Non starting 1999 tahoe 2 door 4wd

[Terry Deason]

Hello to all. When I parked my truck it was running fine. Got in it and started it and I had a dead miss. So I scanned the codes and got po307. Checked for spark and had it so I replaced the Dist cap and rotor. The truck runs great. Drove it a few test miles and parked it. The next day I go out and try to start the truck up and it won't start. So I sprayed with starting fluid and the truck runs for a few seconds and dies. At this point, I listen for the fuel pump and could hear it for about 2 seconds when the key is first turned on. Got a new fuel filter and while I had it off I checked to see if the pump was pumping and It did spray fuel on the ground. Put new fuel filter on and still no start.

At this point, I'm at a loss and need your help on what to do next.

 

[bigfootchiro]

What is the rest of the code? There should be two more numbers on the end. If you know you have spark, then check for fuel. Hook up a fuel pressure gauge on the rail, turn the key to the ON position and look at pressures. Turn key off and see if pressure starts dropping. You could have a bad fuel pressure regulator or spider injector unit

 

[Terry Deason]

Po307 Misfire in cylinder 7. Which replacing the distributor cap and rotor fixed that as the truck ran great during test miles and no code set. I had a fuel pressure gauge and I didn't have any fuel pressure. I'm going to revisit that. Just wondering if a fuel pump can pump gas and not be able to build pressure.

 

[bigfootchiro]

Po307 Misfire in cylinder 7. Which replacing the distributor cap and rotor fixed that as the truck ran great during test miles and no code set. I had a fuel pressure gauge and I didn't have any fuel pressure. I'm going to revisit that. Just wondering if a fuel pump can pump gas and not be able to build pressure.

It can pump gas and have no pressure, but could be very weak, could have a clog in the lines somewhere, and wouldn't last very long if that were the case. Make sure you have the fitting secured well on the fuel rail when doing the test

 

[exp500]

I recommend Ignition before fuel. Swap out coil wire or put spark tester in Dist cap terminal. If you have fuel pressure guage- should be 62-66 at the rail. Should run at 60.
What is the history? Has it been mostly sitting for 2 years since tuneup? Keep posting, If you need any diagnostic tests we will help there.

 

[exp500]

Missed the no fuel pressure post. Replace pump. Likely have a nearly full tank- Murfy's always busy.
When tank out check fuel pump wiring carefully, especially the ground wire to frame back there.

 

[Terry Deason]

Like I said it has spark. It will run with starting fluid for about 3 seconds. Trying to avoid unnecessary work due to back injury. I don't think it has fuel pressure but I'm going to test that again to be sure. When I had the fuel filter off it did pump fuel on the driveway and don't think it is a wiring problem.

 

[exp500]

Based on your tests so far, I would replace fuel pump if it were my truck. I suggested wiring check as a preventative maintenance thing while you are there. Wires sometimes get crispy/corroded back there, its old.

 

[Eman85]

Notoriously bad for fuel pumps. Try cycling the key on and off multiple times and let the fuel pump build pressure, many times they will start after doing this. It's just a hack diagnosis or sometimes will get you home. Need to check with a pressure gauge.

 

[bigfootchiro]

Like I said it has spark. It will run with starting fluid for about 3 seconds. Trying to avoid unnecessary work due to back injury. I don't think it has fuel pressure but I'm going to test that again to be sure. When I had the fuel filter off it did pump fuel on the driveway and don't think it is a wiring problem.

Always worth rechecking. I've had the gauge on dozens of times, and if not secured properly will show no or low fuel pressure, but then it's usually coming out the adapter.

You could have fuel coming out the lines at the filter, but not enough pressure to get it to the rail.

If no or low pressure (should be around 60 at the rail like @exp500 said), then replace the pump. Get an ACDelco GFV pump. It's a slight upgrade over the GFU pump. Got mine at 1A Auto for a good price, and make sure to shop around. Some places overcharge.