2003 Hyundai SantaFe: Looking for a place to stop.

This Hyundai had just over 200,000 miles and complaints were shaking, noise, smell and low power. I could immediately feel a misfire and since a misfire can cause all the other problems, it was the place to start. The ignition coils were not difficult to access and by killing power to each cylinder one at a time, I found the misfire to be on #3 cylinder. The bank of spark plugs nearest the bumper are cyls 2,4,6. The rear bank near the firewall has cyls 1,3,5 and they are only accessible after removing the upper intake manifold. I pulled a couple of the easier spark plugs from the front to get an idea of the condition of the plugs. They were badly worn. If I removed the upper intake for further checks of the misfire I would at least need to replace all the plugs and plug wires when it went back together.
I wanted to drive the car in case there was something that might not be obvious otherwise, like transmission problems or serious engine noise or even exhaust system blockage. I noticed that the car had the misfire and poor acceleration. Also, the misfire would intermittently start firing normally with a slight boost of power when that happened. That would make it even more likely that spark plugs would fix the misfire.
I came up with the game-plan and got an okay to remove the intake for further checks and replace spark plugs and wires. Ellis pulled the plugs and asked me to take a look. The 2,4,6 plugs were all worn but burning cleanly. The 1,3,5 plugs had all been running in a rich mix with black carbon being the clue.

I remembered there had been O2 related codes stored in the engine computer when I had done a scan. Maybe the sensor for that bank was bad, was my thought. If it needed a sensor on that bank, it would probably be a good time to replace it. When I checked printout though the codes were for the bank 2 sensor. This was bank 1 with the black plugs. 

We decided to just continue as originally planned and ran a cylinder compression test. The rear cylinders all ran quite a bit lower than the front bank but enough compression to hit without a misfire. The new plugs and plug wires were installed and on engine start there was no longer a miss. All cylinders were hitting but that is about all that was gained. The engine still shook very badly at idle in gear even though there was no miss. Acceleration was very poor as if ignition timing was slow. The smell of "rotten eggs" was coming from the converter and there was engine noise. Even though all the clues were there, it took me a bit to realize that the timing belt was probably needing replaced. The rear bank cam timing being out of sync could explain all the remaining problems. Or..... it could just be another step in the journey. Next thing though was to pull the timing cover and check the timing marks. I couldn't get a good camera shot of any of the marks but did manage some snaps with the borescope. Sorry for the poor quality. I can enhance the marks for clarity. The timing marks for the crank gear and front cam gear aligned perfectly. The rear cam was very much out of sync. 

There was also a lot of slack in the timing belt. The tensioner design is such that there shouldn't have been any slack. The problem was the tensioner was original with over 200,000 miles. An underhood sticker indicated the belt had been replaced in 2013. After replacing the tensioner and timing belt this car sounded great and ran very well. Found a place to stop! 

It could still use a bank 2 oxygen sensor. The cam sensor code could be related to the timing problem. But the customer wants to stop here and get through the holidays. 

Thanks for reading!

Kenneth Hayes

G&G Auto Repair

Evaporative Emission System P0496

2012 Buick Enclave 3.6 engine, MIL on, stored P0496, "runs bad at times" complaint. 

With the complaint of the malfunction indicator lamp (MIL, Check Engine Lamp) on, checking for stored trouble codes is the place to start. Today we'll be using the OTC Encore for the initial check. The tool was just updated and I want to see how it performs with the updates. My main complaint with the Encore in the past has been system speed. The system seems to be much faster now. On with the show!

We have a pretty solid P0496 stored which is described as EVAP system flow during non-purge. 

The longer description contains the reason for the failure code. The engine computer closed the vent valve and the purge valve and saw (fuel tank pressure sensor) vacuum being pulled on the tank. There should have been no vacuum. 

Evaporated fuel vapors are stored until the purge solenoid opens. When the solenoid opens then vacuum draws the vapors into the engine where it becomes part of the fuel mix. Open at all times is going to upset the fuel mix and cause some driveability problems under particular conditions. "Runs bad at times". I removed the engine cover to access the purge solenoid for testing. 

