Fuel Pump not getting power
 

Yesterday I went to start my car and it just spun over so after troubleshooting I found that the fuel pump wasnt working. So I jumpered the power wire from the pump directly to the battery and the car started up and ran fine. I checked the fuel pump fuse and relay in the engine bay and they are both good but unless I have the pump hooked up directly to that battery the car wont start
Is there anything else that I can check that maybe went out? Im at a loss right now.

Check the resistor wiring...near the passenger side shock tower........ At the air pump :)

Then you can start tracing the wires :(

Ill give that a look but im thinking that its gotta be something simple because before this it ran fine. Is there a fuel cutoff in this car like there is in most domestic vehicles? Or maybe another fuse that ties into the fuel pump?

FIrst thing to do is always check all the fuses :)

I'll pull out the schematic in the AM and see if there is anything I can suggest

the resistor is the plug behind the air pump with a white and blue/red wire coming out of it right?

I tested power at the fuses and relays and the fuel relay doesnt seem like its getting power. Im gonna swap another one into it to be sure

edit - I checked the resistor. It is reading 1.0 ohms (should be .34 right?). Does that mean that it needs to be replaced? And with a higher resistance would it prevent the car from starting or the fuel pump from even turning on?

This morning I read out each relay, both sides of the resistor and the fuel pump. They were all getting power. But after I hooked everything back up I heard the fuel pump prime so I started the car. It started fine but was really weak, wouldnt rev past 4k and was struggling to get there. I let it run up to temp, shut it off started it, let it idle for a few minutes and repeated this about four times without incident. Then I went to start it again and the problem was back, no fuel but power to everything. While it was running I also got codes P0443, P0131, P0031, P0037, P2259, P0661. None of the codes showed up before this fuel problem.
So maybe the ECU is bad? Any help would be appreciated. Im about to burn this car to the ground.

If you havent tried checking your fuel pump or anything and haven't moved anything around this probably wouldn't apply but Id figure Id throw my 2 cents in.

Make sure the black tube connected to the top of the fuel pump doesn't have a bend or crease of any sort.

I had replaced my fuel pump to the walbro one, and while reassembling I wasn't paying attention and put everything back together but had moved the fuel tube more towards the right and reconnected it. So my car wouldn't turn on until I noticed the tube and re-positioned it.

Hi i have a problem with no power for the fuel pump at the fuse box? The pump itself has 11.7volts going to it BUT testing the fuse hole (not a correct term i know) Comes back with 0.00 volts.I have a friend thats an auto electrician (and a bloody good one) but he is away for the bank holiday weekend and i would like to drive it tomorrow! I see someone mentioned hooking it to battery,How can i hook it up to the battery to test?

My resistor reads 0.4 ohms and the fuel pump plug reads the 12volts but not the 3.2-5V at the B terminal ( lower right hand one with the lock facing up ). Car won't start, and died just suddenly during highway speed. Cranks but no start. Fuel pump primes, but doesn't make the high pitched noise or change noise when cranking.

Having the same problem, how did you fix yours?

so what fixed this problem. im having same isusues.

replaced the fuel pump

Yeah i already did that new pump install pump stil not starting.

I'm sure you've checked the 20A 'Fuel pump' fuse, but there are three others that can shut down the pump -
EGI 1 10A
EGI 2 10A
INJ 15A

Check 'em all....

i will re check all my fuses. i bought new relays , starter, plugs . now there is either a grounding or short in the wiring , i fixed the pin connection in the fuse box fuel relay.. it seemed that was the issue but then it wasnt i was gonna test the resistor but one is on its way. i want to temporarly wire battery to pump..til i can fix all this . is that a decent idea?

There is a jumper in the fuse box for the pump . it should turn on the pump if the wiring is OK...
https://cimg7.ibsrv.net/gimg/www.rx8...fa14e2d391.jpg

ok it was getting crazy but i checked the wiring from the pcm and it was throwing a signal and i did a reading on the resistor 1.0 ohm finally i couldnt take it so i called these guys who did a full electrical scan on the whole car. I need a new ECU. and I kind of thoght that. so will keep posted when it comes in if this works...there really cool and will flash it for me and program my spare fob key....if this all works it will be worth the 120.00

well that was a waste of time and money. thank you dannobre. I should have followed your lead. now im in a different situation. my battery drains like overnight and when i start the car it has a very weak and strained crank but what i noticed was the fuel pump and engine fan run even when its shut off for about 10 seconds i can still hear the fuel pump whirring and engine fan going. I am now charging battery and going to do a parasitic draw, ground test hopefully that will get me a little better to ask what i can do next. right now battery is charging. thank you

Sounds like a wiring issue on the fuel pump relay maybe? Are you sure when it was repaired that it is done properly? If the relay is wired so the coil is energized all the time it will draw quite a bit of current.

