Bare with me this will be winded. A couple months back I had an intermittent problem where the car (2007 ls 3.5) would stutter while cruising and then it would die when coming to a stop. It eventually died and wouldn’t start again I got it running again with a new fuel pump and it started again after a couple weeks. Then I found ground on battery loose and fixed it worked another couple weeks then it started to have a stutter while driving again I fixed it this time by thoroughly cleaning the throttle body. I drove it yesterday just fine and today I replaced the spark plug wires and started it and it ran fine for a few seconds then died the kicker is the fuel pump isn’t priming when I turn the key. I have been working on replacing everything in the car that needs it or I atleast consider preventative maintenance. As far as new parts that are related it has fuel pump, fuel pump relay, spark plugs and wires, ignition coil, cam position sensor, MAF sensor, etc. I have been fighting this awhile and hope someone else has experience with this issue thanks in advance.

 

Do you have access to a mechanical fuel pressure gauge and a OBD scan tool that can read live sensor data?

It sounds like this is fueling related, but having the actual fuel pressure readings to compare to spec (plus seeing what the gauge does during prime / crank / run) and the sensor data would help point you in the right direction of where to go next. Of most value would be the reading of key sensors when it stumbles and when it dies (ie does the MAF go nuts just before, do the fuel trims peg because its losing pressure, etc).

 

I don’t have a fuel pressure gauge but I do have an OBD tool on my phone that uses a bluetooth port that hooks to the car I have tried looking at it before while running and driving and noticed nothing out of the ordinary. I wasn’t using it when it happened though and now I can’t use it cause the car has to be running.

 

So now the car won't start at all? And the pump isn't priming?

Do you have any security lights on? If not and the pump isn't turning on at all, its time to break out the multimeter and figure out where in the circuit its not getting voltage / ground continuity.

 

I do have a multimeter where does the wiring run to from the fuel pump? Or more specifically where does it ground to?

 

I'm not sure on that gen ground location as I've got a 5th gen.

If the harness plug for the pump is accessible, I'd unplug it and check the feed side for power and ground. If you're missing either, then you can go further upstream to figure out where its gone wrong.

If it has both, you could also jumper a known good power and ground to the pump side of the harness (with the plug still disconnected so it doesn't back feed the circuit). If the pump doesn't come on - then you've isolated the issue to a very small section of wire / the pump itself.

 

After checking power to relay and finding it good I decided chase wiring and found where the pump grounds to I also looked online to confirm that it was the correct ground. I seen it was on top a thick coat of paint so I scratched it off and bolted it back turned the key the pump kicked in nice and strong and the car started without hesitation. The location of the ground is underneath the plastic trim beside the front of the passenger seat in case anyone else has this issue.

 

And thanks for the help I appreciate it! 😁

 

Well. I celebrated too soon I drove it to work and it died on me and won’t start seems like the same problem I’m mot sure what to do at this point

 

Check the ground from battery to frame. Sounds like a loose connection somewhere that happens with movement or vibration. Just a guess.