89_ho_rs

ok now i have an edelbrock 600cfm on my car. I have a tbi intank fuel pump. it is reading 3psi on my fuel presure gauge that is attached to my mallory afpr. i can make it go down but not up in psi. could that be my fuel pump going bad? could it just be wireing or if its running that means it is working? also what psi should my car be running at if anyone has a clue. i had it at 6 and it smelled like raw gas. thanks for any input.

urmomshot77

hmm, i had a friend with a problem like that once. Turns out the fuel filter that was connected right after the in tank pump had clogged up. Check your fuel filters, blow your fuel lines out with an air hose if you can. if nothing helps, your pump is probably grounding bad, or its just shot. Your fuel pressure should be between 5 - 7psi for your carb

89_ho_rs

ok so this morning i replaced the fuel filter next to the tank. my psi went from 3 up to about 5. i could not make it go higher even if i wanted to. so i took it for a short trip. it still heated up to about 220 to 230. i had parked it. let it cool to about 190. started it. it fluttered a little, stalled, restarted it and ran it for about 5 mins to drive home. when i got home i checked my psi and it said 0. the car was running but not good. now the only thing i did was replace the fuel filter, I think i know what it is but i want more imput . thanks again.

urmomshot77

damn, well it went upto 5psi, then to 0. My first thing i would try is, say **** the regulator for a minute. disconnect your fuel line from it and run it straight to the carburator. Just observe and see if your psi spikes up. I would bank that your pump is still fine, However, the wiring off of it is probably corroded (sp?), or loose. I would check your ground connection off that pump first before you put money into buying another one. If its "iffy", take a wire brush and clean the wire ends off and the part its grounding off of. I would also check to make sure none of your fuel line is coming within 3 inches of your headers. Mine was, and it caused the lines to heat up and slowed the gas flow down. Start making a list of what you've checked so far.....
1) new fuel filters
2) etc
3) etc

89_ho_rs

ok so i will check to see if the grounds are good. also i will check the relay up front. would these pumps slow down on psi like that or is it a all or nothing type deal. I am not sure. I went back out a little wile ago. i had just under 3psi. so this is all over the place . anywhere from 0 to 5 psi. the gauge is under the hood so i can't see it when i am driving. but i think this is one major part of my heating probs. thanks for the input.

urmomshot77

yeah unfortanatly my guage is under the hood as well. I spent 130 bux on my Holley Blue electric fuel pump and its regualted at 7psi, and i know that it doesn't stay at 7, it will drop psi a bit to about 5 psi and recatch itself back upto 7. So sometimes i will pull over and observe my guage at 5 1/2 psi and even at idle it wont jump back to 7 for a few mins. Thats normal though for the pressure to vary a little. But definatly not normal for 5psi to fall to 0psi

Berlinetta00

Something that will help keep your fuel pressure at a constant is using both a return fuel line at the regulator if you don't already, and using an in-line voltage regulator for the pump. As we all know, the actual voltage in a car's system varies between 12.5 and 14.5 depending on how strong the alt. is and how much amperage you use while driving. Try and find a 12.5 or 13 V reg at radio shack, that almost completely stopped my pressure variation.

A note on the in tank pumps: if the relay were bad, it would give no power at all to the pump. They are an all or nothing part. The pump is another story, I would do as urmomshot77 said and ditch the reg and see what happens, could be a problem with the regulator.

urmomshot77- that is one sweet looking Camaro, nice yellow/black touch. Ive never seen one done like that, its one sweet ride.

84z28350

Like said above, double check the wiring then bypass (or swap in another) regulator and see what happens.

I wouldnt doubt it if that pump is on its last legs...




Looks good, but ill bet it still doesnt smell very good inside it though!

89_ho_rs

yes alot of fluctuations in the fuel preasure. the relay is new so i think that is good. i pluged the return side of the regulator and the psi did not go up at all. so i can only assume that the pump is only putting out what the gauge is reading. as in nothing extra that needs to be sent back to the tank. it is not enough for my carb.

so I guess i am going to do a fuel pump. now here is my question. I do plan on running a 125 shot of nos.
should i get another tbi pump?

or should i go with a tpi pump. if i do get the tpi pump will my mallory afpr be able to turn that much psi back to the tank. also are the lines on a tbi car and a tpi car the same?

