334 code. Please help

[94stroked331]

I have a 1994 Mustang. It now has a 331 with all of the emissions intact. The new engine only has about 200 miles on it and it passed emissions with flying colors. Shortly after I noticed that my cats were glowing cherry red. I haven't driven it at all since I noticed this. When I do a diagnostic check I get code 334 (KOER). I know what it means, but what are possible causes and possible fixes?

 

[Hef5.0weisen]

Don't have my book handy...what is 334?

 

[94stroked331]

"EGR valve position sensor voltage above closed limit"

 

[94stroked331]

Please guys! Someone has to know a little about this stuff. I am about to pull my hair out! I have tried everything I can think of. New o2 sensors, cleaning the EGR sensor, timing, fuel pressure. Nothing works and the Ford dealership would not help me at all with any info.

 

[HISSIN50]

What voltage does your EGR position sensor baseline at (KOEO)? If above 0.60V, you have an issue.

 

[94stroked331]

This is going to sound stupid, but how do I find that out.

 

[HISSIN50]

Put a DMM on the signal wire (should be brown/lt green) to the EGR position sensor. Ground the other meter lead. Turn the key on and note the reading. It should be 0.01-0.50 V.

 

[94stroked331]

Thank you, I will try this tonight. I am also going to take off the stock h pipe and make sure the pre cats and cats are not stopped up. The pre cats are what is glowing.

 

[94stroked331]

It is .550 What now? A new EGR or a new EGR position sensor? Or both?

 

[94stroked331]

Hollowed out the cats and pre cats last night. No more glowing pipes, but I still have a 334 and it surges when driving at a constant speed.

 

[HISSIN50]

If you were goin to do that, I would have gotten an O/R pipe instead. The larger diameter would have been nice for your motor anyhow. What will you do next year for emissions?

You did clear the codes after retrieving them last, right?

You would have to do some cutting/grinding on either the EGR valve or the position sensor to reduce the baseline reading. This sounds like it would be a little beyond the scope of what you want to do. The kicker is that new parts might give the same reading.

Did you ensure that while idling, you do not have vacuum in the vac line to the EGR? If not, do this. If needed or unsure, disconnect the vac line to the EGR and rerun codes (after you clear the old ones). IF there's vac in that line while idling, it can generate the code.

 

[hotcobra03]

glowing?

i have had a older gm with a glowing cat problem,,,it ended up being too much fuel...and ive seen once a muffler put on backwards cause a manifold to glow,,,is an egr valve a cause for a cat to glow?

 

[94stroked331]

As far as the cats go I don't know what I will do for emissions. The old ones were stopped up. I will probably just but new ones when that time comes.
Yes I cleared the codes, I think. I discon the battery for about 20 seconds or so. Took a ride and it is still surging at cruising speed. When I got home I Pulled the codes again and ther it was 334. (KOER)
As far as the vacuum line going to the EGR, at idle there was about 2.5 in Hg or about 7 cm Hg.
Wow!! This is really getting frustrating! I really appreciate your help HISSIN50.

 

[HISSIN50]

Ok, to clear the KAM you have to disconnect the battery and create a draw (turn on your headlights, for instance). This will deplete the capacitors much faster than their normal half-life. I do this and let it sit for a couple minutes.

You have found an issue however. At idle, the EGR's vacuum line should have NO vacuum in it. 2.5" hg might not be enough to really trash the idle, but you should be able to notice it. It should also cause off-idle surging.

If you disconnect the vac line to the EGR and plug the line, does it still surge? If you go for a test drive, Drive it easy if you do this because you might get detonation (depending upon if the EEC has shut off the EGR function at that time).

Alternatively, trace the vac line and be sure it goes to the EVR (in the passenger fender well. YOu remove the wheel and fender liner to access it). Your EVR might have a leak, causing manifold vac to bleed across the ports.

 

[94stroked331]

I traced it and yes it does go to thev EVR. I assume I need to test this. By reading my Haynes book I see that to test you check the resistance. It should be between 30 and 70 ohms. Is this with the connector plugged in or unplugged?
I will plug line going to EGR and go for an easy test drive but not before I clear the KAM the proper way.
And yes it does cause off-idle surging!!!!
THANKS again for your quick responses! I will belong to this site for life.

 

[99FiveOh]

Sorry for your troubles man, makes me so glad I live in a place where I can chunk that crap in the nearest lake!

You didn't mention what kind of transmission you have. I had a 94 GT with an AODE a long time ago and it is what caused my surging/popping problem.

 

[HISSIN50]

Resistance tests are generally done with the connector disconnected (applying power to a circuit undergoing a resistance test skews the results).

It should be real apparent real quick if that little niblet is leaking when it should not be.

Good luck.

 

[94stroked331]

Pulled the inner fender off. Something is definately hissing. The engine is so loud that I can't tell exactly what it is. Can I assume it is the EGR vacuum regulator? It is showing 30.5 ohms. That is withen the proper range is it not? Is there any other way to test this? Im getting there, just slowly! I

As far as my tranny, it is a tremac 5 speed.

 

[HISSIN50]

Disconnect the electrical connector and see if anything changes. If not, it's a hard part issue (not electrical).

If you have a vacuum pump, disconnect the feed vac line to the regulator and connect the pump to the inlet side of the regulator. With the engine off, apply vac and listen for hissing.

You could also have a crack in a hose or a cracked regulator. Look for the leak like you would a conventional vac leak.

 

[94stroked331]

Will do. I do not have a vacuum pump thopugh. I just blocked off the line going into the EGR and went for a mild test run. It still surges. It seems like it does it an low RPMs. Also I have noticed that in between changing gears it seems like the engine doesn't idle down at all. (it's been doing this every since i built the 331). I also put a vacuum gague on the line coming off of the intale and there was only 10 or so inHg. It seems like it goes between 8 and 14 pretty steady. This may be a different problem... Cam specs: intake 565 lift and 232 duration, exhaust 574 lift and 240 duration.
Did another code scan with the EGR line blocke and I got 2 new codes but I didn't get 334. The 2 codes this time were 314 and 332. air system inoperative during KOER (bank 2with duel heated oxygen sensors) and insufficient EGR valve opening detected respectively.