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Discussion Starter #1 (Edited)
I Shall Call it Damian...

I now am fully convinced that my car is possessed. Today it was doing the strangest things. Ok, so I get off work and head to the post office. I get up to 50 mph and then let off the gas to just coast along the road. Well, something didn't feel right when I let off the gas. The car didn't feel normal, like it hadn't lost the force propelling it forward. I look at my tach, and it doesn't drop like it normally does when I let off the pedal. Normally it drops a hundred or so (sometimes more) RPM, and when I get back into it it shoots up and then eventually the TC will lock. Well it doesn't drop, and I step on the gas slightly and BAM, the whole car jerks. The TC never unlocked! My foot was off the pedal for a good 7-10 seconds, and the TC stayed locked the entire time! I let off the gas, wait a couple seconds, get back in it and it's still locked. I press the brake pedal, still locked. I take it past 3/4 throttle, still locked. Then at about 7/8 throttle it unlocks. I resume to about 1/4 throttle and after a few seconds it locks back up again, but not smoothly like it normally does. It was almost an instantaneous lock and it made the whole car jerk. I try letting off the throttle and do what I did above and it's doing the same thing. So a minute or so later I come to a stop at a light, and now the car is idling at about 950 RPM. Normally with A/C on I'm at about 700. The idle speed is obviously not supposed to be like that so while waiting at the light I put the car in Park. Normally it would idle about 850-900, but it sits at about 1100. I rev the engine to try and "kick down" the RPM (like one would do if the car had a choke) and it gets up to about 2500 RPM and very slowly drops down and then sits at about 1600 RPM. The light turns green and I'm afraid to put it in gear but I have to, so I do and the RPM came down a little before engaging so it wasn't that harsh. But the evil continues and the TC engagements are quite brutal. At the next stop it's still idling high, so I again put it in Park and turn off the car. I give it about 15 seconds and turn it back on. After that, everything was normal. What gives?!? The damn thing is possessed I tell you! This in combination with other problems I've been having is making me think the car has ghosts! I'm wondering if the cause of the problems experienced here is at all related to this problem I was/still am having.

For the record, no the battery and/or cables aren't to blame. Everything is fine including the grounds. The IAC & MAF are new. I replaced the IAC because I thought it might have been to blame for the high idle as this has occurred more than once, and the MAF was bad. This has happened about 3 times total with the first occurrence in July, another in early August and the third today.

Here's a little background info that might be related and could possibly be what might be causing the problem. In June of this year I had just finished installing the trans back into the car (the engine/trans were both out). I didn't realize it at the time but when I reinstalled the trans pan I pinched a couple wires from the harness to the solenoids in between the case and the pan. About a week later, I went from Los Angeles to Las Vegas and made it there with no problems other than the TC not locking up when it was supposed to (this was later found out to be caused by the MAF). On the way back, I was having the same problems with the TC not locking up so I decided to try and reset the computer. I pulled over (I was already on the freeway heading home), pulled the #15 fuse, waited and put it back in. I took off from the shoulder, got up to speed and about 10 seconds later the car just died. I was like "WTF?!?" and got over to the shoulder. I got out, inspected and found that the fuse blew. I replaced it with one of the other fuses and was planning on going to an auto parts store to get a replacement. I started up the car and it ran for a couple seconds then died. So I got stranded there, called a tow truck and got towed back to Vegas (I was only 40 miles out) to where I was staying. At first I thought I had fried the computer because it was WAY TOO COINCIDENTAL that I pulled the fuse and right after I put it back in it starts blowing. So I got another computer and some fuses, put it in and of course it still blew the fuses. So now I knew I had a short somewhere. I disconnected all harnesses and plugged 'em in one at a time until I isolated it to the trans and eventually to the harness that goes inside the trans. Pulled off the pan and I saw what had happened and cursed for a couple minutes, then I went to Ford and got another harness, put it back together and everything was fine (except for the TC still). Now if you read the description of the problem I'm having in this thread, I can't remember if this was happening before this harness short thing happened.

So...does it all seem related? I believe that the wires that got pinched were to the TCC solenoid but I'm not 100% positive. I'm thinking the ECM is crapped out, but what seems most likely? I'm looking for others opinions on the situation. Could the TCC solenoid have been damaged if the wires to it were shorting out? Could that have done damage to the ECM as well? If so (and that's what my current theory is) that would explain this quite well.

It's also interesting to note that once I got the MAF fixed, everything was working beautifully. The TC locked up nice and smooth and the car ran great. But there were a couple freak occurences on the highway when everything seemed normal but one time I would get 28 mpg and another time travelling the same route in the same direction with the same conditions I would get 21 mpg.

Sorry for the excessively long post. There's just too much going on at once and I figure if I'm gonna ask anyone, I'll say as much as I can about the situation so that everything can be taken into consideration.

Like I said I'm leaning towards the ECM but I could be totally wrong there. Or maybe I should just skip all this and go find a priest right now. Thanks in advance for any opinions!


