rough idle
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New User
Joined: Mar 2009
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rough idle
I have an 02 F-250. This winter it developed a rough idle when I first start it. After about 1-5 minutes it will smooth out and run fine. It doesn't do it all the time. I did get a P1316 code. Where do you start with out tagging the wrong area.
Hotshot
Joined: Jan 2008
Posts: 13,144
Likes: 11
From: Rochdale MA
Welcome to FTE. Can you tell us a bit more about your truck? Any tuners or chips? My truck does that every once in a while. I changed to SYN oil and it made a huge difference in the idle. How cold is it when you have this issue?
P1316 Injector Circuit/IDM Codes Detected
Others will chime in.
P1316 Injector Circuit/IDM Codes Detected
Others will chime in.
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
Welcome to FTE. How long have you had the truck, how many miles are on it, and how often do you change the oil? Higher mileage and lack of routine maintenance can cause the poppets to stick inside the injectors on a cold engine.
A cheaper and easier thing to check, would be for a loose connector on the UVCH (under valve cover harness) If you have a multi-meter capable of reading ohms, locate the wire connector that plugs into the inboard side of each head at the valve cover. Unplug the wiring, and you'll see the connector at the valve cover has 9 pins inside it. Ohm the front 2 and rear 2 against a good ground. These attach to your glow plug wires and you're looking for a reading between 0.1 - 2 ohms. Next ohm the 3rd, 4th, 6th, and 7th pin against the center 5th pin and look for a reading less than 5 ohms. These are for your injectors. If the plug inside the valve cover is loose, it will throw a P1316 code and cause the truck to run rough. Try doing the ohm test when the engine is cold and you would expect it to give you the problems you're describing.
A cheaper and easier thing to check, would be for a loose connector on the UVCH (under valve cover harness) If you have a multi-meter capable of reading ohms, locate the wire connector that plugs into the inboard side of each head at the valve cover. Unplug the wiring, and you'll see the connector at the valve cover has 9 pins inside it. Ohm the front 2 and rear 2 against a good ground. These attach to your glow plug wires and you're looking for a reading between 0.1 - 2 ohms. Next ohm the 3rd, 4th, 6th, and 7th pin against the center 5th pin and look for a reading less than 5 ohms. These are for your injectors. If the plug inside the valve cover is loose, it will throw a P1316 code and cause the truck to run rough. Try doing the ohm test when the engine is cold and you would expect it to give you the problems you're describing.
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The truck has 75,000 miles on it. using Rotela oil and it was just changed. I originally thought it was in the cold weather but we have had a couple of days in the 40-60 degree range and still had the issue. The truck is bone stock. This winter the oil went longer than normal for me, about 4500 miles. I refuse to crawl under the truck at 20 below. Interesting enough I changed the fuel filter and it quit for a couple of days but started again. I changed it again last week with no new results. Must of been a fluke
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
The poppets are internal pieces of the injectors, so it's not really a DIY thing. If you think it's injector issues after exhausting all other possibilities, it's worth paying to have it tested on a scanner before you dump a bunch of money into injectors.
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New User
Joined: Mar 2009
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Thanks, hopefully it is just loose wires. I did replace the glowplug relay this winter. Could wiring have caused that to fail?
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Cargo Master
Joined: Jun 2003
Posts: 3,292
Likes: 6
From: Ardenvoir, Washington
Great news.. glad you got her fixed.. I bet there are a lot of 7.3's on the road with loose UVC connectors.. I fixed mine awhile back ... I hope you secured the connectors with a shim or Ford's plastic repair clip.. or they will come loose again..
