Unbelievably tired of weird issues..

MMAFIGHTER121

MMAFIGHTER121

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Ok.... so... You know how when you're cruising along between 40-70 in 5th the car rolls along then kinda settles down a few hundred RPMs for cruising/ Well - its doing that, but then jumping back up 200 or so RPMs, acting like I'm going to accelerate up a hill oir something, even if I'm just coasting along regularly, then settles back down and a little while later jumps up again. On a possibly related note: my cruise control isn't working. The clockspring has already been replaced. What happens is I'll turn on the cruise switch and hit the button for resume or whatever, then the light will briefly light up, then turn back off. On the occasion that it does stay on, the cruise won't actually activate. I'll just slowly bleed speed as if I just came off the pedals normally. WTF mate?
 
Wild guesses would be:

1. Your torque converter is unlocking when it shouldn't. It could be the PCM, wiring, solenoid assembly, the torque converter itself, or maybe something else.

2. The cruise control issue might be a defective servo. However, you should start by checking the mechanical throttle cable that runs between it and the throttle.


There's a lot of diagnostic information to be had on the transmission from the PCM, but you need a good scan tool to get to it. I wouldn't let this linger, as you may be doing damage to the transmission.
 
With the two problems seeming to pop up at similar times I'm wondering if the TPS could be going.. what should I check to see if its going on of whack?
 
MMAFIGHTER121 said:
With the two problems seeming to pop up at similar times I'm wondering if the TPS could be going.. what should I check to see if its going on of whack?
Click to expand...

Read the voltage as you move the throttle. The voltage should change smoothly with the throttle position. An analog voltmeter is best for this, but it can be done with a DVM or scan tool.
 
I second joegr: that couple hundred RPM is difference between a locking and unlocked Converter: sounds like the Torque Converter Clutch is disengaging.
My experience with other EFIs with lockup converters, while def. not the same car, was that the TCC and the cruise were connected: once when a Vehicle Speed Sensor failed, I could only lock the Torque Converter Clutch manually (pins in the ALDL port to a manual switch) but the cruise wouldn't work. Once VSS was fixed, both worked again.
 
MMAFIGHTER121 said:
Ok.... so... You know how when you're cruising along between 40-70 in 5th the car rolls along then kinda settles down a few hundred RPMs for cruising/ Well - its doing that, but then jumping back up 200 or so RPMs, acting like I'm going to accelerate up a hill oir something, even if I'm just coasting along regularly, then settles back down and a little while later jumps up again. On a possibly related note: my cruise control isn't working. The clockspring has already been replaced. What happens is I'll turn on the cruise switch and hit the button for resume or whatever, then the light will briefly light up, then turn back off. On the occasion that it does stay on, the cruise won't actually activate. I'll just slowly bleed speed as if I just came off the pedals normally. WTF mate?
Click to expand...

I had the exact same symptoms with RPM's and Cruise. Eventually in time it started to run real rough. They found a couple bad COP's, I replaced them all w/plugs and the cruise started working normally and RPM's normal.
 
Turboguy said:
I second joegr: that couple hundred RPM is difference between a locking and unlocked Converter: sounds like the Torque Converter Clutch is disengaging.
My experience with other EFIs with lockup converters, while def. not the same car, was that the TCC and the cruise were connected: once when a Vehicle Speed Sensor failed, I could only lock the Torque Converter Clutch manually (pins in the ALDL port to a manual switch) but the cruise wouldn't work. Once VSS was fixed, both worked again.
Click to expand...

I agree that its the torque converter locking and unlocking, and I hate driving it as is, but I don't have a choice. What should I do to check the vehicle speed sensor?
I have tomorrow off so its time to do diagnostics.
 
MMAFIGHTER121 said:
... What should I do to check the vehicle speed sensor?
I have tomorrow off so its time to do diagnostics.
Click to expand...

There isn't one. Instead, the ABS module averages the wheel speed sensors and communicates the car's speed to the PCM and the cluster (and Nav if you have that). If you don't have an ABS light on, then it's probably not this.
 
it is not on. so VSS (nonexistent) is not the issue.. I have two guesses:
shot PCM (odd O2 sensor readings a few weeks ago adds curiousty)
or TPS.. gotta check that.. can I pull its voltage with a scantool?
 