BTW the title should have been spelled "Damian."
 

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PostSlut
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master486 said:
Eh? Sorry I must have missed something. Or my brain is toast cuz it's Friday.
in other words, thats a lot of shat to read.....could you brake it down to 1, maybe 2 sentences?
 

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Discussion Starter #8
_95badbird said:
in other words, thats a lot of shat to read.....could you brake it down to 1, maybe 2 sentences?
Oh ok. What, you don't like a good story?

3 times in 3 months, my car has acted really strange. For no reason it will idle high, shift weird, and the TC locks harshly and won't unlock when it's supposed to. If I turn the car off and back on, problem goes away, but I'm sure it'll happen again sometime.

Don't know if it's related but in June I pinched wires from the tranny harness in between the pan and case. This caused fuse #15 to blow. Replaced the ECM at first but didn't solve the problem. Diagnosed it and found the harness problem, replaced the harness and all went well. My problems now never happened before that tranny harness shorted out.

I'm trying to find out what might be wrong. ECM damaged from the short? TCC solenoid causing ECM to trip out (I think the wires to the TCC solenoid were pinched)? Just lookin' for suggestions/opinions.
 

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PostSlut
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13,597 Posts
master486 said:
Oh ok. What, you don't like a good story?

3 times in 3 months, my car has acted really strange. For no reason it will idle high, shift weird, and the TC locks harshly and won't unlock when it's supposed to. If I turn the car off and back on, problem goes away, but I'm sure it'll happen again sometime.

Don't know if it's related but in June I pinched wires from the tranny harness in between the pan and case. This caused fuse #15 to blow. Replaced the ECM at first but didn't solve the problem. Diagnosed it and found the harness problem, replaced the harness and all went well. My problems now never happened before that tranny harness shorted out.

I'm trying to find out what might be wrong. ECM damaged from the short? TCC solenoid causing ECM to trip out (I think the wires to the TCC solenoid were pinched)? Just lookin' for suggestions/opinions.
its all good, I was kinda messin with ya more than anything.
 

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Discussion Starter #10
_95badbird said:
its all good, I was kinda messin with ya more than anything.
No worries. It's actually a good idea because I didn't realize I typed so much. You know when you get heated about something and the words flow right out of you (and into the keyboard in this case)? Maybe I'll get some responses now.
 

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Some time in the past I had a Mustang with the 3.8 V-6 (TBI). Every year it ate the Throttle Positioning Sensor. Seems that the design allowed gas to get in it from the throttle plate shaft which ruined the TPS. I assume yours is EFI so I would think that wouldn't happen. The TPS can cause some weird issues with driveability, its something to look at and all you need is a voltmeter or ohm meter to check it. From the RPM symptoms you describe it's possible that's all that's wrong. If the TPS is going bad or is bad it will give the computer false information.
Weird things will then happen. Good luck!
 

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Discussion Starter #15
Yes, the ECM is supposed to unlock the TC when it receives a signal from the BOO switch. The brake lights were definitely working though so for some reason the ECM didn't feel like doing anything right. Hell the TC should have unlocked just by me fully letting off the gas pedal. I replaced it last night and I'm going to see if anything changes.
 

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Discussion Starter #16
Update

Well, I replaced the ECM on Friday. I just did so for the heck of it while it was still under warranty so that I could see if that would fix the problem. So far, everything seems to be working awesome! Immediately I noticed it shifted better and ran smoother. For a couple miles on its second time running it was a little weird, but I'm going to guess that the computer was adjusting itself and relearning all that it needs to because since then it has been fine. Crossing my fingers and hoping all will remain well because in 7 days I'll be travelling over 1,600 miles and I need it to work! Thanks everyone who provided input.
 

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Discussion Starter #17
Short update on this problem. The new PCM didn't help things out at all. But over a year later I found the problem. It was the TPS pigtail that had a bad wire and would intermittently (with vibration) give a false signal to the PCM, thereby causing the strange behavior.
 

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Nobody has opinions/theories/recommendations/weapons to beat the car with?
Hang garlic from the rearview, put a crucifix or a plastic Jesus on the dash and wash the car with Holy water.

Edit: I didn't realize this thread was over a year old either. But, my advice still stands. :D
 

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3rd Gear Chirper
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The TCC solenoid has continuous +V whenever the ignition is on, and the computer supplies the ground when it wants the TCC to lock up. So if you pinched the ground wire against the case/pan, it would be supplying the ground and powering up the solenoid, causing the lockup condition. I don't think this could have damaged your computer as I have a switch that does the exact same thing I described to you, manually locking up the converter whenever I want by grounding the solenoid. The computer is also connected, so either it or myself can do it, and they can both be engaged at the same time.

EDIT: oh crap, I didn't realize the post was over a year old, and I missed the part about you fixing it with a new TPS harness. Sorry, it's Monday and I'm at work.
 
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