desert_starion Posted August 7, 2008 Report Share Posted August 7, 2008 I will try to make this as short as I can. I can not start my car. I have the FIP fuel and ignition computers in my car and when I put the key in and start cranking, the fuel pump does not prime, the ignition computer blinks, the fuel computer does not (both connected to the same power source) But once I start cranking, the fuel pump keeps running (with the key in the on position and once i turn the key to the off pos. it stops obviously.... I thought that may be due to a bad fuel pump realy, so I got a used relay off a running car, still have the same issue except when I stop cranking, the fuel pump also stops (key at the on pos). What I tried to do then was to shoot some starting fluid in the manifold. Upon cranking the engine rumbles to a start and it is then that the fuel computer and the fuel pump start pumping (40psi on the regulator guage) and car idles normally and its all good. What is really bugging me is why are the fuel ecu and fuel pump unavailable until the engine is started via some starting fluid? Why dont they just come on during cranking? Link to comment Share on other sites More sharing options...
scott87star Posted August 7, 2008 Report Share Posted August 7, 2008 Lack of electrical power until the alternator kicks in. Can you check battery voltage during cranking? Scott Link to comment Share on other sites More sharing options...
desert_starion Posted August 7, 2008 Author Report Share Posted August 7, 2008 Lack of electrical power until the alternator kicks in. Can you check battery voltage during cranking? Scott It reads 11.8 during cranking. I started checking all the wires and I started up the engine again with the starting fluid, the fuel pump wires are getting really hot.....is it because my fuel pump is going bad? Link to comment Share on other sites More sharing options...
shift1313 Posted August 8, 2008 Report Share Posted August 8, 2008 maybe its the tach signal? while cranking your tach bounces so your fuel pump starts pumping but because its not primmed it never starts maybe? Im not familiar with the setup so i dont know how everything is controlled/wired but is there a tach signal that goes from your ign comp to the fuel comp? Is there an led or something that comes on for your fuel pump on the ecu itself letting you know its sending power? Most setups have 3 modes for fuel pump. On(prime), cranking(seperate power) and running(tach signal) Link to comment Share on other sites More sharing options...
desert_starion Posted August 8, 2008 Author Report Share Posted August 8, 2008 maybe its the tach signal? while cranking your tach bounces so your fuel pump starts pumping but because its not primmed it never starts maybe? Im not familiar with the setup so i dont know how everything is controlled/wired but is there a tach signal that goes from your ign comp to the fuel comp? Is there an led or something that comes on for your fuel pump on the ecu itself letting you know its sending power? Most setups have 3 modes for fuel pump. On(prime), cranking(seperate power) and running(tach signal) Well the car used to work like you said: once I turned the key to the on position it would prime, then I cranked it and it would start. While cranking, I would normally see the LED's on both fuel and ign computer blink, but now when I crank the ignition blinks while Fuel does not. However, give it some starting fluid and it would start with the starting fluid, and magically the Fuel computer comes alive and starts working To give you more update, I checked the fuel pump's Voltage and it was low, only 9 volts, while the wires also got really hot, so I managed to make a nice 14g wire direct from the fuel pump to a switch upfront so I can just manually control the fuel pump, then tried starting the car, and it was still the same, but again with some starting fluid it started up and the fuel pump ran alot better, getting nice 12.8 volts in the circuit, car idles as it should. But problem still remains...ofcourse I did the rewiring simply because I thought the fuel pump puts heavy draw on those factory lines and it needs its own circuit with heavy gauge wire, perhaps it was also not letting the FIP ecu's get proper power. But I am still on the hunt for this issue.. Link to comment Share on other sites More sharing options...
Indiana Posted August 8, 2008 Report Share Posted August 8, 2008 did you use the stock control relay or wire in some new ones? Link to comment Share on other sites More sharing options...
desert_starion Posted August 8, 2008 Author Report Share Posted August 8, 2008 did you use the stock control relay or wire in some new ones? I wired in some new one with a fuse in line. Link to comment Share on other sites More sharing options...
Shelby Posted August 8, 2008 Report Share Posted August 8, 2008 try this disconnect the fuel pump feed wire,, now go to the fuel pump relay and connect a test lamp to ground and the pump feed terminal , operate the relay,,if the test lamp trys to light at all you have a short inbetween the relay and the pump the pump feed wire should never get hot ,,the pump only draws arround 8 amps and that will not heat up a 14 ga wire , you can test the pump draw with an in line fuse and a jumper to the pump from the batt,, alow it to run for a good while with a 5 then 7 then 10 amp fuse and see what happens , also feel the pump it's self, it should only get warm not hot , if it does it's bad of course if you have the proper meters do an amp draw test on the circirt Link to comment Share on other sites More sharing options...
