E85 flex fuel conversions and using E85 in a gasoline-only powered vehicle:

Is it possible to convert a vehicle that was designed for gasoline to operate on E85? Yes. However, there are no conversion or aftermarket parts that have been certified by the EPA as meeting the standards to maintain clean exhaust emissions. Technically speaking, converting a vehicle that was designed to operate on unleaded gasoline only to operate on another form of fuel is a violation of the federal law and the offender may be subject to significant penalties. No aftermarket conversion company has taken the initiative to certify an E85 kit that would allow a gasoline vehicle to operate on 85% ethanol.

Ok, Then what would happen if I accidentally fuel my gasoline-only powered vehicle with E85?

Although your vehicle was not manufactured to run on E85, no problems should occur if you mistakenly fuel once with the alternative fuel. The largest difference between an E85 powered vehicle and a gasoline powered vehicle is that their computer modules are meant to read different amounts of oxygen within the fuel. E85 contains a higher amount of oxygen than gasoline and E85 compatible vehicles are made to read that higher amount. When a higher amount of oxygen is read by a gasoline powered vehicle, your "check engine light" may appear. A number of other parts on the FFV's fuel delivery system are modified to be ethanol-compatible. The fuel tank, fuel lines, fuel injectors, computer system and anti-siphon device have been modified slightly. Alcohol fuels can be more corrosive than gasoline. Therefore; fuel system parts have been upgraded to be ethanol-compatible.

Topping off conventional coolant with long life coolant

I have heard that if the cooling system in an older vehicle that has conventional coolant is topped off with long life coolant it will shorten the life of the conventional coolant. Is this so?

No, because the normal life of conventional coolant is only 2 years/24000miles, adding long life coolant will have no effect on the service life of the conventional coolant. However, adding conventional coolant to a cooling system filled with long life coolant will shorten the life of the long life coolant.

Diagnostic Tech: 02 Buick Century A/C

It's been a hot summer and that places a lot of demand on air conditioning systems. Today's project is a 2002 Buick Century, automatic transmission and the 3.1 vin J engine. The complaint is no cold air from the air conditioner. On the drive into the service area I notice the blower works fine and the air flow is from the proper vents. When I cycle the A/C switch on I notice there is no compressor clutch engagement and there is no electric cooling fan operation.
Remember, when you turn the A/C switch on you are making a request to the powertrain control module. If the PCM sees the request and determines the conditions are correct it will engage the compressor clutch and it will engage the cooling fan. Since neither the fan or compressor are engaging I'm going to initially look for a condition that would cause the PCM to "decide" not to comply with the request. The system on this particular car is not automatic temperature control but a manual system with dual temperature control. The manual system looks at fewer inputs then the automatic so *should* be easier to diagnose.
One very basic check is system pressure. If the system pressure is too low, the PCM will not turn the A/C on. I choose to connect a set of gauges to the system for the pressure test. That way, if the system proves to be low of refrigerant I'm ready to charge it without missing a beat.











In this case the stabilized pressures are approximately 120psi so there is plenty of refrigerant and certainly enough to allow the compressor to engage. Since I have started along this path though it's a good idea to continue the journey before looking elsewhere. *I* know the system has good pressure but I don't know if the *PCM* knows it. The PCM won't be looking at a set of gauges, it will be looking at the pressure signal voltage from the pressure sensor. The pressure sensor is located in the pressure line in the area below the air cleaner housing.
I can check the voltage at the sensor with a meter but if I start with a scan tool and look at the A/C pressure sensor data I'll be looking at what the PCM "sees". If I start at the sensor and do the voltage check with a meter and the voltage checks good, I would still have to check the scan tool data. But, if I check the scan tool data first and it is good then there is no need to check the sensor voltage.



I can't miss an opportunity to check stored trouble codes so once I connect the scan tool I do just that. The PCM has stored DTC P0530. P0530 indicates a problem with the A/C refrigerant pressure sensor circuit. This code certainly tells me that I'm on the right path and I pull up the A/C pressure data items.

The A/C pressure readings are certainly out of the ordinary. The PCM sees no voltage from the pressure sensor and calculates a VACUUM condition (-15 psi)! I think it is time to do some voltage checks at the sensor. The pressure sensor has three wires. It has a 5 volt reference voltage, a ground and a signal return to the PCM. As the pressure changes the voltage on the signal return will vary. The PCM will use that voltage signal to determine system pressure.

With the sensor wiring connected I verify the reference voltage and ground are good at the sensor connector. A check of the signal wire shows no voltage so I'm almost ready to condemn the sensor. I need to verify the signal circuit is not shorted to ground. A short to ground would kill the sensor output voltage even with a good sensor. It won't work to disconnect the sensor and check for a ground on the circuit because the pulldown resistor inside the PCM would ground the open circuit. I wouldn't know if there was a short to ground unless I also disconnected the PCM connector. I didn't disconnect the PCM. I cut the signal wire a few inches from the sensor and checked for voltage on the sensor side of the wire. When I found no voltage output from the sensor then I KNEW I had a bad sensor.

FIX:

Replace the A/C Pressure Sensor.

Stretched lug nuts!

