first and second gear.
22 is the absolute worse case reading you should ever see at the highest RPM while the car is in between 1st and 2nd,, testing the fuel presure under a load like i describe is the absolute best way to verify your fuel pumps capability to deliver the demand.
there is a **HUGE*** difference in a car at idle vs under load,, many people see good or within specs readings "at idle",,, yet thier comlaints are usually describe what they feel while they are driving, so why not find out what is going on with the fuel pump "while your driving".
hopefully you wil find out real numbers instead of misleading "at idle" readings in order to determine the right next step.
didnt you revert back to HO speed density?
and dont forget the obvious...
check the voltage you have going to the pump such as at the pump side of the fuel pump relay.
the relay on most of our cars brings power from the battery to the relay on a yellow wire.
When the relay is triggered, power is sent out to the pump on the "next big wire" or what my records show as the pink and black.
measure the actual voltage you have at the pink black wire which is the fuel pump power feed.
if your idle voltage is 14.x volts at the alternator output and your reading at the fuel pump relay pink black wire is 11.xx, then you may just have a low voltage problem and the pump is going to spin a little slower.
relay input on yellow wire > if it reads like 13.9v and then the pink black fuel pump wire has like 11.x then the relay contacts are dirty or burnt up and the relay is the fault.
the voltage reading is important.,, it travels a very great distance across the lenght of the car to finally make it to the fuel pump.
to fix this, if it is low, we can discuss that later,, im not trying to ask you to spin your wheels or anything, just mentioning something that people tend to forget.
you can temporary bypass the circuit and feed 12v onto the pink black wire (fused for safety) from the battery and see if the engine feels any different.
I installed the H.O cam, but left the Mass Air. The car idles great, cruises well, but under WOT, seems a bit lacking. I have thought for a couple of weeks that it was a fuel issue. I just picked up the filter and will install it in a little while.
LOL, delete your fuel injector screens,, will be the best mod you've ever done!
I've actually heard that before, but, I'd be afraid of getting in the injectors and killing them. I may be over thinking that. When I did the last intake swap a while back, the injectors looked great. I'll check them again when I install the FPR.
Vinnie check the fuel pressure with the vacuum line off. As Tom said it should be around 40 PSI at idle (37-42 is within specs) with no vacuum. I think people got confused and thought you had 22 PSI with the vacuum line off the FPR.
As others have mentioned the EEC will tune out increases in fuel pressure from an adjustable FPR. I'm running a stock replacement Motorcraft FPR on my Thunderbird and it works fine.
At idle....34 with the vacuum, and 42 without. That's with a Ford FPR. I had 22 or so when I got gas yesterday (vacuum on). Maybe the fuel pump is doing well.....then not doing well.
34 and 42 is right but 22 is bad lol
Haven't had time to test drive it. I will tomorrow. I'll probably go start it up later this evening and see if the numbers stay the same. I'm having a gut feeling that the pump isn't being consistent.
Does running 19 lb/hr injectors with heads flowing at or similar to GT40 head rates go above 80% duty cycle? I have 19's in the red car and a GT40 setup, the silver cougar I used to have had that as well. Never had any fuel starvation issues. Red car is speed density, the silver one was mass air. That's all with stock 100k+ mile fuel pumps as well. Not to mention that I'm considering WOT usage here, where you would actually max out the injectors potentially. 1/2 throttle or less, even the S.O. 14-lb/hr injectors would probably function and give the car enough fuel to just putt around town.
You need adequate fuel delivery to make HP. We go through this every day. Guys build all kinds of engines and all kinds of combinations and run stock fuel pumps with reduced voltage. This is NUTS!!! The very first thing you need to do is install a good aftermarket pump. The 255 comes to mind with adequate voltage. I never have a problem delivering a good voltage supply to my PUMPS. That is the beauty of a trunk battery. You can slave out a relay controlled by the stock feed wire to activate the relays Mounted in the trunk and feed the contacts from the trunk battery. This way you have no voltage DROP whatsoever. There is more to a trunk mount BATTERY than meets the EYE!!! A one volt drop in applied voltage to a pump reduces it 's delivery capability by 14-18%. Thanks
NOTE using the stock fuel pump feed wire to activate the trunk mounted slave relays keeps all safety devices in OPERATION and that is a good thing!!
