no bus wont start
03-04-2011, 09:22 PM
#1
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no bus wont start
ok, so i tried to put in a switch today to disconnect the wire tap to my vp from my comp box. wired it up by putting the wire that would tap into the switch directly into the hot post on switch, grounded the ground wire for the wire tap and ran a ground to the ground post of the switch, then ran new wire into the splice clamp thing for the wire tap to the accessory on post on the switch. i turned the key to on and flipped the switch and the light on the switch came on. I turned it off and the light on the switch went off. then turned the switch back on, went to put some tools away and close the hood and came back for a test drive and went to turn it over and it cranks over but will not fire up. i noticed the air dog does not turn on and has no power to it. the power seems to stop in a relay by the main fuse pannel under the hood. the odo. reads "no bus". any ideas or help would be extremely appreciated. thanks in advance. oh and i tried disconnecting the switch, hooking uo the comp box how it was with the wire tap, disconnecting the comp box and all with the same result of turning over but not fireing up. thanks!
03-04-2011, 10:22 PM
#2
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Did you check the fuses in junction block left side of dash? Fuse 9 is a 10 amp fuse. Is the wait to start light flashing? Gauges inoperative in cluster? Wait to start light come on? Any codes?
03-04-2011, 10:57 PM
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i did check all fuses in the junction block and under the hood. i ran a obdII scanner and it says link error. gauges are not working in the dash, although it looks like the oil pressure gauge moves a tad when i turn key to on but when i crank it over nothing moves, even volt meter. i did not check to see if the wait to start light comes on. i now have batteries d/c trying to see if it will reset. i tried earlier with no success. i hope my computer isnt fried.
03-04-2011, 11:36 PM
#4
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Did you have a diode in the link from the wiretap on the VP44 to the back of the switch? When using a lighted switch, you have to make sure that you can't backfeed power into the load post of switch, because it causes a short. In this case, the signal that normally passes through the wire on the VP44 to control the fuel solenoid was backfed into the switch, so it's likely it caused a short in that circuit. I'll have to check the wiring diagram to see where that signal comes from. But if you didn't see any popped fuses, it might have blown something in the ECM.
could an unlighted switch have done the same?
03-05-2011, 12:03 AM
#7
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With a non-lighted switch, you would only have two posts. You would hook the output of the Comp to one post and the wiretap to the VP44 on the other. When the switch is open, both posts are basically a dead end so you don't have any issues with pushing power into either post. In the lighted switch, your load/accessory post has a path to ground via the light in the switch, which causes the short (at least that's how it was explained to me).
I had the same issue when I wired up my backup lights with an aux switch. I used a lighted aux switch that would feed power into the backup circuit. The switch worked great, but as soon as I shifted into reverse, the power backfed into the switch and would pop the fuse immediately. I put a diode into the line to block the reverse current flow and that cleared up the issue.
So do you have a Wait to Start light or anything else? I checked the FSM and all the VP44 lines are fed from the ECM, so any short would have went back through the ECM. Still hoping there might just be a fuse that was popped that's causing a no power situation to your ECM.
EDIT: Just to make sure I read your original post correctly. Was this how you wired it up?
Power - wire from the Comp
Load/Accessory - to the wiretap at the VP44
Ground - to ground
I had the same issue when I wired up my backup lights with an aux switch. I used a lighted aux switch that would feed power into the backup circuit. The switch worked great, but as soon as I shifted into reverse, the power backfed into the switch and would pop the fuse immediately. I put a diode into the line to block the reverse current flow and that cleared up the issue.
So do you have a Wait to Start light or anything else? I checked the FSM and all the VP44 lines are fed from the ECM, so any short would have went back through the ECM. Still hoping there might just be a fuse that was popped that's causing a no power situation to your ECM.
EDIT: Just to make sure I read your original post correctly. Was this how you wired it up?
