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Discussion Starter #1
For about 3 months now, I had a problem with my O2 sensors where they all read that they were bad, but the car ran fine. Lately it's been getting colder, and the engine started acting strangely, so I figured it was time to do it. I changed out the driver's front oxygen sensor (which was bad) but the passenger side had too short of a cable and wouldn't work, but looked fine. So I disconnected the battery to reset the codes. I figured if the o2 sensor code came back, I would replace it - if not, I wouldn't worry about it. I hadn't been driving the car a lot at this point.

After reconnecting the battery, it ran rough, which I figured "Hey, that's normal" but then it started getting REALLY bad. When you would step on the gas, the engine would bog down pretty bad, and then suddenly rev way up. I took it to Autozone and had the codes read again. (Previously, it was just 4 bad o2 sensors and 4 bad o2 heater circuits) Now there were only two o2 sensor codes, but there was also a code for "engine misfiring" and "running rich". He said what's probably happening is that one of my cylinders wasn't firing, (leading to misfiring) and since it wasn't igniting the fuel, then it was running too rich (too much unburned fuel in the gas). So I changed the spark plugs. That made all the rest of the cylinders run better, but it was still stumbling (although not quite as badly as before) so I changed the plug wires, which had no effect. So today, I figured I'd try one last thing, and I put a new ignition coil on it, which ALSO had no effect. I also thought "Maybe it's bad gas" (wishful thinking, I know) so I put in some Chevron Premium and STP Fuel Injector Cleaner. Which again, made the car run better, but didn't stop it from stumbling.

So now, after all that, the only difference is that the Thunderbird is still broke, and now I am too. Does anyone have any ideas?

The only other thing I can think of is that maybe it's possible that it's missing BECAUSE there's too much fuel, not that there's too much fuel because it's missing. Like something is telling the computer to send more fuel, only now there's so much that it's flooding a cylinder or something.

Please let me know if anyone has any tests or suggestions that might be causing this. Otherwise, my car is going to sit in the backyard until I have enough money to take it to the Ford house so they can tell me what's wrong.
 

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I think it would be safe to assume that the passenger O2 sensor is passing bad info to the computer and that's why it's running rich. Just a thought.
 

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Discussion Starter #3
That's a thought, but just to play devil's advocate, if the passenger side O2 sensor was so bad that it was running so rich that it was flooding one cylinder - wouldn't it flood all three? It runs rough but not THAT bad.

Also, as an aside - Autozone and O'Reilly only offer part numbers for before and after the catalytic converter - the o2 sensor that they want to give me for the passenger side is about 12-18 inches shorter than the one that is on there (and needless to say, it doesn't reach.) Where can I find one that does?

Oh, and if it's that sensor, then I should be able to unplug it and force it into limp mode, which would stop it from running so rich, right? Just as a test? Does anyone know if there's a way to test O2 sensors? Like using a multimeter or something?
 

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Yeah, you can test them. I am not sure where I have seen the exact description, but I think that you basically hook up a multimeter positive lead to the output wire, and the negative to a ground. Set the meter to volts DC. Then you start the engine and create lean and rich conditions and see how the sensor's output voltage changes. I guess you would need an assistant for that. To make it lean, I think you just pull a large vacuum hose to make a leak. To make it rich, spray carb cleaner down the throttle. (Be careful ... it could backfire, and if it does, I'm not responsible.) I forget the proper numbers, but I think the voltage shoud be 0.1 or 0.2 when lean, about 0.5 or 0.6 when normal, and 0.9-1.0 when rich. And it should react almost instantly to the lean or rich.

You can also remove them and test them on a bench. I think that involves heating the sensor and seeing how it reacts.

Sorry for being so noncommittal ("I think" or "maybe"), but that's all I recall right now.
 

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Discussion Starter #5
It finally finished crapping out. Turns out it was a bad ECM - I'm hopefully going to replace it with one from the scrapyard today. They said that the computer (ECM) isn't driving the coil packs. First it wasn't driving one (which was the first problem I talked about) then it stopped driving two, and I just managed to limp it to the mechanic on two cylinders (luckily I was going through the neighborhood) and he 'splained his findings.

96-97 Thunderbird and Cougar are the same computer, right?
 

