L-60 6-CYL. BACK FIRES WHEN GIVING GAS

npca-mkink · Post by **npca-mkink** » Mon Jul 28, 2003 6:08 pm

I need some help I got my L-60 Patrol finaly running. It took Cleaning out gas tank fuel filter hoses carb-rebuild Set the timing 10' TDC on flywheel. throdel body rebushing new condensor coil intake.exhaust manifold gasket adj. valve springs checked compression 150 psi all 6-cylinders IT STILL HAS TROUBLE ACCELERATING UNDER A LOAD. IT BACKFIRES AND MAKES LOUD POP'S. Sounds like a shot gun. It idles good. Any advice. The only thing I can think of is that the vacume advance was taken out on the hitachi distributer. They welded the points plate down. Any advice would be great

npca-eyepez · Post by **npca-eyepez** » Mon Jul 28, 2003 7:14 pm

; Does it eventually accelarate? My best guess is ; that the carb is flooding. It's happened to me before.; ; ----- Original Message ----- ; From: ; Mkink ; To: Nissan Patrol Club ; Albuquerque ; Sent: Monday, July 28, 2003 5:08 PM; Subject: L-60 6-CYL. BACK FIRES WHEN ; GIVING GAS; ; ; ; ; New Message on Nissan Patrol ; Club Albuquerque; ; ; L-60 ; 6-CYL. BACK FIRES WHEN GIVING GAS; ; ; ; Reply; ; ; ; ; ; Reply to Sender Recommend ; Message 1 in ; Discussion ; ; ; ; ; ; From: Mkink ; ; ; I need some help I got my L-60 Patrol finaly running. It ; took ; Cleaning out gas tank; fuel filter; hoses; carb-rebuild; Set the timing 10' TDC on flywheel. ; throdel body rebushing; new condensor coil; intake.exhaust manifold gasket; adj. valve springs; checked compression 150 psi all 6-cylinders; IT STILL HAS TROUBLE ACCELERATING UNDER A LOAD. IT ; BACKFIRES AND MAKES LOUD POP'S. Sounds like a shot gun.; It idles good.; ; Any advice. ; The only thing I can think of is that the vacume advance ; was taken out on the hitachi distributer. They welded the ; points plate down. ; ; Any advice would be ; greatView other groups in this ; category.

npca-bush · Post by **npca-bush** » Mon Jul 28, 2003 7:25 pm

From recent experience-- this sounds like a dirty carburetor. Make sure all the orifices are perfectly clean and open. It took three cleaning attempts on our Rochester to get it truly clean. Good luck!

npca-fud · Post by **npca-fud** » Mon Jul 28, 2003 11:06 pm

well...backfiring is usuually tuned to lean, especially if it fires up in carb. Poping and misfiring can be all kinds of things, if it smokes and runs bad the carb is to rich and fouling plugs. Or timing is out or points are burnt. Bush may very well be right...I have got the same thing going on my 64. Rebuilt Rochester, new tank and lines, new fuel pump, new seperator and filter yet it still won't run right. I am at a loss other than air leaks in my fuel system or maybe the carb just didn't get clean first time around....

npca-mkink · Post by **npca-mkink** » Tue Jul 29, 2003 1:13 pm

It will eventually accelarate. However, But it takes alot of learching and slow acceleration. I adjusted the valves and everything seems to be working good. I am going to spray starter fluid down the carb to make sure that it is not a problem with the rebuilt carborator that I just put on. If the engine accelerates with the starter fluid I will know that the carborator is not working properly. If it still pops then I will turn my focus on the distributor. More then likely I will have to replace the distributor with an HEI distributor out of a late model Nova. This will work however I will have to have a custom shaft made. (Any other advice would be greatly apritiated)

npca-honda guy · Post by **npca-honda guy** » Tue Jul 29, 2003 6:32 pm

It sounds like a faulty or mis-installed accelerator pump. On a Rochester, there is a band of leather that forms a cup or seal in the bore. it needs to be stretched when it is installed to make a good seal in the bore. It is also wise to lubricate this leather with engine oil when installing it. To see if this is the problem on either carb, remove the air cleaner with the engine NOT running and look down the throat of the carb. Make sure the choke is open so you can see, and work the throttle a few times. You should see a strong stream of gas shooting down the throat of the carb. If it is just a trickle or none at all, the pump needs attention. Good luck!

npca-mkink · Post by **npca-mkink** » Wed Jul 30, 2003 3:17 pm

Thanks for the advice I think that you are right. When I did the rebuild kit on the RR carb I only oiled the leather gasket on the accelerator pump. I am going to check now. Thanks I will let you know how it turns out.

npca-danetteandkeith · Wed Jul 30, 2003 9:42 pm

What about backfires while letting off the gas pedal going down hills? Anybody know what to do? Keith

npca-fud · Post by **npca-fud** » Wed Jul 30, 2003 9:52 pm

check for exhuast leaks.....

npca-honda guy · Post by **npca-honda guy** » Thu Jul 31, 2003 11:33 pm

As far as coasting goes, that is due to a overly rich condition caused by engine vacuum trying to pull past a closed throttle plate. The vacuum can pull fuel throught the idle circuit. It could be just that the idle mixture is set too rich. A leaking exhaust will definately increase the backfires by giving the fuel the air it needs to cumbust. To combat this, automakers started using "dashpots". I don't know if the patrol has one stock, but mine does. it is a little thing under the throttle lever that momentarily holds the throttle open a tiny bit right after the throttle is released. That allows air to be sucked past hte throttle instead of just gas. If you have one, check to see that it delays full throttle closure for a second or two. Also check your mixture adjustment. If the Patrol did not come stock with a dashpot, they are readily available for many other cars and as mine has one, it is somthing you could install. good luck!