Going back and reading all your posts in the last few months, and with all the problems you've chased and are still chasing... I vote for 1 or more failing COP's. Others have stated and even a dealership I go to stated you can get other strange electrical problems/codes when COP's fail or start to fail. The Cruise control symptom was exactly like my issue, and then all COP's/plugs replaced and no more codes, idle/rpm issues were gone, "transmission shifts felt better than they ever have", and the cruise control just started working fine again.

You were asking about transmission shift speed in this thread: http://www.lincolnvscadillac.com/showthread.php?p=902835#post902835
If you are having shifting issues or it shifts differently then it used to, this can be caused by electrical problems/bad COP's too.

You've had too many different problems... I'd be leaning towards electrical problems due to bad COP's.
(I see you've replaced cops/plugs before with Accel/Iridium...)

Sometimes the simplest solution is the solution...
(i.e. COP's causing all these problems sounds too easy, but...)

I could be wrong, but if it sounds like a duck...
2000 Ducks - YouTube
 
at 40, my car drops back down to 4th (or at least comes out of lockup). Could be normal operation? If its doing it at 50 or higher though then I agree with all the other posts about the torque converter.

My cruise lights up but does not function just as you described. When I had the driver front fender insert out during a brake job, I noticed what I believe is the servo corroded so badly that a chunk of the aluminum or whatever it is on the case fell off. This is probably my problem, but its low on the priority list. It might be the case with yours too.
 
I really doubt the coils because the acceleration is still smooth, still even have good power, no real idle stumbles, nothing misfiring, and I've had the accels and iridiums for 60K miles now without them causing driveability issues, I've replaced a coil or two along the line prior to the re-wiring but since I did that I haven't had so much as a hitch.
The shift speed question wasn't because it was acting up, it was just a general performance question.
 
Well that's good and bad I guess. Good that it runs well and you won't hopefully have to replace the COP/plugs again. Bad that your still having issues and trying to chase down the problem(s). The cruise thing really stood out to me as it fit the problem I had, and your other problems with various codes your chasing etc... was hoping it was something more simple for you to find/fix. Good luck.
 
Well - that's why I was wondering if I'm having a PCM fail slowly because recently I got back on ye olde scantool and now all 4 O2 sensor voltages are functioning properly at idle. So weird sensor readings.. on and off.. in various seemingly unrelated parts of the car..
 
But id rather test at the end of the line causes and work my way back, rather than starting with expensive PCM and finding out it is the TPS.
 
MMAFIGHTER121 said:
But id rather test at the end of the line causes and work my way back, rather than starting with expensive PCM and finding out it is the TPS.
Click to expand...

It wouldn't hurt to check the PCM relay and socket. (If the power supply to the PCM is noisy, it might cause odd behavior.)
 
I had a similar issue on a way different car - an 88 Firebird. Turned out to be a bad coolant temp sensor. Go figure. lol
 
To get at it we gotta go through the engine bay thought right? Under the cowl shroud?
 
thanks - just checked the relays and they all look fine, could I just test the TPS with a scantool? just run to autozone real quick.. just to eliminate it, i know if I had a bad TPS i'd probably suffer other driveability issues.. but I'd rather eliminate everything I can.
 
MMAFIGHTER121 said:
thanks - just checked the relays and they all look fine, could I just test the TPS with a scantool? just run to autozone real quick.. just to eliminate it, i know if I had a bad TPS i'd probably suffer other driveability issues.. but I'd rather eliminate everything I can.
Click to expand...

Yes, with a scan tool that has live sensor readings.
 
ok - comprehensive breakdown after the trip to autozone:
- on the way down, I didn't have the TC lock/unlock issue until I tried the cruise control, then I had the problem quickly when I hit it, but then not again for the rest of the trip
- I used the Scantool and the TPS is reading correctly
- Odd O2 sensor glitch - at idle, all 4 O2 sensors were reading fine, switching as they should, then after a few rev sessions (while testing the TPS) one O2 sensor refused to return to the switching state at idle and stayed at .04-.08V., well below the others .1-.8V switching
-On the return trip I made an effort to spend as much time smoothly cruising between 40-60 as possible, without touching the cruise controls, and I didn't get the TC problem
-Just before pulling into the house a trouble code popped on - but I couldn't scan it - I tend to believe its the standard P0430 that I've been hunting prior to these new problems... but I can't be sure until I re-pull the codes and I didn't want to drive right back..
I has a confused.
 
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