1g DSM AEM EMS Series 2 Acting Very Weird | AEM
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bosotnhatcher
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1g DSM AEM EMS Series 2 Acting Very Weird

I had a customer bring a car in and he said the car would cutout once he got around 15 psi. I went through the ecu channels and found the map sensor wasn't reading 0 but positive 11-14 psi or so with key on engine off. I rewired the map sensor since the wires used were speaker wire and not braided copper wire. I turned the car back on and now the tps would only go from 0-5% and the map sensor reads -11. Also the map sensor decreases to -7 when I push on the throttle. I have gone through the wiring diagrams and tested every sensor and they are good. Now the ecu reads 16 volts, tps still 0-5%, map still negative, and knock is at 89. Does this ecu need rebuilt? The car ran perfect for about a week (40 psi 660hp) around a year ago and then this cutout issue started. What's going on with this thing?

AEM_NS
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Joined: 06/06/2014 - 09:31
Sounds like you've got some

Sounds like you've got some major wiring issues - especially considering that a MAP sensor was wired in with speaker wire.  A good approach would be to unplug all sensors and then check each one individually by plugging it back in and then unplugging it after it checks good and moving onto the next one.  If Engine Load changes with throttle, it's because the MAP sensor is in error and the EMS reverts load to the TPS to Load table (see Breakpoints tab).  Check the Sensors tab to see if any are in error.  Hopefully you just have wiring/install problems that need sorting and the box hasn't actually been damaged.  

bosotnhatcher
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Ok I did unplug all the

Ok I did unplug all the sensors last night and under the "sensors" tab the TPS, MAP, and engine coolant all had 5V highlighted in red so that's good. With every sensor unplugged the throttle position was twitching super fast between 50-75%. Also the serial gauge that worked perfect shows 16 volts but the ecu shows 11.8 in aemtuner. Also the serial gauge shows 89 knock counts but the aemtuner shows 0. Not really sure what's going on there.

AEM_NS
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Let's ignore the serial gauge

Let's ignore the serial gauge for the time being and concentrate on getting the EMS to read all sensors correctly.  It sounds like you might have a TPS wiring problem.  Maybe try doing a shake test and check the pins going into the ECU connector.  Also, blipping between 50%-75% isn't as important as knowing what voltages the TPS inputs is bouncing between.  That might be a clue as to what's affecting the input.

bosotnhatcher
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It is blipping 50-75% with

It is blipping 50-75% with the 5v and ground wire disconnected at the ecu. Does that mean the tps signal wire is touching something?

AEM_NS
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Maybe.  Remove the TPS wire

Maybe.  Remove the TPS wire from the ECU connector to see if the blipping goes away.  If it goes away with it disconnected then it's something external to the EMS.  If it doesn't go away then there's something up with the TPS circuit.  

bosotnhatcher
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The tps and map are

The tps and map are completely disconnected and the tps still blips and so does the engine load. The tps input is 5.08 constant and the map is 5.09-5.10 volts.

AEM_NS
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Disconnect all sensor inputs

Disconnect all sensor inputs and check all the input voltages.  Do they all read over 5v?  If yes then the EMS is likely damaged and should be sent in for inspection. 

bosotnhatcher
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Last seen: 4 years 8 months ago
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All the sensors are

All the sensors are disconnected at the sensor and all three map and tps wires are disconnected at ecu. The map is 5.1, the tps is 5.08, the air temp is 5.08, the coolant is 5.08, the o2#1 is 2.42 volts, and the o2 #2 which the car doesn't have is .21-.22 volts.

I really prefer not to remove all the pins off the ecu pigtail in fear of damaging the plastic pin keepers

AEM_NS
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Didn't mean to disconnect all

Didn't mean to disconnect all pins from the ECU.  Disconnect all sensors at their connections in the engine bay.  Disconnecting the UEGO sensor from the gauge doesn't disconnect the gauge from the EMS so it's still outputting a voltage.  Try disconnecting the connector from the back of the gauge.  So far it sounds like the EMS is damaged.

bosotnhatcher
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Ok I disconnected the uego

Ok I disconnected the uego gauge and o2 1 volts went to .02 and o2 2 is still .21 volts

AEM_NS
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Hmm well either way having

Hmm well either way having the open circuits pulling up above 5v usually means the EMS is damaged.  You can contact tech support to setup an RMA and get pricing for having the box inspected and repaired.

bosotnhatcher
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Just for clarification I

Just for clarification I should be running the 95-99 turbo eclipse knock sensor correct?