FlattopMike Posted August 8, 2008 Report Share Posted August 8, 2008 (edited) If you jumped the fuel pump to the battery and then cranked: If it started=fuel pump not getting enough voltage while cranking If it didn't start but would start with starting fluid=fuel pump is not the issue and it must be that the injectors are not firing. Edit: Sorry Shelby, I was writing this when you posted. I'm not disagreeing with you. Edited August 8, 2008 by FlattopMike Link to comment Share on other sites More sharing options...
Shelby Posted August 8, 2008 Report Share Posted August 8, 2008 (edited) to be honest we need more info,, did you use the oem pump feed wire already in the car,, have you check'd the ecu program for the fuel pump activation limits (these can be tricky ) what did you use for a power feed for the relays you add'd (wire gauge ) B38 already had a good source for power in it no matter what the wire heating up is a problem and needs to be address'd no problem Mike i wasn't meaning i knew his problem only giveing tips on what and how to test,, not that mine was the only way of doing thing s Edited August 8, 2008 by Shelby Link to comment Share on other sites More sharing options...
Indiana Posted August 8, 2008 Report Share Posted August 8, 2008 (edited) this is how the stock control relay works, the things you hooked up still need power in the start position of the ignition switch the SAME way so unless your relays are hooked up the same way they may not work. There is nothing wrong at all with a stock control relay you should make use of it http://www.b2600turbo.com/images/IM000993.JPG There are 8 wires all different colors. From top to bottom their color and control relay position according to the C/S service manual and a short description. BW-black/white stripe 01 / (+) output / turns on the Fuel Pump when starter is cranking or engine is running WR-white/red stripe 02 / (-) input / signal from ECU to activate fuel pump relay after ign. switch moves from "start" position and engine is running BR-black/red stripe 03 / (+) output / when ignition "on", this sends power to the injectors B -black 04 / (-) grounded to body BY-black/yellow stripe 06 / (+) input / from ign. switch "start" position this activates a relay that turns on the fuel pump R -red 05 / (+) output / when ignition "on", this powers the ECU L -blue 08 / (+) input / from ign. switch "on" position this activates a relay that powers the ECU and the injectors B -black 07 / (+) input / fuse link back to Battery positive terminal Here's the pigtail from the control relay. http://www.b2600turbo.com/images/IM000933.JPG The "control relay" is actually two relays ( magnetic coils ) in one and how the control relay functions is that when the ign. switch is in the "on" position that energizes one of the two coils via position 8 (14ga) and that takes the current coming in from position 7 (16ga) and passes it through to positions 3 and 5. When the ign. switch is in the "start" position that energizes the other coil to pass more of the current from position 7 through to position 1. There's power fed to that relay in the stock harness through the fuse links and it was to run the car and if you cut it out ok but you still need for it to do the same thing. You have to keep the same relay that you have that activates in the "on" position of your ignition swtich HOLD while you move the key to the start position, if it does not you have problems in other words you are loosing power when you are trying to start the car and what ever fuel pressure was there just as the pump comes on for a second etc the injector have power for a second etc ignition for a second. Did this car run before or you just getting started? Maybe a relay has been over loaded and isn't working now. Edited August 8, 2008 by Indiana Link to comment Share on other sites More sharing options...
FlattopMike Posted August 8, 2008 Report Share Posted August 8, 2008 I managed to make a nice 14g wire direct from the fuel pump to a switch upfront so I can just manually control the fuel pump, then tried starting the car, and it was still the same, but again with some starting fluid it started up and the fuel pump ran alot better, getting nice 12.8 volts in the circuit, car idles as it should. But problem still remains. If I am reading this correctly, the problem is not with the fuel pump. There is a problem with it that needs to be addressed as indicated by the low voltage and hot wires, but those symptoms are unrelated to the "no start" problem. The next step on your troubleshooting quest would be to check your injectors to see if they are not firing while cranking. Link to comment Share on other sites More sharing options...
