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Discussion Starter #1
Hi everyone

So I have 2 questions about my 1994 Mercury Topaz 2.3l that I could use some insight with.

When it is a warm day out 90+ degrees my car accelerates very sluggisly, kind of like a diesel pulling a trailer. When its cold it drives a lot better but I still don't think it's accelerating at 100%.

I did trip a 172 engine code a couple of weeks ago going up hill at 70 mph in 105 degree weather (Oxygen sensor not switching – system is or was lean – Single, Right or Rear HO2S – Fuel control). When the happened the car was running very sluggishly for few 100 yards and when I got back onto flat lands the car ran better. The service light only came on for a few seconds and have not turned back on.

I just did another KOEO self test and there are no codes in the system.

I am at a loss of what to do next.

What I have done so far to my Topaz is:
Fuel Filter
Air Filter
Oxygen sensor
Catalytic converter
Cleaned my Mass Air Flow sensor
Flushed radiator
Thermostat
Coolant Temperature Sensor
Lots of new vacuum hoses
Spark Plugs and Wires

Anyone have any ideas of what I should look at next before I take it to the shop?


The second thing is when my Topaz sits in idle for 4-5 minutes my temperature gauge in the car slowly moves from sitting in the middle to going 2 bars before the red line, then my radiator fan kicks in. Once the rad fan kicks in my car drops back into the normal temp at the mid point. I rarely have this happen, but it does happen.

Is this normal for this car?

Dose the Topaz have a low speed for radiator fan?

Do I have another problem?


I'll be checking back on this thread
Thank you for taking the time on posting more questions and any suggestions.
 

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Not sure of fan speeds, but what your describing with the temperature was like the Taurus and Escort I once owned. You've replaced so much, I'd pull the codes and reset them, then drive a while and see what comes back. Are you experiencing any misfire?
 

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One fan speed only on those, I have two of the cars. The motors being pretty doggy get absolutely horrible at over 125K miles. The engine only makes maybe barely 100 hp. and once rings have lost their edge it makes only like 80 and with a/c that will be closer to 60. Severely underpowered unless brand new.

Two temp sensors there, one for fans and one for PCM.................Fan should really come on as soon as the gauge needle begins to drift upwards at all and on 100% of the time with a/c on.

Biggest problem I've had was low fuel pressure from an old pump, they do not like ethanol laced fuel over the long run.
 

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Worked for Ford for over 30+ years. Actually wrote a letter to Ford about the stalling and loss of power on the Topaz/Tempo. I never heard back. Later at a Ford training seminar we had a discussion about the subject and I was told Ford was having disputes over the fuel pump issue. I was told but can't confirm that they were suing the manufacturer of the pump. Later Ford did use a different supplier but with the same results. The problem is not the pump but the design of the fuel cell/tank. At the bottom of the tank is a plastic baffle that surrounds the pickup screen and float. keeps fuel around the pickup while cornering and stop and go. During hot weather the plastic becomes pliable and with the suction of the pump the plastic raises off the bottom of the tank and restricts the pump inlet. To fix this concern remove fuel cell/tank remove pump and feel inside at the bottom. There will be a noticeable bump in the center of the baffle. I used a razor to cut a 2 inch hole in the plastic were the bump is. U must still keep the baffle in place do not remove. just remove a small portion. this will take care of many drive-ability concerns. Hope this helps
 

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There was actually some sort of recall on the earlier '88s, mine got a free pump over it. They made a good chunk of noise when going bad, the whine got much louder.

In my earlier post I just describe a car running correctly, after driving a modern 16 valve motor these can seem pretty down on power while running fine.

Some outright stalling was the TFI module as well as the ignition switch coming apart in the steering column too, had both issues on mine.

Ford showed the TFI as many going bad at 250 degrees and on these mounted in direct radiator exhaust to already be at 220 or so and not much temp margin of error there.
 

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Discussion Starter #9
Thank you everyone for your replies.

I am back to give an update, I think I have it working now. I got most of my power back.

I missed a 2" long 11/32" wide vacuum line coming off the center of the top of the intake manifold. It was loose on the manifold's metal nipple. It's the one that Ts off to something coming off the valve cover. I also changed my oil at the same time (been 4,500 miles since the last oil change).

This seemed to work, in the cold I have some get up and go now, and in the hot weather it still runs a little sluggishly, but it's not crawling from a complete stop.

Glad to know about having 1 fan speed, I thought so, but just needed to confirm that this cars temp gauge is like a slow yo-yo

Thank you The Barber for the little info on the plastic baffle that surrounds the pickup screen and float. It will end up on the to do list one day when I have some time.

Now that everything is back to normal I may have created another random problem.

When the car has been sitting in the hot sun for several hours, it likes to spitter and spatter for a couple of mile. I step on the gas too fast and the engine likes to start bucking and no power. Like it's getting too much air, or not enough fuel, or maybe even I am having spark plug trouble. This has only happened to me 2 time in the past week, and it does always stop after a couple of miles.

Once I get that worked out, I'll post an update.

Thank you again for all your help and replies.
 
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