absz Posted April 30, 2009 Share Posted April 30, 2009 does anyone know what the signal voltage should be from the main ecu to the fuel pump ecu? since i have fitted the AEM ecu i have been having problems with the fuel pump feed,switch ignition on and the fuelpump primes for approx 5secs. crank engine over and the engine starts but the signal to the pump is then lost and the engine cuts out. i have to keep locking/unlocking the car and it then fires into life again and will run fine until the next time. have checked the voltage from the AEM ECU and its a 5VOLT output, would like to confirm if this is right before going further. Quote Link to comment Share on other sites More sharing options...
supra matt Posted April 30, 2009 Share Posted April 30, 2009 its a dual volt euc i belive 9 volt idle and curise and then sw to 12 volt on boost or higher revs . Quote Link to comment Share on other sites More sharing options...
JustGav Posted April 30, 2009 Share Posted April 30, 2009 its a dual volt euc i belive 9 volt idle and curise and then sw to 12 volt on boost or higher revs . That is the output from the fuel ECU... I'll have a shifty through the diagrams and docs I have to find out what the input is... Quote Link to comment Share on other sites More sharing options...
supra matt Posted April 30, 2009 Share Posted April 30, 2009 That is the output from the fuel ECU... I'll have a shifty through the diagrams and docs I have to find out what the input is... O ya right sorry not read it properly ! Quote Link to comment Share on other sites More sharing options...
absz Posted April 30, 2009 Author Share Posted April 30, 2009 I thought the FUEL pump ecu controls the different voltage output, and the voltage from the MAIN ecu should remain constant ? Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted April 30, 2009 Share Posted April 30, 2009 Aem sends a constant 5v Quote Link to comment Share on other sites More sharing options...
supra matt Posted April 30, 2009 Share Posted April 30, 2009 I thought the FUEL pump ecu controls the different voltage output, and the voltage from the MAIN ecu should remain constant ? would it not just be 12 volts then? Quote Link to comment Share on other sites More sharing options...
JustGav Posted April 30, 2009 Share Posted April 30, 2009 I thought the FUEL pump ecu controls the different voltage output, and the voltage from the MAIN ecu should remain constant ? Any particular reason you are still using the FP-ECU if you have a standalone, surely it would make more sense to put a 5v relay circuit in to control the fuelpump? Quote Link to comment Share on other sites More sharing options...
absz Posted April 30, 2009 Author Share Posted April 30, 2009 i do a separate relay and fuse wired in was using the orignal fuel pump feed as a trigger for the new relays, which i will be removing.just trying find the reason my loss of signal. PS will a 5volt output be enough to power a 12v relay ? Quote Link to comment Share on other sites More sharing options...
JustGav Posted April 30, 2009 Share Posted April 30, 2009 will a 5volt output be enough to power a 12v relay ? Normally no...You are better off getting a proper 5v relay, so it latches properly. Quote Link to comment Share on other sites More sharing options...
absz Posted April 30, 2009 Author Share Posted April 30, 2009 Normally no...You are better off getting a proper 5v relay, so it latches properly. thanks job for tommorow:) Quote Link to comment Share on other sites More sharing options...
JustGav Posted April 30, 2009 Share Posted April 30, 2009 thanks job for tommorow:) Just had a quick look on Maplin's website, and there aren't any decent 5v relays current wise (certainly nothing capable of running a fuel pump), so for a quick fix you may want to consider having a small 5v relay off the AEM output, which then simply gives you a 12v feed to the exisiting setup. http://www.maplin.co.uk/Module.aspx?ModuleNo=2512 Quote Link to comment Share on other sites More sharing options...
absz Posted April 30, 2009 Author Share Posted April 30, 2009 i guess i can still use my fuel pump ecu for the trigger voltage to the new relay (which is the way its wired in at the moment) until i can find a 5 volt relay which can handle the current flow. Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted May 1, 2009 Share Posted May 1, 2009 Is your alarm linked to the B+ system at all or does it cut into the FPC wire? Quote Link to comment Share on other sites More sharing options...
TLicense Posted May 1, 2009 Share Posted May 1, 2009 This is what I did with mine:- http://www.mkivsupra.net/vbb/showpost.php?p=1097152&postcount=120 I ran a lead from the battery feed in the fuse box, through a couple of new fuses I put in there and then ran the lead through the relay to the pump. I then ran a lead from the 5 volt output on the AEM to the control side of the relay to turn them on / off. Worked a treat! Quote Link to comment Share on other sites More sharing options...
absz Posted May 1, 2009 Author Share Posted May 1, 2009 Is your alarm linked to the B+ system at all or does it cut into the FPC wire? it seems that the alarm might be linked to the b+ as there is no cuts or spliced wires along the fpc wire. Quote Link to comment Share on other sites More sharing options...
absz Posted May 1, 2009 Author Share Posted May 1, 2009 This is what I did with mine:- http://www.mkivsupra.net/vbb/showpost.php?p=1097152&postcount=120 I ran a lead from the battery feed in the fuse box, through a couple of new fuses I put in there and then ran the lead through the relay to the pump. I then ran a lead from the 5 volt output on the AEM to the control side of the relay to turn them on / off. Worked a treat! Thanks for the info will look into this, cannot see the picture at the mo as my work pc has a firewall preventing it. Quote Link to comment Share on other sites More sharing options...
absz Posted May 2, 2009 Author Share Posted May 2, 2009 UPDATE ripped all the inner panels off the car to trace the fuel signal wire right back, its seems i have a wireless fuelguard module fitted and kept losing the signal even when the engine was running i was having a voltage drop. could be the reason for my fuelling issues over the years. Quote Link to comment Share on other sites More sharing options...
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