Something weird is happening, need input...

[91LTDProject]

Well, my car has always drivin kind of strange in my opinion in the way that it shifts. Its always hunting for the lowest gear possible, and dosent upshift too quickly when you mash the gas. After some research into this problem, i found the article on here about the t.v cable adjustment (about march). I followed it step by step and the car shifted great, but it only lasted a few weeks, and I didnt mess with it anymore. Now this new thing is happening. Whenever the car is cold, and intermittently when it is hot. When you start driving cold and give it gas to accelerate, the whole car jerks and shakes, at first i thought it was a misfire, but on full throttle it gets worse, and you can hear the engine rpm smoothly going up while the car is jerking and shaking, and it dosent seem to accelerate as fast as it did, like all the engines power is no longer being given to the wheels. It does it both under light and heavy throttle. When its cold its worse, but when its hot, it mainly does it while cruising around 80/90 km/h under light throttle, and not all the time. I suspect there is something wrong with the transmission. Anyone got suggestions?

[Archangel]

Just to make sure, put the car in gear, floor the brake pedal, and start increasing pressure on the gas pedal until brakes can barely hold the car, listen and observe - if there's no shaking and jerking, then your engine is fine and the tranny is acting up. If there is jerking and shaking put the tranny in park and start revving the engine (not too high, you don't want to blow something) - again no jerking would means engine is fine.

During the first test in the tranny you have the torque convertor and the clutches working, clucthes are actuated by the tranny fluid pump so if pump doesn't provide consistent line pressure force on the clucthes will be varying and there will be grabbing and slipping (results in jerking).

When car is in "P" the only thing working in the tranny is the torque convertor, the pump is also spinning but it's pressure isn't utilized for nothing so even if it fluctiates I wouldn't expect it to have any effect on the rotating parts.

My not-too-educated guess would be that jerking while in park means problems with the troque convertor (is that even possible?), and jerking while in gear and under load means pump is on its way. Again, that's assuming the engine is running fine and smooth. Someone with more tranny knowledge correct me where I'm wrong please.

[88grandmarq]

what is the trans fluid condition? is it full? is it brown? is there an odor? any debris in the fluid?
You may want to try servicing the trans, if it has not been done. drain the fluid, change the filter and drain the torque converter, then add fresh fluid.

also its best to set the TV pressure with a gauge. 0-5 psi at idle is recommended.

[91LTDProject]

Trans fluid is fine, i check all fluid levels on a weekly basis (when I stop to get gas) Fluid and filter was changed 25000km ago with a bottle of lucas tranny fix added also. I will try those tests when I go out today and update later.

[Nathan in MI]

My guess would be torque converter problems...it gets locked and then can't unlock and it shudders. I'm not sure whether it would cause your exact symptoms, but it could be related.

[91LTDProject]

Ok, I tried the test melikeystripperchicks suggested, and while semi-cold, with the brake pedal mashed and the throttle to the point of breaking the tires loose, the car jerked and shuddered a little bit, but not near as much as while driving. Also, it sounded like the motor was mis-firing to me as the rpm was not constant, also not like while driving. In park it revs smoothly with no problems at all. When warm nothing happened in D or P. I also recorded my shift points on the way home. On a perfectly flat, straight stretch of road, under normal driving from 0-100 km/h, the shift points were 30km/h into 2nd, 50km/h into 3rd, and 80km/h into overdrive. Under full throttle, it was 55km/h into 2nd, 105km/h into 3rd, and I ran out of road before overdrive could kick in. I dunno what the norm is for shift points, but my car is usually hunting for overdrive asap, and dosent stay kicked down when going up hill, have to manually downshift. Theres also one fairly steep hill i always get stuck on on my way home from work, and it tends to very slowly roll back. I'm taking that this is also related to a weak pump in the transmission. Is this pump replaceable by its self, or is it tranny time?

[88grandmarq]

it's very possible the motor is mis-firing. new cap, rotor, wires and plugs would be in order. replace the T/stat also, make sure the motor is making good heat.

[Archangel]

To replace the tranny pump you need to drop the tranny, sorry. However your shift points seem fine to me, similar to what mine were before I ramp up the TV pressure. Just to be safe you may wanna tighten up the TV cable, try with 1mm tighter than what it is now and see how it works as to shift points and holding gears.


On a side note though, the jerking stuff sounds kinda like my problems with the TFI module - it's known to go bad on our engines. Normally whe it starts going out it works fine while cold and starts acting up when warmed up, but mine was actually the opposite. I might be completely wrong about it, but around here some auto parts stores can test those gadgets for free - look around for a place that offers that service.

[91LTDProject]

I just did water pump, 192 degree thermostat at the beggining of September, plugs and new cap and rotor in may, wires were replaced about 4 months before I got the car (probly in summer 05) Now this is gonna be a stupid question, but what does TFI stand for, cant for the life of me figure it out. And for tightening the TV cable, is pulling it out towards the front or pushing it in towards the firewall tightening the cable?

[Archangel]

Tightening the cable = shortening it, hold the black plastic adjuster block and pull the cable out towards the front of the engine.

TFI module = grey plastic box on the side of the distributor, there is a connector with 6 wires plugged into it.

[91LTDProject]

Thanks melikey, will tighten cable tommorow at work and see if it holds gears better, and I'll price out a TFI Module. I also have access to a dynomometer so i'm gonna run it on there tomorrow and see what the liscensed techs think. Will update tommorow.

[gadget73]

Sounds like the TV pressure is too low. When its low, the clutches will chatter like that. Its also a really good way to burn up the transmission. As long as its pretty close to full pressure at wide open throttle, you're OK. I usually run slightly under that but if its hitting overdrive under about 50 mph, its probably too mushy. Mine requires a mild pump-shift at about 50 to make it hit overdive, otherwise it holds to about 58.

Its also possible the engine is missing. I had a bad plug wire that would cause random hitching and bucking, especially in the rain.

[91LTDProject]

I was mistaken, it is a problem with an engine misfire. I had a friend drive it on the dyno cold while i was underneath the hood, and you could definatly hear, feel and see the the motor bucking and mis-firing. I have a hunch that its the wires causing the problem, even though they are not that old, they were cheap, and i had one come apart while I was changing the plugs before, but put it back together. It was very busy today and I didnt have time to re-adjust the t.v cable, so it will get done tomorrow.

[Archangel]

Ya, wires will fuck up your day alright, these engines like (and deserve) good quality stuff - if you're buying from a parts store get a good Belden of Taylor set, though I'd highly recommend the FRPP sets if you can find them easy.

[91LTDProject]

I got a set of taylor thundervolt 8.2mm wires, but I was savin them for when and if an H.O conversion takes place. Plus i got to custom make them. They will probly go on next year, but I'm testing everything I can think of right now to try and fix this before it gets colder out.