2004 Nissan Altima Using Oil and Running Rough

We had a 2004 Nissan Altima come into the shop the other day.  The customer complaint was he was needing to add oil to it frequently; as much as 2 quarts every other day!  He also had a complaint for the engine running roughly.

When I checked the oil level, it was barely touching the stick.  First things first, fill it up with oil before doing any checks.  Once the oil was full (and we checked the coolant as well, it was good) we started the engine.  We noticed some oily places under the hood and inspected for any leaks.  We noticed some small leaks here and there.

Next, I went to the back of the vehicle to have a look at the exhaust pipes.  I was pretty sure, based on how much oil the customer was adding, the problem was an internal one.  I was pretty confident it was going to put out a bit of smoke, indicating a problem with the rings in the cylinders.

I had asked the customer if he had noticed any smoke.  He said he had seen some, but really wasn't sure.
We revved the RPM a bit and as we did smoke started coming from the pipes.  It may be hard to see, but the smoke is visible in the picture below (whitish/grayish in color).

 The more we increased the RPM, the more the smoke boiled out.

When we snapped the throttle to red line, WOT (Wide Open Throttle) the smoke thickened even more (my camera wasn't quick enough to capture it) and oil spit out from the exhaust pipes.

The black specs on the floor in the picture above is oil from the pipes.  Below, I got some of the discharged oil on my finger to show.

Long story short, this vehicle is in need of an overhaul or engine replacement.

2002 Chevrolet Cavalier 2.2, Engine Light on with a P0440 Code Stored

This 2002 Chevrolet Cavalier 2.2 came into the shop with a DTC P0440 Evap Emissions System Fault.  The first thing we did was to give a visual inspection of the EVAP system.

We did not see any obvious problems, such as, broken or disconnected hoses, unplugged components (i.e. purge or vent solenoid), broken wires, or loose/missing gas cap.

Many people, when presented with this code, will automatically replace the gas cap.  While these caps do need replacing from time to time for maintenance issues, this may not solve the problem.  In this case, the gas cap was not the issue.

We then decided to use our diagnostic tool and, using its bi-directional command capability, commanded the purge and vent solenoids on and off.  When we did, we heard (and could feel) each one turning on and off as we commanded it.  We did this several times to ensure there was not an intermittent problem with sticking in the solenoid.

Next, we connected our smoke machine, which we use to check for EVAP leaks.  Again, using the diagnostic tool, we commanded the vent solenoid on (which closes the valve . . . this valve is normally off and thus open, to do the test it must be "On", meaning the vent is closed, so as to allow the system to hold the smoke in), and tested the system with smoke.

The picture below shows the evidence.  It is a bit hard to see, so we have drawn an arrow to point to the evidence.  What we saw was smoke boiling out of the vent solenoid, even though we were commanding it "On", thus closing the vent.  Therefore, with the vent "On" no smoke should have been escaping.

With this evidence, we removed the vent solenoid.  What we found is that someone had tie-strapped the diaphragm.  More than likely, a previous owner (our customer said they had not done this) knew about the problem and tried to rig it to work.  Not a good idea.  The solenoid was actually leaking from around its diaphragm, so a new one was in order.  A picture of the old one, tie-strap still on is below.

The next picture shows the new vent solenoid in place.

  
Just FYI, there is a short wiring harness (see below) connected to the vent solenoid.  These are notorious for fraying and breaking, due to rear end movement.  Like the gas cap above, this was not the cause of this failure.  Silver bullet fixes usually end up costing a customer far more money than simply taking it in to a professional to have it properly diagnosed and repaired.

Here is the short wiring harness (I am pointing to it in the picture).

After completing the repair, we cleared the codes and data associated with it.  We then ran a EVAP system test with our smoke machine.  The test passed.  A picture of that is below.  You will notice the green lit LED indicating the test completed and passed.

There are many variables when it comes to diagnosing and repairing an EVAP system.  A basic understanding of how the EVAP system works on that particular make and model is essential.  A visual inspection is always the first place to start.

Don't jump at silver bullet fixes.  You may get lucky and it may be your problem and repair your vehicle.  Then again, you may spend quite a bit of money chasing several silver bullets and in the end be left with the original problem.

When in doubt, find a professional you can trust and take it to him/her and let them do the proper diagnostics and repairs.  It may end up saving you far more money in the long run.

I know the economy has been rough and times are tough.  But, throwing parts at a problem can compound that problem quickly.

2005 Ford F150 King Ranch Edition 5.4 Misfire

This vehicle came into the shop with a customer complaint of a rough running engine, a misfire.  Customer said he was driving along on a trip and all of a sudden the truck started to misfire and run poorly.

First things first, we verified the customer's complaint.  Took the truck for a test drive and confirmed the misfire.  Next, we connected our diagnostic tool and checked for stored codes.

