4.9L No Fire
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Mountain Pass
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4.9L No Fire
I swapped a 4.9l into a 1997 F-350 that had a 5.8L originally, my issue is the fuel injectors are not working. I did my homework and got the harness that was with the engine out of a 1995 F-150 and also got the correct PCM to go along with my E4OD tranny that is in the F-350. It has spark and 60 plus PSI fuel pressure in the rail and will run with starting fluid shot in the throttle body. Both vehicles came with OBD I so should be compatible there. I do not have 12v to the injectors and obviously the NOID light shows no pulse either. Could be a ground but not sure where to look or what else could cause this. I am so close to getting this running thanks for any and all help.
Brian
Brian
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From: Virginia
See that "PCM power relay" in the diagram in this link?
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=2020
That red wire is how the injectors and everything else gets power.
Here' some other diagrams for a 95 4.9 engine.
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=2021
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http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=2020
That red wire is how the injectors and everything else gets power.
Here' some other diagrams for a 95 4.9 engine.
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=2021
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Mountain Pass
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I realize that I need to find out why I do lot have 12v. Thanks for the diagrams, If I have power to everything except the injectors where do I start probing? It can't be the power relay we'll maybe if one set of contacts is burned but the fuel pumps work and I have spark.
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From: Virginia
s149 and s158 are factory splices. You need the factory manual and diagrams to find the locations, in 95 the factory had this info on cd's also. "s' is a splice, "c" is a connector.
The factory splices are many wires welded or soldered together and then wrapped with tape and in the factory looms. If you look at the factory loom, and see many branches or smaller looms coming off of the main loom, there is a good chance there are some splices under there.
Something else that might give you a clue is to read the codes. The computer may spit out some codes and that may give you hints as to where the problem is located. For instance if you have a code 18, that is a code that says the computer is not getting signals from the distributor. If the computer is not getting codes from the dist, then it thinks the engine is not running and it will not turn the injectors on.
But you said you are not getting power to the injectors correct? I guess you know power is fed all the time the key is in run to the injectors, and the computer grounds the other side to fire the injectors.
The factory splices are many wires welded or soldered together and then wrapped with tape and in the factory looms. If you look at the factory loom, and see many branches or smaller looms coming off of the main loom, there is a good chance there are some splices under there.
Something else that might give you a clue is to read the codes. The computer may spit out some codes and that may give you hints as to where the problem is located. For instance if you have a code 18, that is a code that says the computer is not getting signals from the distributor. If the computer is not getting codes from the dist, then it thinks the engine is not running and it will not turn the injectors on.
But you said you are not getting power to the injectors correct? I guess you know power is fed all the time the key is in run to the injectors, and the computer grounds the other side to fire the injectors.
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From: Virginia
You can see in this diagram, each injector has it's own different colored ground wire going to the computer. That tells me this engine is sequentially fuel injected, some engines group the injectors together and they are batch fired injection.
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=2021
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=2021
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Mountain Pass
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Dave thanks for the great info, the engine will run with stater fluid so I know it is down to the injectors not firing is the only thing left to figure out. Are you saying the 1995 4.9l in F-150's was sequentially fired? I will have to start at the injector loom and work towards the PCM to see where the circuit is broken. Looks to me like it is not getting the constant 12v so I do not believe it is the PCM as everything else works fine.
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Mountain Pass
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OK Here is what I found, the connector from the underhood fuse box is missing the one pin that puts 12V switched power to the injectors. It is not broken it is missing. Must be something different from the 5.8L. Luckily I have a 1995 F-150 with 4.9l and E4OD so I pulled that connector apart to see and the one pin looks to be the only difference. I started by checking and finding the wire in the engine loom that is the power wire to the injectors and when I got to that connector no power so I pulled it apart hoping it was corrosion but pin is not there. Do you think if I jumped 12v switched power to the injectors it will fire? Everything else seems to be working OK so far.
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Mountain Pass
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I may have to go to pick n pull and grab the whole underhood harness with the fuse box. The fuse box is identicle to the one on my f-150 so I may try to put power to the injectors with a jumper just to see if it will run.
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Mountain Pass
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OK I got a complete underhood harness with fuse box from 1993 F-150 with 4.9l and E4OD tranny. I pretty sure this will work and fix my problem. I have one question and that concerns the tranny. In 1995 they moved the solenoids from the tranny to the pcm. I know I have the correct PCM but it there any difference in the harness from 1993 To 1995?
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From: Virginia
You are getting deeper than I ever have on this. But I don't understand how they can move the solenoid that actuates fluid in the transmission to the PCM which is usually mounted inside the cab somewhere.
I did a quick check of transmissions and something else that might be a problem; When I went to look for a transmission for a 1993 they gave me choices from 1992-1994. When I looked for a transmission for a 1995, they only gave me 1995 choices. Something is different.
I did a quick check of transmissions and something else that might be a problem; When I went to look for a transmission for a 1993 they gave me choices from 1992-1994. When I looked for a transmission for a 1995, they only gave me 1995 choices. Something is different.