htiek123
LVC Member
This is what mine is doing.... I live in New Jersey.... The traction light comes on for a second....
00 LS 3.0 5spd - Buck/Jerk - Only When Driving in Snow Dust/Powder
- Thread starter md1twal3
- Start date
This is what mine is doing.... I live in New Jersey.... The traction light comes on for a second....
pragmatic
Dedicated LVC Member
Original Poster and my car do not have traction control so in our cases it is not part of the problem, may or may not be part of the problem for others..
joegr
Dedicated LVC Member
Which is why I was originally wondering if snow flakes were getting to the MAF. Sounds like that's not it either.
As I'm sure you have found with a search, this bucking on manual transmissions has been a subject for quite some time. Here's a bit of my story. And there's more later, but unfortunately I never came to a clean resolution. http://www.lincolnvscadillac.com/forum/showthread.php?90390-The-Bucking-Problem
Appreciate the link TerryinNC. I've replaced the MAF, COPs & Boots, tested injectors, replaced fuel pump, filter, IAC and the PCM has been tested and updated by a friend at a Ford dealer. I'm was thinking TPS but struggling to blame a sensor because of the only time it occurs...snow in the air, and not necessarily wet or melting snow; dry snow with no road melt. I'd think if a TPS was causing an issue like this, that there would be an open in the potentiometer of the sensor but the issue would occur anytime I passed that area through the throttle plane.
The past few weeks, I've had 3 instances where the car didn't want to idle on cold start in cold weather. It flared up to 1500 RPM, bounced around a little and then died. Restarts fine but would still stumble, the idle drops gradually until it kills. No codes. I'm leaning toward an IAC for that, which I understand can cause this issue along with no start/hard start but am not sure how an IAC could cause the firm bucking issues at road speeds unless it's shorting, triggering a "short and reset" in the PCM. I'll probably put one in and see how it goes.
pragmatic
Dedicated LVC Member
If not IAC, I'd go with TPS. Unplug the TPS and then start and drive the car. I think your problem will go away without the TPS (though the car will idle very very high). I'd only try this on a MT car.
I'll give it a shot, pragmatic. Stay tuned...
joegr
Dedicated LVC Member
A shorting DCCV can throw out a lot of electrical noise. It's an extreme long shot that it would be enough to crash the PCM.
pragmatic
Dedicated LVC Member
Good thought. We had buses shutting down when solenoid water valves opened and the voltage spikes caused problems with engine sensors (fixed with diodes to kill the spikes of collapsing fields).
Telco
Dedicated LVC Member
OMG are you freaking serious? THAT can kill the PCM on these cars? I mean I can see the coils doing it since the coils have a direct connection but the DCCV, just through radiated power off a 12V system?
Telco
Dedicated LVC Member
There's a serious problem with the LS electrical system through the ground can kill the PCM. Most every other car out there doesn't have this problem.
Diode on the PCM main ground, perhaps? Wouldn't be a bad idea to put one on every coil to PCM wire too.
Diode on the PCM main ground, perhaps? Wouldn't be a bad idea to put one on every coil to PCM wire too.
1LoudLS
Dedicated LVC Member
there is no serious PCM problem that is anyway wide spread with the LS... PCM failures don't seem anywhere near a common problem, at least no more than any car.
Anything CAN happen, doesn't mean that it is probable
Anything CAN happen, doesn't mean that it is probable
Telco
Dedicated LVC Member
Still, might not be bad idea to do the diode thing on the ground. We do know the coils can kill the PCM, for those of you keeping your LS protecting the PCM would be a good idea.
LSinYourLS
Active LVC Member
Especially since a PCM for a 5-speed is hella-rare.
LSinYourLS
Active LVC Member
But not a 5 spd manual.
I do happen to have an extra on hand from a time when I thought I needed a pcm but never ended up needing it so there is sits. Regardless of the theories or possibilities, why, oh why ONLY with snow in the air? Stupid car.
joegr
Dedicated LVC Member
Yeah, how do it know?
