I have a 2002 5.4 with 30,000 miles. At 4500 miles it developed an idleing problem. Dealer reflashed computer but this did not solve problem, ended up needing 2 new oxygen sensors. At 17,000 miles and in cold weather it started puffing a bluish grey smoke on start up and only on start up after sitting for aprox 8 hrs. Dealer states this is normal and says even a new truck will do this. He says he can not reset the PCM to factory settings. I also asked if this could be caused by something else like valve seals and was told they never have problems with seals and it is just normal for the truck. After arguing with him that I know other 5.4 ltr engines that don't do this Dealer became quite upset and said there is nothing they can do.!!!!

As the truck did not do this new I feel something has changed and needs to be fixed. I,m taking it to another Ford Dealer as it is still under warranty ( 4 months left ) and I don't want to be paying big bucks later.

Any ideas or suggestions would be greatly appreciated !!!!!!!!!!!

Thanks Jim B.

 

Needing two new O2 sensors and the bluish-grey smoke are probably related. Do you lose coolant? That slowly poisons O2 sensors and causes grey smoke.

 

I haven't lost any coolant. The dealer states the bluish smoke is exhaust caused by the pcm telling the engine how to start.

Would a 5.4 ltr in a 2002 F150 be calibrated differently than a 5.4 in a 2002 F250??????

JIM

 

I could have sworn I had already posted this response. Or something very close. The PCM cold starts the trucks very rich. The principal sensor for fuel calculation before startup is the ECT or engine coolant temperature. You could check it with a scan tool. If nothing else, it should read close to IAT before a cold start. But the problem with this is there is nothing blue or grey about over rich exhaust. Sounds like some oil and some coolant to me. But it's very hard to tell from a description.

Replacing light truck emissions parts, like the PCM, with a >14,000 GVW part is tampering. They are also very, very different. Although the basics are there, things like post cat efficiency monitoring aren't. The bible on what Ford OBD does in various model years is the "2004 MY OBD System Operation Summary for Gasoline Engines" or just substitute your year for 2004. There's a free copy here:

www.motorcraftservice.com/ vdirs/diagnostics/pdf/OBDSM404.pdf

I've pretty much read the entire book because I'm trying to land a job at a Ford dealership. Fascinating stuff. One of the sections is the differences between the >14,000 GVWR vehicles and the passenger car/light truck controls.