1993 Ford Thunderbird


Jonathan Gernand

April, 18, 2008 AT 3:00 AM

Engine Performance problem
1993 Ford Thunderbird V8 Two Wheel Drive Automatic 100000 miles

I’ve had this Thunderbird for aprox. Eight years and have had pretty good luck with it. The usual Ford electrical problems, mostly the headlight switch repeatedly burning out. I started having problems about a month ago. I’ll start from the beginning-
On my commute home from work, which is about 25 miles I noticed the temp. Gauge higher than normal. This happens if I forget to top off the radiator on the first of each month. It doesn’t take much coolant loss for this to happen. As little as a 1/3 gal. The car seems to burn a quart of oil between 3000m changes I immediately parked the car and waited for it to cool off some. I carry coolant in the trunk. I left the ignition on (engine off) to watch the gauge and after about a half hour when the needle went completely to the left was going to start the car and then top off the radiator. When I went to start the car the battery was drained and it would not turn over. Probably from leaving the ignition on. I called AAA and when the technician came he could not jump the car with the battery pack. He hooked the cables from the dual battery diesel tow truck and we waited a bit. He looked at the battery and asked how old it was. I told him I’ve had the car eight years and never had to replace the battery. He couldn’t believe it. “You need a new battery “I guess that says something for those Sears Diehard’s. After five minutes the car did start and I immediately drove it to Nationwise and they installed a new battery. When we were putting in the new battery we noticed that it was considerably larger than the old battery. The battery that was in the car was for a smaller vehicle. Not the one designed for that car.
Two weeks went by and the headlight switch burned out again. You had to push it in slightly for the lights to go on. I had a backup switch in the glove compartment and
have gotten to the point to be able to replace it myself. When I put the new switch in you
Still had to push it in slightly for the lights to go on? After a couple of days the driver side tail light bulb blew and I also replaced it.
A week went by and on my commute home from work I was driving the car a little faster than normally. 65mph compared to my usual 50mph. The car started losing power and when I tried to accelerate it wouldn’t go any faster. Also there was a burning smell. To me it smelled like an oil or maybe transmission fluid. I immediately pulled off and shut the car off. When I popped the hood some smoke came out from each side. When I opened the door some smoke was coming from under the door. I inspected under the hood looked under the car but couldn’t see anything. A half hour went by and I started the car and drove it the rest of the way home at 45mph without a problem. I thought it was a transmission problem and that morning took it to A & A Transmissions. They did a 15 point diagnostic test, drove it and said that it was shifting properly.
We decided to go ahead and service it and I brought it back the following day. The receipt says flushed, new filter, new fluid, and Ludeguard IS1, no leaks. One point about the transmission is that when the weather drops below 40’F, on the first start of the day it takes 3 to 5 seconds for the car to engage, reverse works fine. It’s done this ever since I relocated to the Carolina’s from S. Florida. Disappears in the summer but returns with the winter. A couple of days later on my commute to work (10: 30pm at night) I again experienced the loss of power and the burning smell (only slightly). When I drove it home in the morning it was fine no problem. That night on my way to work it happened again more severely this time. I had the Security Guard smell the car he thought it smelled electrical. Each time I turned the ignition switch to the first position there was a humming sound coming from behind my head, drivers side. It always did this when starting but lately I’ve been hearing it while driving, repeatedly. While sniffing around the car and under the hood the smell seemed strongest near the battery. I brought it to the mechanic that morning (Precision Tune) there were no problems during the trip, twice my work commute but at 45mph.
I left the car with them. The mechanic and owner of the of the garage looked at it. They replaced the headlight pigtail (burnt). Right front high beam pit tail and socket. Multi function switch had a short ($285.00 Ouch!) And the passenger side tail light bulb. They found improper installation of wires to headlights, something that was done by a previous owner. I was advised and approved the services & maintence. They were unable to duplicate the loss of power condition or smell. They let the car idle for an hour with the
headlights on and nothing happened. When I picked up the car I was given the old parts and the mechanic showed the burns from the shorts. I said a prayer and hoped that the problems were solved.
On the way home I turned on the lights to test everything. About halfway home of what is probably a 30m trip I started to smell that smell again and the car was not accelerating properly. I turned off the lights and the smell stopped. The car continued not to accelerate properly. When I pulled into the driveway and got out of the car there was a humming sound coming from the exhaust pipes (buzzing). I pushed on the gas peddle a couple of times while in idle and the humming continued. I shut the car off and went inside. Six
hours later I started the car and heard a grinding noise for about 10sec. Then drove it to work the lights worked fine. I didn’t smell that smell. Although I did about 40mph the whole way, scared. I didn’t push the acceleration. I didn’t hear any buzzing from the exhaust. I’ll see what it does on the way home?
I’ve done a lot of research on the internet about the problem and have read everything from a bad universal joint between the engine and tranny. To a clogged exhaust system (catalytic converter). I even went so far as purchasing a fire extinguisher in case I have to deal with an electrical fire on the road. I wish we could pinpoint the problem!
It’s driving me crazy!