Scan tools these days often have databases of common problems. "Code Assist" is available on the Encore. The most common fix for this code is to replace the purge solenoid. That doesn't mean it is bad, replace it. It means that it would be a good idea to start your tests there since it is the most common failure. 

That reminds me, the Encore is also internet friendly. If I wasn't familiar with testing the purge solenoid or with the system I could do deeper digging from within the scan tool without traveling back to the desk computer. Identifix is a good place to take a step further from where we are right now. Since the solenoid is normally closed, disconnecting the wiring and will eliminate an electrical problem. 

I used the vacuum gauge so you could see there is engine vacuum at the port when there shouldn't be. 

After that it is time to go online to the desk pc, enter the car, find the part I want and order. Kinda like getting pizza. 

Always compare the new part to the old.

Also test your new part to be sure it isn't stuck open as well. Always remember NEW doesn't mean GOOD. It just means new. 

Everything worked and I put the engine cover back in place. Time to clear engine codes but first we want to look at the data for misfires. The car is approaching 80,000 miles. The spark plugs are reaching the end of their life with a recommended replacement at 97,500 miles. If I see any misfire history I'm going to do a spark plug inspection. If we clear the computer we'll lose the misfire history. 

Nothing to see here. Looks like we need to clear codes, do some monitor friendly driving and check for any new codes. 

As always, thanks for reading!!

Kenneth Hayes

G&G Auto Repair

Searcy Ar. 

Rough Running Chevy or How Can It Be Missing When It Is Sitting Right There?

A misfire. A cylinder that is not contributing to the engine running is said to be misfiring. I remember that when I first started doing car repair that determining a misfire vs poor running took a very long time to learn. Oh I could tell when an engine was running bad, but that isn't necessarily a misfire. It gets even more complicated, there are varying degrees of misfires. There are different types of misfires. There are different conditions and causes of misfires. All these years later though and I can tell a misfire on a car just driving past the shop on the road out front. I could also tell I had an ignition misfire on the 2010 Silverado that I just drove into the shop.
The customer had said it might be a misfire, or just a rough running engine. Just as I said, it can be hard to say one or the other without some experience. When he added that the check engine light was on and sometimes flashing well that clinched it. Since OBDII was born (second generation on-board diagnostics) automobiles are required to have a flashing check engine light to alert that the engine is misfiring badly enough to damage a catalytic convertor.
The slight intermittent miss I felt under light load coming into the shop is pretty typical of a secondary ignition misfire. Secondary ignition is the spark output to the spark plugs. The problem areas there are coils, spark plug wires and spark plugs. I suspected I would need plugs and plug wires. Problems with either goes hand in hand.
Remember, diagnostics is taking a broad range of possibilities and narrowing that down to the actual problem. I had taken "misfire/rough running" to "intermittent secondary ignition misfire", at least in my own mind. Therein lies the next step. I know that I have a pretty good idea that there is a bad plug or bad wire or both but I do need to go further before just throwing parts at it. I have an 8 cylinder engine here but a misfire on only one cylinder. To test further I need to find out which cylinder is misfiring. Testing secondary ignition on cylinders that have no misfire isn't going to be helpful and is a waste of time. Since the misfire is intermittent it isn't as straightforward as looking for a misfire that is always present but it isn't difficult either on this vehicle.
Years ago this would require might putting an assistant inside to create the misfire and me under the hood disabling cylinders until I found the one with the problem. Thankfully it is pretty rare to have to do that these days. Since the misfire was bad enough to flash the light, then I should have a misfire code stored related to the cylinder causing the problem. P0301 is a misfire code for cylinder one, P0302 is cylinder two and so on. Let's take a look at stored codes:

That was a lot less helpful than I had imagined. P0300 is the equivalent of what the customer told me in the first place. It might be a misfire or it might be a rough running engine. No need to surrender and look for an assistant yet though. This truck has the GM datastream items to allow you to see stored misfire histories and even current misfires (live). We'll look there next. 

