Is this a fuel pump problem, or am I mistaken?

[MelectroK]

Hello this is my first post, hopefully yall can help me please.

I beleive I have a bad fuel pump, but a new sending unit is $125 and requires pulling the tank. Am I accurate with my assumtion?

Case 1- Last two tanks of gas, when under 1/4 tank, excessive cranking required to start. Cycling ignition on-off 3 or 4 times usually started fine then.

Case 2- Two days before problem, noticed extreme loud screaming from fuel pump. (thought it was going bad based on another post here, but not expecting it that soon).

Case 3- Before main problem. 3 or 4 times right after starting constant idle problems, from 400rpm to 1000rpm up and down in pulses.

Case 4- Car will not run. Starts, same RPM problem then car stalls out. Re-crank and rpm continues to pulsate even when given throttle and stalls out. Buddy tells me when its pulsing he cannot hear the fuel pump winding.

After cooling the car did run again to get it back home. However have not been able to recreate the problem in hopes to check voltage at the cytriphical switch (which i have checked first when it didnt run) I know checking power after the cytriphical switch would tell me for sure if it is a power or pump problem (also know relay is in a module i beleive).

So is my assumption correct or do you have other ideas?

(sorry for the long post)

Mike
95MTX

 

[Dr_Thompson]

in my opinion sounds like a bad pump.Try running any codes??

 

[HopefulSHO]

Sounds like you may be right. Check your fuel pressure if you can.
You can get a new 190lph Walbro pump with everything needed to install for about $87.15 from http://www.autoperformanceengineering.com

 

[MelectroK]

no didnt run any codes. I didnt think you would get codes unless the engine light came on? Also dont have a programmer for it yet. I dont mind spending the money on the pump, just didnt want to spend it for no reason

 

[Black91SHO]

That Walbro pump is a nice little pump. You're about to embark on a fun little job. One thing I hate most is dropping the tank. YUCK! But then again, I have dual exhaust, so it makes it a bit more of a pain. And now that I have the subframe connectors, they may cause just a LITTLE more hassle. I made them myself, but I don't think I bent them enough to get them out of the way of the fuel tank coming down. Oh well.

And yes, you're correct: all of the signs you described scream "Fuel Pump Problem". When my last SHO had very light fuel pump problems, I had to prime it a couple of times with the key, then start. It wouldn't hold fuel pressure in the lines while the car was off. Then, when priming the lines upon ignition, it wouldn't put out enough pressure initially to start the car. Hence, the priming multiple times. Wasn't too bad...but your problem is much worse. And of course, no code came up in the computer.

Good luck! Have fun with that tank.

- Brian

 

[HopefulSHO]

Some codes won't neccesarily throw a CE light - but then again, on both cars that I've had fuel pumps replaced on...the light never would have told me anything anyway.
Oh, and you can check the codes with just a pen, a piece of paper (to write them on), and a paperclip to jumper the connectors.
SHOTimes has an article on it.

 

[masho95]

If you are looking for definitive evidence that the fuel pump is done you'll need a fuel pressure tester. If you have one check the fuel pressure after priming the pump and while trying to start the car, low readings on both will tell you definitely if the pump is a goner, but I would already assume that's the case.

 

[MelectroK]

Would a fuel pump have an intermitten problem like this (always when hot and turned off less then 30 min) or is like a pluged pickup. Someone also metioned to me possible regulator, i dont think this is the problem though.

I got the exahust loose. Correct me if im wrong. I undo the rubber hoses from the fill lines to drain the tank. Then unbolt the straps to lower the tank. How far can I pull it down to disconnect the fuel lines?

 

[Hack]

A lot of folks swear by cutting a hole in the floorboard above the pump to change it. I have not done it either way. It seems to me that the hole is a lot easier than dropping the tank. For detailed info, run a search. I am sure I have seen the procedure detailed here more than once. Good luck either way!

 

[Bizzy]

I cut a hole in mine and would do it again in a heartbeat. I didn't do a writeup so to speak of when I had mine done, but I did take pics so you can get an idea of what you're looking at. You can see the pics here

 

[MelectroK]

I dont know if im ready to cut a hole in my floor, i have droped the tank in my mustang once, and it lookes easier on this car, If i have a problem i might decide to cut a hole, but in your picture with those lines right under the panel looks kinda scarry.

Thanks for all your advice

Mike

 

[masho95]

I dont know if im ready to cut a hole in my floor, i have droped the tank in my mustang once, and it lookes easier on this car, If i have a problem i might decide to cut a hole, but in your picture with those lines right under the panel looks kinda scarry.

Thanks for all your advice

Mike

Just remove the filler neck going to the tank. Start loosening the tank straps and lower the tank enough to get access to the fuel lines above the tank going to the fuel pump assembly. Once everything is disconnected I just undid the straps completely and just removed the tank to pull the assembly out.