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Hello all,
I am working on a friend’s 2002 Ford Taurus SES with the 3.0 Vulcan Flex Fuel Engine.I am having an odd problems, it seems like a vaccum leak, and I have fixed 2 Vaccum leaks so far. One on the hard line on top of the engine going from the Vaccum Tree to a T on the other side, and a new PCV valve, line and elbow.
It is getting codes P0402 P1406 and was getting a Cat code, running the car at highways speeds for an hour cleared the cat code (he only drives 5 min each way to work and home pretty much). He has done zero maintenance on this car besides oil changes. Last night I did a the test with few cans of carb cleaner. The only time I heard the idle change was when I sprayed by the intake Plenum, but it only happened once. I have read it could the be EGR Valve, or the DPFE Sensor and as a last resort the Plenum. When I take off the vaccum line for the EGR and cover it with my finger, nothing changes, it still runs a little rough and sounds like a small miss is happening in the engine (like it “normally” does). This makes me think it is not the EGR. I probed the back of the DPFE and I got 5 volts pretty steady, but I haven’t tried a full test on it.
could it be another Vaccum leak I can’t find? Is the DPFE sensor gone?
I am thinking of pulling the plenum, then cleaning the EGR (or replace it for 30 bucks), while I am there, change plugs and wires and then toss it back together.
Any help on what it could be would be great before I get into it more, I don’t want to start throwing parts at it, but after spending 2 night rebuilding the brakes and linkages before I touched the engine, I am pretty much tired of look at this car.
thanks everyone!
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Thanks, I’ll check them out.
I forgot to mention that his A/C is still running through the defrost vents too, so I really think its a vaccum issue.
The HVAC could be a vacuum problem as you suggest. It can also contribute to the codes you have. It’s a good idea to cover the basics though. More information on performance diagnosis can be found here.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Good luck and keep us posted.
If it wasn’t for the HVAC default to defrost vent….the car only driven 10mins a day… I would say carbon deposits stuck inside the EGR valve holding it open slightly.
Main vacuum source is on the top of the plenum right side of the DPFE Sensor. ….also if I remember, those cars had a vacuum reserve tank.
Please post what you find.
It’s the DPFE sensor, when I connected a volt meter to it, I was pulling .9 to 1 volt DC. When I applied vacuum to the EGR and the engine started running rough, it went to 3.5 to 4.5 volts (within threshold). When I released the vacuum and the engine returned to more normal idle, the voltage never dropped. Seeing the engine ran better once the vacuum was off, I assumed that the EGR is good (my minivac doesn’t have a gauge).
I bought a new DPFE sensor today and will toss it in tonight. I also put all new plugs in it, seeing its a Ford, I put in Autolites last night and Autolite Plug Wires. The vacuum leak for the A/C has to be under the dash, cause the T that is sending vacuum to the A/C system is getting vacuum and the vacuum thing in the fender for reserve is getting vacuum. I have checked all over vacuum lines with a can of carb cleaner too, several times. So I don’t need that for inspection, then it won’t get fixed.
Seeing I have fixed 2 vacuum leaks including the PCV and a broken line, it was already running much better, the new plugs and wires (that aren’t melted to the firewall) and new filters, it should run pretty solid.
I’ll let you all know how it turns out tonight. Also, thanks for the video on suspension noises, after fixing the linkages and such on the front end, the car was banging still. Turns out the Transmission mount is bombed out and depleted.
Good find! I agree that there could be a vacuum leak under the dash. Look at the back of the control itself. I sometimes find leaks there.
Keep us posted.
I got it all running, the DPFE and spark plug wires and vacuum fixes did the trick. the new transmission mount fixed the banging in the left front and it shifts better, imagine that. It passed inspection, so its good. In the fall I am going to change the other 2 motor mounts on the right side as they look a bit suspect and a fuel filter it should be good. At that time I’ll look for a vacuum leak behind the dash as well.
thanks everyone for your help!
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