Motor Age Garage: Triple Play - A simple running complaint turns up more than one culprit, and a few more on the way. - SEARCH-autoparts.com
Product and Service Knowledge for Auto Pros // Home of ABRN, Aftermarket Business, Motor Age and Styling & Performance
Survey
Are you expecting layoffs for your business before the end of 2008?
Yes
No
Yes
54%
No
46%
View Results
Motor Age Garage: Triple PlayA simple running complaint turns up more than one culprit, and a few more on the way.

Peter F. Meier
Motor Age

Pages | 1 | 2 | 3 | 4
more

It's late on a Friday afternoon, and I've got my hands full. In one bay is a Caravan with its dash peeled back, waiting for an evaporator core. In my other bay is an Eclipse with its block on a stand and its guts on my workbench. Out of the corner of my eye, I see my service writer coming.

"Pete, I know you're slammed, but I have a customer who is heading out of town, and needs his car looked at," the service writer says. "He says it isn't running right, and he's afraid of breaking down on his trip. Can you help me out?"

I've been in this business long enough to know that you are either too busy or not busy enough. I also know it's important to take care of your customers – or someone else will. Of course I'll take a look at it. So I walked up front with my advisor to see what we had.

LET'S TAKE A RIDE

Up front, the customer and his 2001 Ford Explorer were waiting. I asked him to take a ride with me and tell me what the symptoms were. We got in the car, and the rough idle complaint was obvious. It was a little rough, but not severe.

I also noted that there was no Malfunction Indicator Lamp (MIL) on. I asked him when he first noticed the rough running, and he told me it just started that morning after returning home from the local store. Because he was leaving with his family for a long weekend in the morning, he didn't want to take any chances that there was something seriously wrong.

I turned out of the drive onto the main road that runs by our shop. Our location allows an easy test drive route that has city driving on the first half and highway driving on the second half. Normal city driving didn't reveal anything abnormal, but I did notice that the engine smoothed out off idle. The next symptom showed itself as I accelerated onto the on ramp to the freeway: The engine skipped a beat under load. Again, nothing severe, but certainly not normal.

When we returned to the shop, I dropped my customer off at the waiting area and asked him to give me a few minutes to check it out.

IN THE BAY

I pulled in behind the Caravan and grabbed my scanner. Just because the MIL wasn't on didn't mean the Engine Control Module (ECM) didn't have anything to tell me. I went in using Enhanced Ford mode to see what, if any, codes were stored or pending. This check showed nothing.

The next area I checked was current data. When I check current data, I like to take a look at the listed Parameter Identifications (PIDs) to see if anything stands out. With the key on and the engine not running, I saw that the barometric pressure (BARO) PID was off, reading 150 Hz and 27.03 in/Hg. My town is just about sea level, and normal BARO for us is 157 to 159 Hz and 29.90 to 29.98 in/Hg. This may or may not be related, so I just made a mental note of it for now.


Figure 1 This scanner screen capture shows BARO and fuel trims. Notice the BARO PID.
The next place I checked was the fuel trims at idle and 2,500 rpm. I wanted to know if the ECM established fuel control and to get an idea if there is anything that is causing the ECM to make corrections outside of normal ranges. Figure 1 illustrates what I saw at idle. Note again that BARO is out of range.


Pages | 1 | 2 | 3 | 4
more

post a comment
Your email address will NOT be published.
appears with your comment
read our privacy policy
Note: does not support HTML
All comments submitted are subject to review, and may be delayed before posting. We reserve the right not to post comments.

E-Mail Newsletters

E-News envelopeCheck the e-newsletter(s) you would like to receive. Rollover each title to for detailed information.

The Edge from Aftermarket Business
Auto parts distributors receive valuable business tips, distribution news and technical advice every Tuesday and Friday.
E-Pillar from ABRN
Collision repair shop operators get up-to-the-minute news, innovative products, technical discussions and shop management features every Tuesday and Friday.
The Scoop from Motor Age
Service repair pros receive technical automotive service information, business management tips, news and Web exclusive features every Monday and Thursday.
ES&P from Styling & Performance
Specialty parts distributors get information about performance related parts, industry news and business information every Wednesday and Friday.
Hot Auto Products
Professional auto technicians and parts distributors receive the latest details about new products and services every Monday and Thursday.
Tire Topics from Motor Age
Tire dealers receive a heavy dose of new products and the latest news, trends and business tips every Tuesday and Friday.

Source: Motor Age,
Click here