Power - wire from the Comp
Load/Accessory - to the wiretap at the VP44
Ground - to ground
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03-05-2011, 12:33 AM
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ok, i checked again and i found the 20 amp fuse in the main fuse pannel was blown. it was yrey hard to see. after replacing it with the stomp lamp fuse my gauges work and my air dog kicks on, but it still wont fire up and still no wait to start light. it gave me three codes: Ecu- p1688p, p0253. pcu- p1693
03-05-2011, 12:58 AM
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yes, that is correct as for the wiring of the switch. i figured this would do the same thing as unplugging the wire tap and have less fuel flowing while keeping the timing of the comp box to assist in fuel econ because level 5x5 offers the most advanced timing but flows way too much fuel for me to daily drive with. i read somewhere that unpluging or running a switch to d/c the wiretap basicly turns the edge comp into the edge ez. hope that cleared things up
03-05-2011, 01:42 AM
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ok, i checked again and i found the 20 amp fuse in the main fuse pannel was blown. it was yrey hard to see. after replacing it with the stomp lamp fuse my gauges work and my air dog kicks on, but it still wont fire up and still no wait to start light. it gave me three codes: Ecu- p1688p, p0253. pcu- p1693
Description
Fuel injection pump fuel valve open circuit is monitored when ignition is on. DTC may be stored when Engine Control Module (ECM) senses engine speed is more than 100 RPM and low current or no current is detected at fuel metering valve. Possible causes are: defective fuel injection pump, defective battery, or defective connectors or wiring.
Testing
1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is not equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is equal to zero, go to step 4 .
2. Turn ignition off. Inspect wiring harness and connectors between Fuel Pump Control Module (FPCM) and ECM, and between fuel pump relay and FPCM. FPCM is located on top of fuel injection pump. See Fig. 32 . FPCM is incorporated into fuel injection pump and may also be referred to as the fuel injection pump when referencing to wiring diagram. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Fuel pump relay is located in PDC at driver's side front corner of engine compartment. Fuel pump relay may also be referred to as fuel injection pump relay. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary.
3. Turn ignition on with engine off. Using scan tool, read FREEZE FRAME data. Operate vehicle within FREEZE FRAME data parameters while wiggling wiring harness and connectors between FPCM and ECM, and between fuel pump relay and FPCM. If DTC SPECIFIC GOOD TRIP counter changes to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter does not change to zero, test is complete.
4. Ensure ignition is on with engine off. Using scan tool, check for DTCs. If DTC P0215 does not exist, go to next step. If DTC P0215 exists, perform DTC P0215: FUEL INJECTION PUMP CONTROL CIRCUIT test.
5. Turn ignition off. Using DVOM, measure voltage between battery terminals. If voltage is 12 volts or more, go to next step. If voltage is less than 12 volts, recharge or replace battery as necessary.
6. Ensure ignition is off. Disconnect FPCM connector. FPCM connector is located on end of fuel injection pump. FPCM is incorporated into fuel injection pump and may also be referred to as the fuel injection pump when referencing to wiring diagram. Using 12-volt test light connected to battery voltage, check for voltage at terminal No. 6 (Black/Tan wire) on FPCM connector. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance on Black/Tan wire between FPCM and ECM. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector.
7. Ensure ignition is off and FPCM connector is still disconnected. Turn ignition on with engine off. Using 12-volt test light, check for voltage at terminal No. 7 on FPCM connector. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance on Red/Light Green wire between FPCM connector and cavity No. 87 (Red/Light Green wire) in PDC for fuel pump relay.
8. Perform starter draw test with starter installed. Starter draw should be 450-700 amps. If starter draw is not within specification, repair or replace starter. If starter draw is within specification, using DVOM, measure voltage between battery terminals while cranking engine. If voltage is 8 volts or more, replace fuel injection pump. If voltage is less than 8 volts, recharge or replace battery as necessary.
DTC P1688: INTERNAL FUEL INJECTION PUMP FAILURE
Fuel injection pump fuel valve open circuit is monitored when ignition is on. DTC may be stored when Engine Control Module (ECM) senses engine speed is more than 100 RPM and low current or no current is detected at fuel metering valve. Possible causes are: defective fuel injection pump, defective battery, or defective connectors or wiring.
Testing
1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is not equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is equal to zero, go to step 4 .
2. Turn ignition off. Inspect wiring harness and connectors between Fuel Pump Control Module (FPCM) and ECM, and between fuel pump relay and FPCM. FPCM is located on top of fuel injection pump. See Fig. 32 . FPCM is incorporated into fuel injection pump and may also be referred to as the fuel injection pump when referencing to wiring diagram. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Fuel pump relay is located in PDC at driver's side front corner of engine compartment. Fuel pump relay may also be referred to as fuel injection pump relay. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary.
3. Turn ignition on with engine off. Using scan tool, read FREEZE FRAME data. Operate vehicle within FREEZE FRAME data parameters while wiggling wiring harness and connectors between FPCM and ECM, and between fuel pump relay and FPCM. If DTC SPECIFIC GOOD TRIP counter changes to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter does not change to zero, test is complete.
4. Ensure ignition is on with engine off. Using scan tool, check for DTCs. If DTC P0215 does not exist, go to next step. If DTC P0215 exists, perform DTC P0215: FUEL INJECTION PUMP CONTROL CIRCUIT test.
