K&N filter=check engine light

[DC]

I just put a K&N drop in filter in my 94 EB. Drove it for about a mile and got a check engine light. I then disconnected the battery for about 15 minutes. After about 2 miles of driving the light came back on. I have turned the truck off and back on and drove it about 13 miles. Check engine light keeps coming back on after about 1-2 miles. It seems to run fine.

Any suggestions? I checked to make sure everything was sealed up nice and tight. Also checked around for any loose connections. I put a Borla cat-back on about 2 weeks ago. No problems. Now new filter and check engine light comes on.

 

[SCOTTC]

have you tried putting the stock filter in to see if the light will stay off, the only thing i can think of is the air/fuel mixture is sending a "lean message to the brains!

 

[ERIC]

Before you put the old paper one back in, go look VERY carefully (use a trouble light or strong flashlight) and see if you knocked any of the sensor wires, hoses, etc. loose while putting in the K&N. If not, put the paper filter back in and clear the computer and test. If you did not loosen anything, and if the light stays on with the paper filter, you probably have a coincidental problem...unrealated to the K&N, just coincidentally happened the same time you swapped filters. Hopefully you'll just find a loose wire or hose and that'll be the end of it. Good luck.

 

[1hotjava]

What??

I have a 93 (that is the same engine and computer as your 94) and I have had the K&N on for 65,000 miles of its 76,000 mile life and no check engine light. I would check to see if you maybe unplugged the mass air flow sensor or pulled one of the vacuum hoses loose, or something, because the EEC-IV engine management computer is definitly not sophisticated enough to detect whether you put in a good filter....

my .02
-Paul O.

 

[DC]

When I get home tonight I will check all hoses and wires around the air filter box. If that does not work I will try putting in the old filter.
I have the K&N filter with the rubber gasket side up, is that correct? I don't think it fits in any other way but could I have the filter in wrong?

 

[DC]

I checked and rechecked the hoses and wires. Then I put the old filter back in. The Check Engine light came on. I have noticed that the idle is rough. So now I will wade through all the other check engine threads.
Thanks for all your help guys.
hmm? maybe o2 or fuel pressure regultor or MAF... I gotta get someone to check the codes.

OH, the funny thing is the truck passed the tougher NJ emissions test two days before this started.

Dean

[Edited by DC on 06-13-2000 at 05:53 PM]

 

[ERIC]

As who is gonna check those codes: Fact is, you got a '94...and one really nice thing about the pre-96s is, you can buy the cheap code reader!!!!! Damn things cost a LOT more for the 96 and laters. Anyhow, I'm not sure what a reader for yours goes for,....maybe $30 bucks? But it is worth it...you'd have this problem solved right now if you had one. It's a good investment, especially if you can do repairs such as O2 sensor replacement and such. And even if you can't, at least you'll have less chance of getting ripped off for service. So you might wanta think about getting your own code reader.

BTW, there's a way for using a paperclip/voltmeter to read the codes...but i don't recall if it's posted on this board or not. If so, a search would find it....but you'll still need the Haynes or Chilton to know what the code means.

Anyhow, good luck...and let us know what it was when ya get it figured out.

 

[DC]

Thanks Eric. I will go buy a code reader and a manual tomorrow. My wife was driving this truck for the last 2 years, so I never did any mods. I got her a subaru outback so the truck is mine. Yeah! So its time to get the right tools. Although I did install the Cat-Back myself.

 

[ERIC]

Hey, Dean, if it makes you feel any better, remember you will eventually sell your Explorer (to buy another one no doubt), and having a code reader and manual might well be a nice little bargaining chip in negotiations.

 

[DC]

Well I got my code reader and performed the tests. It was way easier then I thought it would be. I codes came back EGR sensor voltage low, and Insufficient EGR flow. I will now check the threads and hopfully figure it out.

 

[Kris Guilbeaux]

I had teh same problem when I replace the filter but you know what I did... I knocked losse the MAS sensor. Opps...

 

[ERIC]

Originally posted by DC
Well I got my code reader and performed the tests. It was way easier then I thought it would be. I codes came back EGR sensor voltage low, and Insufficient EGR flow. I will now check the threads and hopfully figure it out.

One last thought...before you actually go replacing anything, I'd do some tapping, wire wiggling, and hose bending to again make sure nothing was just dislodged or loosened while you were messing around with the K&N...at least now you know exactly where to look thanks to the reader. Sure, probably won't do any good, but it'll only take a couple of minutes.

BTW. if you DO find something cheap and easy to fix...run out right after and get a few lottery tickets!!

 

[jstagn]

K&N

You probably over oiled the new filter and some oil got onto the first senser right after the filter. This will cause all kinds of problems. Use some kind of spray (don't know which) to clean and let dry. Disconnect battery to reset and don't over oil.

 

[ERIC]

Re: K&N

Originally posted by jstagn
You probably over oiled the new filter

New K&Ns come pre-oiled. At least mine said it was.

 

[DC]

The K&N Filter comes pre-oiled, but I think maybe something(dirt or oil) got into the MAF sensor, so I am going to clean it tonight.

 

[ERIC]

Had you cleaned the MAF before installing the K&N? Just curious. And while you're at it, you might as well clean the TB too. The same stuff does both of them. I use STP TB & Air Intake Cleaner. There are lotsa others, too. Just make sure you get one that is "Safe for Plate Coatings."

 

[DC]

No I haven't ever cleaned the MAF or the TB. I just found the Security Star bit for the MAF. It took me a couple of days to find a Hardware store that carried them.

 

[DC]

Well I cleaned the MAF and TB. Still have check engine light but, and codes for EGR valve not opening and EGR Sensor voltage to low. It's at the dealer for the lift gate bracket recall so I will see what they have to say about it.

 

[wabbit]

code reader recommendations?

I would be interested in getting a code reader for my '91. Does anyone have some recommendations for what brand/type, and how much they cost?
Thanks in advance...

 

[DC]

I just got mine at Pep Boys for $29.99. Brand name Actron(I think) I works great and comes with a book of the codes.