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m0sad
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Last seen: 18 hours 39 min ago
Joined: 02/14/2019 - 07:06
EPM, fuel pump prime.

hello, 

i have a 506 box, AEM pnp harness for 92-95 civic.

with Epm+k20 coils. 

(car is connected just so it can run... )

 

i have a weird problem i was hoping you can help me with, 

my epm is getting the 12v at key-on from the old dizzy 2-wire plug, coils also get the 12v from the same wire (rywire harness). 

coils getting grounded from the engine and the EPM from the battery (for now). 

when epm plug is disconnected, at key-on, i do not get fuel pump prime,

when the EPM is connected, i do not get fuel pump prime. 

when key-off, i disconnected the EPM ground, keyed-on, then when i connect the EPM ground and disconnect it, i get prime for 4 sec (long prime) - attached log - "ign on no pump, connecting ground_on for 2 seconds"

when it happens, first you will see rpm at 1, when on the second time it will be on 1000+rpm (every time i connect and disconnected the EPM ground.. 

i went to the LS0, saw that it on only when rpm is at least 0.10, changed it to -0.10. 

reconnected the EPM ground. now i get at key-on a long prime (4sec..) no matter what i do, i cannot control the prime from the LS0 setup, prime is set to 1sec, and still i get 4 sec.. 

car is starting and working. 

 

tried to look for a detailed wiring scheme for 92-95, but cant seem to find one. my concern is that i'm double grounding my fuel pump relay.. 

 

thx. 

ign on no pump, connecting grd_on for 2 seconds.itlog

ign on no pump, connecting grd_on for 2 seconds.itssn

m0sad
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Last seen: 18 hours 39 min ago
Joined: 02/14/2019 - 07:06
Another thing i noticed now,

Another thing i noticed now,
I use the 96.2 firmware b-series base map, where the fuel pump is prime at 0.10 rpm.

In the 96.3 base map, the pump is prime at 0.00 rpm,
Also in my old aem v1 it's at 0.00 rpm.

Thx.

m0sad
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Last seen: 18 hours 39 min ago
Joined: 02/14/2019 - 07:06
Anyone?

Anyone?

AEM_SB
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Last seen: 4 days 15 hours ago
Joined: 06/07/2014 - 14:29
First, let's describe how the

First, let's describe how the ECU's 'FuelPump' function works. When the ignition key turns on, the ECU will prime the fuel pump. You can configure the option Fuel Pump Prime Time [sec] in the Outputs >> Configure Outputs page of the wizard. Default value for Fuel Pump Prime Time is about 3 seconds, to build pressure before cranking the engine.  You can watch the channel FuelPump turn on and prime: add the channel FuelPump to the layout text grid then turn the key off and back on while connected to the ECU.

 

When EngineSpeed [RPM] is above zero, the fuel pump will run. After the ECU's calculated value for EngineSpeed RPM goes back to zero, the channel FuelPump will turn off.

 

In your log, it looks like the ECU calculated RPM when you unplugged or plugged in the EPM. When the ECU receives a single pulse and then nothing (like you plugging and unplugging ground), the calculated number for EngineSpeedRPM will hold the previously measured number for a short time until a new pulse arrives or it will time out and go to zero after 1-2 seconds. Since the FuelPump function uses that calculated EngineSpeedRPM value, it would run the fuel pump the entire time EngineSpeed was above zero in your log.

 

Hope that helps,

SB

m0sad
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Last seen: 18 hours 39 min ago
Joined: 02/14/2019 - 07:06
SB, thx for that detailed

SB, thx for that detailed answer, always fun to get answers from you [=

so fuelpump channel is the same as i look at LS_0, when the pump is active, it goes to 1.0 value. 

what i understood from you is that the behavior of the EMP is normal.. ?

now when the epm is connected, i do not get prime.

when it's not connected, i get prime.

what i did to get around this is simply raised the value in the zero column to 100duty in LS_0 as shown in pic1

pic1:

the only value that's active is the 1 row. that's now making the pump prime.. twice.. 

and the pin assiment is now at General purpose - pic2

pic2:

 

am i doing something wrong ? fuel pump will prime a 100times perfect without the epm connected.

thx.

m0sad
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Last seen: 18 hours 39 min ago
Joined: 02/14/2019 - 07:06
Up..

Up..

AEM_SB
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Last seen: 4 days 15 hours ago
Joined: 06/07/2014 - 14:29
I'm not sure I understand

I'm not sure I understand your last questions. 

 

Try changing the entire LS0_Duty table to zero, to double-check that nothing else besides the ECU is triggering the fuel pump. Turn the key on and off to watch if the fuel pump primes.

 

Then try changing the LS0_Duty table so it's only 100 at zero RPM (just the first column),  so it will never allow the fuel pump to run if the ECU is calculating RPM when the engine is off.  

 

Then try changing the LS0_Duty table so it's 0%  at 0 RPM but  100% any time RPM is above 1 RPM, to see the fuel pump turn on if the ECU is calculating RPM when the engine is not running.

 

If your tests suggest the ECU is calculating RPM when the engine is off, try running new wires for the EPM's 12V and ground supply. Try to avoid sharing the EPM power with ignition coils.