Taurus Car Club of America : Ford Taurus Forum banner
1 - 18 of 18 Posts

·
Registered
Joined
·
39 Posts
Discussion Starter · #1 · (Edited)
OK, so I have replaced all 3 EGR components. The code P0401 still comes up, EGR insufficient flow. P0411 smog pump comes up also...takes longer to register, more cold starts, but it's there.

I replaced EGR vacuum solenoid first. The plastic part was broken off anyway, and would not bolt on to the intake manifold, so I was using a zip tie to hold it in place. New one, no change. I used a multimeter on all plugs, correct voltage and resistance everywhere.

Haynes manual says apply vacuum directly to EGR valve, and it should hold 4-5 on the vacuum pump. Mine did not. I removed it, cleaned it all up, and put it back on. Still would not hold vacuum. Bought a new one and put it on. Funny...it "failed" the vacuum test as well. So I guess Haynes has incorrect info on that test. That sucks. But a new part won't hurt. Still no change, error code still on.

Today put a used DPFE (EGR sensor) on. The other parts were new as I could not find a used one in a parts yard, and I'm tired of spending money. the DPFE is more common on more years. Put it on today and took the car for a drive. no change. Check Engine Light came back on, EGR insufficient flow.

I have removed the EGR tube and it is clean and no blockages. I have checked the intake manifold (which was new about a year and a half ago, brass tube was broken by previous owner and coolant was leaking out) and the UIM is clean, no blockages. Multimeter shows correct voltage everywhere, and all tubes are clean. Vacuum hoses do not leak to my knowledge, checked all.

Why the error code? What else can I check? By now, all 3 EGR componants have been replaced and the error code is still there. What gives? Maybe DPFE is bad, replace with another?

PS...car drives fine, by the way.
 

·
Registered
Joined
·
56 Posts
Hi
If EGR valve doesn't hold vacuum, it is broken (no matter now long ago you purchased it) - or your vacuum pump (or hose) is broken.
After you fix that and you are sure that EGR valve is OK, simply start engine, let it idle and apply 4-5 psi of vacuum to EGR valve - RPM should drop significantly (usually, engine stalls here).
If it doesn't happen, you have blockage in EGR passage in upper intake manifold what has to be cleaned by wire and proper solvent. Not familiar with 2000, in 1993 I had to remove upper intake manifold to do that.
 

·
Registered
Joined
·
39 Posts
Discussion Starter · #4 ·
Well, the vacuum gauge wasn't working right, would not hold vacuum. I took it back to AZ and returned it, went to another location to get another one. This one works.

EGR valve holds vacuum, steady no problem.

I started her up and let the engine idle. I pumped vacuum up to 5 and the engine sputtered, but never did stall. I took vacuum up to 10 and even 15, same. But the pintle in the valve will only go so far, so no change was expected.

I cleaned up the throttle body and also removed the UIM and cleaned out the port to the EGR. Lightly powdered with black carbon powder, very minor. But I cleaned it all up. Flow of air was never blocked. But, I am approaching this in a systematic manor, touch all the bases...

Now I'll clear codes and take it for a drive. See what happens.

If the code still comes back, what then?
If it doesn't, I'm done. That's what I want...
UPdate later tonight or tomorrow.
 

·
Registered
Joined
·
56 Posts
Looks like EGR valve and passage is OK.

If you will have a code again, the next step should be for a component what modulates vacuum for EGR valve. Not sure about 2000, in 1993 it was a valve with solenoid, vacuum inlet and outlet. Engine vacuum has been connected to inlet, EGR valve to outlet. If 12V is applied, valve is opened, if not it is closed, so it is easy to check.
For a first step, try to disconnect vacuum hose from EGR valve, connect to gauge and measure vacuum when RPMs are ~2000-3000. On idle there should be no vacuum, on high RPMs, there should be ~4-5psi.
 

·
Registered
Joined
·
39 Posts
Discussion Starter · #6 ·
The CEL did come on again.

The vacuum solenoid is brand new.

I will do those tests tomorrow to see what results I get, and report here.
 