I have heard that if you put grease or anti-seize compound on your wheel mounting studs, it will make the threads on the lug nuts stretch, requiring replacement of them.

That’s ridiculous, stretched lug nuts! No. If you want to facilitate removing the wheels, especially when operating in conditions were salt is present (as in northern states or near the ocean), it is prudent to use anti-seize compound on the threads and the mating surfaces where the steelnut seats against the alloy wheel. This will keep the nut from galling the rim, as well as having a chemical reaction between a lug and rim that welds the nut to the rim. Remember that using a lubricant also increases torque values, so you should back off on the torque specs just a bit to compensate.

Diagnostic Tech: 99 Ford Escort

Today's project is a 1999 Ford Escort ZX2 with 2.0 vin 3 engine and with automatic transmission. The complaint is that the A/C is not cold. The blower works. The air flow is good and from the proper vents.
One of the other techs here in the shop has made some initial checks and informs me that there is sufficient refrigerant in the system but the compressor clutch does not engage. With that information I run a simple test on the drive into the shop. I make sure the A/C is turned off before I start the car and on the way into shop turn the A/C on. I'm listening for the radiator fan to run. It does run. The radiator fan is turned on when I turn the A/C on. Why is that important? I'll get to that.
On this car (and on most cars) you aren't actually turning the air conditioning on when you turn the switch on. You are sending a signal to one of the control modules "requesting" the A/C on. Under normal conditions the control module "sees" the request, checks that conditions are met to allow air conditioning to operate and THEN operates the air conditioning system. If the control module sees a condition that isn't within specifications, such as a low refrigerant condition, it won't command the air conditioning on.
The powertrain control module is the module used to control the compressor and fan systems on this car. When the PCM sees a request voltage at its connector pin 41 and it sees no reason not to run the air conditioning it should do two things that are important to this diagnosis. It should command the compressor clutch on and it *SHOULD COMMAND THE COOLING FAN ON*. The fact that the fan came on with the A/C switch turned on means that the control switch works and that the PCM sees no reason not to turn the compressor on. It even verifies the pressure switches are fine because the request voltage from the switch must pass through the low pressure switch and high pressure switch on the way to pin 41 of the PCM.
Since I know the problem is on the PCM output to compressor clutch side of the system the best place to do some tests is at the constant control relay module. The relay module is a true black box containing several relays and mounted directly under the air cleaner housing at the left inner fender. The PCM may be the one making commands but the constant control relay module is doing the work.

Pin 21 of the CCRM is the power feed to the clutch relay inside the module. It should be powered with the key on. This is easily checked with a circuit tester and there is power to the relay. When the relay is closed the power feed to pin 21 should be fed to pin 23 and on to the compressor clutch. When I apply power to pin 23 the clutch does work so I know the wiring to the compressor is good. Since I have power to the relay and know that the clutch will work with power then I know that the relay is not closing. To close the relay needs a ground signal at pin 22. This signal should come from the PCM. It is the "command" for the compressor clutch to operate.

The coil side of the relay is provided power by the PCM power relay. This means that with the engine running and the A/C switch off there should be voltage at pin 22 of the CCRM. With the A/C on and the PCM commanding the relay closed there should be a ground at pin 22. With the Power Probe circuit tester I find I have everything I need at the relay to make the relay close. The relay has failed. Since the relay is integral to the CCRM the entire module should be replaced.

What should be done after machining the brake rotors?

I have heard that after machining brake rotors, before they are ready for use, you must prep them for installation by sanding the machined surface lightly with sand paper. Is this so?

No! This does not remove the metal filings caught in the machined surface, and may even add abrasive material to the rotors. Failure to properly clean freshly turned brake rotors causes metal contamination.This may contaminate the ABS wheel sensor and make the ABS operate during slow speed stops. This can also cause uneven pad wear, pulling and noise. Always thoroughly wash the metal filings from machined rotors with hot soapy water. Then dry them with paper towels before installing.

Auto insurance term- "Betterment"

Has your car been in an accident? Perhaps you have come across the term “Betterment”. Betterment is an improvement that increases the value of the vehicle or part of the vehicle.

Betterment is an interesting concept. Insurance, as you know, is designed to put you back into the position that you were in before a claim occurred. In other words, if your house burns down, insurance should rebuild your house. If your car is damaged, insurance should repair your car. Easy enough, right?
Well, some things need to be replaced and put you in a position "better" than you would normally be in. For example, what if your brakes need to be replaced? If your brakes were worn and now they are brand new, you have been "bettered." In this case, the insurance company can take betterment. Think of this as depreciation.

However, betterment cannot occur to certain things. You cannot better a body part of a car. Why? Because they do not wear out. Betterment only applies to parts that wear out. Have you ever seen a hood wear out? Probably not. Why? Because they generally do not wear out. So, if the insurance company replaces your hood, they should not charge you betterment. If they do, you should yell and scream and tell them that they need to stop!

Letting the engine idle after a long trip

I have heard that once you reach your point of destination after driving from a long trip you should not shut the car off instantly and let the engine idle for a few minutes. Is this so?


No! Unless the engine has a turbo charger, idling like that only wastes gasoline, and does nothing else. But if it has a turbo, let it for a minute so the turbo has time to spin down.