Tuesday, July 19, 2011

1999 Ford Windstar

This Ford minivan with 139,478 miles was towed in as a no start/no crank issue. The shop owner suspected a theft issue and wanted confirmation. When I look at a possible theft issue there is one thing I always look at first. That is what does the theft indicator lamp/led do when the key is turned on. The majority of theft system will illuminate the theft indicator lamp for about 2-3 seconds then it should go out and stay out. But, before that I checked battery voltage first. This is an important step. Nothing worse than starting to track down an issue only to find out that the battery has low voltage and now you question everything you checked prior. Below is a shot of the dash and theft lamp.

 I flipped the key on and the theft light was flashing rapidly. Step one to confirming a theft issue. Next step is to confirm which type of Ford PATS (Passive Anti Theft System) you have. Ford has 5 different PATS systems that depending on year, make, and model all have their wrinkles. A good source of identification information is the PATS jobaid pdf available for free on the Ford website http://www.motorcraftservice.com/
On this minivan it is a type C PATS system. Type C system utilize the instrument cluster as the theft module. In this year, make, and model it also incorporates starter interrupt as well. From the diagram above you can see there isn't much to this system. The PATS transciever module also known as a "halo" has four wires, it gets a fused key on power and a ground. The other two wires send information from the key to the instrument cluster. From there the instrument cluster makes the call on whether it is the correct key and then sends a data buss message to the PCM to allow the car to start. So lets check some codes.
These are snapshots from my Ottotest. The first stop is the PCM. Here we have a P1260 engine disabled by PATS. Ok, we have a theft issue. But what? Think of the system. Let's scan the Instrument cluster.
Now we are getting someplace. I really do not like the description the Ottotest gives this code. I have the Ford description below.

The Ford definition is much clearer. It is saying that there was NO signal being recieved from the transciever. Do we have a bad transciever? Powers? Grounds? Communication? A little trick I do as well is flash out the PATS codes. On some systems leave the key on after about a minute of the rapid flashing. The theft light will go out and then flash a two digit flash code ten times. This will only flash the most recent code. I do this and get a code 13. A code 13 is equal to a B1600. Now, there is no known published information on this as far as two digit to scanned code conversion that I know of. Here, is what I have decoded.
Flash code 13-B1600
Flash code 14-B1602
Flash code 15-B1601
Flash code 16-U1147
So, what is my next step?
Let's have a look at the keys.
Look at how many keychain cards this owner has. There must have been twenty. These can interfere with key transmission. I stress can. The simple test here is to remove key from ring and retry. I really didn't have to though.
These keys are made by Texas Instruments and right where they put the transponder the key is damaged. In fact the transponder is missing. I look on the floor of the vehicle-no dice. I ask the shop owner to call the customer to see if they have another key. Customer informs us that this is the only key. Oh boy! At this point the customer is going to need a key erase and 2 new keys made and programmed. I can do the key erase and programming no problem. But, I don't have a key cutter and access to cost effective keys. I would have to buy the keys from Ford and it would be pricey. The shop owner has a very competent mobile locksmith that he uses and is far more cost effective. He swings by cuts two keys and programs the PATS and away we go. Now I have to be honest here. I knew what was wrong with this truck in about 30 seconds. But, I thought it would make for a decent case study.

Monday, July 11, 2011

2001 Ford Excursion

Here we have our vehicle with 108,904 miles on it. It has the 6.8 liter V-10 motor between the fenders. The complaint is that it originally came in with a MIL lamp on and misfire codes, three cylinder specific misfire codes. The shop replaced those specific coil on plug units and figured they had it fixed. A quick road test revealed it still had a misfire. Not as severe as before, but still an issue. With no misfire codes set the shop wanted to pinpoint the misfire. That is where I come in.....
There she is a big V-10. That is ten Coil On Plug Units to go wrong, ten spark plugs to go wrong, ten cylinders to have mechanical issues with. Get the idea. Well first thing I do is take it for a road test and make sure I put it through its paces. Idle, cruise, hard acceleration. This test drive serves two purposes. One it allows me to get a feel for the misfire and two I drive the car to make sure that the learned correction for misfire detection has been satisfied. On most Fords this is hard acceleration a couple of times making sure you get it up to 55mph. If you dont do this you may get false misfire cylinder results. After the road test I am pretty confident from feel that this is an ignition misfire. I check Mode 6 and sure enough cylinder #2 is showing some value where the other cylinders have nothing. I check fuel trims just to make sure my hunch about ignition is correct. An ignition misfire will not affect fuel trims as much as a fuel related item such as an injector. Sure enough my fuel trims are pretty tight. Out comes the low amp probe.
Here I have my low amp probe around the #2 COP (Coil On Plug) unit power feed. Low amp probes are an excellent tool. They are unintrusive, fast, and concise. They can tell whether you have a shorted coil, poor connection, weak coil, etc. There is a learning curve here. you have to look at a lot of known good patterns before you can tell a bad one. I use the low amp probe frequently on COP units, fuel injectors, and fuel pumps. The uses for a low amp probe are endless.
Well there is the waveform from #2 COP unit. There are three distinct patterns. This Ford vehicle utilizes what is called Multi Strike technology at an idle and low speeds. It was an idea that was supposed to create a more stable and smoother idle and help out with emissions. When the vehicle is raced up passed approximately 1500 rpms we only have the one pattern. Lets dissect the pattern. 
This first ramp is the initial coil on plug activation. What we are looking for is a nice sloping consistent amp charge. It shouldn't go straight up. A straight up pattern is an indication of a shorted coil on plug unit. Things look good here so far.

The next two patterns are the multi strike patterns. These should have upward ramps. Reason being the coils resistance changes after the initial charge. This sloping pattern on the multi strike indicates an issue typically with the coil on plug unit. Here again this is where experience pays off. Scope patterns are usually a matter of interpretation. You have to see plenty of good patterns before you can differentiate bad. Lets put some values on the scope capture.
Here I added some cursors with amperage values. I normally see around 6.5 amps on Ford coil on plug units. So, this is a bit high. I have enough to say I probably have a bad coil on plug. Time to yank the coil on plug unit just to give it a visual.
There it is. No arc marks or discolorations. Nothing physically wrong with this coil on plug unit. I could do a primary and secondary resistance test. But, that is a static test where my low amp probe test is dynamic. One test that I didn't show was checking spark output with a registered 30kv open gap style tester. It failed miserably with inconsistent blueish spark. It should be a nice even white spark jumping across the tester. So lets get a COP unit in and retest.

Looks a lot better....Notice the vertical ramping on the multi strikes. What about my amperage. Lets add some cursors.
There we go. We have the normal 6.5 amps back again. A test drive confirms no more misfires and the performance is back. It feels like a V-10 again.