ajazyasin Posted February 7, 2008 Share Posted February 7, 2008 Im having real problems wiring a new harness for the twin pump setup ive got. Im using a relay triggered by original feed to oe pump from fuelpump ecu. Heres a diagram of the relay using: Ive been advised that the bottom 2 are 12volt and top left is to ecu feed and top right to the new pumps. Does that sound about right? Also, there are 2 from the ecu to oe pump. One blue/black and one white/black. which one is it? if it helps, when wired as above, i get the pumps coming on as soon as i connect the battery even when key is not in ignition. thanks in advance Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 7, 2008 Share Posted February 7, 2008 I'm not 100% sure on this, and I would double check and triple check, but the fuel pumps MAY be negative switched rather than positive. I will have a look at a wiring diagram. EDIT: Nope, they are positive switched... Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 7, 2008 Share Posted February 7, 2008 Which one are you connecting the relay to on the ECU side? Out of interest, how do most people do this mod? Do they put the relay on before the ecu or what? Personally, looking at the diagram, I would put a relay on the fuel pump power (L-R) from the FP ECU, get a 5v relay and use a 5v voltage regulator. That way the stock FP ECU can be used and would provide its usual 9v/12v to the 5v reg which in turn would then throw the relay. This way you would still maintain all the stock safety bits. Okay, been doing a bit more research. http://www.slipstreem.net/mkivsupra/images/fuel.jpg The five pins on the FP ECU are (in reference to the FP ECU) B+ 12v -> This is switched as soon as the ECU is powered up http://www.slipstreem.net/mkivsupra/images/fuel4.jpg http://www.slipstreem.net/mkivsupra/images/fuel5.jpg This is connected to EFI relay 2, which is controlled by ECU pin 31 (E10) DI Input http://www.slipstreem.net/mkivsupra/images/fuel2.jpg This connects to ECU pin 21 (E10), It also provides the FP ECU with a signal to indicate that the engine is running. http://www.slipstreem.net/mkivsupra/images/fuel7.jpg E - Negative connection FP Output Connects to Fuel Pump and the FP port in the engine bay http://www.slipstreem.net/mkivsupra/images/fuel.jpg http://www.slipstreem.net/mkivsupra/images/fuel8.jpg FPC Input Connects to ECU pin 22 (E10). This is the pin that activates 9v/12v mode. This also controls the fuel pumps from activating when you initial turn from off to start (before you click over to ignition) http://www.slipstreem.net/mkivsupra/images/fuel6.jpg http://www.slipstreem.net/mkivsupra/images/fuel2.jpg http://www.slipstreem.net/mkivsupra/images/fuel7.jpg On reflection with this, I would definitely use some sort of circuit that use the actual pump line (FP) to activate the new relays with the addition of a voltage reduction circuit be it a zener diode or a voltage regulator. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.