Still code 95... Keeps Failing: 2nd Walbro pump and sending unit

[ShoMe1More]

SHO just doesn't want to stay on the road!

I had a no start situation in 2012 and pulled code 95 with the KOEO test.

I replaced the fuel pump and sending assembly at that time with a Walbro 155 lph and aftermarket sending unit. The shop that did the work showed me the wiring harness that connects into the sending unit. The plastic harness was melted and they determined that caused the failure.

Fast forward to 2014, I started getting fuel gauge issues and a couple no starts. Then it just wouldn't turn over. Took it to a local shop and they determined the fuel pump yet again.

I had it replaced with another sending unit and pump. I just started driving the car after it sat this winter, and it is shutting off during driving and no start. I pulled the KOEO codes and got 95 again!

I took a close look at the old sending assembly the recent shop pulled and the ground wire coming from the top of the assembly to the pump was loose. The seat on top where the plastic harness clips to the sending unit had black burnt char on the ground pin.

I also noticed that the sending unit I provided the shop was a NOS with the fuel pump built in. And they did not install the Walbro that I provided them.

I am thinking the fuel pump in that sending assembly is for the SLO and they never thought twice about swapping the walbro out, thinking the NOS would be better. Could the low LPH of the SLO fuel pump be causing the issue this time?

 

[rubydist]

a bad fuel pump does not cause a no-crank situation, so you have more going on than just a fuel pump issue.

 

[ShoMe1More]

The only code I pulled was 95 for fuel pump. Could it not be the low output of the SLO fuel pump they installed causing the problem to be intermittent?

Here is the part number for the NOS sending unit that I provided them: F3OY-9H307-A

I believe the sable and taurus non digital dash 18 gal sending units are the same but the lph of the pump would be different

 

[luigisho]

You may have more than one problem. No crank is the starter not engaging to turn the flywheel due to many factors but fuel is not one of them. No start is different as the starter turns but the engine does not fire. That can be many other factors. So does the starter turn the flywheel or is it not turning at all when you turn the key?

Do you hear the fuel pump prime when you turn the key? What's the flow rate on the pump that's in there?

 

[ShoMe1More]

i was able to start it after 15 minutes. then it shut off again a few miles later. i hear the starter. i hear the fly wheel spin down after i let off the ignition. and i hear the fuel pump prime. i don't know the lph of that nos unit because i never intended on the shop installing it without the walbro i provided them.

 

[luigisho]

Ok. So it cranks but doesn't start or shuts down. Normally it sounds like a faulty sensor, which it may be, but the melted wiring makes me wonder. When was the last time you pulled the engine codes? If it's not the crank sensor I think I would look at the fuel pump and the wiring. If there are any recent engine codes that would really help

 

[ShoMe1More]

i just pulled the codes last night. the stored code was 95, related to the fuel pump.

 

[luigisho]

Looks like you have to check the pump and the wiring. You can always tray and swap in the other pump and see what happens. Circuit faults can happen anywhere from the pcm to the relay to the sending unit to the pump itself and any damage to wiring along the path. Might want a good electrical person to dig into this if you think that's the issue.

 

[rubydist]

well, the other thing you need to be aware of is that the code 95 for secondary circuit failure is also set whenever the engine stalls, so your real problem may have nothing to do with the fuel pump.

the engine stalling after it gets warm and then starting again after it cools off is a typical symptom of a bad crank sensor. while a bad crank sensor will often set a code, I have seen times where it did not, so that is suspect as well. I have also seen bad coils and bad dis not set codes, so you have several other possibilities to consider.

 

[ShoMe1More]

ok, i did have a 60k and 120k done with the cps and water pump included about 16k miles ago. what is the easiest way to rule out the DIS?

 

[rubydist]

the typical solution is to replace the dis with a known good part and see if that changes anything.

just because the crank sensor is newer does not mean it is good - I have seen infant failures in any electronics.