An Acura Integra & A Mazda 626

Question: 1994 Mazda 626

Greetings.

Hello Mr. Vince,

Sorry to bother you, but maybe you can help me. I have a 1994 Mazda 626 car, it has an electric cooling fan problem. I told it to a electronics automotive place and they told me it passed all the test they did and the cooling system works as it should. After reading you article Electric Cooling Fan Problems and what the melanic did, I recall some of what he did as you described and indeed they passed.

Here is the problem, while driving without A/C in town, lots of stop and go, the cooling fan does not come on to cool the engine, i say this because the temp gauge on the dash goes more than 3/4 to almost red when i look at it. thats the problem i'm facing. When this happens, I'd Stopped my car turned off the engine. immediately i'd turn the key to the on position where current passes though (not turned on the engine) and the fan begins to spin until the gauge goes back to it midway position, then it cuts off.

Also, if I start up the car and let the engine idle, the temp gauge will go pass 3/4 and the fans does not spin. if the then turn off the engine and turn the key to the on position again as mentioned previously the fan comes on immediately and stays on until the gauge s goes back to the midway point. while driving if i turn on the a/c both fans spins and the temp gauge goes back to the middle or half way, which i believe is normal.

so i either have to drive with a/c all the time, or constantly monitor the gauge so i can manually turn on the A/C. (that is my quick fixed to the problem) Driving on the highway at 55 mph without A/C the temp gauge remains at the midway position because i believe the air passes through the radiator which cools the engine.

Can you explain why this happens and if you can, can you please advise on how to fix it. what to look for test to do, etc. If i remember correctly, we did all the test as you describe in the article, but yet i still have this problem. Any help, i'll appreciate it very much.

Thank You!!

Rick

Answer:

Your questions are never a bother Rick. I'm here to try and help so anytime you have questions, feel free to ask.

The Powertrain Control Module (PCM) controls when the cooling fan comes on and turns off based on engine temperature. It gets the engine temperature from the Coolant Temperature Sensor (CTS). Since the fans come on when you turn the A/C on we know the fan motors and grounds are good. So we are left with the CTS and the coolant fan relays, of which there are three. One relay controls low fan speed operation, one controls high fan speed operation and one turns the fan on when the key is in the ON position.

Since I doubt that the low and high speed cooling fan relays could go bad at the same time, and that you are getting an accurate temperature reading, I would have to suspect there is a problem with the PCM or the wiring.

Question: 1992 Acura Integra GS

Hi Vince, 1992 Acura Integra GS. 3 door. 1.8. Manual transmission. 150k miles. The first start in the moring is very tough then the rest of the day it starts right up. Here is what I have done: New fuel filter distributor cap and rotor new plugs new battery changed oil and filter added fuel injector mix to full gas tank after replacing fuel filter. It seems to have good strong crank but takes awhile to start the first time of the day then it cranks right over the rest of the day. Not sure what else to do. Any ideas would be much appreciated.

Thanks...

Answer:

It sounds like you may have a bad fuel pump check valve. This check valve is supposed to maintain fuel pressure in the fuel system to make starting easier. When they go bad fuel pressure gradually drops until it reaches zero. When you crank the engine with zero fuel pressure, fuel pressure must build up to spec before the engine can start.

A fuel pressure gauge connected to the fuel system over night will confirm the drop in fuel pressure. A quick way to check is this; when you get in the car in the morning turn the key to the 'ON' position but do not try to start the engine. Listen to the fuel pump and when it shuts off, turn the key 'OFF'. Do this four or five times. Now try to start the engine. If it takes right off then you probably do have a bad check valve. This is the most likely cause of the problem. Other cause may be a bad fuel pressure regulator or fuel injector(s). You will need to do a couple of more tests to confirm this.

The fuel pump check valve is part of the fuel pump and cannot be replaced separately.

If you have a question or comment for me, you can e-mail me at autotechrepair at suite101.com.

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