New Guy - Checklist

[MaioCampo]

Hey,

About a month ago I bought a '93 Explorer Sport, 2WD, Auto Trans, with 227,000 miles on it. It is a daily driver, with some fun outdoor stuff mixed in here and there.

I'll try to make this brief. There are a variety of things that need work, but I am currently just trying to get the thing running decent. There is a slight hesitation at initial acceleration, and then acceleration is often sluggish. Then things free up and the X takes off great... until I have to come to a stop and start the whole process again.

What I have done so far:

Changed oil and oil filter
Changed plugs and wires
Changed fuel and air filters
It had a new MAF still in the box, so I swapped that out just for fun.
Changed tran cooler hoses (they were leaking)

Okay, I've pulled codes and here is what I get (hopefully I do this right):

KOEO: 111
KOER: 998
CM: 157

I pulled codes before and after I swapped the MAF with the same result (cleared codes before swapping MAF).

The X still idles rough, hesitates slightly at initial acceleration, and then accelerates sluggish. I've lurked here and found all kinds of things to continue to work on, but I need some help... I'm a bit overwhelmed.

I'm a list guy... I like checklists... so I was wondering if someone had a checklist that I could use as a plan of attack? I can search this great forum for the details, I could just use some help getting organized.

Thanks.

 

[arco777]

Code 998 [Hard Fault] - Failure Management Mode (FMEM). Not good!

Hard Fault indicates a short in the harness or a shorted out sensor or solenoid, from what I've read.

157 is a MAF fault. Might want to check that the MAF wiring is intact.

I'll attach some reading material.

I don't think the MAF being unplugged or nonfunctional would cause a Hard Fault - I've done it before and it never triggered FMEM. You probably have something somewhere else unplugged or shorted out.

 

[arco777]

Also, welcome to the forum!

I wish I was somehow able to let you access the Ford CD I'm using. There might be a download link here somewhere though, under reference materials.

Re-reading your post, it seems like the engine's running real rich. It would be consistent with FMEM or even HLOS operation I'd think, if the PCM is receiving conflicting or missing sensor inputs, or an important solenoid (like the IAC) is seized.

Some people may jump in and say "replace your PCM". Personally I don't subscribe to that crowd that always blames the PCM first. It is possible but it is more rare than most people think. I won't rule PCM failure out in this situation, but I think you should check your sensors and solenoids first, and look for wiring damage too. Most of this stuff can be ohm tested; if you can't find the recommended values for a component let me know and I'll look it up.

Also don't throw parts at the problem - if you do suspect a certain component, it would be smart to try installing a cheap part that you can return, such as a junkyard unit or one off of a donor vehicle.

 

[MaioCampo]

I think you should check your sensors and solenoids first, and look for wiring damage too.

Thanks arco. I'll look at those.

Swapping out the battery cables is on my list of things to do. There is some corrosion and some frayed cable ends there. While checking those out, and while playing with the MAF I noticed that some of the wiring looks a little rough, so I'll give that a closer look as well.