Is It the Fuel Pump?

[ArcherAce]

My 93 ATX has been having trouble starting lately. It seemed that every time I'd try to start it, it had to turn over a little longer before it would finally "catch".

Luckily, the last time it ran was when I started it to back it into the garage.

I hooked a fuel pressure gague up to the shrader valve on the fuel rail, and turned the engine over. It showed that there was no fuel pressure.

I'm thinking that since it slowly failed to start over a period of time, and since I don't have any fuel pressure, that the fuel pump is bad. I've always thought that mechanical things, like fuel pumps, can fail little by little. (As in taking longer and longer to pump up and get fuel to the engine) Electrical things are either working or not. Well, except for that old T.V. I use to have that worked better if you smacked it on the side.

Before I drop the tank, is there anything else I might want to look at? I've checked the safety switch in the trunk, and the red button is still pushed so I'm assuming that is ok.

Thanks for any help,
Rob

 

[zuup_2000]

You can access your pump wires under the rear seat cushion. See if you are getting power to the pump. You can also see if there is continuity (ohm meter) between the pump wires (key off) to see if the pump is good. A manual will explain how its done. Always do everything possible to make sure that the pump is bad before you try to replace it. Nobody likes to waste time and money fixing something thats not bad.

I just noticed you are in the rust belt. Make sure to check for rusted and corroded grounds also.

 

[LOUDSHO92]

Kind of sounds like what ahppened to me. Though when mine went it took out the safety switch as well, which acted like ti was fine. It had to be tested to show that it was bad.

We did the fuel pump in under 2hrs.

 

[ohfosho]

check your engine codes...it could be the cps sensor...im going throught that trouble right now...although my fuel pump is probably original and is due for a change also.

http://www.shophoenixproject.com/eec/eec.htm

 

[ArcherAce]

Kind of sounds like what ahppened to me. Though when mine went it took out the safety switch as well, which acted like it was fine. It had to be tested to show that it was bad.

We did the fuel pump in under 2hrs.

2 hrs.! I'm still fighting with those damn long winded bolts that hold the straps on! Talk about "thread engagement"!

check your engine codes...it could be the cps sensor...im going throught that trouble right now...although my fuel pump is probably original and is due for a change also.

http://www.shophoenixproject.com/eec/eec.htm

Can you check codes when the car won't run? KOEO would be difficult I think.

 

[Blast7]

check your fuel pressure.

 

[projectSHO89]

check your fuel pressure.

He already did. It's missing....

That leaves either electrical power to the pump missing, a defective pump, or a restricted or clogged fuel line as the possiblities.

Check power to the pump at the inertial switch in the trucnk. Remove the trunk liner and get to the wires at the connector. Check for batt power on both wires during a pump priming cycle (or just turn the pump on by grounding the FP terminal of the EEC Self test connector).

If power is present, then either the pump is bad or the lines are clogged.

You can only check KOEO codes when the car won't run. Can't check KOER, though...

Steve

 

[ArcherAce]

Thanks for all your help, guys.

Well, I went ahead and dropped the tank anyway. It turned into a real p.i.t.a.! The long winded bolts that hold the tank straps wound up breaking. Getting what's left of them out of the clips looks to be another project in itself.

I checked the power to the fuel pump at the pumps electrical connector and it reads 11.07 volts on my dmm. So, the power is there.

I'll go ahead and replace the pump this weekend. It's a good time to replace the filter too i suppose.

They wanted $70 for a pump, or $140.00 for the pump and sending unit. (I haven't shopped around for the best price yet) Is it best to replace the sending unit and pump at the same time? I suppose after all this trouble, it wouldn't be worth my going cheap. I'd hate to have to do this again. :cry:

 

[jedhead]

I purchased a 155lph fuel pump here:

http://www.autoperformanceengineering.com/html/fpapps.html

Don't go nuts and get the 255lph unless you have Josh's adjustable fuel regulator.

Bob

 

[ohfosho]

is there a need for a High pressure fuel pump in a stock car, will it make a difference? thats a good price!

 

[projectSHO89]

For a stock SHO, the Master (Airtex) E2001 pump from AutoZone is fine. It has plenty of capacity and is available anywhere, usually within a day or two for around $70.

Replace the sending unit/pump combo only if you have fuel guage problems attributable to the sending unit.

I just replaced mine a few weeks ago (combo unit) due to both a faulty pump and a bad sending unit. I suspect that the sending unit portion of the new unit is improperly marked for the 18.6 gallon tank but is, in fact, for the smaller tank. I now get an EMPTY indication when I've only run about 12-13 gallons out of the tank. I guess I'll pitch a ***** to the manufacturer if it aggravates me enough. Special order at my local AZ store, about $150 including sales tax.

Steve

 

[jedhead]

is there a need for a High pressure fuel pump in a stock car, will it make a difference? thats a good price!

The stock fuel pump is fine. I have been told that some of the 1995 SHO some times have ended up with SLO pumps by the factory. I bought the 155 because it works well with the stock FPR and will support the 30lb injectors I may go to later.

Bob

 

[ArcherAce]

Replace the sending unit/pump combo only if you have fuel guage problems attributable to the sending unit.
Steve

My gauge is fine, so I won't replace the sending unit it suppose. Cash is tight right now anyway.

Does the replacement pump come with the screen, or do I have to buy one seperatly? Also, I'd like to replace the plastic clips that fasten the lines to the pump. Do they come with the pump, or is that something else I should look into?

Rob

 

[ArcherAce]

Well, I finally got around to finishing up the pump install over the holiday weekend. It was in fact the fuel pump.

Thanks for your help, guys.

On to the next problem.