Well it finally happened. The Ty left me stranded roadside. Just driving along, no notice at all, it was like I just turned the key off. Tried to crank it over....nothing. Got the Check Gauges light and that's it. Pulled the ECM-B fuse and well it's blown. Slaved in the wiper fuse and it immediately blew that on turning the key. I already have a Racetronix Harness with Walbro 255, so I don't think it's that. Next on the list is the Oil Pressure switch/Sender I guess. While I am checking that I'll be looking over what can be seen of the harness, Maybe I pinched something when I had the engine in position to put in the solid mounts. Damn it was 105+ when this happened on Edwards AFB. Took forever for roadside assistance. Luckily a friend passed by and I waited at his place on base until they arrived. Hopefully this'll be cheap and simple. Wish me luck.
Engine Just died
- Thread starter green73
- Start date
randy merritt
Donating Member
Re: Engine Just died
Are you getting any reading on the oil pressure gauge after trying to crank it a while? Mine did the same thing. Tooling along, then zero but "check gauges" light. Turned out to be a wiped dist gear ( which powers the oil pump, and makes the dist work). Just something to check. You can check by pulling the dist. cap and seeing if you can turn the rotor.
Note that nothing I have described would make the ECM B fuse blow.
Are you getting any reading on the oil pressure gauge after trying to crank it a while? Mine did the same thing. Tooling along, then zero but "check gauges" light. Turned out to be a wiped dist gear ( which powers the oil pump, and makes the dist work). Just something to check. You can check by pulling the dist. cap and seeing if you can turn the rotor.
Note that nothing I have described would make the ECM B fuse blow.
Re: Engine Just died
Hmmm. Finally got around to tinkering with this problem.Checked the purple wire from the starter visually. It looks good. Changed the Oil Pressure Sensor, and now it gets a little odd. Now as soon as the ECM B fuse touches the polls the IC pump (Hot Wired and the Fuel Pump (Racetronix Harness) both start running. I pulled the fuses for them and plugged the fuse in again. Soon as it touches the polls I can hear a relay clicking... So, Ignition switch? Relay? Fun times.
Hmmm. Finally got around to tinkering with this problem.Checked the purple wire from the starter visually. It looks good. Changed the Oil Pressure Sensor, and now it gets a little odd. Now as soon as the ECM B fuse touches the polls the IC pump (Hot Wired and the Fuel Pump (Racetronix Harness) both start running. I pulled the fuses for them and plugged the fuse in again. Soon as it touches the polls I can hear a relay clicking... So, Ignition switch? Relay? Fun times.
Don W.
Stab it and steer it
Re: Engine Just died
If you're hearing a relay it's the fuel pump relay. Pas side relay of the 2 just above the power brake unit.
If you can plug in the fuse without blowing it plug in the FP relay. Fuse still good? plug n the oil pres sender. Fuse still good? I suspect one will blow the fuse. If not then it's one of the orange wires going to the ECM B1 on the small connector and C16 on one of the larger connectors. You'll have to look to see which one has an orange wire at the C16 (end of connector)
I doubt it's the orange ECM wires though. I'll bet it's the FP relay or the oil pres sw. LMK which.
Edit. The FP relay itself should activate via ECM B unless the key is on and then for only 2 seconds. If it stays on you could have a bad ECM. Or a short in the wire to the ECM. (green/white wire)
EDIT: Or a bad oil pressure sw as I just found out, see below.
If you're hearing a relay it's the fuel pump relay. Pas side relay of the 2 just above the power brake unit.
If you can plug in the fuse without blowing it plug in the FP relay. Fuse still good? plug n the oil pres sender. Fuse still good? I suspect one will blow the fuse. If not then it's one of the orange wires going to the ECM B1 on the small connector and C16 on one of the larger connectors. You'll have to look to see which one has an orange wire at the C16 (end of connector)
I doubt it's the orange ECM wires though. I'll bet it's the FP relay or the oil pres sw. LMK which.
Edit. The FP relay itself should activate via ECM B unless the key is on and then for only 2 seconds. If it stays on you could have a bad ECM. Or a short in the wire to the ECM. (green/white wire)
EDIT: Or a bad oil pressure sw as I just found out, see below.