Looks like we should home in on #7 cylinder. It even racked up a first misfires for me when I started the engine and gave is a slight load. I want to say here that there is NOTHING about a a misfire code that means anything more than the computer on your vehicle has detected a misfire. There is nothing about that code that means you need spark plugs or injectors or valves or anything other than you have a misfire. You may need any, all or none of those things. You have to determine what the problem is for yourself. Now lets look at that #7 spark plug.

Time for spark plug replacement. The engine is burning some oil causing the carbon buildup. 

Thanks again for reading!

Kenneth Hayes

G&G Auto Repair

Help! (or, Can You Assist Please My Car Won't Start)

The complaint was the car stalled on a trip and would not restart. The car was towed over the weekend and setting in the lot to welcome me on Monday morning. I gave it a quick look to see that it was safe to try and crank the engine. It is always better to see that half the engine isn't taken apart or similar while others before you were trying to get the car running. It looked safe to try and crank the engine.
Let me take a moment here to make note of "will not start" complaints. In diagnosing a problem what you are really doing is narrowing the possibilities down to the actual cause. When I turned the key to start position there was no starter engagement. The complaint just went from "will not start" to "will not crank". Engine *cranking* is the starter engaging and turning the engine. Focus was now on why would the engine not crank.
Clues were that the instrument cluster lights were flickering, gauges were erratic and no headlight operation when the light switch was turned on. Those things could be from a discharged battery. If you are not familiar with a "booster pack" it is a sort of portable battery with attached cables. You can connect the cables directly to the car and power the electrical system with a "known good" battery without a lot of trouble. 

With the booster pack connected the lights work, the gauges work, the door chime and interior lights come on AND the engine will crank. The engine will also start and run. The diagnostic problem had just shifted again. I was now looking for why the battery was dead. The next clue was the battery light on the instrument cluster. The red battery light was on with the engine running.  A battery light usually indicates an alternator that isn't working. I checked the system voltage at the booster with a voltmeter and since the voltage was the same with the engine running as it was when not running it also indicated an alternator that wasn't working. 

Ideally I wanted a fully charged battery before doing some charging system tests but the battery was not accepting a charge after quite some time on the charger. The actual battery on this car is inside the fender on the driver's side. It is not readily accessible. I could attach the booster pack and do some charging system checks using that as a battery. An extremely discharged battery can take an overnight on the charger to reach full charge and this one looked like it was going to do just that. I could see through to the battery from the engine compartment and the battery looked new, with good clean connections. I decided to go ahead and test the charging system using booster pack as the power source. 

Since I wasn't seeing charging from the alternator I started by testing for voltage at the alternator. I had power at the output post (large wire). There is a connector with 2 small wires at the alternator. The brown w/gray stripe should have power when the car is running and the computer is trying to energize the field circuit. I had power there as well. The alternator should have been charging, but wasn't. I needed to let the battery charge overnight and get an okay from the car owner to replace the alternator. 

The problem went from no-start to bad alternator step by diagnostic step. 

Thanks for reading!

Kenneth Hayes

G&G Auto Repair

Why You Should Probably Change Your Spark Plugs Now

Changes in ignition systems and spark plug design plus cleaner and more efficient engines have led car manufacturers to extend the mileage for recommended spark plug replacement. It isn't unusual to see a recommended mileage of 100,000 for changing plugs. The trouble is that waiting that long can cause problems. The plugs can be "stuck" or very difficult to remove due to carbon buildup. Some plug designs (Ford) are very easily broken when this happens. The job then changes to a more expensive and difficult procedure.
Other then that, the spark plug can very easily be ready for replacement before the scheduled mileage is reached. If you run worn or deposit covered spark plugs the secondary ignition voltage starts to look for new paths to follow. The path of least resistance can be inside the ignition coil or down the side of the plug.
Here is a spark plug from an 05 Chevy Trailblazer 4.2 engine. The recommended replacement mileage is 100,000 and the truck has 105,954 miles on these original plugs. The truck was not here for spark plug replacement though. It was here for a "rough running" engine problem. I could feel an ignition miss just driving it into the shop so I had already started thinking plugs and coil when I brought it inside. Now there were no codes or engine lights on but when I put a scan tool on and watched "current misfires" I could see intermittent counts on #4 cylinder. The hunt began with #4 spark plug removal.
This application uses iridium plugs which give them the longer expected life. The business end of the plug though had quite a bit of wear and deposit buildup.

