95 w'star 3.8l dpfe

ok guys i'm at a dead end here maybe someone has an idea. replaced the dpfe this weekend and took the cowl off to try and search for the vaccum leak that is causing my 0171 & 0174 codes can't seem to find anything that would be sucking air. the p1407(exhaust gas recirculation no flow detected) code showed up again after about a day. new dpfe and new hoses and i checked for flow with the engine running and they are both blowing air out of them. anyone ever seen the movie "the money pit"

ok guys i'm at a dead end here maybe someone has an idea. replaced the dpfe this weekend and took the cowl off to try and search for the vaccum leak that is causing my 0171 & 0174 codes can't seem to find anything that would be sucking air. the p1407(exhaust gas recirculation no flow detected) code showed up again after about a day. new dpfe and new hoses and i checked for flow with the engine running and they are both blowing air out of them. anyone ever seen the movie "the money pit"

I think that if you removed the hoses to the DPFE you would get "air blowing out of them" whether the EGR was open or not.

P1407 seems to be a different code for the DPFE than the one or 2 that are most common. In any event can you try and manually open the EGR valve using a vacuum gauge while the engine is idling? If the valve opens the engine will run rough and eventually stall. If it does so then you can be sure that the EGR valve and tubing works. Perhaps thens you should look at the vacuum control of the EGR. This would also explain the 171/174 codes.

thanks for the advice drw1000, i pulled the green vaccum line off the egr valve and started the engine and sure enough no vaccum. traced it down to the solenoid and pulled the vaccum lines off of it and the little plastic nipple on the solenoid was stuck in the red vaccum line. so maybe that was my problem all along, but is there supposed to be any vaccum going to the egr when the engine is first started (cold)?

thanks for the advice drw1000, i pulled the green vaccum line off the egr valve and started the engine and sure enough no vaccum. traced it down to the solenoid and pulled the vaccum lines off of it and the little plastic nipple on the solenoid was stuck in the red vaccum line. so maybe that was my problem all along, but is there supposed to be any vaccum going to the egr when the engine is first started (cold)?

The EGR valve should only be commanded on when the engine is warm and reving above 2500 RPM or so. At idle it should be closed. You should have vacuum to the controller at all times. When the PCU wants the EGR on it will send a signal to the controller and this will in turn apply the vacuum to the EGR valve.

I do not know the configuration of the 95s but this is a typical set up.

Since you have a potential vacuum leak (171/174) and a faulty EGR system it is very possible that the 2 are related and I would suspect the vacuum line from the intake manifold to the controller or the controller to the EGR valve.

I hope this helps.

uzzo2
Also check the vacume hose on top of the upper intake plenum. The elbow dries out and the vacume leaks by or actuall sucks the elbow closed. I used a pre bent water pump bypass hose the same diameter cut it in half and made my own with one to spare because it was 90 degrees on both ends. Look at help section at Autozone. Also check your pcv valve and the grommet it goes into.