why run two fuel pumps?

[idiosyncratic]

okay. I found out that my 1989 Dodge Ram50 (rebadged Mitsubishi Mighty Max) has two fuel pumps! Why would the previous owner install an electric fuel pump (small Carter gerotor type) and feed it to the oem mechanical fuel pump?

perhaps the mechanical fuel pump isn't pumping properly due to wear on the cam? since it's cam activated? so instead of paying to pull and replace the cam, he did a bandaid fix and installed an auxillary fuel pump?

note: I haven't really checked to see if the mechanical fuel pump is working properly and or the wear on the cam.

I don't see why the mechanical fuel pump wasn't bypassed since there's an electric fuel pump installed. Isn't this what most people do when they install an electric fuel pump? because they want to replace the mechanical fuel pump?

perhaps the fuel line is run by vacuum? I have no idea... I'll have to see if I can find out... sometimes these store bought manuals are hard to get info... because the info is scattered throught the manual (i bought a chilton... i think).

\/ electric fuel pump:
http://www.carterfueldelivery.com/fuelpumps/graphics/electric/carotor.jpg

\/ mechanical fuel pump:
http://www2.partstrain.com/store/images/prodimage/images/beck_arnley/BA-1518009-1.jpg

the truck still has this annoying intermittent habit of dying out in the mornings...
and as Dennis and I found out... sometimes it's not only in the mornings. :(
but it's intermittent so... I'm actually still driving it around. i think the electric fuel pump gets too hot sometimes and cuts off... and will refuse to turn on until it resets (cool off in a little bit).

**
also need help in trying to find/locate :eyepop:
a carb rebuild kit for this 2.0 L 4cyl engine... "D" based vin... if that actually means anything in regards to a carb rebuild kit... can someone help? :keith: thanks!
(yes, i've googled it... and am running through the sites... hard to find :freakout: :giveup:

[ikeyballz]

if that is true, and the mfp is plugged,it'll also explain why the electrical one heats up...

[idiosyncratic]

That is what I was thinking also
but if the mfp is plugged. why doesn't if fail ALL the time? instead of only once-in-a-while?

i.e. this morning I had no problems... yesterday morning i did, but the problem went away after restarting?

I'm thinking of ordering an electric OEM fit fuel pump
http://cpwstore.carpartswholesale.com/catalog/images/prodimage/images/airtex/AF1395.jpg
can anyone advise or give me their view/tips if I were to go this route?
I think the actual OEM part is mechanical, but if I were to fit an electric one that replaces that... I should be that much better off... I think. (I hope. :fingersx:)

**
I'm thinking the problem will go away after I solve the fuel pump problem
and/or rebuild the carb...

[idiosyncratic]

found the prob... the electric fuel pump is defective... it was probably due to the strain of having to pump through the mfp. the truck was having one of it's moments again this morning... it happened to stop by my cousin's house and her hubby was outside... we said our hello's and then he took time to help me troubleshoot. We ended up bypassing the efp. and just running the mfp. I'll be doing some more testing in the next couple of days to see if the problem is really solved. :)

i still can't figure out why the previous owner ran both fuel pumps... probably someone told him that it was a good idea to install an efp... so he did. he just didn't know that it was supposed to have replaced the mfp? :really: that's a plausible theory.

[Udrivecrap]

hahahahaha.. no way.. that's funny. you should check to see if there is two of anything else like fuel filters and batteries :D

iir, i had a car with two electric fuel pumps.. a low pressure one in the tank and a high pressure one under the chassis. i think that was on my mustang..

does the electric fuel pump match the required psi for your engine? do you need a regulator or is there a factory one after the manual pump and before the carb?

[Hawaiian turbo]

It makes a difference where the Electric PUMP is placed also. It should be in the back close to the tank so it can PUMP the fuel. If it's in the front, it will have to SUCK the fuel causing it to overheat. HTH