[paulaz]

Hello,

I have been having an issue for some time with my Nissan Pickup not starting intermittenly. When it does start I can hear the fuel pump kick on for a few seconds but I do not hear it when it won't start. Furthermore it runs great once it is started - no rough idling or cutting out while driving as I would expect from a bad fuel pump. Could the pump not energize on turning the key but operate fine while the truck is running?

I purchased a new fuel pump relay and the last time it would not start I replaced the old with the new relay and still it would not start. It did, however, start after I sprayed starting fluid into the throttle body/intake under the air filter housing. This leads me to believe that either the issue is the electronic fuel pump is getting power but not initializing OR its somewhere in the electrical circuit before the relay (i.e. maybe no juice is making it to the relay in the first place). I am not sure what other things to check in the path leading from the ignition and the Haynes and Chilton manuals are not much help as they don't even mention or show the starter interlock, fuel pump and other major relays. I don't want to replace a $150 fuel pump until I'm sure that's the problem.

I cannot seem to get it reproduce itself when there is someone around to crank it for me while I test power to the fuel pump leads with a meter. Can anyone tell me in their experience if this sounds like a fuel pump issue or anything else it may be aside from the fuel pump relay which I replaced?

Thanks for your help,
Paula

[TxGreaseMonkey]

Have you checked the ignition switch for wear, pitting, and melting? I would also test all under dash and under hood fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-t...tml#post252145

After, disconnecting the negative battery cable, I would remove the fuel pump fuse, clean the contacts with No. 240 abrasive cloth (or steel wool), and lightly coat with dielectric grease. Do the same thing to the fuel pump relay. Be sure to clean all grounds, including the main ECM ground.

Most electric fuel pumps are very reliable.

When the truck doesn't start, does the CEL stay on?

If the problem persists, the ECM may be failing. Even though the link below is geared towards Hondas, it should give you a methodology and leads to pursue:

https://www.askmehelpdesk.com/cars-t...ml#post1245523

[charlesdavis]

I have a 1991 Nissan Truck ( 4-Cyl ) and it is doing the very same thing as Paula describes above. It seems to occur after truck is good and warm. Also, when it has been left for about 4 to 5 minutes with ignition off. Today, it stranded me at Sears for about 4 hours. After the 4 hours, I heard the fuel pump come on and it cranked. I drove about 25 miles home with no problems. Has plenty of power and no problems once started. What is the CEL? I disconnected the battery and then turned ignition on. Upon touching negative, I could hear and feel the new fuel pump relay clicking but no response from the fuel pump while this was going on. I will check grounds, as you suggested. I am about ready to install a toggle swith on the dash to power the pump from the battery. Or create a bypass for the relay to see if this works.

[paulaz]

Hey Charles! I had an intermittent no start conditon on another Nissan p/u that turned out to be a bad starter interlock relay (about $30 from Nissan and its found inside the engine compartment on the passenger side fender well) and the symptoms were kind of similar.

However this was not causing my current issue as described in my original post above. I haven't had this issue reoccur in a very long time, a year or more, what I found to work as a fix (so far) is from someone else's post I found. I'm not sure why this works - I don't recall if the guy said it was a loose electrical connection on the fuel pump or if the fuel filter was getting clogged (not sure how that would cause the pump not to energize but it rings a bell from his post) but try this - it has worked a miracle for me...

Get a rubber mallet and carry it in the truck with you. Next time it gets you stranded take the rubber mallet and smack the bottom of the gas tank (just below where the fuel pump sits) a few good times. Then try to crank it. It worked like a charm and hasn't failed me yet... In fact after I found this trick I only had to do it a handful of times and then the issue just stopped happening, but I still carry my mallet around just in case. :)

If you actually wanted to fix it you could check the connections to the fuel pump or drop the tank to clean the fuel filter which was way too much work for me to do...

Good Luck!
Paula

[paulaz]

Sorry, I stopped reading a little short... CEL = check engine light (mine was NOT illuminated when this issue was occurring). It's my feeling that with my issue at least, everything seemed to work up to the point of the fuel pump itself. As mentioned I never had someone around to crank it while I put the leads on the electrical terminals so I can't be sure, but I too could hear my relay clicking.

[charlesdavis]

I installed a switched jumper wire to the outlet feed of the Fuel Pump Relay to the battery. Then I ran the truck for a few days. It failed to start after arriving at a Sears store. I switched "on" the jumper relay switch and the fuel pump would not come on. By installing the jumper, I eliminated all other conditions. At that point, I knew the fuel pump was the culprit. I waited at a nearby Wendys for about three hours. The fuel pump apparently cooled down or decided to pump. I drove home and changed out the Fuel Pump on Saturday. So far, there are no further problems. I have noticed better acceleration, since replacing the fuel pump. Maybe these details will help someone else. Thanks for all your help and blog on this subject. And Paula, love your rubber hammer fix! When all else fails carry a big frigging hammer, LOL.!

[charlesdavis]

I installed a fused switched jumper to the fuel pump wire downstream of the Fuel Pump Relay. This jumper was directly connected to the battery. I ran the Nissan Truck for a few days and the pump quit while at a Sears Store. I switched on the jumper and the fuel pump would not run. Therefore, I knew now the fuel pump was the culprit. I changed out the fuel pump on Saturday. This appears to cured the problem. I also noticed better acceleration with the new fuel pump. Maybe this will help someone else in the future. I appreaciate all of you for your input and experiences. This has helped me tremendously. As for Paula, I love you rubber hammer therapy. In the mechanic's code of ethics, it states: "If all else fails, carry a big frigging hammer." LOL and HaHa!!

[charlesdavis]

Sorry, thought the first one did not post!!