egr

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Old 11-04-04, 07:50 AM
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egr

The car: '94 ford Taurus w/ 3.0L V6 and 150,000 mi.

The problem: always have a KOER code 332 and same code sets while driving maybe 1 in 20 trips and the check engine light will stay lighted until the car is restarted.

I have inserted a tee and vacuum gage in line to egr valve. Vacuum is zero at idle as I expected. When I rev the engine and hold it, the vacuum will go to 8" and then drop to 0 in about 4 seconds. I guessed the vacuum should be steady and higher since I recorded 15" at the inlet to the control valve. I replaced the control valve with a dealer part for $45, but I was wrong.

I checked the voltage at the valve and got 14 volts always. The vacuum will change as described above but the voltage is constant. I did not expect this. Is the voltage switching on and off faster than my $10 radio shack multi meter can pick up? How is valve designed to work?

I replaced the EGR pressure sensor with a Wells part from AutoZone for another $45. In this case, the dealer wanted $105 and the parts person said they sold a lot of them. Any idea who makes these for Ford? Pep Boys sells a Borg-Warner part for about $55. This part did not help either.

Phase 3 included double-checking the hoses and pulling off the EGR valve. The valve opens and closes with a vacuum pump. I get exhaust out of the pipe and the little pipe to the sensor. I guessed I could feel vacuum at the EGR port. Should I get 15" here? I could make a fitting to measure vacuum with the valve fully opened w/ my vacuum pump. I want to verify the intake manifold passages are not blocked.

Phase 4 had a vac gage on the line from the egr control valve while the egr valve fully opened with 15" of vac from my pump. Now the vac was steady at 8" when I revved the engine unlike before. When I separately disconnected the throttle position sensor and egr pressure sensor I would get no vacuum. I donít know what all this proved.

Any ides? The only drivability issue is a little knocking while climbing hills. I believe I can pass inspection since the emmission test is only for co and hc and I believe the egr system is designed to reduce nox only. Also, I believe they only check for stored codes on '96 and newer cars, but I am unsure since I don't own one that new.
 
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Old 11-04-04, 04:39 PM
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OK, let's approach this a little differently. First attach a wire to the grounding side of the EVR (solonoid) by piercing the wire. With the engine idling and a vacuum gauge tee-d before the valve, ground this wire to the battery ground. If the engine trys to stall, it tells you everything is OK from the EVR on. If it does not, look at the gauge to be sure vacuum got there, if so, the passage is plugged. If everything checks OK there, then you probably have a bad PFE or related hoses. You can test this either with a scanner or a digital voltmeter. You need to install a vacuum pump on the downstrean hose of the sensor. If you have a scanner you can read the PFE data directly as you apply vacuum, you should see the voltage range between 0 and 5 volts. Without a scanner, you'll have to locate the signal return wire at the sensor and read it there. If you can't get nearly the full range by applying vacuum, the PFE is bad. Key on engine off, of course.
 
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