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I just went back out and hooked he oil pressure pigtail up to the sensor like normal without the jumper in place. The truck is actually starting on its own without the jumper in place. Going off the flow chart you posted, I let the engine idle with the oil pressure sensor hooked up. I unplugged the fuel pump relay with the engine running and the engine immediately died. From what I understand the oil pressure is supposed to take over in case the relay dies. So does that mean my oil pressure sensor is failing and the cause of all my troubles? It is strange but the engine is starting almost like normal now although there is a little hesitation when it first starts up
I just went back out and hooked he oil pressure pigtail up to the sensor like normal without the jumper in place. The truck is actually starting on its own without the jumper in place. Going off the flow chart you posted, I let the engine idle with the oil pressure sensor hooked up. I unplugged the fuel pump relay with the engine running and the engine immediately died. From what I understand the oil pressure is supposed to take over in case the relay dies. So does that mean my oil pressure sensor is failing and the cause of all my troubles? It is strange but the engine is starting almost like normal now although there is a little hesitation when it first starts up
[quote=”college man” post=55818]here is another test with the fuel gauge hooked up.
pinch off the fuel return line with the truck running.
the fuel pressure should jump up.also your gauge should
not drop to zero immediately. It should hold for more
than 5 min. next lets jumper the fuel pressure oil switch
orange and grey wires. see if the truck runs any better.http://www.justanswer.com/gmc/6be2k-gmc-suburban-2500-2wd-1994-gmc-suburban-tbi.html%5B/quote%5D
Ok college man here is the results of the test. I started the truck and let it run and then hooked up both injectors. The pressure was reading around 12-13. I found the other line which runs up to the engine that did not have the fuel filter attached to it. I pinched this line off with a rag and pliers. This caused the engine to sputter a little and the fuel pressure gauge jumped up to around 20 I believe.
Not sure why the gauge goes to zero after the pump stops running.
I unplugged the oil pressure sensor pigtail. I stuck a paperclip in the pigtail from the red and grey wires jumpering them together. Once the connection was made, I heard the fuel pump start running constantly even though the key was turned off. I tried to start the truck with both of the injectors plugged in and the jumper still in place. The truck started and ran normally at this point. I shut the truck off and repeated the test several times to make sure it would still start with both injectors plugged in. It did start every time. Not sure what this means at this point.
[quote=”college man” post=55818]here is another test with the fuel gauge hooked up.
pinch off the fuel return line with the truck running.
the fuel pressure should jump up.also your gauge should
not drop to zero immediately. It should hold for more
than 5 min. next lets jumper the fuel pressure oil switch
orange and grey wires. see if the truck runs any better.http://www.justanswer.com/gmc/6be2k-gmc-suburban-2500-2wd-1994-gmc-suburban-tbi.html%5B/quote%5D
Ok college man here is the results of the test. I started the truck and let it run and then hooked up both injectors. The pressure was reading around 12-13. I found the other line which runs up to the engine that did not have the fuel filter attached to it. I pinched this line off with a rag and pliers. This caused the engine to sputter a little and the fuel pressure gauge jumped up to around 20 I believe.
Not sure why the gauge goes to zero after the pump stops running.
I unplugged the oil pressure sensor pigtail. I stuck a paperclip in the pigtail from the red and grey wires jumpering them together. Once the connection was made, I heard the fuel pump start running constantly even though the key was turned off. I tried to start the truck with both of the injectors plugged in and the jumper still in place. The truck started and ran normally at this point. I shut the truck off and repeated the test several times to make sure it would still start with both injectors plugged in. It did start every time. Not sure what this means at this point.
[quote=”Zirrer” post=55800]ok I figured out why I couldn’t see any videos (unsecure Script on the forum) now when you crank does the voltage drop below 9 volts if so I would try jumping or a charger on it and let it get charge
as for the fuel filter even if there is fuel to the injectors it may not have enough flow or volume to run[/quote]I just rented a fuel pressure tester and installed it per the manual right after the fuel filter with a t fitting. Its showing both 12-13 PSI of pressure both upon turning the key on and the car running. If you turn the key on and leave it on without starting the car, the pressure goes up to 12-13 psi and then drops to 0 once the pump stops running. Also since I bypassed the fuse on that bad wire near the fuel pump relay, the code 54 is no longer showing. However the car still wont start unless one of the injectors is unplugged. I have a video showing the readings Im getting uploading now. Will post once its done. Fuel pressure regulator allowing the injectors to get too much fuel at the same time maybe? From what I have seen 12-13 psi is normal and the pump is therefore good. Not sure if its normal for the pressure to drop down to zero once the pump stops running though.
[quote=”Zirrer” post=55800]ok I figured out why I couldn’t see any videos (unsecure Script on the forum) now when you crank does the voltage drop below 9 volts if so I would try jumping or a charger on it and let it get charge
as for the fuel filter even if there is fuel to the injectors it may not have enough flow or volume to run[/quote]I just rented a fuel pressure tester and installed it per the manual right after the fuel filter with a t fitting. Its showing both 12-13 PSI of pressure both upon turning the key on and the car running. If you turn the key on and leave it on without starting the car, the pressure goes up to 12-13 psi and then drops to 0 once the pump stops running. Also since I bypassed the fuse on that bad wire near the fuel pump relay, the code 54 is no longer showing. However the car still wont start unless one of the injectors is unplugged. I have a video showing the readings Im getting uploading now. Will post once its done. Fuel pressure regulator allowing the injectors to get too much fuel at the same time maybe? From what I have seen 12-13 psi is normal and the pump is therefore good. Not sure if its normal for the pressure to drop down to zero once the pump stops running though.