5 Answers


Service Writer

April, 18, 2008 AT 5:42 AM

The hum from behind is your fuel pump and will enrgize when you turn the key to the on position. IF the hum is constant, you may want to have the fuel pressure checked.

The loss of coolant is a concern and may be related to the burning smell. With good lighting and small mirrors you may be able to locate the source. You need to look along the exhaaust manifold and the front protion of the exhaust system.

What liter engine is this?

If this is burning coolant, the converter may be damaged and may be the source of the power loss.

I would first start locating where that coolant is going, if it is not leaking externally than it is internally and that isn't good.

A pressure test by a shop may uncover it. Pulling the plugs and looking at their condition may also shed some light on it. Once the plugs are out the coolant system can have pressure put on it overnight and then in the morning the cylinders can be checked for coolant intrusion.


Jonathan Gernand

April, 19, 2008 AT 2:39 AM

Inspected the radiator and all hoses on the engine. Originally when it almost overheated. I opened the hood I saw bubbling coming from the upper radiator hose where it meets the engine. I've since tightened the clamp but can see the fluorescent green from the coolant on the hose around the clamp. Also some years back the heater radiator started to leak.
Instead of having it replaced I bought the nipples and applied them to the inlet and outlet in the back of the engine with hose clamps blocking them off. After all it was a S. Florida
car, who needs heat down there. One seems to have some dry rot. I don't think it's leaking though. I added exactly 20oz of water to a cold radiator. The last time I added coolant was in the beginning on the overheating battery replacement day. That was on
3/13 today is 4/17, so aprox. 35days at about 45miles per day = 1300 miles. I have always used straight coolant not 50/50. I thought this was better but after reviewing
your anti-freeze section this might be a mistake?
Answer: It's a 5.0 liter engine
I've crawled up under the car and was surprised when I looked at the exhaust system.
The manifolds come down off the engine are then routed together, pass through the
Catalytic converter then what looks like a small muffler. Continue down a single pipe
Where it then splits behind the rear axel to two mufflers. I thought to myself "that's not really dual exhaust" . Everything looks like the original equipment. Probably so because when the transmission shop serviced the tranny the factory plug was still there and they told me it had never been serviced. I am only the second owner of the car buying it from a housewife; she never mentioned any exhaust work being done.
I am going to replace the upper radiator hose the two heater nipples and use four new clamps. Then pull a couple of spark plugs and inspect them.
The car has always run like a bear. To put it on a 100mph took very little effort. Which is why the power loss situation is bothering me so. I've made four trips back and fourth to work (160m tot.) With no problem but have really been babying it. It hasn't been over 50mph since the drive home from the mechanic, two days ago.
I'm 42y and take very good care of her. Regular oil chng's(synthetic). I never beat on her, she's my baby!


