My 2003 Tribute has gotten into a mode where it frequently stalls when switching from Park or Neutral to Reverse. Idle speed is perfect at 750-800 rpm and, in fact, the idle controller was replaced six months ago. I read that this might be caused by clogged transmission cooler line or fluid. Is that, in fact, the case? Fluid has never been changed. Might that be an issue? Fluid level looks fine, but fluid is sort of brownish rather than pinkish. No burned smell. If I rev the engine slightly before switching into reverse, it doesn’t sem to happen.
Start the engine, and as it idles wiggle/tug on wiring harnesses under the hood to see if the engine stalls.
Stalls with cold engine? And stalls with warm engine?
Re wiggling wires, not sure what that has to do with switching into Reverse. If jiggling wires causes a stall, it’ll stall whichever way the car tries to move.
Seems to happen whether engine is warm or cold.
When in drive, the engine twists in one direction.
When in reverse,the engine twists in the opposite direction.
When in reverse, the twisting of the engine may be pulling on a wire causing an open circuit.
Reverse’s rotational inertia causes engine/transmission ass’y to twist in a different direction (CCW vs CW) compared to a forward gear, which might pinch a wire that otherwise is never pinched.
Given the transmission fluid has never been changed, seems you have to do that anyway. Good place to start. Torque converter could be sticking a little more than it should. However I’m doubting this will help, more likely either the wire pinch theory, or the engine just isn’t running correctly for some reason, likely too lean b/c of intake air leak somewhere. Ask shop to spray starter spray when idling, if rpm speeds up, intake air/vacuum leak likely in that area. Fuel trim numbers might be helpful too.
Hmmm. That’s interesting about wires getting pinched because of engine twist, but I tried jiggling lots of wires,and nothing happens. I believe engine is running fine because,as I said, it came out of the shop having fixed an idle problem. As I said, I’ve read in several places that this condition could be because of clogged transmission cooler line or fluid. I’ve never changed the fluid out or flushed in 20 years, which would include filter change. Could that be an issue here?
If it were a clogged transmission cooler line, the transmission would over-heat and the Check Engine light would turn on.
And the “torque convertor sticking only when going into reverse” theory is nonsense as well.
So, what are my options? Should I just do a long-overdue flush? Now, this certainly isn’t a big problem. Just a minor annoyance.
It’s unlikely that your problem is in any way related to the transmission. With the car at a full stop the engine is turning, the torque convertor is turning and nothing else behind the convertor is turning except the transmission’s pump. Absolutely nothing changes with respect to the engine whether in forward or reverse. The engine simply cannot tell whether your going forward or backwards.
Tester’s comment about wiggling wires is useful because the engine MOUNTS can allow one side of the engine to lift during forward motion and the other side to lift in reverse. Have you checked any of that?
Beyond that you have a simple engine stalling problem. Make the engine run correctly for both forward and reverse.
Well, the engine doesn’t stall. Not by itself. It ONLY stalls when the transmission is put into Reverse. True that putting it in Reverse will tend to drop the rpm, but the same thing happens when you put it into Drive.
If I had that problem myself, I’d use an o-scope to probe the current pulse in one of the spark plug leads, while a helper put the engine in reverse. What to do after that depends on the order of the engine stalling w/respect to the current pulse disappearing.
is the check engine light on?
If the check engine light was on, I would have reported that, and sniffed out the code. That would have been my first action, before bringing it up here.
Have you tried slightly stepping on the gas pedal with the brake on with your left foot before shifting into reverse?
Sorry for trying to help.
My Chrystal ball did not tell me your mechanical ability, nor what you have or have not check out on your vehicle.
good luck with your vehicle.
If you hang around this site for a while, you will see that we frequently find out that somebody’s CEL is lit up only after playing Twenty Questions with the OP. That is why weekend warrior asked that very relevant question.
And/or that it has been on for a quite lengthy time, before they even posted. How many times have we seen “oh, btw the check engine light has been on for close to 2 years, if it matters” You know like it was irrelevant or something.