desert_starion Posted August 9, 2008 Author Report Share Posted August 9, 2008 try this disconnect the fuel pump feed wire,, now go to the fuel pump relay and connect a test lamp to ground and the pump feed terminal , operate the relay,,if the test lamp trys to light at all you have a short inbetween the relay and the pump the pump feed wire should never get hot ,,the pump only draws arround 8 amps and that will not heat up a 14 ga wire , you can test the pump draw with an in line fuse and a jumper to the pump from the batt,, alow it to run for a good while with a 5 then 7 then 10 amp fuse and see what happens , also feel the pump it's self, it should only get warm not hot , if it does it's bad of course if you have the proper meters do an amp draw test on the circirt Got it fixed Shelby...thanks to all of you Shelby: I run an SX performance EFI Pump which draws 10 amps @ 45psi. I rewired everything to a toggle switch no more running off the relay nor the stock harness for powering the FIP ecu's and the fuel pump. Now I just flip the switch, wait a few seconds for pressure to build up and then I crank. The problem is somewhere in the factory harness which I used to power everything up from. I really do not use the factory harness anyways, as I have rewired everything pretty much and even have a toggle switch for the AC compressor clutch. I am not interested to find out whats wrong with the factory harness either as I am yanking it out completely. Thank You all for your replies. and for those who have this system, I recommend that you also use a toggle switch, I dont trust the factory harness to carry loads for aftermarket pumps (that is if you have one) and use nice wires that are able to carry the load. FIP Computers even Megasquirt ECU's are very voltage sensitive and you want to make sure that they are always getting the req'd voltage. Last but not least USE FUSES EVERYWHERE PLEASE. I dont want anyone melting and blazing up their SQ's Link to comment Share on other sites More sharing options...
desert_starion Posted August 9, 2008 Author Report Share Posted August 9, 2008 this is how the stock control relay works, the things you hooked up still need power in the start position of the ignition switch the SAME way so unless your relays are hooked up the same way they may not work. There is nothing wrong at all with a stock control relay you should make use of it http://www.b2600turbo.com/images/IM000993.JPG There are 8 wires all different colors. From top to bottom their color and control relay position according to the C/S service manual and a short description. BW-black/white stripe 01 / (+) output / turns on the Fuel Pump when starter is cranking or engine is running WR-white/red stripe 02 / (-) input / signal from ECU to activate fuel pump relay after ign. switch moves from "start" position and engine is running BR-black/red stripe 03 / (+) output / when ignition "on", this sends power to the injectors B -black 04 / (-) grounded to body BY-black/yellow stripe 06 / (+) input / from ign. switch "start" position this activates a relay that turns on the fuel pump R -red 05 / (+) output / when ignition "on", this powers the ECU L -blue 08 / (+) input / from ign. switch "on" position this activates a relay that powers the ECU and the injectors B -black 07 / (+) input / fuse link back to Battery positive terminal Here's the pigtail from the control relay. http://www.b2600turbo.com/images/IM000933.JPG The "control relay" is actually two relays ( magnetic coils ) in one and how the control relay functions is that when the ign. switch is in the "on" position that energizes one of the two coils via position 8 (14ga) and that takes the current coming in from position 7 (16ga) and passes it through to positions 3 and 5. When the ign. switch is in the "start" position that energizes the other coil to pass more of the current from position 7 through to position 1. There's power fed to that relay in the stock harness through the fuse links and it was to run the car and if you cut it out ok but you still need for it to do the same thing. You have to keep the same relay that you have that activates in the "on" position of your ignition swtich HOLD while you move the key to the start position, if it does not you have problems in other words you are loosing power when you are trying to start the car and what ever fuel pressure was there just as the pump comes on for a second etc the injector have power for a second etc ignition for a second. Did this car run before or you just getting started? Maybe a relay has been over loaded and isn't working now. My goodness I didnt even see your post. You are awesome man, what a write up.. Mods need to sticky it up since this is a wealth of info here. I "think" my problem is resolved for now (please read previous post) I had too much draw on the circuit and I mean the ECU fusible link was also getting really hot. I changed the relay and it still wouldnt prime the fuel pump, the fuel pump was not getting enough current. So with the rewiring it is working fine. Both FIP ecu's blink while cranking and ofcourse the Fuel Pump is also working as it should. Link to comment Share on other sites More sharing options...
Shelby Posted August 9, 2008 Report Share Posted August 9, 2008 ignoreing a problem any problem is not good esp when it's in the main relay,,i'd sugest it's not the relay but maybe wireing to it or from it Link to comment Share on other sites More sharing options...
Recommended Posts