CertusExpo
Customizing trucks since I was 7 with my Legos
Okay...
Yesterday afternoon I went to leave work and found myself in the good cranking but no start scenario. I immediately started processing the possible causes and it came down to ignition or fuel delivery.
I went back up to my office and began researching and found several forum threads from multiple sources that pointed to either the pump itself or the relay. The main issue being my location/distance from home/tools and limited amount of resources on-board as well as availability in downtown Dallas.
I made a trip via train to the nearest auto parts store that was the shortest stop from the train stop and while there, I purchased two cans of starter fluid, electrical tape and a handy 10-foot retractable test lead with alligator clips.
When I got back to my office I began troubleshooting and through process of illumination the issue came down to fuel delivery as the engine would start when spraying the stater fluid into the throttle body. I then went back to my office and searched YouTube for videos on replacement of the fuel pump so I could make a list of needed tools for my son to bring out to perform the pump replacement on-site. I also came across this video.
While watching that video he showed a schematic of the fuel pump relay and he explained which wire on which plug on the fuse box was the hot (14-gauge Green w/ Yellow Stripe) that went to the fuel pump. Then it suddenly hit me. I can unplug it, carefully expose some of wire and using the test lead I purchased, I could validate/invalidate if the failure was the relay or the pump by running power straight to the pump and bypassing the relay.
I took a small paper clamp, removed one of the silver finger tabs and shaped it to fit inside the plug of the DG/YE plug itself. (https://cdnimg.webstaurantstore.com/images/products/medium/234014/1258245.jpg)
Once I had pushed my test clip in I then clipped one of the alligator clips to it and then exposed some of the insulation of the hot lead coming off a cigarette lighter plug from an accessory and clipped the other end of the test lead to it. She cranked and tried momentarily to start but didn't. I then figured that the plug needed to be plugged into the fuse box to complete some kind of circuit for the PCM or ??
I plugged it back into the fuse box with the test lead still attached and gave her a crank.
VAAAROOOOM! SUCCESS!
She idled just fine and I didn't have any fires or explosions
I had just verified that the pump was good, the relay was bad AND found a way to get myself home all in one fell swoop.
I burned up two cigarette lighter adapters on the way home due to both the distance from home as well as the amount of voltage being drawn through too small of gauge wire for the adapters but at least I wasn't stuck in the middle of downtown Dallas over-night, didn't have to call a tow or leave her behind and come back to a, most-likely broken into Expo.
Once I got home, I made a heavier-duty lead using 14-gauge wire and larger alligator clips so that I could finish out my week and come up with a better long-term solution.
That being said, I think I've figured it out.
Replacing that fuel pump relay is not an easy task as it requires completely uninstalling the entire fuse box, then carefully dismantling/opening the 'clam-shell' design, then de-soldering the OEM relay, soldering in the replacement relay then reassembly and finished off with re-installation into the truck.
I've decided to use a standard but HEAVY DUTY relay, powered off a switched lead to bypass the OEM relay but also, install a hidden toggle switch so I can essentially use this re-engineered design as an anti-theft device.
Thank you for reading this write-up and any comments/suggestions/advice is of course, welcomed.
Yesterday afternoon I went to leave work and found myself in the good cranking but no start scenario. I immediately started processing the possible causes and it came down to ignition or fuel delivery.
I went back up to my office and began researching and found several forum threads from multiple sources that pointed to either the pump itself or the relay. The main issue being my location/distance from home/tools and limited amount of resources on-board as well as availability in downtown Dallas.
I made a trip via train to the nearest auto parts store that was the shortest stop from the train stop and while there, I purchased two cans of starter fluid, electrical tape and a handy 10-foot retractable test lead with alligator clips.
When I got back to my office I began troubleshooting and through process of illumination the issue came down to fuel delivery as the engine would start when spraying the stater fluid into the throttle body. I then went back to my office and searched YouTube for videos on replacement of the fuel pump so I could make a list of needed tools for my son to bring out to perform the pump replacement on-site. I also came across this video.
While watching that video he showed a schematic of the fuel pump relay and he explained which wire on which plug on the fuse box was the hot (14-gauge Green w/ Yellow Stripe) that went to the fuel pump. Then it suddenly hit me. I can unplug it, carefully expose some of wire and using the test lead I purchased, I could validate/invalidate if the failure was the relay or the pump by running power straight to the pump and bypassing the relay.
I took a small paper clamp, removed one of the silver finger tabs and shaped it to fit inside the plug of the DG/YE plug itself. (https://cdnimg.webstaurantstore.com/images/products/medium/234014/1258245.jpg)
Once I had pushed my test clip in I then clipped one of the alligator clips to it and then exposed some of the insulation of the hot lead coming off a cigarette lighter plug from an accessory and clipped the other end of the test lead to it. She cranked and tried momentarily to start but didn't. I then figured that the plug needed to be plugged into the fuse box to complete some kind of circuit for the PCM or ??
I plugged it back into the fuse box with the test lead still attached and gave her a crank.
VAAAROOOOM! SUCCESS!
She idled just fine and I didn't have any fires or explosions
I had just verified that the pump was good, the relay was bad AND found a way to get myself home all in one fell swoop.
I burned up two cigarette lighter adapters on the way home due to both the distance from home as well as the amount of voltage being drawn through too small of gauge wire for the adapters but at least I wasn't stuck in the middle of downtown Dallas over-night, didn't have to call a tow or leave her behind and come back to a, most-likely broken into Expo.
Once I got home, I made a heavier-duty lead using 14-gauge wire and larger alligator clips so that I could finish out my week and come up with a better long-term solution.
That being said, I think I've figured it out.
Replacing that fuel pump relay is not an easy task as it requires completely uninstalling the entire fuse box, then carefully dismantling/opening the 'clam-shell' design, then de-soldering the OEM relay, soldering in the replacement relay then reassembly and finished off with re-installation into the truck.
I've decided to use a standard but HEAVY DUTY relay, powered off a switched lead to bypass the OEM relay but also, install a hidden toggle switch so I can essentially use this re-engineered design as an anti-theft device.
Thank you for reading this write-up and any comments/suggestions/advice is of course, welcomed.
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