If you do a current test and pull fuses you should see where the draws exist.

The only thing that should draw current with the key off is the immobilizer circuit and the ECU... and it shouldn't be very large...

im not sure it was done properly. I am watching youtube vids on parasitic draws and how to find it. so am i on the right track in pulling fuses once i have the negative battery and harness wired between the meter? I know we did a pull on the relay and it started up when he had pulled the relay i believe and had a probe inserted. im sorry im being so unsure. I am gonna be doing all of this on my own. so im trying to find the right starting point. thank you

so you think i should do a fuel pump relay test 1st? I will look up on how to do that. cause all of this again rose up recently after doing dumb things like changing ecu and such. I went back to original ecu and had it keyed correct per your advice seems like im a little more focused and i know it has something to do with a short a ground .

Basically that's the way it works. Don't turn on any circuits or you may overload the meter. Some multimeters don't do too many DC amps... you shouldn't need to worry though unless you have a pretty big problem. If you pull the root fuses and find something you can narrow down the smaller branches after that.... instead of pulling them from the other end of the tree one at a time.

And I'd start with the fuel pump circuit first...

thank you. as soon as some of this snow clears i will do that. I did a battery neg to harness and i definatly have a large amp 10.47 thats alot. thats why my battery was getting drained. but im gonna do as you suggested above. thank you.

That's huge. Make sure you disconnect the battery until.you start the testing... thats a lot of heat going somewhere

i will and i will make sure that all my doors and and everything is off before i start to pull. Question i cannot find anything on where the major GROUND points are on the vehicle. 2005 rx8 A/T

ok I did a parasidic battery test all doors shut car off before i turned on the car and pulled all the fuses inside cabin and engine. (did not pull any relays) every thing stayed at the same voltage of 12.78. I am trying to research on doing a ground test but there are so many grounds. Im not sure which or all to test. started to look for ECU ground seems like it comes from the harness, but for me to find the battery drain im trying to research i have a 2005 A/T . I havent done anymore test as its cold out and dark i think the cold would have some play on my testing. but i did complete the fuse pull. thank you

OK i put on a warm jacket just got finished wtih doing a positive battery to ground test., I started at 12.70 and its was consistant with the metal on engine and the 3 other grounds i could see in top bay area. dang I think its a short thats still not letting me get to my initial problem of crank but no start......2 weeks this car has been with this issue.

You need to do a current draw test... not voltage.

The voltage won't change until the problem draws down the battery

It is unlikely that you would get a sudden ground problem... and there are enough grounds on the harnesses that you wouldn't get no ground at all.

And when checking grounds you want to check using resistance values not voltage

Gotcha will do that now. Question can isafley overturn the engine fuse box to check ckck for damages

There are little clips on the sides of the fuse panel and the brownish fuse holders will come out of the white base if you hold them and pull up on that part. Easier if you remove the 2 wires attached to the firewall end of the fusebox... might need to undo a couple if zip ties on the front end to get the loom to move as well

It will let you turn over and access the underside of the fuse/relays and should be able to see if there are any obvious issues

ok thanks

OK I HAD A 5.00 MULTIMETER. I NIXED THAT and bought a good one from autozone. I did the test to see if my parasidic drain number was and there is no drain. It says .07 i left it on for about an hour (i did this text with all doors shut and no key so it wasnt turned on)
so now i went to start it and again a very labored whine of a crank but no start. I checked under the connections for the relays and i couldnt see anything odd althought there was a metal piece in tray i dont know what that is for or if it is even from this block of relays. i didnt want to twist it more as i didnt want to upset any wires. not sure what i should do next.

Start with this. Some things wont apply since you have an automatic. Also, stop messing with the electronics and wires for a bit as youre probably making compounding issues and making it harder to solve.
Watch this and report back whatever issues remain.

Thanks Ricky I think you are right. ill leave the electronics alone. thanks i will watfch this video now.

ok i followed the previous video you sent. even cleaned the MAF sensor. the thing is it sounds so labored in its starting. its not a tough crank at all . i read that it could be the starter or the battery. both are new and if you spray starter fuel in the intake it cranks tough and starts and then when it comes to the relay the fuel relay if a prob is put in it cranks up hard and starts. but fully charged battery it sounds like its suffering in its cranks. now the ignition coils? well prior to this it was the priming of the fuel pump not delivring fuel so that seems to be where i was focusing. any thoughts?

