98' Legacy Outback hot start issue

[GorgeSuby]

Hi Guys, I have searched the archives & found quite a bit of useful info but still have a few lingering doubts... my 98 Outback EJ25 is having issues with starting after driving in the heat. First off there is no indication of overheating, & the car never stumbles while driving - hwy, stoplight - all fine. But after driving hard for 20min, shutting off & re starting, it will start then die & eventually fail to start. After cooling down for an hour or so it will start & run normal.

 

I think I have isolated it to fuel pump or fuel pump relay &/or associated circuitry. So far, here is what I have done:

 

1) Listened for fuel pump on turning ignition switch. As expected the pump does not turn on when in "failure mode" but does as soon as it sits for an hour or so.

 

2) Listened/felt for fuel pump relay clicking on turning ignition switch. Relay does seem to click reliably when I turn ignition.(...& yes it is a massive PITA to get to!!!)

 

3) While the car was still warm & still failing to start, I swapped out the relay with another I found under passenger side near glove box which seemed to have the same configuration. Did not seem to make any difference...

 

4) Tested for power at fuel pump harness. Did not have voltmeter - just test light: 3 of 6 pins have current when ignition on regardless of "failure mode".

 

So, I am thinking I have narrowed it down to Fuel pump but want to make sure as I replace it about a year ago - though with a NAPA part   

 

Any ideas?

[1 Lucky Texan]

coupla things to try, when you feel it will fail, or immediately after a failure - hold the gas pedal to the floor while starting. Don't pump it or lift until after it starts.

 

that is the 'clear flood' condition for the ECU.

 

 

 

if you think it's fuel startved, try spraying some starter fluid in the intake.

 

 

 

also, some older soobs have had crank position sensors fail when hot.

[GorgeSuby]

Thanks, will try those just to narrow it down. Had that crank position sensor go out on my old Loyale...hmmm

[Fairtax4me]

Aftermarket fuel pumps are not known for reliability.

 

Check with a voltmeter to be sure you have good power getting to the pump, also make sure the ground is good by checking for voltage on the ground with the pump running.

 

Order a Denso or Bosch pump.

[GorgeSuby]

Aftermarket fuel pumps are not known for reliability.

 

Check with a voltmeter to be sure you have good power getting to the pump, also make sure the ground is good by checking for voltage on the ground with the pump running.

 

Order a Denso or Bosch pump.

Yeah, I'll have to check that when I yank it tomorrow. Curious why there are 6 pins on that harness? If it is the pump, It might be under warranty. If so, I will upgrade it.

[Fairtax4me]

Pump power and ground, Level Sender signal and ground, and fuel temp sensor signal and ground IIRC.

[GorgeSuby]

So I had a chance to try a few of the suggestions & run the OBD.

 

First I check voltage to fuel pump harness & found 11.5+/- at 1 pin & 4.7+/- at 2 other pins, the other 3 were at 0. This reading was the same whether the car was cool & starting right up or failing. First thought was this confirms bad fuel pump?

 

Next borrowed freinds generic OBD bluetooth code reader:

 

Confirmed Trouble Codes

-P0183: Fuel Temperature Sensor "A" Circuit High (Powertrain,
Generic)

-P0301: Cylinder 1 Misfire Detected (Powertrain, Generic)

-P0302: Cylinder 2 Misfire Detected (Powertrain, Generic)

-P0325: Knock/Combustion Vibration Sensor  1 Circuit Bank 1
or Single Sensor (Powertrain, Generic)

-P0335: Crankshaft Position Sensor "A" Circuit (Powertrain,
Generic)

-P0463: Fuel Level Sensor "A" Circuit High (Powertrain,
Generic)

-P0506: Idle Control System RPM - Lower Than Expected
(Powertrain, Generic)

I'm sure some of these codes are as a result of the issue rather than cause, but 2 that stood out to me are the Fuel temp & Crank position.

What do you think?

[Fairtax4me]

Was the CEL on? That many codes usually means they haven't been erased in a while. Clear them, see if any come back.

[GorgeSuby]

Was the CEL on? That many codes usually means they haven't been erased in a while. Clear them, see if any come back.

Yes it was. Cleared codes & restarted. CEL did not come back on until after it warmed up & tried a restart with typical failure. CEL is on again but have not checked codes yet... I am pretty sure now that the only relevant code is the Crank position. Otherwise, I think it is probably a bad pump...

[Mike104]

I would change the CPS first as it's much easier and cheaper than a fuel pump.  Fuel pumps usually work/not work IMO.

[GorgeSuby]

I would change the CPS first as it's much easier and cheaper than a fuel pump.  Fuel pumps usually work/not work IMO.

Probably just do both. Fuel pump is under warranty. Where is the Crank sensor on this thing?

[Mike104]

It is on the front of the engine on top of the Oil Pump (the orange thing)

 

[Mike104]

Here is another pic.  Disconnect the plug, one 10mm bolt and it should come out

 

Edited August 15, 2017 by Mike104

[GorgeSuby]

 

Awesome, way easier than my old Loyale .... Thanks!

Edited August 15, 2017 by GorgeSuby