EGR troubleshooting (code 332)

[fastpakr]

I'm getting a KOER code 332 on my '94 for insufficient EGR flow. So far, I've verified EGR operation by providing vacuum to the EGR and seeing an immediate drop in RPM. Vacuum lines all appear intact. The troubleshooting sequence refers to an EGR position sensor (EVP), but I don't see one on my '94. There's an EGR regulator solenoid (EVR) at the back of the engine that I still need to test.

Other than testing the EVR, what's left to look at? There's a DPFE, but that's not referenced in the troubleshooting for 332 and IIRC that usually triggers a different code. I'm actually not sure how to get to the bottom bolt securing the EGR tube between the manifold and the valve.

 

[Mazda]

I'm getting a KOER code 332 on my '94 for insufficient EGR flow. So far, I've verified EGR operation by providing vacuum to the EGR and seeing an immediate drop in RPM. Vacuum lines all appear intact. The troubleshooting sequence refers to an EGR position sensor (EVP), but I don't see one on my '94. There's an EGR regulator solenoid (EVR) at the back of the engine that I still need to test.

Other than testing the EVR, what's left to look at? There's a DPFE, but that's not referenced in the troubleshooting for 332 and IIRC that usually triggers a different code. I'm actually not sure how to get to the bottom bolt securing the EGR tube between the manifold and the valve.

Check out this site. Lots of helpful info. Used it many times for many ranger owners. Even though it's for a different motor the principles are the same.

http://easyautodiagnostics.com/ford/4.6L-5.4L/how-to-test-the-egr-system-1

Also when I had problems with mine. It was the EGR regulator solenoid. I just removed it. Popped the cap of and cleaned it out and reinstalled it and everything was fine again.

Bryan

 

[fastpakr]

Thanks for that. Does your '94 have a position sensor? If so, a photo or description would make my day. I'll pop off the regulator solenoid this evening and test/clean it as well as I can.

 

[Mazda]

I believe the position sensor and the regulator solenoid are the same thing on the 2.3 engine. And I should have clarified when I said I cleaned it all I did was take it apart and blow it out with a little compressed air and put it back together.

What motor do you have so I can look further.?

 

[fastpakr]

Sorry, I should have clarified. I have a '94 Ranger with the 2.3 Lima engine. Everything should be identical to yours.

 

[tomw]

From what I understand, the EVP - position sensor - is part of the EGR valve assembly. If you have wires and a connector plugged into your EGR, then the sensor is there. The ones I am familiar with use a variable resistor to indicate valve position, which is fed back to the computer. OTOH, if your EGR valve has a diaphragm but no wires, then I have no idea how the computer can tell how far open the valve actually is.
tom

 

[fastpakr]

OTOH, if your EGR valve has a diaphragm but no wires, then I have no idea how the computer can tell how far open the valve actually is.
tom

That's where I am with this - there's only a vacuum line on the valve. Even though the diagnostic procedure clearly refers to it, it doesn't appear that there's any position sensing ability in the system.
Does DPFE replace the position sensing? That would make sense to me - measure the vacuum levels on the EGR tube to determine system state.

 

[Mazda]

That's where I am with this - there's only a vacuum line on the valve. Even though the diagnostic procedure clearly refers to it, it doesn't appear that there's any position sensing ability in the system.
Does DPFE replace the position sensing? That would make sense to me - measure the vacuum levels on the EGR tube to determine system state.

Reading up more on it. I am thinking both the EVR and DPFE regulate the EGR. I could be wrong.

Fastpakr, I'm sure that you already checked but make sure both hoses are connected to the DPFE and the tubes. Every time I get my truck back from the shop replacing the clutch one or both are off and I get a CEL. Also check that they are not cracked or corroded. I eventually put small hose clamps on them (like the ones for lawn mower fuel) and haven't had a problem since. If you need a new DPFE it should also come with a new pigtail as they changed it a few years back. Now I think they are all the same cause I pulled mine of to check my brothers Focus and they were the same.

 

[fastpakr]

I swapped the DPFE out a few years ago and IIRC it came with the new pigtail at the time. Not sure though, I may be remembering the one I swapped out on the '94 Explorer I had. The vacuum lines are good. One was questionable but I replaced it the other day.

 

[fastpakr]

Update...

I later realized that there's a misprint in the Mitchell manual. For some reason all Rangers are redirected to the Non-DPFE troubleshooting sequence. If you go to the correct one, the sequence makes a lot more sense and makes no reference to EVP.

At this point, I've replaced the EVR solenoid with a new one. No change - still getting 332 KOER but not continuous. I've verified that the vacuum lines are all intact (picked up a new Mityvac just for this). At the EVR valve I'm getting about 17-20in HG at idle. Not seeing much of any vacuum at the EGR valve itself at idle even at part throttle. Still need to road test with the meter to see if the EGR system is ever activated.

The EVR is definitely getting 12 volts. The DPFE is getting 5v, has a solid PCM ground, and is returning .5v with the EGR closed, increasing smoothly to about 1.9v as I engage the EGR with the vacuum pump.

Any idea what's left to test? The only obvious things in the pinpoint test that I can't easily do are steps 37 (check DPFE circuit resistance between sensor harness and the PCM) and 38 (check DPFE circuit or short to Signal Return and Ground). Both of those call for the use of a breakout box.

 

[tomw]

Noted you just had a question over at ford trucks, to which I posted an answer. It may or may not help, but it seems you have checked out what's going on pretty well.
There should be little to no EGR operation at idle. The EVR should not produce enough vacuum to unseat the EGR valve, I think(don't bet the farm..)
A reported 'insufficient flow' would be the DPFE not picking up a 'low enough pressure' on the EGR side when the valve opens. The pressure 'after' the metering disk should drop as the EGR valve opens, and back pressure is released. (At least I think it would). So, the system thinks the EGR valve did not open sufficiently.
If exhaust back pressure in the system were too low, there would be little to no pressure difference across the metering disk, so the DPFE would think the EGR was flowing just dandy. OTOH, if back pressure were high, such as due to a rusted out clogged muffler or similar, no matter how much the EGR valve opened, the back pressure across the valve would always be high, because the pressure on the muffler side was high, so the pressure would build up in the whole system after a while, and there would be little pressure drop through the EGR as the flow would be limited by the disk, no matter how far open the EGR valve actually was. IOW, because it was so backed up, the EGR could not get a pressure drop over the disk even wide open. More or less... ymmv a whole lot.
tom