Fuel Pumps Problems...

[5seryan]

So the other day driving home form work my car suddenly died. I lost all engine power. So i tried to start it back up thinking my stalling problem could be rearing its ugly head again. But nope. It wouldnt turn over. So i glided into the nearest gas station and sad a while hoping the car might turn over. Then i realized that the humming noise i had grown so accustomed to was gone. OH NOES! i said, although with a different choice of words. I knew my fuel pump had met its demise.

Skip to yesterday. After talking with Wes i had ordered the appropriate items from Joe and from ebay. I got my pump and O-ring and a new fcpu. the pump i ordered arrived promptly at 10 am due to the miracle of overnight shipping. So after i got done with class i set off to tear apart my car and yoink that devil of a pump. which i succeeded in doing. I took it out care, cautious not to screw up the float. then i put the new pump in exactly as i had seen the old one. the only thing missing was the new fcpu.

Today. I got the new fcpu today and threw it in. NO GO! I couldnt believe it. i know i put the pump in right. and the fcpu had come from a car with a working pump. thinkin there was a possibility the fcpu was faulty i attempted to ground the pump just to see if it would run. NO GO! Now i was really quite angry. I called Wes and we thought about it and it came up that i could hear the relay. but the pump still wouldnt go. So i tried a new relay. NO GO. somehow it seems as if the pump is not getting power. I really miss my car and desperately need it to come alive again. all help is appreciated in the matter. im sure ive left out some details. so ask away. thanks in advance for your help.

[redmanfx]

Nasty little problem bud! Are you getting power to the rest of your car? Example: my battery post cables went bad once and cause my car to stall and act the same way, once changed all was fine. They actually corroded to the point of not making good connection. I stalled something like 4 or 5 times before we figured it out.

Sounds to me like you should check power back to your pump and FPCU. Make sure you have power to other parts of the car. You know you have good parts so work from the battery back checking fuses and such. You'll find the problem so be methodical and it will be sooner rather than later.

red

[5seryan]

I definately have pwer to the rest of the car. I know this becuase my beer was temporarily stuck in the trunk cus the battery had drained. but I cahrged it overnight and everything electronic works so... Im left bewildered.

[redmanfx]

When you changed the pump, how did the connectors look? Are they connected tightly and are all the pins there?



and



The little connecting pins can break so just check those, use multimeter if your have one or a power light to make sure you're getting power.



once that's done then I'm outa the loop because I'd start throwing things myself

red

[5seryan]

on the fcpu there are only six pins in an 8 pin housing. they all look good to me. i made sure all the connectors we conected tighly as well. unfortunately i dont have a multimeter. im pretty sure its getting power becuase the relay is clicking which i assume it wouldnt if there was no power... this it what really baffles me.

[redmanfx]

The FPCU has 8 pins not just six. I've got a spare I'm looking at now. If you only have six something is wrong. Just took a pic with my phone but can't retrieve it. The FPCU has 8 pins that the connecting plug plugs into. That could be your problem.

red

[5seryan]

alright. im goign to go take some picutres and maybe a video. Ill show you the connector.

[redmanfx]

I'm looking at a G50 FPCU so your FY33 may be different, but I did not think they had only 6 pins. Post your pics and maybe a 97 or later owner will chime in. I sent you a pic to your email via my camera phone, hopefully you will get it.

Errr. what year Q do you have? If it's 96 or earlier forget what I just said above. 8 pins for G50 for sure.

red

[elwesso]

he has a G50 (95Q)

[elwesso]

Red. It is an 8 pin connector BUT there are only 6 wires...... See figure below.

[5seryan]

here is the connector to the fcpu. six pins..

[redmanfx]

That's great! Just making sure there were 8 PINS from the FPCU. The clicking noise throws me then....

red

[5seryan]

the clicking npoise is the relay. this connector is after the relay...

[elwesso]

Basically the pump isnt getting power.....

Here is what we have right now.....

The red lines indicate the circuits we know are correct..... The blue lines indicate what we KNOW are not getting power.. The green indicates what we need to find the problem with..

Please note I edited some of the diagram out (that had the ECU and some other stuff we're not concerned about with here)

[squeefoo]

Just a thought ... did you take the cover off the FPCU and check the infamous solder joint near the connector ? Could be bad if the PO had a weak pump.

[maxnix]

I wonder if you have too bad FPCM? Might read the post detailing the burnt connectors in Infiniti Mechanic, where this post should be.

[5seryan]

Maxnix there is a twin of this post in infintit mechanic. Wes let me double post to get it some attention. My question is this. if i ground the pump and bypass the control unit, then why wont the pump run. a bad fcpu is kinda meaningless right now. all i wan tto do is get the pump some power.