Fuel Pump not turning on.

**FlipediS** · 06-06-2008, 06:38 PM

OK what happened was i bought this trans am from a dealer in Florida, And i live in Hawaii. SO i had a shipping company come pick up the car and it ran and they drove it on the ramps and all and then it ran when the drove it off the ramps and in to the create to be shipped to Hawaii.. But once it got here it would not start. And there is no fuel pressure what so ever. So i changed the fule filter and still nothing the pump doesn't even kick on what so ever. And i switched out relays with other ones under the hood and still nothing. But i dont relay see any power at the relay. Now when i pull the relay out and check the voltage at two of the prongs should i be seeing any time of reading? Or am i checking this wrong? Because dose not look like any of the relays seem to have a reading , SO i'm thinking i'm checking this wrong or something. the fusees all have reading to them.

Also if i wanted to hook up a battery to the fuel pump to see if it kicks on how would i go about doing this? i went under the car and seen the plug but what wires would i hook up to a battery?

I have read allot of the threads but have not found the information i need. Im sort of a newb so im a bit lost

**Cutlass** · 06-06-2008, 07:06 PM

Probablly doesn't matter but what year car is it?
I'm gonna go off info for a 2000. You're looking an 8 pin connector(only 7 wires are used) to the fuel tank. The Gray and Black wires power up the fuel pump.
Another thing you could try is have a friend crank the engine while you hit bottom of the gas tank with your fist or a rubber hammer. Sometimes that'll jar the pump past it bad spot and it'll start up.

**FlipediS** · 06-06-2008, 07:49 PM

Actually its a 98, and there are 7 wires in the harness... so is it still the grey and black one? dose it matter what one is positive?

**0rion** · 06-06-2008, 09:31 PM

grey is positive......is the security light staying on or flashing? Does the car crank and not start or is it not cranking at all?

**FlipediS** · 06-07-2008, 02:05 AM

THe car cranks over fine. And will start if i spray starting fluid in it. but the fuel pump is not turning on at all..

**Cutlass** · 06-07-2008, 03:46 AM

Gray is positive, Black is negative. GM has been using those colors for the fuel pump for many many years. You could also check for power and ground at the vehicle side of this connector. Have a buddy turn the key to on (no need to start it). The fuel pump grey wire should have power for 2 seconds after key on. If you have power and ground to the pump and the pump doesn't pump, then you need a new pump.

**Too Fast** · 06-07-2008, 04:05 AM

^^^Some good advice there, but if I needed a pump I would not have a smiley face. More like a frowny face! Gas tanks are not that easy to drop in our cars, but I have heard of people cutting an access panel from above and behind the rear seats to do it, I don't remember where. Maybe on this site.

**SVG210** · 06-07-2008, 08:44 PM

if your fuel pump is dead youll get a ses code (i belive) its gotta be a ground somewhere try starting from the BCM to the relay. it could be a Vats issue.

**FlipediS** · 06-07-2008, 10:46 PM

Well today i crawled under the car. and disconnected the plug where the pump plugs in to and tested where the the grey and black wire belong and had someone start turn the key in the ignition and i got power for like 5 seconds or so. SO it looks like the fuel pump should be getting power? So as far as i can tell the only thing it can be now is the fuel pump?

**FlipediS** · 06-07-2008, 10:54 PM

Also if it is the fuel pump, Im thinking about going with one of them Racetronix fuel pumps and wire kits. Would i be better off with that? Right now the car is stock. But plan later in the future to try and get one of the sts turbo kits on it. what do you all think?

**Cutlass** · 06-08-2008, 04:50 AM

I think your diagnosis is correct. You need a fuel pump. As to which brand...I have no opinion

**squee** · 06-08-2008, 01:20 PM

I'd say a Walbro 255 should do ya.

**SVG210** · 06-08-2008, 01:57 PM

try adding direct power to the pump before you attemt to replace it.

**FlipediS** · 06-08-2008, 02:46 PM

I have tried to connect power to the grey and black wires in the plug under the car and did nothing but seemed to warm up the wires that i was using ...

**FlipediS** · 06-09-2008, 12:27 AM

Also if anyone knows of a good guide to help with replacing the fuel pump on my 98 Trans Am, I have not decided if im going to drop the tank or make the cut.. Would rather drop the tank if i could do it withing say 5 hours or so. plus i bought the racetronix kit with the wiring harness... will i be able to get the harness on if i was to to the cut job? If i remember correctly i think i read someone that said they had problems getting it on without drooping the tank...

**Cutlass** · 06-09-2008, 02:53 AM

The service manual says you have to remove the cat-back exhaust and the rear axle before you can drop the gas tank out.

**Orcus79** · 06-09-2008, 06:01 AM

Service manuals are a deconstruction of how things were put on during assembly, I never trust them entirely. I haven't had mine out yet *knocks on wood* but have looked at it. I don't think you need to drop the exhaust and rear axle. Maybey the panard bar.

Just have to drain the tank and roll it the right way. OR so it looked like to me.

***Ed Blown Vert*** · 06-09-2008, 06:03 AM

Dumb question, but do have fuel in the tank?

Pump does not run unless the engine is running.

You won't hear it if the key is in the on position. But it will prime when you initially turn the key to on.

**Frost** · 06-09-2008, 06:59 AM

Originally Posted by hurraquio

if your fuel pump is dead youll get a ses code

That would be nice, but unfortunately it's not the case

**0rion** · 06-09-2008, 08:59 AM

If you do end up dropping the tank buy a Haynes manual. That'll help you. Dropping the tank really isn't a huge job but it is labor intensive. You'll have to pull the catback off then drop the rear down as low as you can get it before the tank will come out. Watch the brake lines on the drivers side and make sure you don't break them. There's a central block on the drivers side you can loosen from the car to get you a little extra slack in the brake lines.
Just make sure you're not missing anything and it's the actual pump before tearing into this. You put 12 volts on those wires and nothing? If that's the case then the pump very well could be your problem.