·
Registered
Joined
·
23,579 Posts
To test egr valve, remove vac. hose and replace with a scrap piece of hose. With engine idling, suck on sampling hose opening egr flow to uim (manifold). Eng. should stumble or die signalling egr valve is working properly because there should be no egr flow at idle or wot (wide open throttle).
 

·
Registered
Joined
·
23,579 Posts
Fwiw, out of the 3 egr components ive never had to replace any but the dpfe on 15-20 cars. Prob. replaced it on all of them. Dpfe is not a good salvage yard item choice. Odds on getting a good one are low.
 

·
Registered
Joined
·
1,365 Posts
Well, the vacuum gauge wasn't working right, would not hold vacuum. I took it back to AZ and returned it, went to another location to get another one. This one works.
Now you just need test equipment for your test equipment. :D

Sheila is right, most junkyard DPFEs will be bad. There is a test procedure for DPFE correct voltage. If you can access the sensor you can backprobe the terminals.

http://www.tomco-inc.com/Tech_Tips/ttt36.pdf
 

·
Registered
Joined
·
39 Posts
Discussion Starter · #12 ·
OK...replaced DPFE sensor with a brand new one, Borg Warner, from O'Reilly's.

STILL get the error code insufficient flow EGR.

By now, all 3 EGR components have been replaced, with BRAND NEW PARTS. Applying vacuum to EGR makes the car have a rough idle. There is correct voltage to the plugs. The EGR port has been cleaned.

Still, the error code persists. What to check now?
 

·
Registered
Joined
·
65 Posts
Is the CEL light coming on, or are you scanning memory codes? No CEL, clear the memory. CEL on, You might try to trace the vacuum line from EGR valve back for cracks or breaks.
 

·
Registered
Joined
·
23,579 Posts
Did you clear the po401 code after installing the new dpfe sensor with a scan tool or by disconnecting batt. neg. cable for a few mins.? If so, i would check the elec. wiring to the dpfe and its 2 hoses. Also check egr valve vac. line for breaks or leaks.
 

·
Registered
Joined
·
39 Posts
Discussion Starter · #15 ·
I know you've asked an obvious question, but of course I cleared the code with a scan tool. I use OBDCOM, software on my laptop with a USB cable that connects to the car connector under dash. Code was cleared, the CEL was out. In a short drive of about half an hour, the CEL came back on. I read the codes, and got insufficient flow to EGR.

I am also getting insufficient flow for smog pump. Could the two be related? I know they are supposed to be completely seperate and unrelated. I was getting smog pump error code a long time before.

Will double check, again, vacuum lines and electric lines to DPFE and EGR vacuum solenoid.
 

·
Registered
Joined
·
56 Posts
As for now, after all work you did, the only two things are certainly known:
1. EGR valve is good - you tested it;
2. EGR passage in throttle body is not blocked - you personally cleaned it up.

All other things are unknown. You replaced solenoid and sensor, but you didn't say that you tested them, so you cannot be sure that new ones are operational.
For example, did you test solenoid valve operation?
Did you measure vacuum on EGR solenoid outlet at high RPMs?

And, by the way, even if everything in EGR system is OK, you may have insufficient EGR flow if you have major exhaust leak and backpressure in exhaust pipe is not enough to maintain sufficient EGR flow.
 

·
Registered
Joined
·
1,365 Posts
I am also getting insufficient flow for smog pump. Could the two be related? I know they are supposed to be completely seperate and unrelated. I was getting smog pump error code a long time before.
I suppose if the check valve in the air pump line to the exhaust has failed you could have low backpressure. I looked at Mitchell's to see what the pressure should be at the two supply hoses to the DPFE, but can't finad any values. Check both hoses while running though just to make sure there is some positive pressure in each. If the low hose isn't outputting, the orifice in the main supply tube from the EGR may be blocked. Also, according to Mitchells, the electric air pump supplies air to both the exhaust manifold and catalyst, so look for rust-though in those spots. The diverter valve that allows flow from the exhaust is computer + relay controlled, so you'll need to look at that assuming the electric pump motor is working.
 
1 - 18 of 18 Posts
Top