We pulled three DTC's.  They were P0171 System Too Lean (Bank 1); P0303 Cylinder 3 Misfire Detected; P0316 Engine Misfire Detected on Startup; and P0353 Ignition Coil C Primary/Secondary Circuit Fault.  We checked the freeze frame data and started our diagnostic.

We weren't concerned with the first code, with an active misfire on that bank, the lean code is explainable.  We needed to know what was causing the misfire.  Just a head up, on the last code P0353, the Ignition Coil C . . . C is number 3 cylinder.  Ford uses letters to correspond to the cylinders.  So "A" is 1, "B" is 2, "C" is 3 . . . "H" would be cylinder 8.  Okay, you get the idea.

Another FYI for you, Ford commonly mistakes cylinders.  So it may throw a cylinder 3 misfire, but when you start investigating you determine it isn't number 3 that actually has the misfire.  So be careful with that too.

Now, we needed to see what was causing this misfire.  Was it a plug, coil, wiring, or PCM?  With the P0353 code, any of these could be possible.

So, we hooked up our lab scope and sync probe and did some investigating.  First, let's rule out the PCM and wiring.

We checked battery voltage at the PCM with key off and with at KOEO, both showed good.  So wiring seems to be fine.  What about the driver in the PCM?

That's where our lab scope and amp probe come into play.  The picture below shows two traces (one red and one green).  The red trace is through the amp probe connected around the power feed.  This wire was accessible in the steering column and was fairly easy to get to.  It is a dark blue wire with light green tracer.  The green trace is our sync probe, allowing us to know which cylinders are which.  In this case, we were connected to number one cylinder.  With that info we could go by the firing order if we saw any problems in the patterns.  Here, what matters, is that all 8 cylinders are accounted for.  You will notice there are 8 red "lines" between each green "line".  This would suggest the PCM is onboard and functioning.

Now, we need a closer look to see where the problem lies.  The below pic shows a zoomed in view of the above pic.  Notice the difference in appearance of the two sets (3 spikes each) of red traces.  The first is nice and pointed, the second image (to the right) sort of curves over to a point and then drops straight down and then straight back up.  The first one is a known good pattern.  The second is a view of a shorted secondary ignition component: either plug or coil.  I know these trucks and engines are known for bad coils, but you have to follow the evidence to make a proper diagnosis and the right repair.

The next pic is an even more zoomed in look at the known good pattern.

The pic below is the faulty pattern . . . again, notice the differences between these last two images.

As I said earlier, these vehicles are known to mis-identify the offending cylinder.  So, we moved our sync probe from cylinder number 1 coil (control wire) to cylinder 3 coil (control wire), the cylinder that is supposedly the misfiring cylinder.  Below is the pic of this.

Based on the above pic, we knew it was indeed cylinder 3 that was the misfiring cylinder.  So, in this case, the PCM had the right cylinder pegged all along.  Now it was a case of determining if it was the spark plug or the coil that had shorted.

It turned out to be the spark plug.  The plugs had been replaced about a year ago.  So, we removed that one plug and replaced it with a new one.  We also ended up replacing another coil because it showed signs on the scope of weakness.

Started the truck and it ran like new.  Took it for a test drive, allowed the monitors to run, double checked no misfires being reported, lean situation straightened out with the misfire no longer present, cleared the codes, and shipped the truck.

The Little Things Matter

This is just a quick post to remind everyone (including myself) that the little things matter.  And not taking care of the little things, or paying attention to them can cause a lot of unnecessary headaches down the road.

Case in point, I ordered some new OE (AC Delco) spark plugs for a 2006 Chevy Cobalt 2.2.  If I had not taken the time to pay attention to the little things, in this case checking the gap on each plug, I would have had a problem as soon as I started up the vehicle.

I would encourage you to always, always check the gap on any new plug you get.  I know the argument about them being pre-gapped and all that, but humans are involved, which means errors can creep into the equation.

It doesn't take but a couple of seconds to give each plug a visual inspection.  Simply put, use the diagnostic equipment God gave you, your eyes, and look over each plug.

Here is what I found on the plugs for the Cobalt.  This first picture is the proper gap:

No problems with that plug.  In fact, three out of the four looked like the above plug.  Good and ready to go.

However, one of the plugs looked like this:

As you can see from the above picture, this gap is far too low.

Again, this is just a quick and simple reminder.  Be sure to do the little things, it can save you a lot of time and hassle down the road.

Just because something is new or right out of the box, doesn't mean it is good.  Always check it.

2007 Chevrolet Colorado LT 3.7 2WD, P0128 Code

Just FYI, the Colorado pictured above is not the one this issue occured.  I did not take a picture of it, but I thought this one (another customer's) would do.