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Re: Engine Just died
Yep Fuel Pump relay.
Played relay swaparoo with the IC pump disconnected and Fuel Pump fuse pulled, put them back in and connected. Problem stopped when I plugged the AC relay into the Fuel Pump plug. The relay had broken tabs for the mount since I bought the truck anyway, so... Have a Fuel Pump Relay on the way from Rock Auto now.
I already replaced the Oil Pressure Switch and it stopped blowing the ECM B Fuse after that alone. Seems as though 2 things at one time though, and that is just weird.
On another learning note: This one is for anyone else that will need to replace the Oil Pressure Switch. There is a proper socket made for this. At your local parts house look in the OEM tool section. OEM part number 25254 "Oil Pressure Switch Socket". You don't have to cut down a wrench, pull the distributor, or anything else, All I had to do was disconnect the right side plug wires from the cap, and move the cap out of the way, I also disconnected the module connectors to the distributor. Nothing else!. The socket made the switch swap quick and easy. Well worth the $12ish bucks, and I have a super deep socket for whatever later on. A quick google search will reveal them much cheaper but I only have one parts store nearby, so...
Yep Fuel Pump relay.
Played relay swaparoo with the IC pump disconnected and Fuel Pump fuse pulled, put them back in and connected. Problem stopped when I plugged the AC relay into the Fuel Pump plug. The relay had broken tabs for the mount since I bought the truck anyway, so... Have a Fuel Pump Relay on the way from Rock Auto now.
I already replaced the Oil Pressure Switch and it stopped blowing the ECM B Fuse after that alone. Seems as though 2 things at one time though, and that is just weird.
On another learning note: This one is for anyone else that will need to replace the Oil Pressure Switch. There is a proper socket made for this. At your local parts house look in the OEM tool section. OEM part number 25254 "Oil Pressure Switch Socket". You don't have to cut down a wrench, pull the distributor, or anything else, All I had to do was disconnect the right side plug wires from the cap, and move the cap out of the way, I also disconnected the module connectors to the distributor. Nothing else!. The socket made the switch swap quick and easy. Well worth the $12ish bucks, and I have a super deep socket for whatever later on. A quick google search will reveal them much cheaper but I only have one parts store nearby, so...
Re: Engine Just died
Back on the road under its own power!!!
Weird but I think 2 problems happened at roughly the same time.
Oil Pressure Switch change: ECM-B fuse quit blowing after replacement, but fuel pump and Intercooler Pump ran after replacement, a new fuse and no key even in the ignition
Fuel Pump Relay: Swapped Fuel Pump and AC relay and everything went to normal. I put the new relay in the AC slot due to draw on that circuit.
Gald it wasn't anything too expensive. With the search feature here troubleshooting was quite easy and pretty much no guess work involved!
Back on the road under its own power!!!
Weird but I think 2 problems happened at roughly the same time.
Oil Pressure Switch change: ECM-B fuse quit blowing after replacement, but fuel pump and Intercooler Pump ran after replacement, a new fuse and no key even in the ignition
Fuel Pump Relay: Swapped Fuel Pump and AC relay and everything went to normal. I put the new relay in the AC slot due to draw on that circuit.
Gald it wasn't anything too expensive. With the search feature here troubleshooting was quite easy and pretty much no guess work involved!
Re: Engine Just died
Well. Problem persists. Has happened twice since the original failure. This last time I thought i was ready and quickly swapped the relay and fuse as before (oil pressure switch already replaced). No start. Went through 6-8 fuses. Late at night, had to leave it and get a ride home. Calling roadside assistance as early as I can to get it home and start looking for wiring issues. More frustrated having to leave it than digging in deeper. At least it is on Edwards AFB and not in town or a normal highway.
Well. Problem persists. Has happened twice since the original failure. This last time I thought i was ready and quickly swapped the relay and fuse as before (oil pressure switch already replaced). No start. Went through 6-8 fuses. Late at night, had to leave it and get a ride home. Calling roadside assistance as early as I can to get it home and start looking for wiring issues. More frustrated having to leave it than digging in deeper. At least it is on Edwards AFB and not in town or a normal highway.
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Don W.
