Questions about VCT System - P0012 and P0021 Codes
I have a 2005 Expedition that I recently bought at an auction so I don't have any service history on it. It has 160k. When I bought it had the following codes: P0012, P0021, P0345, P0349 and P0316. It lacked power at 3500-4500 RPMs and sounded like a diesel at idle but otherwise seemed to run fine. My mechanic found the left timing chain guide was broken and one of the phasers came apart when he was removing it. He installed 2 new Dorman phasers, Cloyes timing kit with guides/tensioners, checked VCT solenoid screens, changed the oil with semi-synthetic 5w-20 (didn't use Ford oil or Motorcraft filter) and replaced 1 camshaft position sensor. He said that he saw very little sludge. He said it was running fine but I couldn't notice any change other than it stopped making noise. It still had P0012, P0021 and P0346 codes. I replaced the other camshaft position sensor and the P0346 hasn't returned. I driven it for 300-400 miles since I got it back. It seemed to run best immediately after clearing codes and when it was cold. But it feels like it has a miss taking off from of a stop with light throttle. It pulls pretty good throughout the RPM range at partial throttle opening, but seems real bogged down at fuel throttle from 3500-4500 RPMs. It has an intermittent rough idle, but it happens more frequently when engine is hot. It started surging a few times as much as 1000rpm but I have only noticed that when it is hot. It still has the P0012 and P0021 and it throws misfire codes when it is surging. They were always different cylinders and one time it through a random misfire code. My mechanic thought AC voltage may be leaking into the system causing errors in camshaft position reading so I replaced alternator and both coil suppressors but there was no change.
I am not sure if it is still a problem with VCT system or if the timing is off. My mechanic said he checked timing several times before putting everything back together. My understanding is the VCT is only active when engine is warm and above 3500 RPMs. Is that correct? If I clear codes it shows the P0012 and P0021 immediately after the next startup even if engine is just left at idle. So I wonder if the timing may actually be off. If the VCT system may still be acting up. Does anyone know if Dorman phaser work properly? Or should I have used OEM? We haven't replaced VCT solenoids, but if the solenoid was bad it would throw a code for it correct? Should I try new VCT solenoids? I haven't put an oil pressure gauge on it yet. I have never seen a low oil pressure light, but know that isn't a good indication. If the VCT system could be active at idle I am guessing that should be next step? Anything else I should look at? Thanks
Sounds like its out of time and the surge could be bad spark plugs. The VCT starts working above 1200 rpms hot or cold. The only experience I have with aftermarket phasers is one failed and I replaced it with a OEM part. The phaser did not fit on the cam properly and damaged itself and the cam. Not sure if it was a Dorman part.
Thanks for the response. I am going to have the mechanic check the timing again. I forgot to mention that he also replaced the plugs so they shouldn't be causing the surging. Hopefully those Dorman phasers are ok. They were $90 each instead of $240 each through Ford so I tried to save some money since I don't know if I am keeping the vehicle or if I am going to resell it.