Trouble displaying correct fuel pressure in Smanager

[1158]

Last week I noticed fuel pressure in Smanager was reading lower than the gauge on the fuel rail. Yesterday I replaced the 0-100psi sensor and with an 0-150psi AEM one. After setting up the Analog 2 table correctly I keyed the ignition and checked the pressure. The pressure in Smanager was reading higher than the fuel rail gauge. For reference I took the 5v and ground signal from D20 and D22 (TPS Voltage and ground) on the ecu. Signal from the sensor goes to B6 and R2 and R3 have been removed. Smanager had been displaying what looked to be the correct, albeit noisy, fuel pressure before the sensor started acting up.

At that point I figured it must be a wiring issue so I started checking voltage with my voltmeter. I checked power/ground at the sensor (solid 5v). Then I checked the sensor output. It was 1.38v which matched the fuel rail gauge perfectly. Then I went and checked the voltage at the B6 pin also 1.38v. Finally I changed the Analog2 display in Smanager from integer to volts. Smanager was showing the Analog 2 input at 1.84v. I am trying to figure out what would cause Smanager to see voltage almost 0.5 volt higher than actual.

Anyone have any ideas?

Thanks

Not sure if it matters but this is a V1 S300 Serial number is S300-8690
I am using the May 6 2.2.7.0 version of Smanager

[Spunkster]

You may have to offset the voltages in the tables to compensate for any voltage differences you are seeing.

[1158]

That makes perfect sense. I tried looking for somewhere in Smanager before making my post but couldn't see a place to add an offset. I can search Smanager help when I get home.

Thanks again

[1158]

You may have to offset the voltages in the tables to compensate for any voltage differences you are seeing.

I'm not sure what is going on now. I was going to look at 3 different fuel pressures to see if I could come up with an average offset value.

at 37 psi, keyed but not running, I get 1.38v actual vs 1.84v in Smanager.
at 43 psi running I get 1.56v actual vs 1.40v in Smanager
at 50 psi (vac line disconnected and plugged) I get 1.77v actual vs 1.39v in Smanager.

The voltage coming out of the sensor is very close to being spot on with gauge.

The engine and transmission grounds are brand new Honda and contact surfaces are clean. I was having trouble with misfires so I replaced the distributor, ICM, coil, cap, rotor, wires and plugs. Everthing but wires & plugs are OEM Honda. The wires are standard NGK replacements and the plugs are BKR7ES-11.

[Spunkster]

Is this gauge designed to have the output from it split off and go to a separate device at the same time?

[1158]

Is this gauge designed to have the output from it split off and go to a separate device at the same time?

It is not a gauge, just the AEM 5 volt pressure sender. AEM 30-2130-150
http://www.aemelectronics.com/Images/Pr ... ensors.pdf

The gauge pressure I am referencing is from my mechanical, liquid filled gauge on the fuel rail.

[Spunkster]

where do you have this sender mounted?

[1158]

where do you have this sender mounted?

Sender is mounted in the port on the aftermarket FPR (Aeromotive mounted on firewall). The gauge is mounted on the end of the fuel rail, where the stock FPR would mount.

[Spunkster]

Have you tried using D12 for analog input 1 and see if that reads correctly?

[1158]

Have you tried using D12 for analog input 1 and see if that reads correctly?

I have not. Is the OEM capacitor on the board 0.1uF or does it need to be added. I looked and there is one on there but I cannot tell if it is correct. If it isn't the correct one and I hook it up will it cause an issue or just display the wrong voltage/pressure?

Thanks again for your help.

[1158]

After searching and seeing that it wouldn't cause a problem if the correct capacitor wasn't there I tried hooking up the 5v output to D12 and configuring Analog 1.

I had to make a slight adjustment to the voltages in the Analog 1 table but the difference I was seeing in Smanager vs the output from the sensor was always the same voltage regardless of the fuel pressure.

Does this mean that there is a problem with the Analog 2 input? I noticed Analog 2 was still showing 1.35v even though nothing is hooked up to B6.

Would this cause other issues?

[Spunkster]

Post a high resolution and in focus picture of the inside of your ECU.

[1158]

Wow, those are big lol. Sorry about that.

[1158]

Here is the full ECU shot

[Spunkster]

IT sounds like the analog input on B6 on your ECU my be damaged. At least the other input is working properly for you.