Fuel problem

[Jester76086]

I recently purchased a 1990 Infinity Q45. I was warned when I got it that there have been problems with the fuel computer. I work in a junkyard so getting a new one wasnt an issue. The sat for about 8 months before I got the keys. Iv been running premium fuel through it to help clean it out. Iv replaced the spark plugs with NGK Irodium gaped to .40.

I havent had a single problem out of the car mechanically until now. After putting 800 miles on it the motor died as I pulled out of the bank. After a few tries it starts again. I drove about 2 miles to have it die again. Started right up and drove for about 1.75 more only to die about 2 blocks from my home. I tryed several times to get it to start but stopped when i heard two sharp pops out of the exaust.

Had a friend pull me home and we replaced the fuel computer in the trunk. The plug was burned to the point that it was un-usable. we spliced another into it and now it does nothing. it will turn over but not fire. I also noticed that the replacement plug (used) was a bit brown around the same white wire on mine that was fried.

Total we have changed out all the relays, the fuses, the fuel filter, fuel computer, and the fuel pump.

I'm at a loss and have no idea where to go from here.

[pabs324]

Use NGK platinum pfr5g-11. Joe has them for $8.25 each.

[goody90q45]

Judging by your description of the burnt plug it sounds like you may have pulled a 2nd bad FPCU. At this point try grounding the fuel pump, making it run on the highest of the 3 speeds only, and see if your Q runs. You need to have a jumper with an alligator clip or equivalent on each end. Use wire the same size as the wires in the connector.

Here's how:You should recognize the connector in the pic as the one that plugs into the FPCU (which is behind it in the pic). Run the jumper from the lower left pin shown in the pic to a paintless ground on the chassis. Scrape paint off if you have to to ensure a good ground. You may have to grind down the teeth of the other clip to get a good grip on the connector pin. If your Q starts and runs, it points to a bad FPCU. If it won't start at all then the dying FPCU, drawing high amperage and burning the connector, may have fried the fuel pump. Listen to your fuel pump from the open trunk. If it sounds like a swarm of bees it's on it's way out. If none of this works for you then checking fuel pressure will be your next step. And if by luck your Q does start, don't drive too long (100 miles?) without putting in another FPCU.

There's a lot of good information using the search function (been discussed many, many times) along with some of the keywords in the last few paragraphs. Read a lot of previous posts and you'll learn a lot about the FP, FPCU and the fuel system on the Q. Good luck.

[Jester76086]

After following goody94q45's advice i have gotten the car to start and run. I ordered another FPCU from Wukkamon that arrived today. After plugging the new FPCU in place I still cannot get the car to run. I also finnaly got around to listening to the fuel pump. The discription of a swarm of bees is quite accurate. crap....

I have another fuel pump in the trunk right now. I'll be installing it at some point. Is it possible I have a 3rd bad FPCU or could the problems now be from my fuel pump?

Sidenote: Has anyone tried to install an aftermarket fuel pump?

Edit: i r dumb..... the unit has to be installed to work right. Had a dirty ford mechanic figure it out. *shame*
Modified by Jester76086 at 6:27 PM 5/14/2008

[Q45man1]

Never tried an aftermarket FP. I trust the OEM and don't buy a used FP.

[Q451990]

You're putting the egg before the chicken - or however that works... The old pump is pulling too much current, and will damage the controller. If your pump hasn't trashed the latest pump yet, it will soon. Install your new pump ASAP!

Welcome to NICO!

Heath

[Jester76086]

The new pump will be going in tonight. Seems its always the case that you have a full tank of fuel when the you have to replace a pump. Thank you everyone for your suggestions and help.

[StarPD]

The new pump will be going in tonight. Seems its always the case that you have a full tank of fuel when the you have to replace a pump. Thank you everyone for your suggestions and help.

Not an expert on this by any means, but the consensus seems to be that once one of the components relating to the fuel pump goes bad, the best solution is to replace ALL associated components; fuel pump, controller, fuel level sensor, and pigtail WITH ALL NEW ONES. They all interrelate to each other, and excessive current draw can ruin other associated components in short order if only one item is replaced or if already compromised used ones are installed, even if not completely shot. Even good used ones probably have a limited life, as these components seem to be maintenance items, usually good for only around 60 to 90 k miles.

If I'm as full of crap as a Christmas turkey, someone TRULY more knowledgeable chime in here.

[96Qowner]

Many of us are running used FPCUs on the G50.

Dennis said T3 had some troubles with intermittent FPCUs, but few here have experienced it. They're really spendy new. You can buy 9 used ones ($50) for the price of a new one ($450). Maybe some pigtail issues, depending on how hot the plug got, but the fuel level sensor comes with the new fuel pump.

[Q45tech]

"the fuel level sensor comes with the new fuel pump" Say What?

The pump does come with a new bottom hose and filter sock, you must order a new o ring for tank separately.

[96Qowner]

Am I having linguistic troubles again?

Level float does not = fuel level sensor? I was under the impression that the float comes with the pump. Then again, I didn't install mine - only had them bend the float back into shape after they screwed it up. Now that I think of it, I guess I have another hole in my Q45 knowledge.

At any rate, I don't recall hearing anyone say they needed a new sensor before.

Solly for the misinformation.

[maxnix]

Use NGK platinum pfr5g-11. Joe has them for $8.25 each.

On special for May! Load up now!

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