258 4.2 fuel pump diaphragm fails. 3rd replacement

dougiet

Well-known member
Why are the diaphragms failing, is it with the installation?
It can only go in the right way? any advice? what can I do to fix this?

2 Delphi's and a Cartier all out the weep hole. Can still drive with the
pump leaking. 3 pumps in a row, my nerves are shattered.

3 mechanical fuel pumps in 2 months on a YJ with no plates, the failures happen when driven @ 3 miles.
My engine oil has to go too. !@#%^&

I had purchased some kinda odd 15w40 oil for import diesel engines, could the oil weaken...
Please login to view full content. Log in or register now.
 
Last edited:

Kunker

Administrator
Club Member
What is the method of failure? Anything you can see in common there? Did you replace upon purchase? If so, did the original one when you bought the Jeep also fail?
 

dougiet

Well-known member
pump leaks3.jpg
What is the method of failure? Anything you can see in common there? Did you replace upon purchase? If so, did the original one when you bought the Jeep also fail?
The pump on the Jeep when purchased was a Delphi and it was working with the 15 40 diesel oil, I replaced it for under $50.00 as a precaution. The pump failures are when the motor is driving at neighborhood speeds and all failed in the past 2 months. Testing the jeep after installs of various new parts the gas starts out the weep hole on all 3 failed pumps.
Benson's replaced the 2 Delphis the next day and CT is replacing the Cartier the next day after pumps failed.
I am calling friends in Toronto and their mechanical fuel pumps are being replaced within mere months after new installs.

Yes, the common event is all pumps are failing at the same duration of operation of garage idle and neighborhood street testing of @ 3 k's
honestly, you can run a stopwatch, that's how common it is.

Thanks for the reply Kunker, I have to get to Perth in 2 weeks for a DOT safety inspection.

I am draining the oil now and will not use diesel 15 40 but will go with gas 10w30.

The fuel tank on the jeep has been cleaned out last year as seen in my build thread.
 
Last edited:

Kunker

Administrator
Club Member
Do you still have one of the failed pumps? I ask as my inclination would be to tear it apart and see what's failing. I would almost assume it's a fuel issue vs oil, but I could well be wrong as I know nothing about mechanical pumps beyond "they fail less than electric". AKA every elec fuel pump I've run failed at about 200K km, while I've never had a mech pump fail.
 

dougiet

Well-known member
About the fuel, I did remove the tank and clean it out last year. whatever fuel that was affecting the diaphragms has been burnt and new gas is in. Also, the other rubber fuel parts like fuel lines did not show signs of contamination.

The oil at 15 40 is better for this engine I agree, just need to remove the maybes. The mech pump was working when it was replaced, I reinstalled it after the new pump failed, and would not work after sitting on the shelf for a month. This is true, not lying.

I am scared to go with an electric system anywhere that's why the engine is carburated. The tech online did say the micro mini Mr. Gasket fuel pump 12S would not last as long as their $150.00 red pump. HE PREFERED IF I BOUGHT THE 'RED' ONE

I WONDER IF I SHOULD CANCEL THE ELECTRIC FUEL SYS COMPONENTS AND INSTALL A MECHANICAL PUMP THAT IS ON ORDER AND TOW THE JEEP TO THE GARAGE FOR CERTIFICATION AND PLATES. 200 K ONLY ON ANY PUMP IS B.S

LINK RED PUMP MICRO MINI 12S
.
 
Last edited:

dougiet

Well-known member
OK, I BOUGHT 2 NEW DELPHI MF0009 MECH PUMPS OFF AMAZON FOR $22.00 EACH 45% OFF, CT IS REPLACING THE CARTIER PUMP THIS WEEK.
I WILL TRAVEL TO PERTH FOR THE PLATE CERTIFICATION WITH 3 BRAND NEW FUEL PUMPS AND REPLACE THEM ON THE SIDE OF THE ROAD WHEN NEEDED.

WE NEED MANUFACTURING IN CANADA NOW.
 

dougiet

Well-known member
SPOKE WITH DELPHI TECH, "EITHER ETHANOL HIGHER THAN 15% IN THE GAS FROM THE GAS STATION, OR OLDER PARTS TOO LONG ON THE SELLER'S SHELF"

ETHANOL ON OLDER PARTS STOCK IS HARSH. ENGINE OIL IS NOT A PROBLEM FOR THE DIAPHRAGM. 3 PUMPS, 2 MFOOO9'S 1 CARTER

ON THE ENGINE, GET A SMALL HOSE TO THE FUEL PUMP INLET AND POUR A TEASPOON OF MINERAL SPIRITS IN AS YOU CRANK THE ENGINE UNTIL THE OIL IS SEEN AT THE THREADED OUTLET.
 

dougiet

Well-known member
Still experiencing pump failures, I am looking for an electric fuel pump set up for 6 lbs at the carb. I am not sure if it should be a pump in the tank or inline. A regulator is ok. 4.2 2bbl

Any suggestions?
 

Richard

Commoner
Club Member
Nothing wrong with an inline pump, my Mopar MPI kit came with an inline and that worked fine for 25 years. Of course that was a high pressure pump but I'd think a carb pump would be OK too. At least you don't have to take the tank down to get to it.
 

dougiet

Well-known member
You got that idea right, an inline pump instead of dropping the gas tank on my foot once a year!
I believe 25 yrs for a fuel pump, I had countless used cars, trucks, and heavy equipment, and more likely changed 3 mechanical fuel pumps in 25 years.
Bygone era.

Yes, there are volume pumps rather than high pressure.
 

Richard

Commoner
Club Member
I did replace it once, what I meant was having it outside the tank didn't cause any problems. Maybe it's harder to prime but once running it's all good.
 

Kunker

Administrator
Club Member
If it's mounted properly, an inline pump should already have head pressure and prime without issue. If it's mounted poorly, all bets are off.

IIRC, the Holley red pump is kind of the standard here.
 

dougiet

Well-known member
Yes, you are right Kunker. The Holley red is what was strongly suggested by the Holley tech guy and a wire harness.

I will call the Holley tech guy real soon and ask if that pump can deal with ethanol.
 

dougiet

Well-known member
Removed the distributor and used the drill on the oil pump. Backed off all rocker bolts and drilled away for 10 minutes to charge the lifters. I need a good engine flush. This engine needs to be driven for christ's sake, this mechanical fuel pump issue has delayed the long drive by 6 weeks.

The idea of Dextron II added to the oil will provide some assistance.

Any suggestions?
 

Kunker

Administrator
Club Member
Please note that I have never, at any point, used any sort of engine flush mix, as I question running the engine, even for a few minutes, with intentionally thinned out oil to be a very questionable idea. If I'm that worried about crap in the engine, it'll get pulled apart and hot tanked before a rebuild.
 

dougiet

Well-known member
Yes, Kunker you are right! These two youtube videos are from 'PROJECT FARM' which tested a tranny & oil mix and a oil & diesel fuel mix and both were determined to cause metal particles during the running of the engine.

Diesel & Oil

Tranny oil & oil

Thanks, Kunker.
 
Top