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Daniel Wilson
Daniel Wilson,
Category: Ford
Satisfied Customers: 4883
Experience:  Owner at DJ Wilson
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I have a 1996 F350 that I just replaced the injectors and

Customer Question

I have a 1996 F350 that I just replaced the injectors and glow plugs. I followed all the recommended procedures to purge the liquid from the oil/fuel rails that may have drained into the cylinders by hand cranking 8-10 revolutions. Fired it up, (after some cranking and resting between tries), ran ok but a noticeable miss and lots of smoke, unburnt fuel, coming out of the tailpipe. Checked a few things and upon inpection of the valve cover gaskets noticed one pin was burnt on the front drivers side pigtail. Went and bought a new one and installed it with new pigtails, now it does not start at all and I noticed that the same pin was burnt on the new gasket after trying to start. When I replaced the pigtails I noticed that they had been replaced before and that there was a bare wire wrapped around the harness wires and covered in black tape, not sure what that is. I dont know where to turn now??
Submitted: 1 year ago.
Category: Ford
Expert:  HDGENE replied 1 year ago.

Hello, if you replace the valve cover gasket it will come with the harness,if it shorted out it could have caused a failure of a fuse of taken out the Injector Driver Module. You would need to check for codes with a scan tool to see if any injector codes are stored. Repair any wiring that is damaged.

Customer: replied 1 year ago.
I dont have a proper code reader, only an OBD2 scan tool, will that work? Also the original valve cover gasket and the new one has the same burnt pin, so that tells me there is a short somewhere. Where would I look for that
Expert:  HDGENE replied 1 year ago.

It will only give you limited information depending on the type of scan tool but will be a start. The burnt wire will depend upon what pin number, colored wire to identify which circuit is having an issue

Customer: replied 1 year ago.
There were no codes, when cranking sounds like it wants to fire but I think only the passenger side bank is working. The wire that the pin is burnt on is black, the very first wire on the pigtail if you look at it from the front facing the driver
Expert:  HDGENE replied 1 year ago.

That goes to an injector or glow plug or at the main connection of the valve cover. What side drivers side or passenger side?

Customer: replied 1 year ago.
Drivers side
Expert:  HDGENE replied 1 year ago.

Ok but for what, an injector connector, a glow plug, main harness connector? I dont know what you are looking at

Customer: replied 1 year ago.
It is for cylinder #1 glowplug
Expert:  HDGENE replied 1 year ago.

OK, the old glow plug wire was burnt, and you changed it and its burnt again, but you replaced that glow plug with a new one? Where was the wiring damaged that you found?

Customer: replied 1 year ago.
I replaced all glow plugs with new ones. When I went to splice the pigtails in for the valve cover gaskets I removed some black tape and noticed that they obviously were replaced before as they were already spliced with butt connectors. What I thought was strange was the middle wires for the pig tail were wrapped with a bare wire then wrapped in tape. The main harness has the two end wires separate from the middle three on the pigtails, these were fine, but the middle three even as I peeled it back had this strange bare wire wrapped with what looked like a tin foil, then a sheath
Expert:  HDGENE replied 1 year ago.

Thats a shielded ground wire probably silver in color. Butt connectors arent a good connection, want to solder together or use a good metal splice with heat shrink, the oil will short it out if exposed. One other thing to inspect is the glow plug relay next to the fuel filter housing. Looks like a big starter solenoid. They can melt over time and cause glow plug circuit issues.

Customer: replied 1 year ago.
but it goes nowhere just wrapped around the three wires, is that ok? I will solder the connections on the new UVC gasket that I will pick up tomorrow. The glow plug relay was replaced last year, but I noticed it was acting funny today. The "wait to start light" would go off and then come back on and it would click on and off. My main question is why wont it fire at all now that I changed the UVC? Is there another problem? Would the glow plug relay have anything to do with a no start?
Expert:  HDGENE replied 1 year ago.

No the glow plug relay only heats the glow plugs, it will still run, just harder to start when cold. Question of if there is an electrical issue or loss of ipc oil pressure. Check for codes with your scan tool, see if anything comes up, clear the codes and recheck to see if there is anything resetting a code. CHeck all connectins in the area you worked on, the injectors and glow plugs can pop apart easy.

Customer: replied 1 year ago.
Ok, I will check tomorow. Do you think the glow plug was bad? They are cheap enough to replace that one, I just find it odd that the same pin is burnt from before I did the glowplugs and injectors untill after. Is there anything else I should be looking for? What else could burn that one pin over and over? It was hard to start after the injector install but it did eventually fire. I realized the valve cover problem when I stood at the back and watched the exhaust while the truck was running, you could hear the sputter as if a cylinder was out, then a second later a puff of smoke
Expert:  HDGENE replied 1 year ago.

WHen you change the injectors it takes a very long crank time to bleed out the air from the fuel system in order for it to run. So not unusual for a really long crank time after the repair on first restart.It is a possible bad plug. You would have to compare resistance on a good known one to the one in question

Expert:  HDGENE replied 1 year ago.

Hello, do you need more help with this concern?

Customer: replied 1 year ago.
I suspect it's an issue with the idm. I tested the voltage to the injectors with the key in the on position and only one injector is getting power and it's only getting 1.1 volts. Not sure if you can check that way. Any advice on testing for power to the injectors or testing the idm?
Expert:  HDGENE replied 1 year ago.

