7.3 no start issue
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Mountain Pass
Joined: Nov 2010
Posts: 176
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7.3 no start issue
Ok so i have a 95 7.3 powerstroke manual it cranks but doesn't fire. I replaced the cps unplugged the icp sensor and still no smoke out the tailpipe the oil level is full in the motor and the hpop reservoir. I haven't tested fuel pressure but the fuel bowl does fill fast and I did make sure the main fuse was good. I also rebuilt the whole fuelbowl and regulator with new orings from diesel orings. So it cranks and reads on the tach no smoke out the tail pipe has around 240k miles and yes there is fuel in the tank. What's next? I got a Bluetooth obd adapter but for some reason the apps I'm using won't communicate with the ecm so i can't see what the hpop is doing does anyone have any suggestions. My dad's 97 has this wierd chip like anti theft thing under the dash and mine doesn't is that normal? So please help. I also did read many threads and went through the checklist matrix thing but now I'm stumped
Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
You might be able to pull the icp sensor out of the head and bump the starter to see if the HPOP is moving any oil.... It will make a mess and really probably isn't recommended but it would rule that one out.
When I say bump, I mean bump lol
When I say bump, I mean bump lol
Thread Starter
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Mountain Pass
Joined: Nov 2010
Posts: 176
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The icp sensor I think is already bad since the inside is covered in oil but I'll try it and let u know what happens. Is there a way to test to see if the injectors are even getting a signal or do I just assume the wiring is good? I have no reason to believe it's not but I'm down to desperate measures.
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
Ok so i have a 95 7.3 powerstroke manual it cranks but doesn't fire. I replaced the cps unplugged the icp sensor and still no smoke out the tailpipe the oil level is full in the motor and the hpop reservoir. I haven't tested fuel pressure but the fuel bowl does fill fast and I did make sure the main fuse was good. I also rebuilt the whole fuelbowl and regulator with new orings from diesel orings. So it cranks and reads on the tach no smoke out the tail pipe has around 240k miles and yes there is fuel in the tank. What's next? I got a Bluetooth obd adapter but for some reason the apps I'm using won't communicate with the ecm so i can't see what the hpop is doing does anyone have any suggestions. My dad's 97 has this wierd chip like anti theft thing under the dash and mine doesn't is that normal? So please help. I also did read many threads and went through the checklist matrix thing but now I'm stumped
One parameter you want to look at is IPW (injector pulse width). When the PCM see's valid CPS pulses it will change IPW from 0.0 to 0.4 ms. This means the PCM and IDM are in sync, valid CPS pulses and waiting for high pressure oil to ramp up. This usually happens very fast. Once HP is ~ 500 PSI or above the IPW will change from 0.4 ms to over 1.0 ms and the injectors will fire. Also just because you see RPM doesn't necessary mean the CPS pulses are correct. Is the new CPS a Ford dealer part or did you get it at an auto store (bad), Ford part only here please?
Unplugging the ICP would allow the truck to start so I doubt that's the issue, however if the inside of the plug connector is covered in oil then it's bad and needs replaced at sometime.
There is so much interacting in a short period of time is is very difficult to troubleshoot without a working scanner to point one in the correct direction. A guessing game.
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Mountain Pass
Joined: Nov 2010
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I'm using forscan and dash command it's powering up the Bluetooth adapter and it's connected to my phone but says can't connect to the ecu is a 95 obd2? And it had a new ford cps in it but I bought a cheap one from autozone it was a weekend and I needed it
And the idm being bad wouldn't matter if I wasn't getting any fuel into the cylinders at all right. I'm gonna test fuel pressure at the regulator to rule that out
And the idm being bad wouldn't matter if I wasn't getting any fuel into the cylinders at all right. I'm gonna test fuel pressure at the regulator to rule that out
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Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
I'm using forscan and dash command it's powering up the Bluetooth adapter and it's connected to my phone but says can't connect to the ecu is a 95 obd2? And it had a new ford cps in it but I bought a cheap one from autozone it was a weekend and I needed it
And the idm being bad wouldn't matter if I wasn't getting any fuel into the cylinders at all right. I'm gonna test fuel pressure at the regulator to rule that out
And the idm being bad wouldn't matter if I wasn't getting any fuel into the cylinders at all right. I'm gonna test fuel pressure at the regulator to rule that out
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Thread Starter
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Mountain Pass
Joined: Nov 2010
Posts: 176
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Hey sorry for not getting back to you guys I ordered a motorcraft cps and I'm gonna try the icm from my dad's truck. Now the new thing that came up is I pulled the valve cover on the passenger side and 3 of the 4 yellow wires have the insulation cracked and u can see the core they weren't grounded out or anything and the plugs look good and I have continuity between them at the injector to the external plug any idea?
Postmaster
Joined: Sep 2007
Posts: 4,195
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From: Medford Oregon
On the wiring pics it looks like someone removed a section of insulation for troubleshooting purposes. I doubt it will hurt anything at this time. You indicated you rebuilt the fuel bowl. Was this before or after this problem. Checking the fuel pressure is cheap and easy and you need to rule that out. Just because the bowl fills up fast means nothing as the fuel pump is a two stage. Top part is the suction from the tank and fills the bowl, bottom section is the high pressure piston that feeds the heads. While cranking you should see ~ 20 PSI or more, use a cheap stick type tire gauge if necessary, a bit messy but functional.