Starting problem
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Starting problem
I hope I didn't severly screw up.
I have a 1987 f150 4.9 I just replaced rocker panel and floor. I went to move my truck around and do the other side and it wont start. I did weld under the computer at the floor but not weld directly close to the computer.
I had been having a problem starting ocasionally due to yellow wire about pulled out of the fuel pump relay. I cut wires off pigtail at fuel pump relay and soldered another pig tail in. I checked it and when I turn key to "on" it clicks and it started. I put fender back on "no click" and now it won't start. Is there anyway to check relay to see if it is good.
One other question if I may. I have a compuuter out of an 89 with a 5.0 in it and was wondering if computer will interchange.
Any help will be appreciatd
ZZ
I have a 1987 f150 4.9 I just replaced rocker panel and floor. I went to move my truck around and do the other side and it wont start. I did weld under the computer at the floor but not weld directly close to the computer.
I had been having a problem starting ocasionally due to yellow wire about pulled out of the fuel pump relay. I cut wires off pigtail at fuel pump relay and soldered another pig tail in. I checked it and when I turn key to "on" it clicks and it started. I put fender back on "no click" and now it won't start. Is there anyway to check relay to see if it is good.
One other question if I may. I have a compuuter out of an 89 with a 5.0 in it and was wondering if computer will interchange.
Any help will be appreciatd
ZZ
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From: Virginia
The computer will not interchange from a six to a v8 or vise-versa.
Since you are messing with the sheetmetal over there, I would suspect possibly a ground problem. See if you can figure out were the relays are getting their ground. There may be a small ground wire coming from the battery negative that you forgot to attach. I think it's the ground for the computer too.
If you have been doing a lot of rust proofing, you may have to scrape some of the paint or whatever off to get the ground back.
Since you are messing with the sheetmetal over there, I would suspect possibly a ground problem. See if you can figure out were the relays are getting their ground. There may be a small ground wire coming from the battery negative that you forgot to attach. I think it's the ground for the computer too.
If you have been doing a lot of rust proofing, you may have to scrape some of the paint or whatever off to get the ground back.
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Thanks Dave I will give that wire a check.
I didn't think the computers would interchange.
I tested with a test light and the yellow wire is hotall the time . But not to the brown wire when the key is turned on. hummm!. ( I believe going to the pump)
ZZ
I didn't think the computers would interchange.
I tested with a test light and the yellow wire is hotall the time . But not to the brown wire when the key is turned on. hummm!. ( I believe going to the pump)
ZZ
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From: Virginia
The yellow is hot all the time for the pump power going into the relay.
And you are correct, the brown wire is power going out to the pump.
There should be a red wire going to the relay. This should be hot with the key in run, and the power for this wire comes from the eec or computer relay. This red wire powers all the fuel injectors, and eveything else to do with the computer.
There should be one last wire coming from the fuel pump relay. It should be tan/lightgreen. This wire goes to the computer, and when the computer grounds this wire, it turns the pump relay on, sending out power on the brown wire to the pump.
And you are correct, the brown wire is power going out to the pump.
There should be a red wire going to the relay. This should be hot with the key in run, and the power for this wire comes from the eec or computer relay. This red wire powers all the fuel injectors, and eveything else to do with the computer.
There should be one last wire coming from the fuel pump relay. It should be tan/lightgreen. This wire goes to the computer, and when the computer grounds this wire, it turns the pump relay on, sending out power on the brown wire to the pump.
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Thanks Franklin That helps when I know where the wires are suppose to go.
I have found a wire someone spliced in from main pump( Looked orange) in the frame rail and when I put electricity to it I can hear that pump run.
I did check the red wire coming from relay with key on and I got nothing. Looks like my brown wire goes back into firewall loom. any way to test a relay. Kinda hard to find anything open Sunday beofre this holiday. BTW Happy 4th everyone.
ZZ
I have found a wire someone spliced in from main pump( Looked orange) in the frame rail and when I put electricity to it I can hear that pump run.