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Discussion Starter #6
The module that powers the coil packs, is that the one behind the passenger headlight, or the one behind the glovebox?
 

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If you're thinking of the Ignition Control Module, in the later years of the Thunderbird, the ICM was 'absorbed' by the Powertrain Control Module, which is the one behind the glovebox. The 1994-5 model had the ICM positioned in the righthand side of the engine bay.
 

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Discussion Starter #8
ok, more update - the stumbling and missing problem ended up being due to a double gasket on the connector into the coil pack - at low rpms it would shake loose and not make a good connection - at higher rpms the vibration was less and it would make better contact. I took the second gasket off and snapped it down and now the engine runs great -
With the exception of the white smoke coming out of the exhaust. The engine runs strong still, and there's no evidence of coolant in the oil, and doesn't seem to be any oil in the coolant - I'm still thinking it's the head gaskets though, so I'm going to change them before I drive it again
 

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try running some seafoam through the engine and see if that helps with the white smoke, it could just be your valves. I'd try that 5 dollar seafoam before jumping to 200 dollar head gaskets.
-Thomas
 

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Discussion Starter #10
At the risk of sounding ignorant, what's seafoam?
 

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Discussion Starter #12
And now - the smoke is gone, but the shaking is back. No codes on the computer yet either, and I ran it for 30 minutes, including a drive around the block. The plugs, wires, coil, and PCM are all new. I'm open to suggestions - I was even open to the suggestion to get rid of it, but I love my Bird when it's working, and you can't sell a car broken or you're not going to get anything for it. Especially when book value on a 97 V6 LX is only $2200. My bird is worth more to me than that. Other than the engine thing and a burn in the paint from overzealous buffing, it's in excellent condition. Any ideas anyone?
 

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Well, I would recommend that you test your passenger O2. It could be bad, but since they're expensive, I would test it.

Also, take a look at this article:
http://www.asashop.org/autoinc/july/tech2tec.htm

Autoinc.com has a lot of archived newsletters with "Tech Tips" and "Tech to Tech" columns that talk about EFI and emissions problems.

I would also check your Coolant Temperature Sensor, and possibly clean your MAF (very carefully, of course).

edit: Oh, one more thing I wanted to comment on: It's possible that the PCM isn't firing certain injectors because it is trying to correct some other fault that it sees. You know what I mean? OBD-II systems do that kind of thing. So if your mechanics just tested for current at the injectors, they may have seen none and thought, "Oh, bad PCM," when really the PCM was fine and was following a pre-determined strategy.
 

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Richter12X2,

My $.02. Are you hearing any noises that shouldn't be?

I have a 97 V-6. Things that caused my shaking that I had to fix.

1. Old plugs. The original owner was taken by the place he had serviced the car because only 3 spark plugs had ever been changed on the car in 7 years and 50,000 miles.

2. IAC. You didn't say if it just shook at idle or near idle. I have a friend that changes his IAC every couple of years.

3. Plugged injectors. There is an article in January 2004's Hot Rod talking about injectors, rebuilding them or replacing them. Good article since they took 8 injectors from a junked Mark VIII for the article. If you find one fouled plug, check that injector.
 

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Discussion Starter #15
No noises other than the rough idle - when the coil wasn't connected I heard popping from the front which was gas igniting in the exhaust manifold, but now it's just running a little rough across the board. I also replaced the IAT sensor and checked the MAF, nothing was out of the ordinary although I'm going to say this to the tech article - where the person claimed it was reading 10.5v or something across 3 and 4, in my experience it should read your charging system voltage at those two terminals, which only makes sense. How do I go about testing the injectors?
 

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Joshua,

Unfortunately the Hot Rod article didn't have a home test. I guess you'll have to find a shop that actually looks at the injectors instead of pushes fuel injecter cleaner through the fuel rail.

From the article in the Jan. '04 magazine and another I found on the Hot Rod site, for your engine to run smooth, the injectors should all put out at a rate within 1cc of each other.

If you know of someone with a good set of injectors, see if you can swap them in for a test. If the problems stop, then you have your solution.

If anyone knows how to rebuild or refurbish injectors please jump in.