5. Turn ignition off. Using DVOM, measure voltage between battery terminals. If voltage is 12 volts or more, go to next step. If voltage is less than 12 volts, recharge or replace battery as necessary.
6. Ensure ignition is off. Disconnect FPCM connector. FPCM connector is located on end of fuel injection pump. FPCM is incorporated into fuel injection pump and may also be referred to as the fuel injection pump when referencing to wiring diagram. Using 12-volt test light connected to battery voltage, check for voltage at terminal No. 6 (Black/Tan wire) on FPCM connector. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance on Black/Tan wire between FPCM and ECM. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector.
7. Ensure ignition is off and FPCM connector is still disconnected. Turn ignition on with engine off. Using 12-volt test light, check for voltage at terminal No. 7 on FPCM connector. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance on Red/Light Green wire between FPCM connector and cavity No. 87 (Red/Light Green wire) in PDC for fuel pump relay.
8. Perform starter draw test with starter installed. Starter draw should be 450-700 amps. If starter draw is not within specification, repair or replace starter. If starter draw is within specification, using DVOM, measure voltage between battery terminals while cranking engine. If voltage is 8 volts or more, replace fuel injection pump. If voltage is less than 8 volts, recharge or replace battery as necessary.
DTC P1688: INTERNAL FUEL INJECTION PUMP FAILURE
Description
Information for when fuel injection pump is monitored is not available from manufacturer. Possible cause is defective fuel injection pump.
Testing
1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is not displayed and equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is displayed and equal to zero, replace fuel injection pump.
2. At this time, conditions required for DTC to be stored are not present. Ensure ignition is on with engine off. Using scan tool, go to FREEZE FRAME data and operate vehicle within FREEZE FRAME data parameters. If DTC SPECIFIC GOOD TRIP counter does not change to zero, test is complete. If DTC SPECIFIC GOOD TRIP counter changes to zero, replace fuel injection pump.
DTC P1693:DTC Detected In ECM Or PCM
Information for when fuel injection pump is monitored is not available from manufacturer. Possible cause is defective fuel injection pump.
Testing
1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is not displayed and equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is displayed and equal to zero, replace fuel injection pump.
2. At this time, conditions required for DTC to be stored are not present. Ensure ignition is on with engine off. Using scan tool, go to FREEZE FRAME data and operate vehicle within FREEZE FRAME data parameters. If DTC SPECIFIC GOOD TRIP counter does not change to zero, test is complete. If DTC SPECIFIC GOOD TRIP counter changes to zero, replace fuel injection pump.
DTC P1693:DTC Detected In ECM Or PCM
03-05-2011, 02:56 PM
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ok. thank you so much. ill have to see if i can borrow a legit scanner and dovm form someone. i have my batteries charging now and i'm out of things to check untill i get those. man what a pain in the d!ck. i almost put in a led lighted switch but didnt because of the mounting options with the one led they had in stock would require a hole in the dash and i wasnt sure this switch would be permenant. now i wish i had a simple hole in my dash as my biggest problem rather than no hole and a big mess of electricl issues
03-05-2011, 07:35 PM
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i had my batteries d/c all day and hooked them back up. my wait to start light comes on now. I also checked the pos and grnd to the vp with a test light and all is good. i still need to check volts but still dont have access to volt meeter. i cracked #1 injector line and cranked it over. fuel along the head says the pumps at least poshing some fuel. on Blue Chips site theres a very good troubleshooting guide. im might try to hardwire the vp directly to the battery like chip describes.
03-06-2011, 02:49 PM
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well, last night i managed to nearly follow the instructions on Blue Chips website for hard wiring the VP to the battery. He says to use insolated female spade connecters to hook up to the pins directly on the pump and hook those batt. well, i just had uninsolated connecters, so like a beer drinkin fool would do, i wrapped electrical tape around them to insulate them. had my buddy crank her over while i kneeled on the support over the radiator. it was really good seats to the fireworks show. looks like the rain made the elect tape not so sticky and opened up, allowing the hot and grnd on the pins of my pump to weld together short for 5-6 seconds while i watched in awe. if my pumps electrical wasnt smoked before, im very confident in promising that it is now.
looks like a new SO pump to replace the HO pump. anyone know if the pop off pressures will have to be lowered on the injectors due to the lower pressure of the SO?
looks like a new SO pump to replace the HO pump. anyone know if the pop off pressures will have to be lowered on the injectors due to the lower pressure of the SO?
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