Fuel pump failed

[renchero]

there i was thinking its a nice day. Ill go for a drive in the Ranchero, got it out the garage locked the garage, engine cuts out and won't restart fuel pump not running. this is the second pump failure i have had on a vehicle that does very few miles. bad luck or am i using the wrong pump? ranchero has Atomic EFI and the pump is a Walbro GSS 340 in the tank .
pump control is Pulse Width Modulation. just to make this even more fun to change the pump i need to remove the tank and that is full

 

[saleen 192]

Pump fail? Blown fuse? Loose connection? E5 or e10 fuel?? What have you checked so far?

 

[renchero]

not fuse,not loose connection,it is ok on E10 not that it drinks that stuff. power on lead that feeds the pump [front end] i am shaw it is the pump. just need to work out how to disconnect the pump wiring without removing the tank . cutting a hole in the floor is not an option

 

[saleen 192]

Good luck . Was thinking might be relay but need to check pump connections as you say looks like tank will have to be dropped once drained

 

[renchero]

i know it can not be the relay as there is not one, can't drain the tank for about 2 weeks as i need to use up the full tank of gas in the p100 to give me some where to put it

 

[saleen 192]

shame on on you no spare fuel containers , lol what about putting fuel in your daily driver or is that diesel or worse electric lol

 

[TransAmDan]

That is a pain to get to. With Sarahs car an access hatch wouldn't help anyway as there are solid fuel lines to near the back axle, to get the ump out the hatch would need to cut the lines and rejoin.
I did syphone fuel out of the car into a container to make the tank a little more manageable to take it out again.

The pumps are usually good. I have a Walbro 255lt/ph pump in the TA since about 2006. Its probably a differnt range to yours as I get 58psi at the fuel rails, the pump is always full speed(no PWM) there is a return path near the fuel filer near the back wheels that regulates things.

You mentioned PWM signal to the pump, is that present? Could be a case the PWM isn't there as the EFI system decided something wasn't ready?

 

[renchero]

i have 2 jerry cans they hold 5 gallons each, p100 holds about 12, ranchero holds about 20. i read somewhere that not all pumps are suited to PWM control but can not now find that article. also when looking at replacement pumps i found one that said suitable for PWM, adverts for most don't . i can just touch the top of the pump in situ so at the weekend i might drain 1/2 a tank of fuel and lower it slightly so i can undo the pump wires to test it properly. if i am right the new pump will be a lot more expensive than the old one, not buying anything until i know what is wrong

 

[saleen 192]

Good plan ranchero

 

[renchero]

had a good look at this today, i can just feel the pump but not enough room to get a spanner in there not helped by the sealant i put over the terminals to help prevent corrosion so i bought this

then cut the wire, result i know that the pump is dead. pump feed will light up a bulb, put a battery across the pump nothing.

 

[TransAmDan]

Odd why the pump failed soo soon. I heard the fuel acts as cooling for the pump, so running with no fuel can kill them. I know you said you had fuel in there, so it's no that. Frustrating how much work needed to be done to get to the pump, especially multiple times.

 

[saleen 192]

good luck ,so plan to drop tank is it like the two metal strap design like on my TA? and a few hoses

 

[renchero]

tank is held in place with 2 straps so is easy to remove. i once read that not all pumps are suited to running on PWM, i don't understand why and am unable to find the article i read about it. most adverts for pumps don't mention PWM, but i found one that advertises that it is suitable,shame its about twice the price of the other type. yes i could switch off the PWM but the Ranchero runs better with it

 

[saleen 192]

Diagnosing Pulse-Width Modulated PWM Fuel Pumps – UnderhoodService

Just this summer, I experienced a situation in which the fuel pump had been replaced four different times on a single vehicle with no result because the various repair shops attempting to repair the vehicle didn't understand how to diagnose a pulse-modulated fuel delivery system. Here are five...

www.underhoodservice.com

PWM Fuel Pump | Halfords UK

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One-stop shop for Kit Car and Classic Car Parts, Kit Car repairs and painting. Tools and Accessories for the Kit Car and Classic Car Enthusiast.

www.carbuilder.com

might be of help for you ??

 

[renchero]

thanks i have now ordered a new pump of the correct type [ i hope]. the bit i don't understand is what is different in the design of the pump i guess i will just except it is different.

 

[TransAmDan]

thanks i have now ordered a new pump of the correct type [ i hope]. the bit i don't understand is what is different in the design of the pump i guess i will just except it is different.

Pumps have an inductance load. Switcihng them on and off has a high surge current on start up. Straining components. I guess PWM pumps get around this in some way. I'm not saying this is the issue with your pump, but regular pumps and PWM pumps must be built different to change start up load,. Perhaps this is where the extra costs comes from for PWM.

 

[renchero]

thanks Dan. i was aware of high start up currents. the new pump is a bit bigger one end so maybe its got more "stuff" in it. when i get it/do the swop i will post a picture for comparison. but i am not taking them apart to see what's inside.

 

[saleen 192]

take the old unit apart just for the fun of it once the other pump in and working, the link i posted as well says a little about PWM

 

[renchero]

pump nearly turned up today, but i was out so it din't . the text they sent said they left a card, they din't . i have read those links, put the ranchero's reg in the halfords website just for a laugh, no response.

 

[saleen 192]

Any update??