Sounds like all this trying may have burnt out your new starter, which may not have even been a good quality unit to begin with. Also 2kw but you have an automatic? To my knowledge there was never a upgraded starter available for the automatics. The 2kw starter typically references the upgraded starter available for the manual transmission cars. Where did you even get the starter from? What brand is it and how much was it?

How do you know your charger is truly 100% fully charging your battery? And does your charger have a "Start" or "Jump" function you can use when you are trying to start the car?

Whats happening with your red "immobilizer" light on the dash? Does it flash quickly or like one time each second?

You can sometimes faintly hear the fuel pump prime when you first turn the key to the "On" position before trying to start the car. Did you damage or incorrectly install the fuel pump? You may need to check and be sure you didnt screw anything up during that install because sounds like you probably might have.

Pictures of what you are looking at and dealing with would be helpful.

The starter started to smoke. Im wondering if i had a bad one to begin with. I ordered an online 2kw. and i put it in the day before it died out. but just noticed it smoking so stopped all that i did and ordered a new. one.

ok all great points your making and i will answer all. The battery is charged up as I do a test with a multi meter, before it was getting a drain and now no drain. So battery can stay over night and not have a drain on it. as for the fuel pump it now primes up which is another good sign. And no I dont have a jump on my charger. I used a friends car. I ordered the last starter from im sure ebay. i oredered a new one from napa. i had done alot of research for starter as i was having idle and start issues from the get go. So i replaced coils and plugs I then bought the new starter as it had the upgraded one that mazda had recalled. but it wasnt a 2kw. I researched and found that the A/T can use the 2kw. But I probley shouldnt of gotten it off Ebay. the new one is below. thanks for all your imput im really gonna follow thru on all of your recomendations.

napa has one for 140.00 with core trade
amazon has one for 185.00
a/t 2kw

I want to appologize to all who put there time and effort in helping the many problems i faced with this car. I am appologizing because I found my problem and it is fixed now. I put in a new starter and never fullly tightend the bolts i found this out as i was gonna swap for my old one but i litterlly could move each bolt with my fingers. all three. therefor this caused the car poor grounding and welll again sorry everyone.

Don't sweat it. Thankfully/luckily it wasn't anything worse and the problem is also solved now. Just be careful in the future, and truthfully I'm willing to bet that the starter you originally bought was probably going to fail that quickly anyways.

Thanks man...you guys really did teach me alot. and boy i feel dumb but thats also why it was having labored start and also why it started to smoke...but you are right....im gonna go get one from mazmart. Now i can take it in to mazda and have the recalls done....thanks buddy....

Similar issue
 

I’ve just been reading this thread with great interest!

I guess first up…..first time RX8 owner, current RX7 owner together with a myriad of other cars. I’m no stranger to cars and mechanics but auto electrical tends to stump me!

I purchased a non running RX8. On investigation I found the fuel pump doesn’t prime / run when the ignition is switched on. I can “jumper” the relay terminals and the pump will run continuously. I have good pressure and good flow from the pump.

Even with the pump “jumpered” the car still won’t start.

I get good spark from all 4 coils. I have reasonable compression (the motor has about 20,000 miles on it from rebuild) and though not tested with a specific rotary compression tester I have tested with an analogue tester with valve removed to get basic reading. I have fuel with the terminals jumpered….too much fuel so I have completed the de-flooding procedure with plugs removed.

My starter cranks fairly slowly and I suspect this will be the starting fault, however it doesn’t explain the fuel relay fault. I have tested the relay and it works, it’s just not getting 12v from the wiring harness.

if anyone can suggest what the problem may be or where to look it would be greatly appreciated!

Also, I plan on pulling my starter out and repairing / replacing it. It’s an auto so the starters are quite expensive, therefore does anyone know if the windings and “electrical” side of the starter will bolt up to an auto starter body? I’ve previously successfully combined an RX8 manual starter with an early RX7 manual starter body and wonder if the same can be done with manual to auto. I know the manual is 14 teeth and the auto 18 but that is via a intermediate gear in the auto body. I know it might seem like a lot of bother but here in Australia an Auto starter is about $500 while manual ones can be sourced for about 1/4 of that price.

Hopefully someone can help!

Hello, I am having this same problem and I don't know if the fuse socket is supposed to not have power or something, but my car won't start. Did you ever get this problem fixed?

Hello, I am having this same problem and I don't know if the fuse socket is supposed to not have power or something, but my car won't start. Did you ever get this problem fixed?