I just want to make sure that I will have enough fuel for my needs.

urmomshot77

Berlinetta00 - I don't have a return line on my regulator. I noticed my friend had one off his mechanical fuel pump. I was wondering how the return line helps with fuel pressure? b/c I'm actually still suffering at top end power b/c lack of fuel pressure. Also how much does one of those voltage regulators cost?? Glad you like the car, i wanted something with a unique look. I almost lost it in a fire about 2 weeks ago

84z28350 - lol, yeah man it took a **** load of axe body spray haha. The new insulation i put in called for sprinkling water on it, to make it set in faster. So instead of water, i used body spray, in hopes that it would lock in the fragrance smell. It didn't work, but it all aired out completely about a week later. She's running good now, but im still a little paranoid each time i start it up.

chevyboy07 91

"or should i go with a tpi pump. if i do get the tpi pump will my mallory afpr be able to turn that much psi back to the tank"


i have the same question about the afpr and TPI pump

89_ho_rs

also i am wondering what brand i should be looking for.

bosch, edelbrock, napa, accell, I am not sure what is better. i would like to run a intank pump but if i have to run a holley blue pump or a inline pump i will.

Berlinetta00

Ive been trying to find the best 12V solid state reg that carries above 2 amps, most of the higher amp regs don't hold voltage as consistantly. I got mine at a radio shack, and I tried looking up the part number again (its a 20A solid state 12v) but with no luck.

The return line helps lower fuel temps by circulating it back to the tank, while at the same time bleeding off the excess fuel not used by the carb, which does not put as much of a load on the fuel pump. Without a return line, even with the best reg, you could see a spike in pressure at idle due to the pump trying to flow more fuel than is being used by the engine. This will also cause the pump to heat up, expanding the fuel in the lines, again increasing pressure.

For pumps, if you are using a carb, as long as it holds a contant 6 psi or above and can flow 50+ GPH, it will work fine. A higher flow rate may be desired if you are using a return line, all it means is the fuel will circulate faster and better over long distances.

89_ho_rs

well i have done some pricing on fuel pumps. i am looking at the in tank ones as well as a summit inline one.or the holley blue. now would pulling thorugh the intank pump restrict flow that much or should i drop the tank and put in the intank pump or remove the pump in tank to put in a regular sending unit. i just don't want to be pulling the tank more than this one time.

would this be a pump that could supply my car with enought fuel. 400/carb/125 nos


http://store.summitracing.com/partde...5&autoview=sku

urmomshot77

Well that Mallory pump doesnt look too bad. Just remember there are lots of elctric fuel pumps in that price range, so make sure you check them all out if possible. The only thing im wary about is that Mallory its a 6psi max. A good carburator can handle 6.5 or even 7. With the addition of nitrous, you may want a pump that you can regulate a tad higher than 6 psi.... About the intank pump, i would not "pull through it." I would remove it, Because if its going bad, its only going to cause restrictions and make your new electric pump work harder

Auggie

Here is the wiring diagram I use for my NOS system.

Berlinetta00

I rin the summit pump on my car, great quality. Advertized pressure is 14 PSI max, with a 140 GPH flow. This pump should work well for your application, paired with the right reg and proper plumbing. I would definitly recomend against pulling through the old pump, it will cut both your pressure and flow in half, while placing additional strain on the pump. Pull it out and install the carb pick-up, or look in the stickies at the top of the board to see how to convert your stock pick-up.

89_ho_rs

thanks for the imput. i have found a trick flow pump from summit for 114.99 140 gph at 14 psi. a summit one for 94.99 with 140gph@14psi and the holley blue pump for 124 but i don't need the regulator. i don't know if these are good street pumps or not.

89_ho_rs

ok i have decided on the holley blue pump. I hear some people say to mount it under the car close to the tank. other people told me to mount it in the engine compartment. I don't know if it matters or not. just thought i would see if anyone had advice on this.

urmomshot77

i mounted my holley blue on the firewall for ease of installation. Has been working great for 3 weeks so far. Staying consistant around 7psi, and never dropping lower than 5.5psi

89_ho_rs

that is what I was thinking. do you have any pics of your instal?