New Fuel Pump -- Won't start

[Aus94Q45]

I read all of the related topics via search. Installed a new OEM pump (from Joe). Prior to installation the car ran fine. Pump buzzed at idle and quieted out when running after a while.

I followed the instructions posted on replacement. It cranks but will not fire or start. Here is what I found:

0. I cranked for at least ten 5 to 7 second cranks with no indication of even getting close to starting. 1. I cannot hear the new pump running.2. After cranking, I opened the gas cap and it released good presure. (I had left it open during the replacement process)3. I checked the resistance on the new pump and it measured the specified .5 ohms.4. From the FCU I get 12v from the bottom center pin, 7.4v from the one above it and no volts on any other pin.

I cannot understand that service manual on this test section. I am tired and have given up for tonight.

Should I crank more?

How do I check to see if I got a bad pump?

Any easy way to test the FCU? While I know they fail, it seems odd that it would fail at the precise moment I replace the old pump.

How would I get air pressure at the gas cap if the pump were not running?

How do you set the alligator clip trick? What leads do you jump?

All suggestions appreciated. Thanks for your help!


Modified by Aus94Q45 at 8:03 PM 12/14/2005

[Q451990]

After letting the car sit for a while, you should be able to feel the fuel line swell as it enters the rail (between the filter and rail) right after you turn the key to the "on" position. Are you sure you're not getting fuel pressure?

I would go back and re-check your connections... make sure the polarity is correct on the pump, etc.

Heath

[Aus94Q45]

Fatigue and darkness make for stupid mistakes. It runs now. Here is the run down:

1. Bypassed the FPCU to ground with a alligator clip wire -- nothing. Leans to a bad FPCU?.

2. Pulled the new pump and jumped it at the battery to make sure it works. It worked fine. Reinstalled the unit to the tank.

3. Decided to pull the FPCU and started to figure out how to remove the mounting bracket.

4. On a whim I decided to check the fuse. Although it looked good last night, sometimes you cannot tell. I was going to put in a fresh fuse just in case. THERE IS WAS -- IN the darkness I put the 15A fuse in the blank post two or three slots below where the fuse it to go. Moved the fuse back up to the proper spot -- like rocket science -- it powered up!

I had not suspected the fuse last night as I was getting 12v's and 7.4v's from the harness connectors from the FPCU, as noted above, with the key on. Thus, I was falsely convinced that the pump was getting power. WRONG! I have not checked but I guess those leads go to the fuel level/gauge indicator.

I guess it is not a great idea to tackle the fuel pump after an 11 hour day at the office, in the dark. I had removed all of the seats, panels, etc. in the lit garage; but I pulled it out into the drive when I removed the pump just in case of fire (I would rather lose the Q than my house!).

I know that I was very tired and probably just did not lean down far enough to see the fuse slot, as it is a bit under the dash for the fuel pump post.

Some closing thoughts:

1. The searched posts on this topic are very comprehensive. Every thing you need to know is there.

2. The stated ablility to change the fuel pump in 44 mins. is perhaps a worlds record deserving a spot in the Guinness Book of Records -- do not count on it. Getting out tools, removing the panels, changing the pump on the harness, etc. + the reverse of putting it all together (and getting it right the first time) should be about a 1.5 hr Min! or 2 to 2.5 hr at a reasonable pace. Thus, if you are 3 hours into this do not get frustrated! Anything under an hour may only be possible by those who have done this over and over. With all of the panels removed, count on 44 mins. to get the pump out of the tank, remove the old pump from the bracket, install the new pump on the bracket, replace the O ring, clean up the fuel spilled, reinstall the pump assembly to the tank, and hook up the lines and tubes. THEN you get to put all of the panels, seats, etc. back together. Not complaining here, but others should have legitimate expectations as to what time to allot to this task.

3. The old pump buzzed at idle and got quieter as it ran. The FPCU clips showed no signs of heat. I experienced no failures, shut downs or stumbling with the old pump. I replaced it (hopefully) to avoid having to buy a new FPCU at this time. However, that may be the next purchase as it has been pointed out that it may fail later.

4. I disagree that this was an "easy job". If you are a novice at working on cars, you may want to have your shop do this for you. I consider myself to be a mid-ranged DIY'er. I have done the knock sensors, under plenum hoses, spark plugs, front suspension, shocks, etc. This one was not particularly difficult, but it requires patience and finess to remove all of the lines and particularly to snake the pump and float assembly in and out of the tank. It is a messy and smelly job -- all a tad more dangerous due to the high exposure to fuel and fumes. Be careful!!!

Thanks to all who have taken the time and effort to educate the rest of us on this much repeated and necessary replacement. Cheers!

[DougQ45]

Don't fret I did the same thing!!! That empty fuse bay is trouble.

[Q45tech]

Nothing worse than RUSHING the job and not getting all the rear top cover/seat clips screws right and having to dissassemble AGAIN due to a squeek/rattle.

OR bending the sender float arm [even minutely] and creating a CHANGE in the way the fuel level gauge tracks.

Even worse is not examining the bottom of tank [the fuel strainer cup] for rust or drops of water.

[Aus94Q45]

Agreed! Tank and cup clean. Was very careful with gauge arm -- read empty this morning as I had run the tank down to about 1.5 gallons; moved to full at fill-up. We will see how it travels down the tank. I can see how guys would bend or bust it by being too rough getting the pump in and out of the tank. Seats, with all clips will go back in tonight. Then a big cold Sol beer!

[Rex]

Glad you got it figured out, my first guess was going to be the fuse, but I'd have never thought it was put back in the wrong slot. Good work sticking to it. I bet there's beena few cars towed in, just to find this type of fix is needed.

[maxnix]

Like I said when I spoke with Steve eralier today, I think that space is used on the Q45a.

We're going to meet next week for a fuel pump hum-off as I am conerned mine is louder than it should be for one year and 10K miles.

[DrewQ45]

Nothing worse than RUSHING the job and not getting all the rear top cover/seat clips screws right and having to dissassemble AGAIN due to a squeek/rattle.

OR bending the sender float arm [even minutely] and creating a CHANGE in the way the fuel level gauge tracks.

Even worse is not examining the bottom of tank [the fuel strainer cup] for rust or drops of water.

I think my fuel pump must have been changed at some point as my fuel gauge has never gone to the top when the tank is full. It stops a little above 1/4 tank. Annoying yes but I can live with it. In my years of ownership (8) I've only seen low fuel displayed on the read out once.

Drew