Stab it and steer it
Re: Engine Just died
FWIW I just changed out a failed "new" oil pres sw. (Installed last winter.) I was purging air out of the IC system so the key was on and the fuel pump started running?? WTF. Got my hand down there, wiggled the wires, and it quit. I could fiddle with it and still make it run occasionally. Pull the dist so I can get to it, replace it, and all is well. Before this I had two symptoms that should have alerted me. One, the ga went clear to the top with engine running. Also on shut down the FP would continue to run for an extended length of time. (Continuing to run for a brief moment after shutdown is normal.) Another new OP sender fixed both symptoms.
So after all that you might consider unplugging your "new" OP sw and see what happens.
FWIW I just changed out a failed "new" oil pres sw. (Installed last winter.) I was purging air out of the IC system so the key was on and the fuel pump started running?? WTF. Got my hand down there, wiggled the wires, and it quit. I could fiddle with it and still make it run occasionally. Pull the dist so I can get to it, replace it, and all is well. Before this I had two symptoms that should have alerted me. One, the ga went clear to the top with engine running. Also on shut down the FP would continue to run for an extended length of time. (Continuing to run for a brief moment after shutdown is normal.) Another new OP sender fixed both symptoms.
So after all that you might consider unplugging your "new" OP sw and see what happens.
Re: Engine Just died
Before calling roadside assist I drove out to see things in the daylight. Nothing visibly wrong. I did wiggle the wires to the sender and disconnected it. No change with the oil sender connected or disconnected. I guess when I get it home time to dig in. I did notice after the initial oil pressure sender change the oil pressure gauge was not stable at idle as in it would twitch quite a bit. Things are pointing to that section of wiring.
Before calling roadside assist I drove out to see things in the daylight. Nothing visibly wrong. I did wiggle the wires to the sender and disconnected it. No change with the oil sender connected or disconnected. I guess when I get it home time to dig in. I did notice after the initial oil pressure sender change the oil pressure gauge was not stable at idle as in it would twitch quite a bit. Things are pointing to that section of wiring.
Don W.
Stab it and steer it
Re: Engine Just died
Disconnect the OP sender again. This takes it out of the circuit. (Unless there is a short or crossed wire somewhere.) Turn the key on. Does the FB run for 2 secs then stop? If so you should be able to start the truck. If fuse still blows then rig up a test wire with a fuse. Leave OP sw disconnected and disconnect the relay. Connect your test wire to the underhood fuel pump term (Empty female elec term near dist.) and a "hot" term, like the + side of the alt. Does the pump run without blowing the test fuse? If so then the FP wiring to the fuel pump and the Racetronix are probably good. Your issue is probably in the red wire from the F/P fuse to the relay or in the red wire from the relay to OP, or the OP sw, or???
IOW what you've just done is isolate the actual fuel pump circuit, including the Racetronics, from everything that normally would activate the FP. This allows you to determine if the problem is "after" the relay and op sw, or before.
Intermittent elec issues will drive you nuts. Good luck.
Disconnect the OP sender again. This takes it out of the circuit. (Unless there is a short or crossed wire somewhere.) Turn the key on. Does the FB run for 2 secs then stop? If so you should be able to start the truck. If fuse still blows then rig up a test wire with a fuse. Leave OP sw disconnected and disconnect the relay. Connect your test wire to the underhood fuel pump term (Empty female elec term near dist.) and a "hot" term, like the + side of the alt. Does the pump run without blowing the test fuse? If so then the FP wiring to the fuel pump and the Racetronix are probably good. Your issue is probably in the red wire from the F/P fuse to the relay or in the red wire from the relay to OP, or the OP sw, or???
IOW what you've just done is isolate the actual fuel pump circuit, including the Racetronics, from everything that normally would activate the FP. This allows you to determine if the problem is "after" the relay and op sw, or before.
Intermittent elec issues will drive you nuts. Good luck.
Re: Engine Just died
I was studying the diagram in the FSM and was planning on doing what you described. Essentially isolating and bypassing the OP and FP circuits individually, along with their relays, sensors, etc... I was also planning on doing a thorough check of the racetronix harness and it's connections. No time today though, so... I am betting on the initial failure of the OP switch it cooked the wires there. Not going to be fun repairing that. I so do not want to remove the distributor or anything else. If I have to though.
