Sorry for the repost. I had CIL in my previous post instead of CEL. Ooops..

Hi All,
I'm having some trouble with my 1994 Ford Explorer. I took it for an oil / air filter change and now it's not running right. The shop that did the oil and air filter change is claiming they didn't have anything to do with the problem, but it ran rough out of their shop!

It's got 108,000 miles on it. I took it to a shop and they found a bunch of codes:
1. EGR Valve
2. EGR Pressure Sensor
3. Coolant Temperature Sensor
4. Mass Air Flow Sensor

I had the EGR valve and pressure sensor replaced. Since I did that, it runs a bit smoother without much foul exhaust (but still some bad fumes present) However the CEL still comes on now and then. When it's on, the car occaisionally idles rough and hesitiates on acceleration.

The CEL isn't on constantly. It will go on and off from time to time. The car seems to have good power and drives on the freeway pretty good. I did notice an occaisional knock at high speeds but that was very intermitent.

Just as an interesting side note, these bozos that replaced my oil and air filter said the air filter housing wasn't attached at the back (the plastic clips) when they opened it. I assume it's been running that way for quite some time? Is it possible that something in the KAM is expecting a higher airflow because the filter housing wasn't attached for so long?

Just an idea..

Anyone else have any thoughts?? Thanks for your help!!
-Brett

 

Need to get the trouble codes from the computer. Don't need a shop or a fancy scanner to get them from an EEC-IV computer. A jumper wire/paper clip is all you need. Instructions can be found at www.dalidesign.com/hbook/eectest.html or any good repair manual.

 

Hi,
I got the codes. They are:
117 - ECT
157 - MAF low
158 - MAF high

I reset them and they showed back up after starting the engine again.

BTW, I tested the resistance of the MAF from sig to gnd and it looked good. However I tested the voltage from sig to gnd while running and it was about .01V. This didn't go up at all when the engine was reved.

The MAF harness showed normal battery voltage from B+ to gnd.

I think it's the MAF. I've heard of a procedure to clean the MAF. Is this worth doing? Or does it simply need to be replaced.

BTW, where is the ECT sensor? I can't find it for the life of me. I've got a '94 4.0L OVH

Thanks,
Brett

 

Were the codes KOEO hard faults, KOEO continuous memory codes, or KOER codes?
Before bothering with the ECT code, was the engine at normal aperating temperature when performing the test (PCM expects it to be)? ECT is located in the intake manifold near the thermostat housing.
You can try cleaning the MAF (It's cheap and easy), but it might be an electrical fault. I would get a hold of the circuit "pinpoint" tests for those codes and diagnose it properly. They are available here in a file called "gtest.pdf." A link was posted last summer in this forum, and you'll find it if you run a quick search for it (be sure to set the time option correctly. Default last time I ran a search was only back one month)