Mine are about to the age where the O-rings should be replaced, and aftermarket injectors spray the fuel rather a pencil thin "laser shot" of the OEM injectors.
 

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Discussion Starter #17
Alright - I found the procedure for partial testing of the injectors - it says they should be about 12.5 to 15 ohms of resistance across them, but they are rather difficult to get to. However, I think I've located the problem, are you ready for this?

There appears to be a short in the fuse box.

After testing and running and idling it in the driveway for 2 months now, I finally got too low on gas, but it's running well enough that I limped it to the gas station on the corner. I went and put a couple of dollars worth in and on the way I noticed my blinkers weren't clicking. I figured there was a bulb out somewhere and went on. On the way home, driving not even a damn MILE, I got pulled over by 5-0 which apparently has nothing better to do than bother people with every damn thing. He pulled me over and told me my brake lights were out and asked for my license and insurance. After giving it to him, I explained that I didn't know my brakelights were out and this was the first time the car had been moved in almost 2 months. So he wrote me a citation. I'd like to get a big star put on the back window of my car in his honor, with words around it that say "To Harass And Annoy"

Anyway, while I was checking fuses to see why my brake lights weren't coming on, I pressed against the fuse box with the palm of my hand trying to pry the fuse out, and I heard a weird stuttering sound, then my hazards came on. (I had set them on when I had the car towed back to my house, and they hadn't worked then) Then they went out again. I grabbed the back of the fuse box and pulled it down and they started to work again.

I tried it with the engine running to see if that could be the problem, but my results are inconclusive, I guess. Everytime the engine would act weird I'd put the flashers on and it wouldn't work, so I'd pull the fuse box and they would come on, but since the engine problem was intermittent to begin with I won't know for sure until after I've stopped it from shorting or pulling loose or doing whatever the heck it is it's doing.

Oh, and I'm going to go to court and fight the ticket. So if you hear about someone in the north end of Dallas being held in contempt of court for telling the judge that the whole legal system is a farce, and that technically according to our laws, I could get a ticket for obstructing justice just by showing up to court and forcing the policeman to come in off his beat, then that's me.

This is an aside, and the start of a really good rant that I'm fighting like crazy, but I've known some really good and helpful police officers. But the majority of the ones I've come across lately are more worried about writing tickets and shaking fingers over trivial stuff than actually for God's sake helping a motorist for example with a FLAT TIRE or warning them that their brakelights are out and they should really get that fixed. If the officer was honestly in fear for someone's safety, then shouldn't he have offered to escort me home to make sure noone rearended me? I quite honestly am shocked that he didn't wait for me to pull out and turn into my street so he could write me a ticket for failure to signal. Not to mention careless and imprudent operation of a motor vehicle, as well as failure to conform to current safety codes.
 

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Sorry about your experience with the police, Richter. I had a similar experience lately that I thought would turn out similarly, but the officer let me explain and he was reasonable.

About the car: Good job finding a new lead. Maybe you could take out the battery and test the connections in the fuse block.

Also, a full injector service goes like this here:

http://www.off-road.com/isuzu/injectors.html

I've seen it advertised for about $25 per injector. That's not too cheap ($150 for a V6), but it beats a new set ($350-$400).

I hope you can get to the bottom of it soon, and beat that ticket!
 

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From the article S_Mazza posted and the articles I've seen, it doesn't look like you can really rebuild these injectors in the home garage, unless you have SOME garage. Dang!
 

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Discussion Starter #20
Well, I checked again and my coolant is starting to turn brown, but there's nothing in the oil yet. So the good news is, if I can isolate that short under the dash (which after disconnecting and removing the fuse box and checking the whole thing over with a multimeter has NO problem) and patch that, then all I'll have to do is change the head gaskets and maybe replane the heads again lightly and it'll be up and going again. Unfortunately after throwing parts at it, I'm flat broke, and my 92 Capri project car that I was using in the meantime just spit up its gum. Luckily my company got me a rental for Thursday and Friday, and I'll spend my whole birthday weekend and leftovers from this paycheck to try like hell to have ONE of them going again by Monday. I was so proud to own 3 Fords too. They really let me down on this one. The headgaskets I can understand, but there's no reason for a 6 year old car to have electrical shorts under the dash. That's more like 20 year old car.
 
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