Battery Goes Dead Overnight

This is an older vehicle, 1998 Chevrolet Express 3500 1 ton van. The complaint is that the battery discharges overnight, even after replacing with new. The owner had been recently disconnecting the battery overnight to prevent the drain and that did work. Since the van was now running, I drove it into the shop and did a quick voltage check that the alternator was working.

The alternator looked to be doing what alternators are supposed to do. I shut the engine off and opened the hood. I would be charging the battery but after that looking at battery draw so anything obviously on would need to be off. The underhood light was on but I would need to disconnect it for the draw test. The interior dome light was also on even when it shouldn't have been. Dome Override got the dome light off. I wonder if the dome light was the drain. I'll get back to that later after the battery charge.

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Okay. The battery is at 100%. I'll attach the cables and give it a few cranks to dissipate the surface charge. Then I'll wait a few minutes and measure current draw.

8.5 mA is well under the 25 mA spec for this van. It will sit tonight just in case I have an intermittent draw but I'm pretty sure the problem was the dome light staying on. Sometimes a problem is staring you in the face. Or, glaring you in the face.

Thanks for reading!

Kenny@ggauto.repair

1958 Chrysler-DeSoto Electrojector

Desoto Electrojector System

2006 Toyota Camry XLE 3.0 MIL

This one came in with MIL (malfunction indicator lamp) on and a request to "check for a tune-up". The stored trouble codes were P0031 and P2195.

Both are related to problems with B1S1 air-fuel ratio sensor. It does the same job as an O2 sensor but it works differently. Bank 1 or B1 means this sensor is on the same side of the engine as cylinder #1. Sensor 1 or S1 means this is the first sensor in the exhaust. So B1S1 tells you the location of the sensor.

I pulled up a live graph of the bank 2 sensors that have no stored codes. You can see from the coolant temp reading that the engine is still warming up. The B2S2 sensor is the cat monitor and works like a standard O2 sensor. The converter will need to warm up more to stabilize that signal. The B2S1 is the air-fuel ratio sensor for bank 2. The signal from them is very different than a standard O2. I usually look at the S2 sensors on these when trying to determine fuel mixture under load.

Here is a shot of bank 1 under basically the same conditions.

The cat monitor sensor is at 0.00 v and the B1S1 sensor is flat-lined. I don't have any stored B1S2 codes and the B1S1 looks like it might be a subsituted signal for failure management. Interesting. Great learning moment if I had free reign to study this further. But in the real world I need to try and get this car repaired and back to the owner. Best move here is replace the B1S1 with new and take a look again after clearing codes. Also, there was the "tune-up" query.
The spark plugs are NGK iridium and 209,000 miles. No question it does need spark plugs.

Replaced spark plugs, cleaned throttle plate, replaced B1S1 sensor, cleared codes and grabbed bank 1 screenshots. Before fully warm and just as warm. I'm not fully convinced there isn't going to be a code set related to the B1S2 sensor at some point. Right now though no codes and no pending codes. The converter could be recovering from a bad fuel mix and get better. We'll see. 

Thanks!

Kenny@ggauto.repair

1999 Toyota Land Cruiser 4.7 Engine Misfire

I could feel the engine misfire as I drove the vehicle into the shop. There are a lot of ways to test a misfire but usually the best start is to find which cylinder is misfiring and concentrate your efforts there. You can also benefit from having a cylinder with no misfire to compare with the bad one. I started with an ignition scope check at the cylinder #1 coil.

#1 is the front cylinder on the driver's side of the engine. Next back would be #3 and there is where I found a problem.

Verified the misfire was ignition related and was at cylinder #3

I removed the coil and spark plug from #3. The spark plug boot was baked onto the plug and I had to remove a bit at a time to allow the spark plug socket to be used. Not the hardest thing I've ever done but tedious none the less.

I could see the spark plug was completely worn out, the boot was destroyed and the coil was not firing. I needed to verify that a new plug and coil would fix the miss. The easiest way to do that was to install the parts in just that cylinder. Parts installed and misfire gone. The other plugs would need replaced as well and I did have to consider I may have other boots in bad shape.
In the end though new spark plugs, new coil on #3 and the Land Cruiser was ready to cruise some land again.

Kenny@ggauto.repair