Fuel pump?

AboveAverageJoe.

AboveAverageJoe.

Greenie N00B Member
So I finally get to spend some time with the CX-7. I start it up. It idles and runs fine for two maybe three minutes and then it the engine cuts off. Just like turning the key to off. It cranks and cranks but will not start. I let the car sit for an hour or two. My BIL and I go back out the cars starts right up and idles fine and then it shuts off again, same thing. I'm leaning to the fuel pump but I'm a caveman when it comes to this electronic stuff. I laid under the car and I can hear the tank pump run for two seconds when the key is turned and then it I can't hear it run anymore. Other than testing the pump relay, which I will do tomorrow, what's next?
The fuel tank is 1/4 full and the gauge is accurate.
Thanks,

Joe
 
Needs logs and codes read. If the in tank pump is humming, it's sending fuel, or trying to.
The car will idle even if the HPFP shits the bed, so you really need some kind of logs to know what's going on, unless you want to just pull the ITFP basket and give it a look.
 
Intank Fuel pump will prime for 2 seconds whenever turning the key to ON position so thats normal.
by any chance any code? you can scan with versa and check the fuel press, forgot the KOEO??? procedure for the fuel pump. but does it shut off still even pressing the gas if you ever got the engine running?
 
Eroler1 said:
Intank Fuel pump will prime for 2 seconds whenever turning the key to ON position so thats normal.
by any chance any code? you can scan with versa and check the fuel press, forgot the KOEO??? procedure for the fuel pump. but does it shut off still even pressing the gas if you ever got the engine running?
Click to expand...
No codes, car runs great and after two minutes it shuts off. I have no idea what KOEO means. Sorry guys, I'm a geezer back from the days of adjusting points and vacuum advance on a distributor. When it runs, I can rev it up but it will still shut down. I will try to video the whole thing when I hook up the laptop.
 
Key On Engine Off. Before a cold start, the fuel rail pressure should be 40-60. After a hot shutdown, it should be over 400 and slowly climbing.
 
just my opinion. is your hpfp spill valve connector plugged in properly? or the rail pressure sensor? i know it will throw a code but sometimes in weird cases (especially on my cars) wont throw a code till you actually get the engine running more than 10 sec.

i know i experience your symptoms before, with no code and it was the rail pressure sensor. whenever you start it, would start fine then dies and then if you start it again you can rev it but dies after 3 seconds or when above 2k

not sure if the cx7 have the test terminal for in tank fuel pump.

free versatune cant monitor fuel pressure? your fuel press on key at on position while engine off should be around 65-75 psi
then when running should be above 1k since cold start.
 
Started the car, the engine was missing very badly. It threw a P0304 code and would barely rev up and then it died. It wouldn't restart but I think VersaTuner logged the whole event. Should I post the log in the excel format? Thanks Joe.
 
Looks like it's leaning out terribly, but fuel pressure looks good. Either you've got an injector not firing or your O2 sensors are shitting the bed.
You could try unplugging both O2 sensors and see if it stays idling then (don't drive it though, not a great idea).


For future logging:

Get rid of these:
Relative throttle position (%)
Mass airflow (lb/min)
Actual equivalence/air to fuel ratio (?)
Desired equivalence/air to fuel ratio (?)
Fuel injection amount (mg/cyl)
Fuel injection pulse width (ms)

Add these:
Actual equivalence/air to fuel ratio
Boost Pressure
Boost air temperature
Long term fuel trim
Mass airflow sensor voltage
Injector duty cycle
 
Enki said:
Looks like it's leaning out terribly, but fuel pressure looks good. Either you've got an injector not firing or your O2 sensors are shitting the bed.
You could try unplugging both O2 sensors and see if it stays idling then (don't drive it though, not a great idea).


For future logging:

Get rid of these:
Relative throttle position (%)
Mass airflow (lb/min)
Actual equivalence/air to fuel ratio (?)
Desired equivalence/air to fuel ratio (?)
Fuel injection amount (mg/cyl)
Fuel injection pulse width (ms)

Add these:
Actual equivalence/air to fuel ratio
Boost Pressure
Boost air temperature
Long term fuel trim
Mass airflow sensor voltage
Injector duty cycle
Click to expand...

Enki, should I disconnect the O2 sensors when I'm logging data or before I start logging?

I will add/eliminate the items you posted.

Thank you.
 
Last edited:
Unhooked the O2's and the car ran alot longer. I cleared the P0304 code before I started but it did throw a P0300 and a U2064 code while I was logging. I videoed the whole thing and I am uploading it. I'll post the link when I'm done.
 

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