AEM Fueling Issue
09-23-2018, 04:59 AM
#1
AEM Fueling Issue
Afternoon everyone,
Its been a while since I've last posted on here; much less driven the S. The S was supercharged in the beginning of last year, and it then developed a weird issue where the fuel pump would not prime after the vehicle is powered off. Only by resetting the battery (remove the power) will it then prime. I remember speaking to AEM about this; to quote:
Which sensor is he referring to? Are we talking about the sensors in the engine bay, so things like the MAP, TPS etc?
Its been a while since I've last posted on here; much less driven the S. The S was supercharged in the beginning of last year, and it then developed a weird issue where the fuel pump would not prime after the vehicle is powered off. Only by resetting the battery (remove the power) will it then prime. I remember speaking to AEM about this; to quote:
Well if you are fully up to date, the description of your issue is still indicative of some type of feedback issue that is keeping your unit connected when you power down.
Seeing as that you do not have any upgrades that required wiring aside from the wideband gauge which has been isolated, the only other way to troubleshoot this would be to start unplugging sensors one at a time when you are unable to get the fuel pump to prime. You want to do this in sequence.
When you key off and key back on where the fuel pump does not prime, Unplug a sensor and cycle the ignition again. Repeat this until the fuel pump primes. Once it does, you will know that it was likely linked to the last sensor that was unplugged. Plug it back in to recreate the issue and we can go from there.
Seeing as that you do not have any upgrades that required wiring aside from the wideband gauge which has been isolated, the only other way to troubleshoot this would be to start unplugging sensors one at a time when you are unable to get the fuel pump to prime. You want to do this in sequence.
When you key off and key back on where the fuel pump does not prime, Unplug a sensor and cycle the ignition again. Repeat this until the fuel pump primes. Once it does, you will know that it was likely linked to the last sensor that was unplugged. Plug it back in to recreate the issue and we can go from there.
09-23-2018, 10:26 AM
#2
sounds like it, the stuff which feeds the AEM, you can see the wiring diagram in the service manual to see what is wired there, it would be things like TPS, MAP, coolant temp etc i guess
09-24-2018, 02:52 AM
#3
I've got the wiring diagram from the service manual; it lists the various sensors. The knock sensors on the back of the box aint it - that's gonna be a ball ache to get to if its that.
09-27-2018, 03:47 AM
#4
Mine had this issue but normally if i crank it then off and on again it would prime and would normally only do this when warm. I have to admit I cannot remember how i fixed it.
It hasn't done it since my second visit to EFI so maybe Chris fixed it.
It hasn't done it since my second visit to EFI so maybe Chris fixed it.
09-28-2018, 01:22 AM
#5
Well Chris was the one who initially mapped my supercharged S 
The S has been sitting for over a year; so its overdue on a number of things. Once I fix this issue, I can get started on changing four tyres (these should be changed as its literally sat on the drive) discs and pads and fluids before.. geo bolts.
The S has been sitting for over a year; so its overdue on a number of things. Once I fix this issue, I can get started on changing four tyres (these should be changed as its literally sat on the drive) discs and pads and fluids before.. geo bolts.
10-01-2018, 01:20 AM
#7
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04-18-2020, 12:46 PM
#9
Mine occasionally used to do this on the AEM. During some datalog pulls at night i pulled into a lay by and i could not for the life of me get the car to restart. I switched the headlights off, pulled the key out all the way and then when i put the key back in and turned it the pump instantly primed.
It seems to happen where there is some electrical load on the battery. The key for me was to make sure i fully removed the key and then reinserted it. That seemed to cure the issue. When i swapped to another ecu(ecumasters) last year the issue went away.
It seems to happen where there is some electrical load on the battery. The key for me was to make sure i fully removed the key and then reinserted it. That seemed to cure the issue. When i swapped to another ecu(ecumasters) last year the issue went away.
04-19-2020, 02:48 AM
#10
Mine occasionally used to do this on the AEM. During some datalog pulls at night i pulled into a lay by and i could not for the life of me get the car to restart. I switched the headlights off, pulled the key out all the way and then when i put the key back in and turned it the pump instantly primed.
It seems to happen where there is some electrical load on the battery. The key for me was to make sure i fully removed the key and then reinserted it. That seemed to cure the issue. When i swapped to another ecu(ecumasters) last year the issue went away.
It seems to happen where there is some electrical load on the battery. The key for me was to make sure i fully removed the key and then reinserted it. That seemed to cure the issue. When i swapped to another ecu(ecumasters) last year the issue went away.