2007 f150 VCT problem
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Junior Member
Joined: Mar 2018
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2007 f150 VCT problem
Im new to the forum and i need help with my 2007 F150. It has 135k miles and has always run good. About 3 months ago it started to idle rough when it was warmed up, I assumed it was time to do a complete timing chain kit fix. Last week I finally had time so I started the project, I replaced The timing chins, Phasers, VCT solenoids, guides and oil pump. Put it all back together, primed the oil pump and started it up. It started right up and ran fine until it warmed up and i started to drive it. When I stopped the first time it started to idle rough again. I disconnected the passenger side solenoid and no change, when I disconnected the drivers side everything runs fine. I checked the oil pressure and its about 26psi when the engine is warmed up. Does anyone have any suggestions?
Senior Member
Joined: May 2015
Posts: 362
Likes: 11
From: San Antonio, Tx
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When I stopped the first time it started to idle rough again. I disconnected the passenger side solenoid and no change, when I disconnected the drivers side everything runs fine. I checked the oil pressure and its about 26psi when the engine is warmed up. Does anyone have any suggestions?
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When I stopped the first time it started to idle rough again. I disconnected the passenger side solenoid and no change, when I disconnected the drivers side everything runs fine. I checked the oil pressure and its about 26psi when the engine is warmed up. Does anyone have any suggestions?
However, when there IS a change ... consider these things.
The VCT solenoids spool valve _should_ be closed at idle, routing 100% oil flow into the advance oil passageways to advance chambers of phasers. The PCM does NOT apply any duty cycle control signals to the VCTs below 800 RPM, OR below ~25% engine load - thus the VCT spool valve should be totally closed. Unplugging one could only INSURE there is no current flow in the VCT coil and thus the spool valve _SHOULD_ be closed -routing 100% 'available' oil flow/pressure into the advance chambers / holding phasers at full advance (or NO retard).
IF unplugging a VCT improves idle - it MUST have been allowing a small amount of oil flow/pressure get into the advance chambers / oil passageways. (either sticky spool valve and bumping it caused it to close --- OR spurious current flow in the VCT coil holding it partially open). The latter possibility would be eliminated by PLUGGING it in again to check if the rough idle returned. If the rough idle returns, the problem would be WHY is current flowing in the solenoid coil when the PCM is not calling for retard. If it did not - the solenoid is not closing properly (- bad out of the box).
Hope this helps.
Last edited by F150Torqued; Mar 30, 2018 at 09:59 AM.