Rav4 fault code 78(8)

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Burt_100
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Rav4 fault code 78(8)

Post by Burt_100 » Sat Jun 15, 2019 9:58 am

I have a Rav4 showing a fault code 78(8) fuel pump malfunction (short) the scv’s had a high duty and current draw so I replaced but the code returned and now the car has sudden bursts of power when driving along but only when warm, Is there a test I could do to check fuel pressure and would it need to be done while the fault occurs or is there another way to get it to show up?

landroverman1958
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Re: Rav4 fault code 78(8)

Post by landroverman1958 » Sun Jun 16, 2019 9:43 am

Disconnect the injectors electrically,disconnect scv or imv crank over and watch the pressure rise,on graphing meter or scope should rise imediately .5 to 1 second,and go to full pressure=4.0volts or over.

Burt_100
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Re: Rav4 fault code 78(8)

Post by Burt_100 » Sun Jun 16, 2019 10:04 am

The car has got 2 scv’s should I disconnet both, does that tell me the pump and supply is ok?

KimAndersen
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Location: Denmark

Re: Rav4 fault code 78(8)

Post by KimAndersen » Sun Jun 16, 2019 2:34 pm

Hi

When you replaced the suction control valve (SCV) - did you make a "FUEL PUMP ECU RESET" of the SCV !!! - if thats not the case, then read this document. :wink:

DENSO_HP2_FUEL_PUMP_ECU_RESET.PDF
DENSO HP2 FUEL PUMP ECU RESET
(121.86 KiB) Downloaded 57 times

Regards
Kim

Burt_100
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Re: Rav4 fault code 78(8)

Post by Burt_100 » Sun Jun 16, 2019 4:01 pm

I have already done the reset, there must be something additional wrong

landroverman1958
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Re: Rav4 fault code 78(8)

Post by landroverman1958 » Mon Jun 17, 2019 6:55 pm

Good evening Burt,has the fuel rail got two electrical connectors one at each end of the high pressure rail?what model year is the Rav4?
If it has two connectors the one is the fuel rail pressure sensor,the other one the other end is the pressure control solenoid,the rail sensor measures the pressure stored in the rail,the control solenoid controls the pressure within the rail.
So as before disconnect the imv or scv(same item) disconnect the injectors electrically,the rail pressure solenoid is duty cycle controlled,if the pressure does not rise when cranked the fuel rail solenoid may be allowing the pressure to escape,check to see if its a normally open or closed solenoid.

victor2k
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Re: Rav4 fault code 78(8)

Post by victor2k » Tue Jun 18, 2019 1:36 pm

Hello,
Without some captured files :D use only the attached files.
Best regards

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