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Misfire from hell

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Old 07-15-2013, 02:18 PM   #1
Danielsmustang
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Default Misfire from hell

Whatsup guys. Havent been on the forums for a while but I got my stang. Her name os sandy. Shes been sweet but I have been ioing crazy trying to figure her out. So I have been having this small misfire since day one. I bought it and he said it could be a rich misfire. The car had 24lb injectors with a 19lb maf. It only misfired on idle and low throttle. So I went home, changed the plugs. It stayed the same. So I bought a used c&l 80mm maf. It ran like crap. When I fully gas it it goes away. So I said, maybe vacuum leak? Checked and I had one between upper and lower. So I replaced it. It stayed the same. So then I went back to the old maf. It drove better but the same as before. Only on idle and low throttle. Then I bought new wires and ignition coil. Same. New cap and rotor, same. then I put 19lb injectors. Same. Now when I drive it, as it warms up it gets worse. If I fully gas the car it goes away. I just bought a new tfi. As I was installing it, I took out dizzy. Now its out of timing and got to fix it. But I thought maybe, since it has roller rockers, the previous owner didnt tighten them correctly. Could that affect? Or floating valve? What do you guys think? I also cleaned the salt and pepper.
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Old 07-15-2013, 02:38 PM   #2
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I think valve float would manifest itself at wot or very high rpm .
Have you tried a different dizzy or replacing the pip in side the dizzy? Pretty common for the pip when it starts going bad to cause misfiring.
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Old 07-15-2013, 02:49 PM   #3
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Originally Posted by dawson1112 View Post
I think valve float would manifest itself at wot or very high rpm .
Have you tried a different dizzy or replacing the pip in side the dizzy? Pretty common for the pip when it starts going bad to cause misfiring.
What is the pip inside dizzy?
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Old 07-15-2013, 03:19 PM   #4
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PIP or Profile Ignition Pickup sensor is responsible for telling the ignition coil to start firing. If the pip is not working at all you will achieve a no start condition , however they have been known to intermittently cause problems creating a miss fire.

This is fords name for crankshaft position sensor and is located inside the distributor.. A complete tear down of the dizzy is required to replace it, most times pple opt to replace the distributor completely rather than just tear it down and replace the pip.
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Old 07-15-2013, 03:36 PM   #5
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Hmm. Okay havent thought of that. Now, how would i be able to diagnose that? Any test i can do to see if it working properly or not? And mind you, it only misfires on idle and low throttle. not under wot. I can be cruising in 4th gear going like 50mph and if i slowly gas it, it will start misfiring, but if i step on it, it misfires for a sec then goes away.
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Old 07-15-2013, 04:08 PM   #6
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If the pip is working but intermittently cutting out you have no real way to check it, but this page has a lot of very useful tests you can perform NOTE: This test is assuming you have a no start condition.

http://easyautodiagnostics.com/ford_...d_module_1.php
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Old 07-15-2013, 04:11 PM   #7
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You will have to scroll down a bit to find the pip section
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Old 07-15-2013, 05:21 PM   #8
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Originally Posted by Danielsmustang View Post
Hmm. Okay havent thought of that. Now, how would i be able to diagnose that? Any test i can do to see if it working properly or not? And mind you, it only misfires on idle and low throttle. not under wot. I can be cruising in 4th gear going like 50mph and if i slowly gas it, it will start misfiring, but if i step on it, it misfires for a sec then goes away.
That's an EGR misfire. Probably a bit lean, given your conundrum with the inj/maf combo.
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Old 07-15-2013, 06:16 PM   #9
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That's an EGR misfire. Probably a bit lean, given your conundrum with the inj/maf combo.
Alright, so I start the car up , car idles and runs good, so I drive down the road and shift at 3000rmp and its fine, then if I rev the car over 4000 when I shift the car will start to over heat after about 5 mins after being ran hard and stay hot , it has a 180degree thermostat in it , so to sum it all up, when I run the car hard the car will over heat pretty much immediately
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Old 07-15-2013, 06:22 PM   #10
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Alright, so I start the car up , car idles and runs good, so I drive down the road and shift at 3000rmp and its fine, then if I rev the car over 4000 when I shift the car will start to over heat after about 5 mins after being ran hard and stay hot , it has a 180degree thermostat in it , so to sum it all up, when I run the car hard the car will over heat pretty much immediately

Lol how did you get in this thread
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Old 07-15-2013, 09:55 PM   #11
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Quote:
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That's an EGR misfire. Probably a bit lean, given your conundrum with the inj/maf combo.
I dont have an egr. It was taken off. Would that affect?
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Old 07-15-2013, 09:57 PM   #12
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And yeah I might as well replace dizzy but would just like to make sure before I replace it. Because when I bought the car I drove it for a 1 hour and half trip and didnt do this at all. It was after me trying to fix it that it got like that.
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Old 07-15-2013, 09:58 PM   #13
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So I feel that maybe I did something that made it like this.
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Old 07-15-2013, 10:09 PM   #14
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Quote:
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And yeah I might as well replace dizzy but would just like to make sure before I replace it. Because when I bought the car I drove it for a 1 hour and half trip and didnt do this at all. It was after me trying to fix it that it got like that.
Well you said it did this from day one lol so what do you think you tried to fix that caused it?

And electronics tend to act up more the hotter they get.
The longer it goes on the more it will appear until it just fails to function at all.
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Old 07-15-2013, 10:12 PM   #15
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see if you can get a video of the idle miss posted up so we can hear what you are experiencing.
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Old 07-15-2013, 11:50 PM   #16
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Well you said it did this from day one lol so what do you think you tried to fix that caused it?

And electronics tend to act up more the hotter they get.
The longer it goes on the more it will appear until it just fails to function at all.
Yeah it did. But after it started getting worse.

This is the order in which everything happened:

Bought car had a misfire on idle and light throttle but barely noticeable. Drove fine but I could feel it.

changed spark plugs. Same.

Put c&l maf and drove bad. Misfire on idle and light and medium throttle.

checked for vacuum leaks, found one between upper and lower. Replaced it. Same .

put back stock maf, got better. Back to when I bought it.(but didnt drive it too much)

bought msd wires and ignition coil. Same. ( didnt drive it too much)

put 19lb Injectors, drove the same as before but then as car warmed up started getting bad similar to how it was with c&l maf.

Cleaned salt and pepper and put some fuel injector cleaner. Same

so I bought a new tfi module. But havent turned on the car since. I have been having a hard time getting it in timing.
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Old 07-15-2013, 11:52 PM   #17
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ok as soon as I turn on the car. And thanks guys. Appreciate the help.
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Old 07-17-2013, 07:28 PM   #18
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Ok so we are making progress here. I replaced the module with a duralast. I know I know I know motorcraft is better. But at my auto parts it was either that or accel. And I heard accel tfi isnt thatgreat and it was like 20 bucks more and mine has lifetime warranty. But point is... the misfire while driving is gone(so far) its just misfire at idle and very low throttle. I am currently uploading video for you to hear it. So could it be pcv valve ? I have two pcv valves. No oil filler.
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Old 07-17-2013, 08:41 PM   #19
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Old 07-17-2013, 08:52 PM   #20
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Does this occur the entire time the engine is idling or is it only till it warms up?

It sounds more like its hunting idle and less like a miss.

Do you know if it has a different cam in it? it could just be cam lope
but it definatly does not sound ignition related.
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Old 07-17-2013, 08:52 PM
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