(http://i28.photobucket.com/albums/c209/tfalconier/null_zps610b9cd8.jpg) (http://s28.photobucket.com/user/tfalconier/media/null_zps610b9cd8.jpg.html)
@ what fuel pressure????????? They are very close to being at 90-95% i would think @ stock fuel pressure and delivery of the shiznitty stock pump!! Very questionable because you did not say if you have an UP-DATED pump and or stock Fuel pressure Thanks
NOTE low voltage at the pump also reduces it's life span by the same percentages APP 15%
I have a 255 lph pump. I have been so busy I haven't had time to get back under the hood and do some gauge checking or anything else. Saturday, I will. A battery will NOT go in my trunk. I like a clean, empty trunk.
Trunk battery was not the issue. I just pointed out that there is more reasons to mount one in the trunk. There is other ways to increase or should i say decrease voltage drop. I like an engine without holes in the top of my pistons rather than an EMPTY TRUNK !!!!!!!!!!!!! But if you are having fuel delivery issues and low volume or pressure i would fix that pr0nTO. Thanks!!
I hope to know more Saturday. Doing the work that I do, and 12 hour shifts leaves little time for the Sport during the week. I'll report in with some news tomorrow.
I know the feeling Vinnie those 12 hour days are tough. Good luck!!
Stock non-adjustable fuel pressure regulators and in both cases, a stock original fuel pump with at least 100k miles on it. I'm well aware that the stock pumps are barely adequate for 200 HP or so, I haven't had a problem yet so I haven't bothered to upgrade :hick: LOL. My black cougar with an entire Trick Flow top end setup and 24 lb injectors may or may not have an aftermarket fuel pump. Are they all louder than a stocker? When I click the key to IGN, the thing sure as hell sounds like a wimpy stock pump. How that car pulls like it does and doesn't cut out altogether is beyond me. The logical explanation would have to be an upgraded pump. Someday maybe I'll be REAL bored and drop it to find out...
i couldnt agree more on the voltage drop issue,,
stock layout for fuel pump power integrates three connectors plus the wire.. lots of opportunity for a resistance.
im going to for the helavit check my voltage to my pump,,
keep in mind i just found out the design of electric fuel pumps are based on Alternator volatage,,, 13.5v float voltage, not 12v,,, with such a low voltage every volt means soooooooooooo much.
I've been busy around here. Not much time for the Sport. I did check the gauge. At idle, it's holding on about 28psi. I am going to swap the FPR when I can (probably Friday due to my work schedule), and we'll see what happens. Fuel pump check after that if need be.
Jay always remember the closer you get to the work the More Efficient things work. Example having a trunk mount battery brings more current and voltage to the pumps. Simple deduction less wire less voltage drop. Just an example. Thanks
I thought that point was already made, and, I already stated, no battery is going into my trunk.
Come on Vinnie..... Everyone is doing it!
Travis
could measure your actual voltage drop to see if its a problem, then upgrade throughe wires going to the relay...
In my view there is nothing more UGLY than an UNDER HOOD BATTERY. Just me
Common Tom....a nice optima....looks good....also in a 60/70's muscle car with an original reproduction delco is pretty sweet in my opinion....
Travis
I am not talking about a 100 point car with a replica DELCO or motorcraft. Also the underhood heat is a KILLER TO A BATTERY. Why do you think all new cars have them covered or blanketed???????????????
I hear you talking, but no battery in my trunk. I agree, an engine bay looks good without it, but, that's where mine is staying.
Got it not going to argue that. But the battery will love you LONG TIME!!! If it does not get HAMMERED WITH under hood heat. Batterys hate HEAT. Just saying CARRY ON !!!!!
My last battery lasted almost 6 years, so I was happy with that. Especially considering the Oklahoma heat. Friday I'll be addressing the car a bit more. Gotta work at the Hospital, and that takes up a total of 13 hours a day, so, the Sport has to wait. Hoping to swap the FPR and is necessary, fuel pump. The new 255 is in route. I may not need it, but if so, I'll have it.
Ive had great luck with my Walbro pumps. Cost a little more, but I feel they are worth it. Just my .02 :shakeass:
I've had a 155 lph Walbro in my Thunderbird for 6 years. I've never had an issue with it. Yes it did cost more than a cheap parts store pump but it was worth it.
Vinnie,
I know you have the trap door in the floor of your trunk so check the voltage at the pump and if that looks good then pull it and inspect the filter. Do you think you might have been a victim of bad gas? Anyhow, lots of good advice here. My Coupe has a 255 lph Walbro pump, stock lines, stock injector rails, 42 lb/hr injectors, Aeromotive FPR, and a thirsty 331 under the hood and have no issues.
I do remember a car having some fuel issues one time and it turned out to be the fuel pump relay being all corroded up inside so that is a thought but a quick voltage test of the battery side of the relay compared to the fuel pump side of the relay will tell you that story.
Anyhow, good luck!
Darren