Fuel pump issues.

M

Mechanicboy

Dedicated LVC Member
Joined
Nov 18, 2009
Messages
1,406
Reaction score
3
Location
Durham
So I was going to use the search function but apparently it doesn't let you just search the LS forum so here it goes.

I recently had a no start problem with my LS. I found out I didn't have any fuel pressure at the schrader valve. I thought it might have been low fuel so I added a few gallons to the tank put still no fuel pressure and I couldn't hear the pump trying to prime either. I traced it to a blown fuel pump fuse in the trunk. I didn't have any spares so I pulled a 30amp fuse from an un-needed accessory and after a few key turns and attempts to start fuel pressure returned and the car started. It ran fine the rest of the day.

A returned to the car a few days later and same problem, no start, no fuel pressure. This time the fuse was good. My thought is that the fuel pump is shorting out internally.

What are the brands of fuel pump that are good and bad?

Edit, found this thanks to google: http://www.lincolnvscadillac.com/forum/showthread.php?70490-rear-seat-removal
 
I doubt the the fuel pump is shorting out. It's more likely that the bearings are failing, which causes the pump the draw too much current.

I think that replacing the 15A fuel pump fuse with a 30A fuse was a very bad idea. If you are lucky, the motor windings of the fuel pump burned out (instead of the over sized fuse). If you are unlucky, the power transistor in the REM burned out instead and you will be replacing the REM with the fuel pump. The REM regulates fuel pressure by controlling how much power goes to the fuel pump motor. The transistor that does that is sized so that it is protected by the 15A fuse. The 30A fuse may (or may not) have allowed enough current the kill that transistor.
 
Walpro fuel pump. You just need the motor, not the whole pump. Remove back seat. Dig into the pump housing, sometimes the hose couplings can be a bear to release. I broke mine. Take ring off by turning ccw with tool. you can borrow the tool from auto zone or just use a large screw driver and hammer to loosen the ring. Pull out pump, replace motor. Put it back together, i used epoxy to reattach hose clips. replace fuse. all done.
 
joegr said:
I doubt the the fuel pump is shorting out. It's more likely that the bearings are failing, which causes the pump the draw too much current.

I think that replacing the 15A fuel pump fuse with a 30A fuse was a very bad idea. If you are lucky, the motor windings of the fuel pump burned out (instead of the over sized fuse). If you are unlucky, the power transistor in the REM burned out instead and you will be replacing the REM with the fuel pump. The REM regulates fuel pressure by controlling how much power goes to the fuel pump motor. The transistor that does that is sized so that it is protected by the 15A fuse. The 30A fuse may (or may not) have allowed enough current the kill that transistor.
Click to expand...

That's possible but I'm pretty sure it was a 20a that was in there before. I removed the seat, found a bunch of crap under there and probably $3-4 in change. My connector is a 4 pin though. Do you know what the resistance of the pump should be?
 
Walbro's are very common, sorry i spelled it wrong, its walbro not walpro. ebay has it. check on previous posts of mine for item # or just look it up. its about $99. with the rear seat removed and a good fuse, turn key to on, you should hear the pump start. no noise? bad pump, check for 12v to the pump, if 12v and no noise = bad pump.
 
Mechanicboy said:
That's possible but I'm pretty sure it was a 20a that was in there before. ...
Click to expand...

Maybe someone else had already up-sized from 15A to 20A.

It's always a very bad idea to replace a fuse with another fuse with a higher current limit.
 
joegr, do you know of a way to release those hose clips on the pump housing?
 
Well, I went to check out power again and noticed the battery was low so I charged it. After a few hours on the charger I turned the key and heard the fuel pump. I've been driving it that last two days with no issues. Weird stuff. I think the car just hates sitting. In the past when I've let it sit in the cold it sometimes won't start the first time but if I try once or twice more it will be fine. I wonder if I have some corrosion on the fuel pump brushes or relay or ???

It's working for now. I'll report back it something changes.
 
These cars are battery sensitive. All kinds of wierd things start to happen when the battery is low. You may have a charging issue (bad alternator) or old battery. you can check for proper operation by putting a volt meter across the battery terminals and have a friend start the car. watch the voltage, it should drop below 12v on the start then as the alternator kicks in the voltage will rise.
 
I was under the impression that the fuel tank had to be dropped to change out our fuel pumps in the LS? Or at least I thought I had read that somewhere. So it's accessible and swappable from under the rear seats?
 
SoulSoak said:
I was under the impression that the fuel tank had to be dropped to change out our fuel pumps in the LS? Or at least I thought I had read that somewhere. So it's accessible and swappable from under the rear seats?
Click to expand...

No need or reason to drop the fuel tank.
The fuel pumps are very accessible after removing (easy to do) the rear seat bottom.
 
You must log in or register to reply here.

Members online

No members online now.
Total: 1,123 (members: 0, guests: 1,123)
Back
Top