Did you change the IAC, and did it have any effect?
http://www.lincolnvscadillac.com/forum/newreply.php?do=newreply&p=2037310830
Did you try clearing the KAM and doing a drive cycle? I think disconnecting the battery clears the KAM, but not sure. Also not sure the AutoZone etc. readers clear the whole KAM - the Ford tech implied you needed the proprietary reader to fully clear it. ??
http://www.lincolnvscadillac.com/forum/newreply.php?do=newreply&p=2037310830
Did you try clearing the KAM and doing a drive cycle? I think disconnecting the battery clears the KAM, but not sure. Also not sure the AutoZone etc. readers clear the whole KAM - the Ford tech implied you needed the proprietary reader to fully clear it. ??
TerryinNC, I have not yet. Unfortunately, I tore my quad tendon from my knee and have been recovering for the past several weeks. I've had a new electrical issue crop up that I need to chase next...LF lowbeam headlight inop. I've had water intrusion issues in harness 14290 underneath the RF wheel well and suspect the new issue is related. I'm hoping to do some testing this weekend and will be chasing it. I know the FEM can be an issue and have no way of cycling it but figure I can do simple circuit tests to at least narrow it.
I wanted to replace the entire harness as I have intermittent front ABS codes on both front wheels at the same time, I had a no start issue that I thought was the PCM and it was a wire, I have HVAC temp differential issues, that bucking issue and now a headlight issue. The harness is discontinued and I can't find my specific harness (BA suffix) on the web anywhere either. Honestly about ready to throw in the towel and trade it off on an older BMW xi of some sort. Frustrating!
I wanted to replace the entire harness as I have intermittent front ABS codes on both front wheels at the same time, I had a no start issue that I thought was the PCM and it was a wire, I have HVAC temp differential issues, that bucking issue and now a headlight issue. The harness is discontinued and I can't find my specific harness (BA suffix) on the web anywhere either. Honestly about ready to throw in the towel and trade it off on an older BMW xi of some sort. Frustrating!
Been a while since posting so figured I'd give and update. Turns out, I had several corroded wires in the 14290 harness, directly behind the RF headlamp. A few years ago, someone backed into the car and damaged the harness. Their insurance company refused to replace the harness and authorized a few hours for repair. If I recall, the harness carries around 75 wires and I've performed 35ish repairs. Anyway, the resistance was creating all kinds of issues, mostly in the ABS and some circuits powered out of the aux panel under the hood. Cruise control was also effected. So, all is good there but am again pushing for replacement.
As for the bucking, I believe it was related to the airbox cover not being properly latched. One side was not secured so I am thinking that the snow was getting sucked in through the leak and into the throttle body. Water in throttle body = bucking. I've secured the cover but will have to wait until winter to know if it's fixed.
Replaced left and right hubs and ABS issues are gone. This is good.
Only the HVAC issues to deal with now. AC no longer cools, the incoming air seems to be ambient temp. Heater is either full blast or none, regardless of where the temp is set. I'll be digging into that soon.
As for the bucking, I believe it was related to the airbox cover not being properly latched. One side was not secured so I am thinking that the snow was getting sucked in through the leak and into the throttle body. Water in throttle body = bucking. I've secured the cover but will have to wait until winter to know if it's fixed.
Replaced left and right hubs and ABS issues are gone. This is good.
Only the HVAC issues to deal with now. AC no longer cools, the incoming air seems to be ambient temp. Heater is either full blast or none, regardless of where the temp is set. I'll be digging into that soon.
LSinYourLS
Active LVC Member
There are three temperature sensors in the HVAC housing unit; Evap core temp, driver's output temp, and passenger output temp. they are cheap and easy to replace (there's also a cabin air & outside air temp, but that's probably not the issue). Just remove the kick panels under the glove box & steering wheel and you'll see them in the center stack. A lot of people will say you need a DCCV, but these sensors are common failure point (I sell Ford parts). For what it's worth, I had the same issue as you. I chased my tail bleeding the coolant to remove air, replacing the DCCV, electrical tests, etc. And it ended up being the sensors; the HVAC head unit can't provide anything but full hot or full cold without a temp reference value from both input and output!