I did check the red wire coming from relay with key on and I got nothing. Looks like my brown wire goes back into firewall loom. any way to test a relay. Kinda hard to find anything open Sunday beofre this holiday. BTW Happy 4th everyone.
ZZ
Last edited by zzjonze; Jul 2, 2006 at 02:18 PM.
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I also found a lil purple and orange stripe wire that was broke going back that direction (couldn't trace it down right now but I jumped it together and still nothing.
Does anyone know where I could find a good wiring diagram of fuel system online?
ZZ
Does anyone know where I could find a good wiring diagram of fuel system online?
ZZ
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From: Easton,Ks
Originally Posted by zzjonze
I also found a lil purple and orange stripe wire that was broke going back that direction (couldn't trace it down right now but I jumped it together and still nothing.
Does anyone know where I could find a good wiring diagram of fuel system online?
ZZ
Does anyone know where I could find a good wiring diagram of fuel system online?
ZZ
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Fleet Owner
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From: Easton,Ks
Originally Posted by zzjonze
Thanks Franklin That helps when I know where the wires are suppose to go.
I have found a wire someone spliced in from main pump( Looked orange) in the frame rail and when I put electricity to it I can hear that pump run.
I did check the red wire coming from relay with key on and I got nothing. Looks like my brown wire goes back into firewall loom. any way to test a relay. Kinda hard to find anything open Sunday beofre this holiday. BTW Happy 4th everyone.
ZZ
I have found a wire someone spliced in from main pump( Looked orange) in the frame rail and when I put electricity to it I can hear that pump run.
I did check the red wire coming from relay with key on and I got nothing. Looks like my brown wire goes back into firewall loom. any way to test a relay. Kinda hard to find anything open Sunday beofre this holiday. BTW Happy 4th everyone.
ZZ
The pumps should run, this bypasses the EEC and is also used for checking the fuel pressure with a gauge.
Here is a diagram.
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I think you are right.
I will get out there and work some more on it today. (Unless rain)
Yesterday.. I took old fuel relay end off and pushed the contact at the bottom and the brown wire was hot with the key on, I hear high pressure pump running and fuel lines going to back of the engine move.
I have found another red wire with white stripe( not the one out of the fuel relay) loose but not sure where it goes. It comes from the firewall pins.
I will get out there and work some more on it today. (Unless rain)
Yesterday.. I took old fuel relay end off and pushed the contact at the bottom and the brown wire was hot with the key on, I hear high pressure pump running and fuel lines going to back of the engine move.
I have found another red wire with white stripe( not the one out of the fuel relay) loose but not sure where it goes. It comes from the firewall pins.
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Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
Originally Posted by zzjonze
I have found another red wire with white stripe( not the one out of the fuel relay) loose but not sure where it goes. It comes from the firewall pins.
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Just got it started. But it has come a downpour and I still can't tell exactly what I done.
I'll try to explain what I done.
The doner cab I got the rocker panels from still had wiring harness and relays attached. So I cut them out and removed mine. I spliced the new wires and relays in and checked. I still got 2 wires not hooked up but when I turned the key I thought I heard the fuel pump relay click ( was raining by then) So I tried to start and it fired up and ran on both tanks. I'm relieved to know I didn't melt the computer down.
Many thanks to Dave. I am usually the one people bring stuff to and say here fix it. from computers to cars ect. But I was wondering who I would turn to when I didn't know how to fix somethng.Now I know. Thanks a million all.
I will try to report what I actually done or if it was the ECC relay. But it is raining right now.
ZZ
I'll try to explain what I done.
The doner cab I got the rocker panels from still had wiring harness and relays attached. So I cut them out and removed mine. I spliced the new wires and relays in and checked. I still got 2 wires not hooked up but when I turned the key I thought I heard the fuel pump relay click ( was raining by then) So I tried to start and it fired up and ran on both tanks. I'm relieved to know I didn't melt the computer down.
Many thanks to Dave. I am usually the one people bring stuff to and say here fix it. from computers to cars ect. But I was wondering who I would turn to when I didn't know how to fix somethng.Now I know. Thanks a million all.
I will try to report what I actually done or if it was the ECC relay. But it is raining right now.
ZZ