Plz help! Missing and a “thump” noise coming from Exhaust.

[Spl Explorer]

Hello everyone. My 94 X XLT with 160K has been sick lately.

A week ago I started noticing that my check engine light would come on when under load, around 3K+ RPM and turn off within a minuet of easing my foot on the gas.

I have also noticed recently a little miss in the motor. Nothing bad at all but enough to feel it. Then today after getting home from work I heard a “Thump” noise coming from my truck and realized it’s the exhaust. Every time you hear the thump the exhaust system would shake a bit. I put my hand over the exhaust tip and every time I heard the noise it gave out a puff of air but has a constant air flow like normal...

Any ideas on what this could be will greatly be appreciated!!!

 

[James909]

Since the CEL came on you should read the stored codes. There is a how-to thread in the "Under the Hood" section that says how to read the codes without a code reader.

 

[Spl Explorer]

Forgot I had a code reader. Going to go have to dig that thing out. I can run the code reader with the truck off but ignition on to get saved codes right?

 

[Spl Explorer]

Ok so I scanned it and it came up with...

181cTrucks ONLY): HEGO (HO2S) sensor
fault unable to switch / lean during part
throttle

186c: Fault in injector pulse width circuit / high

So where should I start/ look at?

Thanks guys!!!

 

[Spl Explorer]

bump

 

[Spl Explorer]

anyone?

Should I look into 02 sensors... MAF...?

 

[Blacksheep Josh]

In my Haynes manual:

Code
181:
Adaptive Fuel rich limit reached at part throttle, right side

Code
186:
Mass Air Flow higher than expected

Here's what I'm thinking, your MAF is either sending the wrong signal, it's way dirty, or just broken all together. The MAF (depending on what's wrong) is sending the wrong signal, which in turn is making the computer adjust the mixture wrong, which means it's probably makign it too rich giving you the too rich code.

Try this first, disconnect your battery for about 10-20 minutes and reset everything. That may fix it, or you may need to just clean or replace your MAF. Good Luck man.

 

[Spl Explorer]

In my Haynes manual:

Code
181:
Adaptive Fuel rich limit reached at part throttle, right side

Code
186:
Mass Air Flow higher than expected

Here's what I'm thinking, your MAF is either sending the wrong signal, it's way dirty, or just broken all together. The MAF (depending on what's wrong) is sending the wrong signal, which in turn is making the computer adjust the mixture wrong, which means it's probably makign it too rich giving you the too rich code.

Try this first, disconnect your battery for about 10-20 minutes and reset everything. That may fix it, or you may need to just clean or replace your MAF. Good Luck man.

Thanks but according to my manual that came with my code reader the codes mean what I previously stated...

http://www.partsamerica.com/productdetail.aspx?MfrCode=EQU&MfrPartNumber=3145&CategoryCode=3389

 

[Blacksheep Josh]

Dude, just try cleaning the MAF, I think the cleaner at the store is all like 4 bucks. That and about 30 minutes and you can have a clean throttle body, MAF, MAF sensor, reset computer, and you might even have everything fixed.

While that code reader does read codes, it doesn't tell you whether the code is for a truck or car. If you look at it again, the code definition for 181 I listed is almost the exact same as in the user manual for that reader but for the "car" definition. So perhaps the Explorer isn't using a "truck" computer, but a "car" computer.

 

[Spl Explorer]

Dude, just try cleaning the MAF, I think the cleaner at the store is all like 4 bucks. That and about 30 minutes and you can have a clean throttle body, MAF, MAF sensor, reset computer, and you might even have everything fixed.

While that code reader does read codes, it doesn't tell you whether the code is for a truck or car. If you look at it again, the code definition for 181 I listed is almost the exact same as in the user manual for that reader but for the "car" definition. So perhaps the Explorer isn't using a "truck" computer, but a "car" computer.

Will do. I did clean the MAF about 5-6 months ago just for the hell of it but ill give it a try again. Thanks

 

[MrShorty]

Basically those codes mean that computer is seeing a lean signal from one/both of the O2 sensors. I don't have pinpoint tests right in front of me, but the usual 1st "by the book" test for fuel control codes like that is to check fuel pressure.

Another thought with the miss/thump. I've heard of cases where a misfire can trigger lean codes like that. O2 sensors see the excess O2 in the exhaust stream from the misfiring cylinder. I might also suggest in your case a cylinder balance test to see if you have a dead/weak cylinder.

If you clear the CM codes, do you get the same ones come back? What do you get from the KOER test?

 

[mawrazen]

It may be time for new O2 sensors.

 

[Spl Explorer]

Thanks guys. I’m going to go mess around and see what I can do today. I do have a K&N filter so maybe the oil junked up the MAF. So im going to start there… Ill let you guys know what I come up with. Again thanks allot!!! I’m not a ford fan but absolutely love the Explorer ever since I bout it. Just gotta make this one last till I save up for a 02+ X.

 

[Spl Explorer]

 

[Blacksheep Josh]

I hear ya man. I'm currently trying to find a second generation, around 98-01 specifically.

Any luck with the MAF? If you have a K&N filter it's a HIGH possibility that may be causing the issue with the oil gunking up on it.

 

[Spl Explorer]

Ok, so I cleaned the MAF and I no longer have the miss but I have rough idleing now. The MAF was dirty looking at it. I did get better performance though.

Im going to be heavy with the gas peddle for a bit and see if I can get the CEL to come back on then go from there.