Buick Lesabre & Acura Integra

Question: 1989 Buick Lesabre

My 185,000 Buick started backfiring through the throttle body when cold until it reaches normal operating temperature. It starts very well even by -25 Celsius. Lately I went uphill driving about 30 mph with engine warm and it jerked and backfired through the throttle body. It has new plugs, wires, PCV, injectors have been cleaned and MAF also cleaned. I never send my car to a garage for repair but this time it outpaced me.

Thanks in advance...

Answer: At this advanced mileage I would have to suspect an intake vale problem. Either a chipped or burnt valve or weak valve spring(s). I would start by checking for Diagnostic Trouble Codes. Then do a wet/dry compression test and a cylinder leak down test to diagnose the problem. This is assuming the ignition system is in good working order.

Question: 1993 Nissan Pathfinder

Question: 1993 Acura Integra GSR

Hello, I have read many responses by you for questions asked by people about car problems. I have a problem that I really cannot figure out on my 1993 Acura Integra GSR (B17A1 engine). The car originally had a minor problem with overheating (temperature gauge would go above normal by a little and drop back to normal on its own). Eventually I thought that problem was associated with a bad water pump that was overdue for replacement (lots of water leaking).

After replacement of the water pump, I used 1 gallon of Prestone anti-freeze 50/50 mix. Though this was not enough as all the water was depleted from the engine and radiator, I continued to top if off with a factory Honda anti-freeze that was blue in color. The cooling system has been burped for about 1 hour as well. After replacing the water pump, the original problem was still there, but is now followed by higher temperature fluctuations on the temperature gauge. A few days later, I replaced the thermostat as well, and again burped the cooling system and topped it off with some blue coolant and water. Now the temperatures fluctuate even more.

I know very well that mixing of coolants is bad and that is the first thing I will do tomorrow. It's just a shame that I did not know that before I had done it. But during the burping of the cooling system, I have a new thought. I don't believe that my engine is overheating at all. I can literally smack the instrument cluster on my dashboard and the temperatures would change. I was wondering if this could be a faulty coolant temperature sensor. I was also wondering if mixing coolant could have caused such a problem. I am not getting any fault codes for the temperature sensor because this engine is an OBD-I

Thanks a lot for your time

Vance

Answer: I don't believe the mixing of coolants is the cause of the problem since the problem was there before the work was done.

If you unplug the Coolant Temperature Sensor (CTS) the temperature gauge should go to dead cold. Ground the sensor connector and the temperature gauge should go to dead hot. The needle should travel in a smooth and steady fashion. If not, the instrument panel temperature gauge is bad. If it does the I would go ahead and replace the CTS.

Now some rise and drop is normal. When the engine is running, especially at idle, the temperature will rise until it is hot enough to kick on the cooling fan(s). Then the temperature will drop until it gets cool enough to turn the fan(s) off. So you will get a little rise and fall as a result.

What you can do is unplug the fan and let the engine idle. Watch the gauge and see if it rises toward full hot. If it does then the CTS and gauge are recording the proper temperature. Plug the fan back in and let it cool down. As long as everything works as described I don't believe you have a problem.

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