Last night I went to the track to watch everyone here in Spokane when I noticed that my fuel pump started making noise. I then started to lose fuel pressure.



The norm for my cars fuel pressure is about 42psi. (this is where it likes it) Standing at Idle the pressure started to decrease to 30psi after it warmed up a bit. The fuel regulator that I have in my car is suppose to go to 65psi. The fuel regulator was then tightened down as far as it could go and the best reading that I could get was 50psi on the gauge. When at idle the pressure wants to drop to 30psi, (just not enough for my car) but on freeway the pressure seems to be ok, until I pulled in my driveway. The regulator was reading 50psi till I let it idle for a bit. Then it started to decrease again.



So my question is I have replaced my fuel pump and fuel filter. Car also has ½ marine tubing all the way around the fuel system. Do you think my fuel regulator is bad, or what else could it be?

Thanks for your help

 

Does your fuel pump have a return line back into the fuel tank? So you would have one line coming in and one large and one smaller one going back into the tank while the larger one heads to the motor?

 

Yes it does Jamie

Is there any High performance shops here is Spokane?

 

Since you cant see a fuel leak, and the pump is making "new" sounds
Your car isnt flooding out and cant maintain low volume pressure
I would guess that its your pump is going out on you. It can maintain pressure on higher demand because its a high gpm pump. When there is no real demand the pump slows the blow by on the pump is more aparent.
I dont know of any shops but im sure a few guys here do. Good luck I hope its just somthing minor

 

Thats what I thought. Thought it was my fuel pump since this has happened before, so I went and bought a new fuel pump and sent the old fuel pump back for repair. It came back from repair saying nothing was wrong with it. damn rotaries....hate them, love them, hate them love them.

 

sounds like a power issue to me. try running new power wires to the fuel pump.

You might need a new alternator or one with more power.

 

How is the fuel pump wired? If it is running off an seperate relay from stock (not one like the fcs that drops voltage at idle) then it should be the same voltage as the battery. Generally if the pump is going out, it should be decreasing its voltage as the revs go up as it will be using more fuel. You obviously don't want to try your luck too much reving it out in this state but if you can figure out whether it drops between idle and 2000 rpms, that should be a sign as to what is causing it. This is not a 100% promise that your pump is dead but it's most likely. What is the pump you are using?

 

I would take a multi meter and check the voltage to your fuel pump when its not making pressure. That would tell you if its the 26yr/old wiring or the fuel pump. Try testing to see if an electrical load afects it like the lights etc..

If its the power supply - Test alternator. If the alternator is ok wire your existing fuel pump power supply to a relay and run a fused wire directly off your battery all the way to the relay to your fuel pump. Similar to the fuel pump rewire on 1300cc.com

 

Well 1300cc.com is remodling. So you need a inline 15a fuse right off the battery run all the way back to your fuel pump (10-12 gauge wire). The automotive relay (Radio Shack) turns your existing power supply into an on/off switch.

 

In our troubleshooting today we took the Alternator off as Metallic Rock and Kettlman suggested. Went to Napa and they said the bearings were fried and was only putting out like 2.5 amps. So I got another alternator and will install it tomorrow. To get to our Alternator we have to pull off the intake manifold and throddle body just to get to it. So hope this is the problem. Will see in the morning.

Thanks you guys would have never thought of possible alternator for a problem like this. Though it does make a lot of sense. Hope this is the prob.

 

it's crazy how after being around a car so long how you can diagnose a problem like that without even seeing the car. I hope that fixes the problem!



Oh, and Darlene would love to ride around with you in the CodeBlue car sometime!


and if I'm dead in the morning from meth fumes from my neighbor, you can blame it on them. I want all my money, car and everything to go to my son. Brian Strange gets the 58.

I don't know if you can call it sound mind when you're smelling strange fumes, but I'm calling this good...

Chris - out.

 

What kind of pump and regulater are you using?

 

I have a Aeromotive 800hp efi fuel pump a Pro Series Fuel Filter,-12AN Inlet/Outlet 7'' Long x 2.5'' Dia. Cleanable 100-Micron Stainless Steel Element, and a Aeromotive compact efi fuel pressure regulator/w gauge. I have discovered after getting my alternator tested that it was shot. Installed the new alternator and also bought a optima red top battery crankiing amps 980. This has seemed to fix the problems not only with my fuel problems but all the other little things.

Heres some pics

 

good. now get some miles on that beast. and tune it befor abf

 

Good deal, glad it was a "quick" fix

 

awesome, great to hear.

 

Yeah Yeah Allan....plans are for this coming weekend to go to Seattle and get her tuned. If all goes well. Gary might be coming to Apple Blossom this year if he has no plans for that weekend. If so I'll just get my car tuned at Apple Blossom.

Thanks Allan and Chris...you guys saved me a big headache with your smarts.

 

OK, need to jump on this one, a few things here, a TII has a duel speed fuel pump, runs on a resister at normale speed which drops the volteg and on stsrt up and full throtlle bypasses the resister, so the rule is chech for battery volteg 12. to 12,5, you will find the bypass relay under the air filter, on start up go to the fuel pump and check volteg at cranking speed 12 to 12.5 is what we want to see, but in the real world it's going to be less and any thing under 11V most likly means falty wireing or a bad battery and it sounds like a battery was your problem, no system is going to maintane battery doring cranking "big block or a lawnmoer", so if we go back to the relay and by pass it with out cranking the motor and at the same time checking the volteg at the pump we want to see battery volteg one or two tenths less then the volteg at the battery, if not find the falt and repair, then there is fuel pump ramping, sorry guys none of you are able to do this,why? you need a inductive amp probe and a O scope, whit these tools one can actly check the cerunt the each feld winding is pulling and determin the condetion of the bushes comuntator bars, RPM , flow and perssure, so if you got a hafe *** pump where the car runs good and then after time starts to run poor becouse the pump is over heating this will let you know, Think I better stop now befor some one says what the **** are you talken about

 

everything is working great right now, but now the freakin heater core is leakin AGAIN.
I see fun times in the near future. oh joy

These mazdas are neverending !

 

good god its always something with these ******* cars

 

ok here we go again. changed out the Alt. & got a new battery, everything seem to be working fine, but now its doing the same thing all over again.

What are the two wires that go to the Alt. This is how i have mine hooked up
Also what is this box for?
Im not sure if it should be hooked up for my set up ?

 

sorry dp

 

anyone have a multimeter I can use.

 

it has to be in the charging system, anyone around here good it fixing this problem.

I suck at trouble shooting.

 

that box is the voltage regulator. does your new alt have one internaly?