I disconetted the pigtail that goes to the oil pressure sensor and put a volt meter on it. The red wire shows 12 volts constant. The top wire shows approximately 8 volts when the engine is cranking. I had to disconnect the pigtail from the sensor to test it, its too tight of a fit to test it with the plug connected.
I don’t have a fuel pressure tester.
I disconetted the pigtail that goes to the oil pressure sensor and put a volt meter on it. The red wire shows 12 volts constant. The top wire shows approximately 8 volts when the engine is cranking. I had to disconnect the pigtail from the sensor to test it, its too tight of a fit to test it with the plug connected.
I don’t have a fuel pressure tester.
[quote=”Zirrer” post=55792]i can’t find the video your talking about im new the the form is there a link im missing ?[/quote]Here is the video. If you skip to approximately 1:54 of the video you will see the wire I am talking about
[quote=”Zirrer” post=55792]i can’t find the video your talking about im new the the form is there a link im missing ?[/quote]Here is the video. If you skip to approximately 1:54 of the video you will see the wire I am talking about
[quote=”college man” post=55783]see if this helps you.
Thanks for that information. Here is what else I found this morning. I leave the fuel pump relay plugged in so its getting fuel. I disconnected one of the injectors and cranked it over. Truck starts up, I have to keep feeding it gas for the first few seconds and than after that it idles on its own but its idling rough. While the trucks running, I reconnect the disconnected fuel injector and the idle immediately speeds up and smooths out. Truck runs normally at this point. All gauges are working on the dash EXCEPT for the oil pressure gauge. It is staying around 50 no matter the engine speed.
This gauge used to read around 20 at idle and would go up around 40 while cruising. It would vary with the engine RPM. Now it is just stuck at 42 or whatever and is not moving at all with the RPMS.
I used a test light and checked for power at the pigtail with the pigtail unplugged from the sensor. The red or orange wire lit the test light bright. The other connection was showing ground and the top prong showed nothing until the ignition was turned on and than the test light illuminated dimly.
Hopefully this helps narrow down the problem and someone can steer me in the right direction. Seems like the injectors are spraying too much fuel upon start up and flooding engine out. Once one inj is disconnected the engine starts and the other injector can be plugged back in and the truck runs as it always did. I did just replace both the engine coolant temp sensor and the engine temperature switch when I did an intake manifold gasket job on this truck a month or so ago. Also the temperature gauge in the truck does appear to work.
Also I think the code 54 was because of the intermittent wire connectivity issue shown in my video on the prior page where I showed how one of the fusible links was breaking and corroded. When I probed the wire, it was not getting voltage after the fuseable link. It is a red wire that hooks into the convenience center close to where the fuel pump relay is so I believe this is the cause of the code 54. By the way, since I jumpered the wire as shown in the video, the CEL did not illuminate when the truck was running. I will try getting the wire to loose signal again and see if it brings back the code 54 again.
[quote=”college man” post=55783]see if this helps you.
Thanks for that information. Here is what else I found this morning. I leave the fuel pump relay plugged in so its getting fuel. I disconnected one of the injectors and cranked it over. Truck starts up, I have to keep feeding it gas for the first few seconds and than after that it idles on its own but its idling rough. While the trucks running, I reconnect the disconnected fuel injector and the idle immediately speeds up and smooths out. Truck runs normally at this point. All gauges are working on the dash EXCEPT for the oil pressure gauge. It is staying around 50 no matter the engine speed.
This gauge used to read around 20 at idle and would go up around 40 while cruising. It would vary with the engine RPM. Now it is just stuck at 42 or whatever and is not moving at all with the RPMS.
I used a test light and checked for power at the pigtail with the pigtail unplugged from the sensor. The red or orange wire lit the test light bright. The other connection was showing ground and the top prong showed nothing until the ignition was turned on and than the test light illuminated dimly.
Hopefully this helps narrow down the problem and someone can steer me in the right direction. Seems like the injectors are spraying too much fuel upon start up and flooding engine out. Once one inj is disconnected the engine starts and the other injector can be plugged back in and the truck runs as it always did. I did just replace both the engine coolant temp sensor and the engine temperature switch when I did an intake manifold gasket job on this truck a month or so ago. Also the temperature gauge in the truck does appear to work.
Also I think the code 54 was because of the intermittent wire connectivity issue shown in my video on the prior page where I showed how one of the fusible links was breaking and corroded. When I probed the wire, it was not getting voltage after the fuseable link. It is a red wire that hooks into the convenience center close to where the fuel pump relay is so I believe this is the cause of the code 54. By the way, since I jumpered the wire as shown in the video, the CEL did not illuminate when the truck was running. I will try getting the wire to loose signal again and see if it brings back the code 54 again.