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Discussion Starter #1
Well I finally found my Thunderbird. Its only take two years. :D So its a '94 4.6L and I have a problem. Its running rich and running rough. When you stop it dies. But if its out of gear it'll idle. I was told by the PO that it was the DPFE sensor. So I picked one up from Autozoo. I was looking for the vacuum tee at the back of the intake to see if it was cracked. I have some other things to check as I just brought it home like 20 min. ago. Also are the '94 4.6L OBDI Or OBDII? I don't have my manual yet so just thought it would help. I thought maybe you guys would have some other things I could check. Thanks for the help, gotta finish making dinner. :cool:
 

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They are OBD2. I don't see how a DPFE sensor could make it idle rough or stall. A stuck opened EGR valve could do that, but the sensor can't do anything other than set a code. Also check for vacuum leaks, and see if it maybe needs plugs and wires, or maybe the IAC is stuck. Those are the common things I can think of off the top of my head that could make the car stall and run rough.
 

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Discussion Starter #3
The PO said he just put new plugs and wires on it. I don't know if I believe him.Thanks for the heads up . Yeah I planned on checking the rest of that stuff tomorrow when I had some sun light.
 

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Discussion Starter #5 (Edited)
Well like gas coming out of the tail pipe. The check engine light is on. I planned on reading the codes after I put my kids to bed.
Its running like it has a massive vacuum leak. When you stop it idles real low and sometimes lopes. Or it stalls after its warmed up. One guy at the parts store seems to think its been overheated and popped the head gasket. I'm REALLY hoping not. I dont have the money to put a new motor in this thing. Plus what I would hear from my wife. But there wasn't any oil in the coolant or water in the oil. I pulled the plugs and re-gapped and cleaned all of them. It ran smoother but still like a vacuum leak and the smell of unburned gas out the exhaust.
 

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Check to see if all the injectors are firing. The easiest way to do this is take a long flat-head screwdriver and put the tip of it on the injector and put your ear on the handle. You will hear the injector clicking on and off rapidly. If you get to one that isn't making noise, then that is your problem. The 94s have a problem where sometimes the computer will fail in such a way as to hang 1 or 2 injectors opened all the time, which would cause gas coming out of the tailpipe, a misfire on those cylinders, and possibly stalling. The fix if it is doing this is to replace the computer.
 

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Discussion Starter #7
I did the OHM test and all the injector were within specs. I'll listen to them tomorrow. Also where is the diagnostic port for this car? Its not on the passenger side fender well.
 

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The diag port is under the dash on the passenger side. The injectors will all ohm out fine because the common problem is not in the injectors, but rather in the computer. Listen to them and see if any aren't pulsing. If one isn't pulsing, replace the computer.
 

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Discussion Starter #9
I just searched and found out alot of info. To think I really believed Joe, my parts guy for 8 years. Man I need to whip him into shape! I'll have him read the codes tomorrow. Thanks for the great info and help Mike. Its been priceless!
 

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No problem. Also if it does turn out to be the computer, I have a good one sitting here from when I parted out my 94, so if it turns out you need one, let me know.
 

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sounds like a stuck injector or a malfunctioning pcm. both would cause this issue.
 

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Discussion Starter #12
I found out its the #6 injector causing a problem. All the other ones are working fine. Oh and thanks to whoever moved this. Its turned into more tech than hello. So I swapped the #5 and #6 injectors which had no effect. I did a tune-up and replaced the injector connector both of which had no effect. This was the only injector that had resistance when I OHM checked it. All the others were zero. I pulled the codes and they were 443, 1400, 306 respectively. Anyone who could help I would GREATLY appreciate it. I really don't feel like running a new wire from the injector to the PCM.
 

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Discussion Starter #13
So here's how I fixed it to get it working again. Cyl. #1 & 6 fire at the same time. Therefore the injectors have to pulse the same. So I piggy backed the #6 injector to the #1 leads. Runs like a charm. No this is only a temporary fix until I have the money for a new computer. Cause it seems like its blowing a ton of white smoke. So I'm worried it has a cracked head or blown gasket. Its all coming out of the exhaust and its white. So I know that its water. I'm kinda pissed because it didn't do any of this when I test drove the car. So I'm feeling suckered. But none of the other signs were there. Oil in the coolant or coolant in the oil. Didn't smoke at all. Ran just a little rough. I'm not happy either way. Thanks for the info guys.
 

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The white smoke is most likely unburnt gas in your catalytic converter. If your oil and coolant look fine then i wouln't be too worried. I would be supprised if the smoke lasted more than a few weeks. You may want to consider new cats if the existing pair have more than 100k miles. Magnaflow make a nice set of bolt in repalcement converters - part #23343 Thats what i got when my cats cloged at 110k.
 

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hey, we live in Michigan!!!!!!

We don't buy exhaust or emissions equipment, we remove them, and then get money for them at the local scrap yard.

They'll melt it down, and china will buy the scrap.
Soon enough, everything will be going and/or coming from there.

Yeah, I wouldn't get so pessimistic right away, it's been too cold this week in Michigan to determine if the white smoke is problematic.
 

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So here's how I fixed it to get it working again. Cyl. #1 & 6 fire at the same time. Therefore the injectors have to pulse the same. So I piggy backed the #6 injector to the #1 leads. Runs like a charm. No this is only a temporary fix until I have the money for a new computer. Cause it seems like its blowing a ton of white smoke. So I'm worried it has a cracked head or blown gasket. Its all coming out of the exhaust and its white. So I know that its water. I'm kinda pissed because it didn't do any of this when I test drove the car. So I'm feeling suckered. But none of the other signs were there. Oil in the coolant or coolant in the oil. Didn't smoke at all. Ran just a little rough. I'm not happy either way. Thanks for the info guys.
That is not correct. While both cylinders get spark at the same time, the injectors do not pulse at the same time. One cylinder goes through the compression and combustion strokes while the other goes through the intake and exhaust srokes. If both injectors were to fire simultaneously, the fuel will spray on a closed intake valve for whatever cylinder is on the combustion stroke.
 

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Discussion Starter #18
No that is correct. Our firing order is 1-3-7-2-6-5-4-8. So two cylinders are firing at the same time. Because this is a V-8 and a four stroke motor. The first one in the timing and the fifth one fire at the same time, so #1 and #6 are firing at the same time. Plus these motors bank spray if I remember correctly. So you are actually spraying twice. Once on the intake and once on the exhaust. If I'm wrong then my car is way out of whack and shouldn't be running this good.

The smoking has died down for the most part. I'll ride it out to see how it does. Thanks guys.
 

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Discussion Starter #19
hey, we live in Michigan!!!!!!

We don't buy exhaust or emissions equipment, we remove them, and then get money for them at the local scrap yard.

They'll melt it down, and china will buy the scrap.
Soon enough, everything will be going and/or coming from there.

Yeah, I wouldn't get so pessimistic right away, it's been too cold this week in Michigan to determine if the white smoke is problematic.

You're right about the emissions crap. Well it's hard not to be a little pessimistic when you've only had the car for a couple days and it seems to be falling apart. So where in the Detroit metro are you? I'm north by The Palace. Here are some pics of the $450 beast!




The camera makes it look better than it is.
 

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This thread is so useless, full of bad/wrong tech about how cylinders fire and how injectors fire, that I'm just putting it out of its misery.
 
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