I could see that the truck needed spark plugs. The smoking gun wasn't at this end of the plug though. The evidence of the misfire was down the side of the porcelain portion of the plug. When the high voltage of the secondary finds that path of less resistance it often leaves evidence. 

The misfire was due to the spark traveling down the outside of the plug instead of as designed. Because of this carbon trail it wouldn't be a fix to just replace the spark plugs. The miss would not only still be there but would cause the new plug in this cylinder to need replacement again. The reason for that is the carbon track isn't just on the plug. It will also be on the inside of the plug boot. The plug boot is between the coil and plug and slides over the porcelain section of the plug. 

I've sliced the boot open so you can see what I'm talking about.

Okay, now if we replace the spark plugs and the plug boot we should be good right? Probably not. The coil is very likely to be damaged internally as well. The coil isn't something that can be easily seen as damaged so the thing to do is replace the coil now rather than put it back and watch for it to fail. 

So....... lets replace those spark plugs now before the complications arise.

Thanks for your time!

Kenneth Hayes

G&G Auto Repair

Diagnostic Tech: Finding the battery drain.

Sometimes things don't work out, sometimes they do. A little over a week ago I had a good customer bring his '09 Mercury Grand Marquis with two complaints. Occasionally the battery would go down overnight. The same problem was there after he had the battery replaced. The second complaint was that the radiator cooling fan had stopped working and caused the a/c to release refrigerant. The radiator cooling fan not running with the air conditioning on would allow the system pressure to get too high. There is a pressure relief valve at the bottom of the compressor.
Whenever I am going to be testing for a battery drain I want to know the condition of the battery. This battery had been on the car less than a month but tested bad. I needed a good battery on the car while testing so installed one from my own stock. I forgot something very important. New does not mean good. We'll come back to that.
With a new battery on the car I did charging system tests and battery draw tests. The battery draw would be where any excessive battery drain would show up. Battery draw was fine at this time so I was probably looking at an intermittent problem. There was the possibility as well that the original battery was bad but so was the replacement. Not likely, but possible. I told the customer I should keep the car overnight and see if anything showed up as a drain. That being settled I moved to checking the cooling fan. The fan was working at this time. So far, I was getting zero co-operation from this car! I have seen a lot of problems with intermittent cooling fan operation on these though. The system is usually fine after replacing the fan module assembly. Rather than wait for the fan problem to appear at a bad time it was decided to replace the fan module and recharge the a/c.
No battery drain happened overnight, the car cranked fine, the a/c worked great and the cooling fan was fine. We put the bad battery in the trunk and left my new battery in place on the car. I parked the car outside and about an hour later the customer comes to pick it up. It wouldn't crank. The battery was completely dead. I was completely at a loss for words! After stuttering and sputtering and head scratching a bit I just started testing from the beginning. Remember "new does not mean good"? When I tested my new battery it was bad. I don't mean discharged, I mean bad as in not good. I pulled another new battery but tested this time. Testing good, I installed yet another new battery. I told the customer to let me know of any problems. I was still pretty sure the car had an intermittent drain but after this unforeseen battery fail fiasco I was off my game just a bit. He had no other ride and no time to wait for another battery draw test.
Let us now move forward. The car was fine for several days before once again draining the battery overnight. It was arranged to leave the car for at least a couple days if needed. Once the car was dropped off I parked it inside the shop to get it prepped for tests. First, test the battery. My preferred tester works best if I connect it directly to the posts with the car's wiring completely out of the picture. Especially when I could have a problem with excessive draw. I have a "memory saver" unit that connects to the car diagnostic connector and provides power to the car electrical system while I have the battery disconnected. This preserves memory and prevents a sudden power loss that could affect any cause of excessive drain that might be present.

