Chipped p28 - not priming fuel pump

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03-24-2005, 06:46 PM

#26

JRciv

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Re: (93turbo16)

It took me a while to pick the right replacement capacitors on digikey. For future reference, these are the part # for the 7 replacement caps needed for a P28:

P5518-ND
P5517-ND
P5552-ND
P5549-ND (x3)
493-1733-ND

You will notice that the last number differs from the others. That's because the NHG series didn't carry a 47uf 10v cap. I had to order from the PW series.

And the cap that goes out and causes the fuel pump not to prime is P5552-ND.

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09-03-2015, 04:51 AM

#27

averyvm

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Re: Chipped p28 - not priming fuel pump

bump for some really good knowledge here.

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09-03-2015, 12:44 PM

#28

hardcore97

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Re: Chipped p28 - not priming fuel pump

stop bumping 10 year olds threads

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09-04-2015, 09:23 AM

#29

averyvm

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Re: Chipped p28 - not priming fuel pump

Is there a rule against doing that?

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03-27-2017, 02:03 PM

#30

petr0lb0mb

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Re: Chipped p28 - not priming fuel pump

Agreed, this old thread is worth a bump. I just ordered the capacitors from Digikey. Cost $2.13 + shipping. Cheap insurance in my opinion.

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12adman!

10-20-2018, 02:55 PM

#31

Ptp28

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Re: (JRciv)

Quote:

Originally Posted by This One

Ive had a few ECU'S with bad fuel pump output or something.
On those we just took the Fuel pump output whichever pin it is, and ground it on the harness side.
the fuel pump should come on with ever you turn the Ignition on now.

i can you make a little scheme to do this jumping to a p28 who have a delay prime pump? Thank you

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05-31-2019, 10:18 AM

#32

TcCali 559

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Re: (JRciv)

Quote:

Originally Posted by hybridb18

where is this capacitor at???? where in the ecu?? What number on the board?? i have the exact same problem with my ecu

I believe this capacitor is “c14” on the ecu, mine fried and now it doesn’t prime/run my fuel pump. Its on the far right side of the circuit.

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06-30-2021, 03:34 PM

#33

wasiba100

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Re: Chipped p28 - not priming fuel pump

hello.

I have a problem. I already replaced all the capacitors (c14, c19, c18, c24, c21, c15, c40) in my ecu p28 but it didn't prime the fuel pump. also check the entire circuit is ok. What else can I do?

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07-01-2021, 05:42 AM

#34

DaX

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by wasiba100

Other components may be damaged. Try another ECU.

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07-01-2021, 06:05 AM

#35

Full_Tilt

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by wasiba100

Probably QM3
IIRC that is the transistor array that controls the main relay

also, double check the main relay. lol

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07-01-2021, 06:05 AM

#36

wasiba100

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by DaX

Other components may be damaged. Try another ECU.

Hi, I have already tried with another ECU and I not have problems in my car, but with my ECU I have problems it does not turn on the fuel pump

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07-01-2021, 06:11 AM

#37

wasiba100

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by Full_Tilt

Probably QM3
IIRC that is the transistor array that controls the main relay

also, double check the main relay. lol

QM3 or DM3?

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07-01-2021, 10:58 AM

#38

Full_Tilt

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by wasiba100

QM3 or DM3?

QM3
Its one of the 3 transistor arrays used for the high current outputs (injectors, IACV, relays, etc.)

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07-01-2021, 11:18 AM

#39

Txdragon

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Re: Chipped p28 - not priming fuel pump

IC17

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07-07-2021, 07:49 AM

#40

wasiba100

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by Full_Tilt

QM3
Its one of the 3 transistor arrays used for the high current outputs (injectors, IACV, relays, etc.)

Very good answer, it is correct, the QM3 chip was a problem, I replace this chip and the fuel pump works correctly.
thx...!!

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07-08-2021, 06:42 AM

#41

Full_Tilt

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Re: Chipped p28 - not priming fuel pump

Glad to hear that worked. Ive tried a few times and it doesnt always work. I think sometimes its the microcontroller that has failed.

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wasiba100

07-11-2021, 09:25 AM

#42

B and B

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Re: Chipped p28 - not priming fuel pump

Damn, awesome!
Did not know this.
🗻

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07-11-2021, 09:39 AM

#43

B and B

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Re: Chipped p28 - not priming fuel pump

Why is there no C201 in that ECU? All mine have it by C14.

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08-08-2021, 05:21 AM

#44

wasiba100

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by B and B

Why is there no C201 in that ECU? All mine have it by C14.

Because it's P28? i see p29 has a c201

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08-08-2021, 05:25 AM

#45

wasiba100

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by Full_Tilt

Glad to hear that worked. Ive tried a few times and it doesnt always work. I think sometimes its the microcontroller that has failed.

umm I have a p29 but this ECU when I open the ignition, the fuel pump takes a while to turn on, I have changed all the capacitors but it remains the same, does anyone know what the problem is?

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02-16-2023, 01:27 PM

#46

hitvtecgetloud09

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Re: Chipped p28 - not priming fuel pump

Quote:

Originally Posted by B and B

Why is there no C201 in that ECU? All mine have it by C14.

Bringing this thread back from semi dead...

does anyone know why the ps28 doesnt have the C201...ive searched google but cant find any answers.

TIA.