This vehicle came in with a customer complaint of the CEL being illuminated.  I ran the codes and discovered it had a P0128 DTC.  P0128 is a Coolant Thermostat code.  However, some tests need to be performed before relacing a thermostat.

I first performed tests on ECT and its wiring.  Everything checked out okay.

I then started the vehicle and let it idle for several minutes, long enough to reach normal operating temperature.  Below you will notice the temp hand has hardly moved even though the truck had been idling for several minutes.

I then connected my diagnostic tool to see what temp the sensor was showing.  Again, as with the temp hand, it was woefully low.  Sorry for the glare, but the temp is reading only 140 degrees. 

After taking it for a short drive, the temp remained very low.  It only got as high as 150 degrees.  Obviously, there is a problem in the coolant system not allowing the vehicle to reach normal operating temperature.

After gathering the evidence, I decided it was time to take a look at the thermostat.  To easily reach the thermostat on these vehicles, raise the vehicle and go through the driver's side wheel well.

After removing the left tire, the inner fender trim has to be removed. 

Here it is on the floor.  It has six retainers holding it on.

Now, the thermostat housing can be observed.

In order to drain the coolant on this vehicle, the lower radiator hose must be removed from the radiator.  There is no drain plug on these models.  It can be a bit messy, but not too difficult.  In the picture above, you can see the lower hose connected to the thermostat housing.

There are two 10 mm. bolts holding the housing on.  Below is the entire assembly (lower hose still attached).  On these models the thermostat, housing, and gaskets come as one assembly.

Upon inspecting the thermostat it was obvious what the problem was.  Notice below (I'm pointing to it) that the gasket has come out of place.

This was allowing coolant to bypass through the opening.  As a result, the thermostat was partially open and not allowing pressure to build in the system or allow the coolant to reach normal operating temp.

Once the new one was installed and the coolant was at full, the temp hand at idle came up as it is suppose to do.  The difference in temp can be seen below on the scan data.

Now the temp is reading around 200 degrees.  This is where it should be based on the amount of time it was idling. 

A quick test drive and check for leaks and a recheck of coolant level (after the vehicle had cooled) and the repair was verified.

1994 Ford Taurus Wagon 3.8, Cooling Fan and Fuel Pump Run Continuously With Key in On Position

It's been a while since I've been able to post.  I have several to post and I'll start with this one.  This is a 1994 Ford Taurus Wagon with the 3.8.  The customer brought it in after working on it himself since before Christmas.  Basically, after many repairs and swapping parts, the original concern was still present.  He gave me a list of all the parts he had replaced:  fuel pump, fuel pressure regulator, ECM, CCRM, Coolant Temp, Ignition Switch . . . etc.  He had tested the grounds several times and had found no problem.

The symptoms were when he would turn the key on, the cooling fan would come on immediately and the fuel pump would run continuously and not cycle after two seconds, and he could not get his code reader to communicate with the ECM.  From that description, I felt something was going on with the grounds: either with the ECM or its contacts or a ground on the vehicle.

I knew from other repairs a common problem on these was the ground connector located between the battery and the radiator.  Often times, when you unplug this connector (a two wire connector) it will be corroded.  When I unplugged this one I saw no corrosion.

However, to be sure I jumpered the two wires (harness side) straight to the negative battery post.  When I turned the key to the on position, the cooling fan did not engage and the fuel pump primed for two seconds and shut off.  Also, my diagnostic machine would now communicate.  Presto!

I tested it some twenty times or so and each time it worked as designed.

I spliced two good wires together and drilled a new ground contact on the body and put loom around it.

 I again tested it several times and each time it worked properly.

Here is a look at the orignal connector.

Apparently, the wiring on the ground side (in the picture the longer wires) was faulty and not allowing the ECM to have a good ground; hence, the running of the cooling fan and the fuel pump without cycling off after its prime.

Again, sometimes it's the small things that make a big difference.  After telling the customer of the repair, he told me he had probably unplugged and plugged in that connector numerous times.  It did look okay, but upon testing it was faulty.

2004 Chevrolet Colorado 3.5 Gas Smell From Vents

Had this 2004 Chevy Colorado come into the shop with a customer complaint of smelling raw gas fumes when he had his heater running.  He was worried gas was somehow entering into his vent system.

First step was to raise the hood and inspect for any leaking fuel components under the hood.  I had in mind a possible leaking injector, but instead found a leaking fuel pressure regulator, as you will see below.  You will notice the wet spot on the regulator where it had been leaking.

I replaced the faulty regulator with a new one.  There are a couple of torx bolts to remove along with the regulator from the fuel rail and a fuel line.  There are two o-rings that have to be replaced as well.

Finished the repair and no more raw gas smell coming from the HVAC vents.