First thing to test the IDM is to see if there any injector driver codes stored when performing a self test on the PCM. They do go bad.

Customer: replied 1 year ago.
I don't have a scan tool. Is there any way to check voltage with a multimeter
Expert:  HDGENE replied 1 year ago.

You can test for power and ground to the IDM in the fender. CThe injectors run off a 115 Volts DC when commanded on so its not the type of circuit you want to backprobe by mistake. You really need to run a diagnostic before probing circuits so you know what area to check.

Customer: replied 1 year ago.
Ok I don't have a tool and I don't want to take it to a shop. The truck is old and only used for pulling a trailer. If I take it to a shop it will cost me a tow and then min $500 to diagnose. I don't mind messing around with it but I'm not spending more $$ on it after dropping $1500 for injectors. I will cut my loses and scrap it. Do you have any educated guesses? If not I will just keep searching the Internet. I thought maybe this service would be more helpful
Expert:  HDGENE replied 1 year ago.

You can probably rent a code reader from your local parts store for free to run a base test for codes which would help confirm if there are any IDM codes. Since you had wiring issues this is a good possibility. DIesels arent cheap to maintain when they have issues I hear you on the injector costs. Its very hard to just guess at these things, You have to be able to monitor icp oil pressure and IPR percentage when checking for no start issues. Many special tools are required to diagnose them properly. Id hate to guess and say buy and IDM and try it without knowing more abou if there are injector circuit codes from the valve cover to the IDM or an IDM fault itself

Customer: replied 1 year ago.
I rented a code reader and scaned the computer but there were no codes. I also check the injector harness from the injectors to the idm for continuity and all checks out. not sure where to go from here. Any suggestions?
Expert:  HDGENE replied 1 year ago.

Can the scan tool do a cylinder contribution test or injector buzz test? That would be whats next to check, if its running rough it can be a faulty new injector or issue with an oring on one of the new injectors causing a leak.Being able to monitor ICP pressure and IPR percentage is another thing to look at. The ICP sensor or IPR solenoid can be leaking oil into the electrical connectors and causing an issue as well

Customer: replied 1 year ago.
It can do a buzz test but nothing happens when I run it. No buzz
Expert:  HDGENE replied 1 year ago.

Ok then that is either an issue with the scan tool or problem with the idm, but you said the truck will start and run, just runs rough at times?

Customer: replied 1 year ago.
After I originally replaced the injectors it fired up and ran rough. That's when I checked the UVCH and found a burnt pin. The next day I replaced the UVCH and tried to start it but it wouldn't fire, crank only. I checked both UVCH's and found the new one had a burnt pin just from cranking I guess. After that I replaced that glow plug and tried again, no luck. From there I have done a continuity test and visually inspected the injector harness back to the idm all checks out. Wondering if I should run a 12v test through each wire from the idm plug to the other end of the harness?
Expert:  HDGENE replied 1 year ago.

Yes, you can do a voltage drop test to check integrity of the wiring. Just odd it wont do an injector buzz test. Curious to know if the ICP is at least 500 psi building up or not, this would tell if there is a problem with the high pressure oil system, The injectors must have a minimum of 500 psi to open and dump fuel and fire the engine. Will it start and run if you spray some silicone spray into the intake?

Customer: replied 1 year ago.
Haven't checked that. Would need to get some. I will check that on Monday as I am away for the weekend. Will get back to you
Expert:  HDGENE replied 1 year ago.

No problem, if it starts with spray, then you know the injectors arent firing

Customer: replied 1 year ago.
How much do you spray into the intake?
Expert:  HDGENE replied 1 year ago.

Just for a few seconds to get a small charge in the engine to see if it will try to fire.

Customer: replied 1 year ago.
Ok thanks
Expert:  HDGENE replied 1 year ago.

No problem, its most likely gonna come down to an issue in the area you were working in since it ran before and now it wont.So double check everything you were involved with. Even with the one connector burnt the truck ran prior.

Customer: replied 12 months ago.
Hi There,Finally got a hold of a guy with a proper scan tool. We did some tests last night and came up with the following three codes P1274, P1294 and P1295. We tested all of the wiring from the injectors back to the IDM and all checks out ok. Tested the resistance in the injector harness and there is less than 3 ohms resistance. We checked ICP and while cranking we are getting over 3000 psi. Do you have any advice from here? We swapped out the IDM already for one we thought worked, but when we did that it threw even more codes all relating to high to low open side for all cylinders.
Expert:  Daniel Wilson replied 12 months ago.

Hi Peter, My name is***** will be glad to help with this. First lets confirm is this the 7.3L you have or 6.0L?

Expert:  Daniel Wilson replied 12 months ago.

with your scan tool set in live data watch for crank sensor signal and tach response for a possible faulty crank sensor or harness issue. If the ECM gets no RPM signal the injectors wont be commanded to fire. Also verify fuel pressure. Should see around 80 PSI and ICP pressure around 870PSI to start. disconnecting the ICP sensor will put the ECM in default status and try starting with the sensor unplugged forcing the ECM to use default pressure values. Let me know the results.