Hi all! New to the forum here and I need some help. My truck starts some days and not on other days. I have battery and it is turning over. I have no fuel when it doesn't start ( I can't hear the fuel pump) and the relays are clicking, so I know it's not them. It doesn't start in the morning or when it's cold out. After I crank it a few times, it usually will start in 30-40 mins. I've had it to the shop, but they said the truck starts fine, and it does after it's hot. They don't think it's the fuel pump. Any help please, thanks, Anthony

 

The next time it is failing like this, try the following test:

Cycle the key from "off" to "run". Wait 5 seconds, then turn the key back to "off". Do not attempt a start. You should hear the fuel pump run for two seconds, and then shut off, each time you do this. If the fuel pump does not run, track down the problem with the fuel pump power or relay. If the fuel pump does run, go to step 2.

Step 2:

Crank the engine over. Watch the tach on the dash (if you have one) during crank. Does it indicate 200 to 300 RPM, or is it stuck near zero? If it is stuck at zero, you have no spark. If you have no spark, the computer will not engage the fuel pump and you will have no fuel either.

If you have no tach, connect a timing light during crank and observe whether you have spark going to the plugs.

Step 3:

If you appear to have spark, attempt a start. Listen carefully for the whine of the fuel pump just as the starter stops turning. The fuel pump should run for about 1 second longer than than the starter. If it doesn't, you have a fuel pump control problem.

Step 4:

If you have spark, and the fuel pump seems to run, you will have to invest in a fuel pressure guage. Connect it at the Schrader valve at the rail and check for proper fuel pressure and lack of bleed down.


I had similar symptoms to yours, and practically tore my hair out trying to find the intermittant failure. It was temperature sensitive and would come and go. The problem turned out to be bad grounds at the battery and the radiator support in front of the battery. This after spending $100 on all new ignition parts. I didn't think the grounds were a problem because the engine cranked over fine with the starter and the connections looked OK on a cursory visual inspection.

 

Thanks a lot for the advice. The fuel pump never runs when it doesn't start. I replaced both relays and still ahve the problem. I will do your tests next time it doesn't start. So, maybe it's the fuel pump power? Sorry to sound ignorant, but what is that? LOL!

 

Try the following test. Hold the 6 pin self test connector in your hand. Hold it such that the two pin row is on top, and the 4 pin row is on the bottom. (So it looks like a face with two eyes and a wide "smile"). You should be looking into the sockets.

Now find a jumper that can short the rightmost pin in the top row to the rightmost pin in the bottom row. Install it into the connector. Turn the key on, but do not attempt a start.

The jumper ties FP to SIGRTN. This should ground the low side of the fuel pump relay coil, pulling the relay contacts together and forcing the fuel pump to run.

If the pump now runs, you have a wiring problem to the PCM, or a problem with the FP signal driver in the PCM. If the pump does not run, something is wrong with the fuel pump relay, the fuel pump, or the power to the fuel pump relay.

 

maybe just get a new fuel pump?