Service Writer

April, 19, 2008 AT 5:46 AM

This loss of power. Does it seem that the engine rpm raises, but the car just doesn't pick up speed?

Or is it more that the rpm of the eninge is not raising on acceleration?

Good that the coolant is an external leak. Just foolow up with 50/50. If it hasn't been flushed in the past 2 years, it would be good maintenance.

So to re-cap, we just have this acceleration loss issue now? Assuming the coolant leak has been solved.


Jonathan Gernand

April, 21, 2008 AT 1:57 AM

Sunday night 4/20-10: 30pm.
First the good news. Over the weekend I flushed the radiator as recommended. Replaced the upper radiator hose and the two heater block off nipples in the back of the engine. While I was in there I decided to replace the small inlet and outlet hoses from the water pump. Used all new clamps and the cooling system is now running on 50/50 instead of
straight coolant. I think that continuous small loss of coolant has been taken care of.
The electrical work the mechanic did at the garage seems to be holding. I don't have to wiggle the light switch for the lights to go on. Now have high beams (yea!). It was expensive but if I don't have to worry about the lights failing while I'm sailing down the road at 50mph, then it's well worth it. I live in Surfside SC (Horry County) and work as a night auditor at a hotel in Pawley's Island. As soon as I go from Horry into Georgetown County the street lights stop, about halfway on a 25m trip. I don't know if you've ever had your lights go off while going 50mph in complete darkness. Afterwards you need a change of boxers! I'm knocking on wood with electrical work though, time will tell.
So to recap we just have the re-accruing loss of power problem. It happened on the way home from the garage on Thurs. Afternoon (4/17) when I was testing the work that was done. Thru. Fri. Sat. Home to work and back no problem but I was really babying it. The round trip is 45m each day. Tonight Sun.4/20) on the way to work it did it again. Before when it happened I was more concerned in finding a good place to park it. There's nothing worse than being down on the side of the road! Tonight I really paid attention to what was going on! Here goes- The car starts fine. Seems to drive Ok for about 10m. Your traveling at about 50mph when it starts feeling heavy and slowing down. You start to smell the burnt electrical smell. It's running at about 1300rpm and to keep the car going you have to give it more gas but it doesn't speed up. The rpm's go up to under 2000. The engine is working hard to keep the car at 35mph, you can hear that. The smell gets stronger. The transmission goes back and forth between what I think is 2nd and 3rd gear depending on how much gas I give it. I drove it aprox. Another 5 to 8m like this and then proceeded to pull it into the left turn lane at the light. When I came to a stop I could see smoke coming from the driver's side probably exiting around the light area. It idled for a minute or two at the traffic light. After the turn it seemed better for the last mile and a half at about 20mph. When I pulled into the parking space I noticed the temp gauge was higher. Probably at 1/3 than the usual . Shut the car off and opened the hood but could not see where the smoke was coming from. The smell is strongest in the corner where the battery is, drivers side. I put my nose right next to the alternator, smelled OK. An hour later I went out to the car to get my laptop and standing next to the car you could still smell the lingering odorl. To me it's definitely an electric smell. The volt gage never moved, the oil pressure gauge stayed the same, headlights didn't dim.
Answer: The rpm rises from 1300 to about 1900 and the car does not pick up speed. I'm giving it allot of gas at that point. The 600rpm increase didn't raise the acceleration.


Service Writer

April, 21, 2008 AT 5:25 AM

It would be good to pull the codes from the computer.

It sounds like a converter is plugged and it can be intermittant. Sometimes if you rap on the bottom of it you can hear it rattle if it is broken internally. It may be a piece flipping sideways preventing flow.



It will give off a distinct smell and give the power loss. Sometimes when the problem is happening you can see the converter glowing from the excess heat.

The way to test it is to drop the exhaust in front at the manifold, wire it so it doesn't drag and drive it.

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