Battery was good, slightly under a full charge but good. I reconnected the battery, put the memory saver away and tested the charging system. 

Good battery and good charging. I shut everything off and figured I would put the charger on to top off that battery while I was waiting for the cars computers to go to sleep. After that I could test draw. Now I had noticed the 96% capacity on the battery test results but the charger showed 90%. 

This bothered me a bit. It made me keep a closer watch on the charging progression. After about a half hour the 90% was still 90% and that was odd. I decided to test the battery draw. Depending on the system if you check draw while a computer is still active you expect 100 to 400 mA. If the system is asleep you are looking for about 50 mA, again depending on the system. 

Wow! Something was on and it was more than a computer not sleeping. It was by now shop closing time but if I didn't find this now it might not be there in the morning or the battery would be down and I'd have to start all over. Or both. I decided to find this problem while it had decided to give me a chance. The next step was to find which circuit had the draw. For that you begin pulling fuses and watching the meter. I started with the underhood fuse block and the smaller mini fuses. These fuses will usually have fewer things on the circuit that they power. Once you find which fused circuit the problem is on you have to trace further to isolate the component of that circuit causing the drain. 

Decide where to start when pulling the fuses and follow a pattern. It also helps to take a "before" picture as a guide later just in case you get confused as to where the fuses go back. Have a place to lay each fuse as it comes out. I try to re-create the same pattern as was in the box. As you pull each fuse you'll want to watch for the meter reading to drop. If you pull a fuse and there is no drop don't put the fuse back. Putting the fuse back could trigger another system to kick on and now you aren't looking at the same draw. I started with that green fuse at the top right and went down that row. 

Not much was happening until I pulled that last blue 15 amp fuse next to the bottom of the row. Then the meter showed I had found the circuit with a problem. Something that fuse powers was causing the battery drain. 

Before going further on though it is best to close up the other circuits. To me, it makes things less likely to lead to false conclusions if I keep the system as intact as possible. I put back all the fuses except for the one with the problem. If you put a fuse back at this point and it does wake up a system, you wait for the timeout and go on with your diagnostics of the problem. In this case though no other draw appeared and I was only with one fuse out of the block. 

Now it was time to find out more about this fuse and what was on it. I just stuck the fuse into the block once again and noticed that besides the draw jumping back up on the meter that I heard the a/c clutch on the compressor kick on. I distinctly heard the click. While that did seem like a big clue it could also be a false lead. There might be a software program in place that has the computer cycle the clutch once anytime that circuit powers up. You have to find out just what fuse this is. The fuses are numbered and the schematic is on the fuse block cover. According to the cover I was looking at fuse 11. 

A quick check of the wiring schematic for fuse 11 shows it to power (surprise!) the a/c clutch relay. 

I put the fuse 11 back into the box and pulled the a/c clutch relay out instead. The draw was gone. The relay was powering the a/c clutch even after the car was off and sitting parked. That was the battery drain. The relay was stuck or something in the wiring was closing the relay. It seemed like it would be a simple check to take one of the other relays (same part #) and place it in where the a/c relay was before. I did that and there was no draw. I put the original a/c relay back in and the draw came back, clutch kicked on. The a/c relay was stuck on. 

I replaced the a/c clutch relay this morning and patted myself on the back a few times. I have to say the car was much more co-operative the second time 'round. Just a few more pictures, bear with me. I wanted you to see what is a typical key off battery draw on this car with the computers still awake. (after the fix)

After the computers go to sleep.

If you know me, you won't be surprised that I just had to take that relay apart. I was amazed at the picture I could get with the iPAD. You can see the contacts that were burned and sticking. 

As always, hope this helps you. 

Kenneth Hayes

G&G Auto Repair