I was studying the diagram in the FSM and was planning on doing what you described. Essentially isolating and bypassing the OP and FP circuits individually, along with their relays, sensors, etc... I was also planning on doing a thorough check of the racetronix harness and it's connections. No time today though, so... I am betting on the initial failure of the OP switch it cooked the wires there. Not going to be fun repairing that. I so do not want to remove the distributor or anything else. If I have to though.
Don W.
Stab it and steer it
Re: Engine Just died
Well that's what the fuse is for. Not to say you don't have a bad wire somewhere just that unless you installed a much larger fuse the OP or FP relay would not have toasted a wire. Personally I think giving the Racetronix wiring a thorough check is a good next step.
If you're not blowing the Racetronix fuse (at the alt) then from there to the Racetronix relay and from the Racetronix relay to the FP are good. It could easily be that whoever installed the Racetronix didn't properly protect the stock FP wire.
Well that's what the fuse is for. Not to say you don't have a bad wire somewhere just that unless you installed a much larger fuse the OP or FP relay would not have toasted a wire. Personally I think giving the Racetronix wiring a thorough check is a good next step.
If you're not blowing the Racetronix fuse (at the alt) then from there to the Racetronix relay and from the Racetronix relay to the FP are good. It could easily be that whoever installed the Racetronix didn't properly protect the stock FP wire.
Re: Engine Just died
Think I found the issue! Found the wire someone spliced into the Fuel Pump Prime wire ran along the frame rail ended at a bare terminal lug open to the world. Took 4 years of my ownership for it to start making contact with the frame. I have been working on another project that distracted me from this which is why I haven't done anything with it until today. Here's the other project. Did a 4" chop, needed a seat, glass, and wiring. Still has the old 4-banger, but it isn't stock. It's balanced, bored, High compression head, dual carbs, electronic ignition....
Think I found the issue! Found the wire someone spliced into the Fuel Pump Prime wire ran along the frame rail ended at a bare terminal lug open to the world. Took 4 years of my ownership for it to start making contact with the frame. I have been working on another project that distracted me from this which is why I haven't done anything with it until today. Here's the other project. Did a 4" chop, needed a seat, glass, and wiring. Still has the old 4-banger, but it isn't stock. It's balanced, bored, High compression head, dual carbs, electronic ignition....
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Re: Engine Just died
Not gonna do anything to the 4Banger. It had all that when I bought it. It'll be getting a old Flathead V8 with a noisy cam, 2 carbs and EAB heads driving a T5 trans. Chassis will be swapped out for a custom 32 ford frame but will still be solid front axle and the rear will be traverse spring as well. Fenders are coming off too.
Not gonna do anything to the 4Banger. It had all that when I bought it. It'll be getting a old Flathead V8 with a noisy cam, 2 carbs and EAB heads driving a T5 trans. Chassis will be swapped out for a custom 32 ford frame but will still be solid front axle and the rear will be traverse spring as well. Fenders are coming off too.
Re: Engine Just died
Finally got the dash back together after the troubleshooting and LED light change. Drove it to and from work without driveability issues(no blown fuses):lol::rotf:
. Now I have no right turn signal in the dash. Damn I don't want to tale that back apart again. The outside lights work. It is going to bother the crap out of me until I fix it, but I am not in a hurry. Oh yeah forgot I need to put the tank cover back on too and get a good alignment. The last alignment must have my camber off a bit as the insides of the front tires are wearing faster than the outside. I am betting the shop used settings for a regular Jimmy. That or being a bit lowered skewed things.
Finally got the dash back together after the troubleshooting and LED light change. Drove it to and from work without driveability issues(no blown fuses):lol::rotf:
. Now I have no right turn signal in the dash. Damn I don't want to tale that back apart again. The outside lights work. It is going to bother the crap out of me until I fix it, but I am not in a hurry. Oh yeah forgot I need to put the tank cover back on too and get a good alignment. The last alignment must have my camber off a bit as the insides of the front tires are wearing faster than the outside. I am betting the shop used settings for a regular Jimmy. That or being a bit lowered skewed things.