Bits and pieces from the TST bays

July 1, 2015
The TST/ATTS training center is also a full-time shop located north of New York City and its keeps me current on the problems my students and readers are facing. Here are a few of the recent challenges we faced.

The TST/ATTS training center is also a full-time shop located north of New York City. Even though my days are long and my free time short, keeping my hands dirty keeps me current on the problems my students (and my faithful readers) are facing. Here’s a few we had recently.

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A Faulty Ford
We had a 2003 Ford Expedition 4.6L V8 with 110,552 miles come in with Diagnostic Trouble Codes (DTCs) P0135, P0141,  P0151,  P0161 and  P0443. The vehicle had already been to the Ford dealer, and they told the owner that the O2 sensors had to be replaced along with the PCM (Powertrain Control Module). Since the owner was not happy with the Ford dealer diagnosis (or the repair cost they were quoted), they came to see me. I checked the vehicle out, confirmed the DTCs and checked for Technical Service Bulletins (TSBs) and found one that related to our DTCs. We called a local parts store looking for a replacement for the PCM, but no one had a listing but the dealer.

The cost of this PCM was more than $800, so we wanted to make sure that it would solve the vehicle’s problems before we replaced it. We checked all the O2 sensors’ heaters for battery power and ground to make sure that the heaters actually worked. The O2 sensors were very difficult to reach, but we had to test all in order to rule out if they were good or bad. What we found was that the sensors had power but no ground — that is supplied by the PCM. We used a PowerProbe to supply a ground to test the sensors and found that they were capable of drawing the correct amount of current along with heating up properly. The problem of a failed PCM was now confirmed since we proved that the components (O2s) could function properly if they were provided with power and ground.

The vehicle owner did not want to spend a bunch of money on an old vehicle and asked us to find the most reasonable (read “cheap”) way of repairing it. Since the new unit was so expensive and there were no aftermarket units available, I came to remember a company called Ourecms. Years back I used this company and recommended them to my students because they would ship you a unit to try for $75.  Now remember that you are not working on your father’s Oldsmobile anymore and PCMs are not “plug and play” without reprogramming them. I thought since I have the Ford IDS I could get a used PCM and program it to confirm our diagnosis. So I decided to go to the computer and typed in www.ourecms.com and get a used PCM. The site was no longer available but what came up in the Google search engine was www.autoecms.com. It was the same location in Pennsylvania where I had purchased PCMs years ago. I read through their site and found this, “Misdiagnosis no problem, if an electronic unit was ordered but a misdiagnosis was discovered, after the unit was installed, yes you may return our unit for a refund less a $75 test/restock fee and all shipping charges.” Wow, it was the same company that I used years ago to solve some hard problems after testing all the sensors, actuators and wiring only leaving the computer as the possible problem!

We ordered the PCM, installed it in the vehicle and reprogramed (Figure 1) the unit so the vehicle would have all the correct information and start. When you are programing a new or used Ford PCM you have to deal with their antitheft system PATS (Passive Anti-Theft Systems) and program the keys as well. Make sure to have at least two OE keys available or the procedure cannot be completed properly, and the vehicle will not start. You should also have all the key fobs for the vehicle and know if there is remote start available on the fobs. If that is the case you will have to program the fobs as well. Another important step when you program a vehicle is to utilize a battery maintainer and make sure you type in the vehicle VIN number and other important information.

After the programing was completed, the engine started up and ran great. I took the vehicle for a test drive to make sure that Mode $06 would display passing test results. I was lucky because after two of us drove the vehicle all the monitors except EVAP (evaporative emissions) were “Ready.” After the vehicle sat overnight, we test drove it again and completed all the monitors, confirming our repair.

An unhappy Honda
Our next vehicle is a 2009 Honda Pilot with 135,739 miles and DTCS P0420 and P0430. This vehicle had not been maintained properly and the owner (of course) did not want to spend any money. We told the owner we had to charge him for a diagnosis to reveal the vehicle problems. We found it needed a tune up, thermostat, coolant flush and new catalytic converters. The Mode $06 data (Figure 2) displayed failures on the catalyst and misfires on cylinders, along with an Air Fuel sensor that was borderline. To get this vehicle back in good running condition, it needed the oil changed, a complete tune up (had never been done), a fuel system cleaning and new converters.

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Figure 5

Take a look at some of the test results on this vehicle starting with fuel trim. The Escan STFT and LTFT (Figure 3) graphs for both banks were way over the normal limits. Bank 1 at idle was commanding +26 and Bank 2 was adding +16 and both had rich commands all the way through the range with the exception of rpms over 3500.

The engine also had a thermostat problem that most likely contributed to the P0420 and P0430. Looking at the thermostat (Figure 4) test, I noticed that the cooling system was not warming up in the proper time frame. This condition would have made this engine run richer while still producing heat inside the vehicle and not raise a flag. This is a common problem that is overlooked since there is no complaint of a lack of heat. It’s a good idea to make sure that the engine temperature is rising about one degree a minute while warming up.

Our next test was to check Volumetric Efficiency (VE) on this 3.5L engine by using the VE (Figure 5) tab. As the throttle was depressed during this test, I noticed the yellow line (actual results) versus the red line (calculated amount) did not look right. One problem with the test results not being as accurate was due to the elevation reading about 460 feet lower than the correct elevation of 660 feet that we are at. The setting of the wrong elevation could cause the wrong calculation of the red line, causing it to be lower than normal. Even with the wrong setting, the results of the test had the important information indicating a problem.

The problem with the VE test results was not that the MAF and intake system would not reach the proper height on the test, but rather what the top of the yellow test line indicated. The zig zag at the top of the yellow line indicated that we had a clogged exhaust system. This information made sense, since the vehicle came in with the complaint of low power and theMalfunction Indicator Lamp (MIL) illuminated. Now when you put all the information together — DTCs, Freeze Frame, Mode $06 information, thermostat, misfire information, VE test and an engine that had never been tuned up — we can conclude that the catalytic converters were indeed bad.

 Unfortunately for us, the vehicle owner decided not to fix the vehicle. If he decided to repair this vehicle, we would have recommended a complete tune up, fuel system cleaning and after the cleaning we would perform a back pressure test to see if the converters were clogged. Most of the time we will test the converter to see if it will clean up by viewing Mode $06 data after performing a cleaning. The cleaning is done by disconnecting a coil or wire (ground the spark plug wire) on each bank. With the spark disabled the converters load up with fuel, then the idle is raised up to 2500 rpms for 3 minutes. If Mode $06 numbers drop after we complete this procedure, we will recommend a fuel system cleaning that may have to be repeated a few times to try and bring the cats back to life. Remember that if the engine has more than 60,000 miles on it, the carbon build up can be more difficult to clean up. We have been very successful using this test and clean procedure and can usually get the system working correctly without replacing the converters. Now in this case, there is a big possibility that these converters would not come back to life since the VE test indicated a possible restriction.

Since training is a diagnostic tool I thought I would write a brief description of the training that took place this April at Automechanika in Chicago. If you missed it, I am sorry. If you attended this event you will agree that technicians were exposed to all types of training from drivability, transmission, management and more. There were some great instructors such as Bernie Thompson, Wayne Colonna, John Thornton, Scot Manna, Ken Zanders, John Anello, Vin Waterhouse, myself and too many more to list. If you missed it, you really missed out on some of the best training under one roof and all for an unbelievable price — FREE. Keep an eye on the Motor Age website and in the magazine for the next big training event. Thanks to all the sponsors who made the event possible along with Messe Frankfurt, Advanstar (Motor Age), ATSG, ATTS and TST.

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