Mallory Fuel Pump Question (1 Viewer)

[dhanney]

History: Own a S/C 97 with a Mallory fuel pump with 168,000 miles. Had the rig 3 years with zero problems. I did a PM HG replacement last year with all the recommended maintenance (shaved/cleaned the head, cleaned the injectors, fuel filter, etc.). The S/C and Mallory fuel pump has been on the truck for over 10 years and 130,000 miles. My fuel pressure guage is at 42 psi at WOT and 40 psi cruising.

Question: Ever since the HG replacement, at startup the rig sputters for a second or two, then smooths out. The rig as always had slow starting issues since I've owned it...cranking for 4 or 5 seconds before firing. I'm thinking it time for a replacement Mallory pump (or maybe a different pump?) but I thought I'd throw it out there for some opinions. I'm not sure why an aftermarket pump was used in the first place. Lastly, I was at camping at 9800 feet last weekend and she sputtered for about 4 seconds before smoothing out.

Thanks.

 

[Photoman]

The stock in the tank fuel pump has a built in check valve. When the cruiser is shut down it maintains fuel in the line by not allowing it to flow back in to the tank. The Mallory has to pick up from the tank each time and get up to pressure hence the lag in starting.

Bill

 

[dhanney]

Bill,
Thanks for the reply...makes sense.

Again, not sure why the original owner installed the mallory pump to begin with. Any reason why not to got back to the stock configuration? Stock should have plenty of pressure since my S/C is a TRD setup. I'm wonder if going back to stock will eliminate the lag and stumble at start-up

 

[Photoman]

My Mallory pump came with a 44 gallon long ranger tank I bought from MAF. It turned out to be a nightmare. If your cruiser did not have an auxiliary tank I wonder if someone just added the pump without removing the old one from the tank? That way it would pull fuel through the nonworking stock pump and sort of have a check valve. Otherwise it would be interesting to see what they did in the tank for the fuel pickup.
I would say going back to a stock pump would help with the start up lag. On mine if I was on the throttle when I would switch tanks the cruiser would buck for a couple of seconds while the Mallory pump picked up. I learned to switch while coasting until I replaced the Mallory with another stock pump..

Bill