Pred Posted May 8, 2011 Share Posted May 8, 2011 Hi, i have a crazy fuel pump ecu problem. if i turn the ignition on, the fpecu gets no signal from the ecu. if i start the car it runs 2 seconds and then it comes off. with 12v fuel pump mod, the engine runs. i checked all relays, all fuses - all fine. tested a other fpecu - same problem. tested a other mainecu - same problem. rewired the fpc and di wires directly from the mainecu to fpecu - same problem. errorcodes ? - nothing. i cant find the problem. have anybody a idea? my last option is the 12v mod but i want to find this failure :/ regards from germany andi Quote Link to comment Share on other sites More sharing options...
RobUK Posted May 8, 2011 Share Posted May 8, 2011 Check the grey connector in the passenger foot well.... It might have come loose Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 8, 2011 Share Posted May 8, 2011 (edited) Was the other fuel pump ECU a known good one? Edited May 8, 2011 by Swampy442 (see edit history) Quote Link to comment Share on other sites More sharing options...
Pred Posted May 8, 2011 Author Share Posted May 8, 2011 Check the grey connector in the passenger foot well.... It might have come loose i connected the wires directyl from the mainecu to the fpecu - same problem Quote Link to comment Share on other sites More sharing options...
Pred Posted May 8, 2011 Author Share Posted May 8, 2011 Was the other fuel pump ECU a known good one? tested a other fpecu - some problem :/ Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 8, 2011 Share Posted May 8, 2011 Yeah but did the ecu come from a running car? Quote Link to comment Share on other sites More sharing options...
Pred Posted May 9, 2011 Author Share Posted May 9, 2011 yes, both ecus running fine in a other car Quote Link to comment Share on other sites More sharing options...
CanisLupus Posted May 9, 2011 Share Posted May 9, 2011 If both FP ECUs Fail in your car but work in another i would suppose it's either a signal wire gone wrong to the FP ECU or something with the main ECU. EDIT: Just seen you've rewired it. Try to rewire the whole FP ECU not just the two wires. Maybe it's one of the others not working. Quote Link to comment Share on other sites More sharing options...
Pred Posted May 9, 2011 Author Share Posted May 9, 2011 EDIT: Just seen you've rewired it. Try to rewire the whole FP ECU not just the two wires. Maybe it's one of the others not working. The fpecu have 5 wires: fpc = signal from ecu di = diagnostic +b = 12V fp = fuel pump E = earth all wires are ok, but the mainecu sends no signal to the fpecu Quote Link to comment Share on other sites More sharing options...
CanisLupus Posted May 9, 2011 Share Posted May 9, 2011 Might be your ECU is +*#! then I've looked at the plan. Have you checked the Relais(EFI No. 2 Relais) for Battery + to the ECU? Maybe it's the cause. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 9, 2011 Share Posted May 9, 2011 Is it a standard standard ECU? Quote Link to comment Share on other sites More sharing options...
Pred Posted May 9, 2011 Author Share Posted May 9, 2011 All relays and fuses are fine, checked a other mainecu - some problem. i use the standard 6spd ecu Quote Link to comment Share on other sites More sharing options...
CanisLupus Posted May 9, 2011 Share Posted May 9, 2011 I would check all pins and signals going to your Main ECU maybe it doesn't get another feed or signal it needs to run the Pump the right way. There are pictures with the pin outs of the ECU and a guide what pin should read with ignition on/off/idle Could be a ground or positive fault somewhere. Quote Link to comment Share on other sites More sharing options...
Pred Posted May 13, 2011 Author Share Posted May 13, 2011 Checked all, plugs, ecus etc. I cant found the failure. No error codes... I do now the 12V Mod with a relay. Have anyone a idea which wire from the ecu i can use to "start" the relay? I cant use the wires from the fuel pump ecu, the dont have any signal... Quote Link to comment Share on other sites More sharing options...
Steve Posted May 13, 2011 Share Posted May 13, 2011 Have you actually checked the signal that is sent from the ECU using a multimeter? If you aren't getting anything from there try refurbing the pins to ensure you are getting a good connection - http://www.mkivsupra.net/vbb/showthread.php?35917-How-To-Refurbish-electrical-connectors Quote Link to comment Share on other sites More sharing options...
antno Posted September 25, 2022 Share Posted September 25, 2022 On 5/13/2011 at 8:47 AM, Pred said: Checked all, plugs, ecus etc. I cant found the failure. No error codes... I do now the 12V Mod with a relay. Have anyone a idea which wire from the ecu i can use to "start" the relay? I cant use the wires from the fuel pump ecu, the dont have any signal... Hello. I have this same issue did you get to the bottom of it? cheers Anthony Quote Link to comment Share on other sites More sharing options...
Homer Posted September 25, 2022 Share Posted September 25, 2022 Im fairly certain it works like this: The FPC wire (pin 22, block e10 on the Ecu) sends the ‘on’ signal to the FP Ecu. The engine Ecu also needs a signal back from the relay (DI, pin 21, block e10 on the Ecu) otherwise it will stop sending the on signal. DI is basically reporting the FP ECU is working. 1 Quote Link to comment Share on other sites More sharing options...
antno Posted September 28, 2022 Share Posted September 28, 2022 On 9/25/2022 at 9:07 PM, Homer said: Im fairly certain it works like this: The FPC wire (pin 22, block e10 on the Ecu) sends the ‘on’ signal to the FP Ecu. The engine Ecu also needs a signal back from the relay (DI, pin 21, block e10 on the Ecu) otherwise it will stop sending the on signal. DI is basically reporting the FP ECU is working. Thanks for that pal. Can you shed any light on this? when starting from cold with no residual fuel pressure am I right in thinking that you turn the ignition on the fuel pump should prime the system then turn off again? my problem is there is no fuel pressure on ignition so she coughs and sputters then stalls on that first start up. while this happens it does generate a bit of fuel pressure which is kept in the lines. second fire up it has enough to get running then it works perfectly. Stop and start it as many times as you want as long as you don’t leave it long enough to loose all the residual fuel pressure. any ideas of what signals I should be getting on key (ignition on)? its just odd it seems to work fine once the engine is rotating over a given rpm I’ve got an oscilloscope to check the pins cheers Antno Quote Link to comment Share on other sites More sharing options...
Homer Posted September 28, 2022 Share Posted September 28, 2022 No, it does not prime the system when the ignition is turned on. It runs crank enrichment when you first turn the car over which dumps extra fuel to get the engine started. You won't get any signal with just the key on because the ECU won't send the 'on' signal to the pump until it is cranking. Great that you have an oscilloscope, the FPC wire should be sending a modulated 0v-5v signal to the FP ecu while it's cranking and running. However, I'd first check the pump operation is good. Bridge B+ and FP n the diagnostic port and make sure your pump is running consistently. This will also confirm that the EFI relay is sending a signal to the pump ecu. Quote Link to comment Share on other sites More sharing options...
antno Posted September 28, 2022 Share Posted September 28, 2022 7 hours ago, Homer said: No, it does not prime the system when the ignition is turned on. It runs crank enrichment when you first turn the car over which dumps extra fuel to get the engine started. You won't get any signal with just the key on because the ECU won't send the 'on' signal to the pump until it is cranking. Great that you have an oscilloscope, the FPC wire should be sending a modulated 0v-5v signal to the FP ecu while it's cranking and running. However, I'd first check the pump operation is good. Bridge B+ and FP n the diagnostic port and make sure your pump is running consistently. This will also confirm that the EFI relay is sending a signal to the pump ecu. Ah cheers Homer this helps a lot. I will check the pump again 1 Quote Link to comment Share on other sites More sharing options...
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