Lurching problem and I'm out of ideas.

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You dead sure you have a 999 trans? I thought they were not that common. It sounds like a lock up problem to me. We have a 2012 caravan 3.6 VVT and the trans is a 6 or 8 sp. All electronic solenoid operation and the darn thing compression brakes in gear down to around 17 mph. Drives me crazy driving it as it feels like it's dragging, then it releases and it coasts. In the day of fuel economy, I would think the thing would want to coast as much as possible? Had the trans flashed when we bought it, Carmax is great about stuff like that when you purchase from them. We drove it off the lot and I took it back the next day telling them to check the trans code and they glashed it for free. No change...supposed to do that? Does it in both trans modes, ECO on and off.
 
Ben Ainsworth said:
I haven't experienced any issues with tight turns at that low speed. Only noticed it when coasting down from a higher speed than I would likely do in a parking lot. That said, I'll do that neutral test today and also try in a parking lot... Maybe I just haven't noticed it.

I haven't paid too much attention to the whine because I figured it's a separate issue. It's just that they rebuilt it twice and it still whined, so I thought that was maybe telling...
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Whine in park & drive until 2nd gear and up?
Does it get quieter in neutral?
 
Dartswinger70 said:
Not sure Ive never heard of a hydraulic lockup converter though interesting. I looked into it briefly here is the link. It seems there is a hydraulic and electronic system You could pull the trans pan and see ethey hydraulic system for example. It would still avoid pulling the whole unit.

Mechanical override: Lockup torque converters
Click to expand...
"RE" series (R for rear wheel drive, E for electronic) are electrically controlled. "RH" series (H for hydraulic) are hydraulically controlled- all internally controlled, no external (electrical) inputs needed to operate. HOWEVER, they use an electric solenoid to lock out the overdrive (if equipped) and convertor lockup function- think of the "Tow/Haul" button.
A999/32RH are hydraulically controlled non-overdrives with a lockup convertor.
I forget exactly when Chrysler went from the "A" designation to the "RH/E" designations for their transmissions.
 
Ben Ainsworth said:
Problem: When car has been warmed up for a while and driven for 1hr plus, I get a hard jerking/lurching between 1200-1300rpm when coasting down (no braking or accel). The jerking stops when rpm drops to around 1100, and disappears if I accelerate or brake.
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disappears if I accelerate or brake.

Com'on guys;
I'm no genius but Ben says
"the problem disappears when I accelerate or brake."
I don't know how you come up with some of the ideas you do.
Clearly this has something to do with coasting down, which is a closed-throttle situation. In this situation, enertia is driving the engine against compression braking. So the engine is pulling very hard on the "closed" throttle blades.
Ben, if you were to shut off the engine at this time, having EFI, no more fuel could find it's way into the engine. If the lurching stops, badaboom, it proves my Transferslot/ hot plug theory.
With EFI the solution is a lil different.
If you have an AIS motor, I would work on the synchronization between that and the closed throttle stopper, together with the fueling. 1100rpm is what roadspeed? 25/28 mph? And you are slowing from hiway speed right? By this time, if you have the right speed-O gear for the rear end, the trans, if it had an automatic lock-up TC, it should have outshifted a long-time ago; unless your Line-Pressure has been boosted by way too much Throttle Pressure via the KD linkage.
Since you say the problem goes away with application of throttle this pretty much absolves the trans of any wrong-doing. Since you say the problem goes away with the application of the brakes this also rules the trans out.
But it simultaneously also proves the brakes have nothing to do with this problem. And to top it off it rules out the rear end.
IMO this is 100% an AFR problem; the engine is either misfiring in this circumstance or the mixture is pre-igniting, fired by something hot in the chamber. And, because of what preceded it, namely the long cruise period; if it was a carb I would be blaming it on hot plugs.
But since it is EFI, it could be your O2 sensor is giving the wrong feedback to the computer on account of the 230* cam. If you can turn it off during deceleration, that is the first thing I would try. Ok no, second thing. The first thing I would do is prove that the headers are sealed to the heads, and to the exhaust pipes, and that the exhaust valves are sealing. That cam has a lot of overlap, I mean a lot! I'll guess close to 70*.
During closed throttle, the pistons are gonna put a heavy pull on the plenum.
During the overlap phase, BOTH valves of every cylinder are gonna be open, each pair in turn, and the headers are ALSO gonna pull on the intake.
So; if there is fuel in the plenum, the headers are gonna yank it out and pull it down to the O2 sensor, and the O2 will do it's job and tell the computer that something is waaaay messed up, and the computer will try to lean the mixture out, cuz at the high manifold vacuum, the programming should have been set quite lean.
However;
If your headers are pulling in air from another source, like the flanges, then the O2 could be reading who knows what.
Therefore, I say; prove the headers then put the ECU into open-loop during decel; see what happens.
 
I do not think this is a drive line problem. Sounds engine related.

I think the engine is going very rich when you lift off the loud pedal. At higher rpms, the engine can use the extra fuel. But at lower rpms, it doesn't need as much fuel & goes overly rich. Which gives a surging/lurching feel. When you brake, the engine is no longer 'free wheeling' & is under control, so no surge. When accelerating, the engine can use the extra fuel.

Also, you want Champion '12' or NGK '5' [ preferred ] heat range plugs. Champion 9s are too cold, & if you have a rich mixture, will only make it worse.
Have you checked your dist? Make sure springs/weights are working, lubricated, etc.
 
AJ/FormS said:
disappears if I accelerate or brake.

Com'on guys;
I'm no genius but Ben says
"the problem disappears when I accelerate or brake."
I don't know how you come up with some of the ideas you do.
Clearly this has something to do with coasting down, which is a closed-throttle situation. In this situation, enertia is driving the engine against compression braking. So the engine is pulling very hard on the "closed" throttle blades.
Ben, if you were to shut off the engine at this time, having EFI, no more fuel could find it's way into the engine. If the lurching stops, badaboom, it proves my Transferslot/ hot plug theory.
With EFI the solution is a lil different.
If you have an AIS motor, I would work on the synchronization between that and the closed throttle stopper, together with the fueling. 1100rpm is what roadspeed? 25/28 mph? And you are slowing from hiway speed right? By this time, if you have the right speed-O gear for the rear end, the trans, if it had an automatic lock-up TC, it should have outshifted a long-time ago; unless your Line-Pressure has been boosted by way too much Throttle Pressure via the KD linkage.
Since you say the problem goes away with application of throttle this pretty much absolves the trans of any wrong-doing. Since you say the problem goes away with the application of the brakes this also rules the trans out.
But it simultaneously also proves the brakes have nothing to do with this problem. And to top it off it rules out the rear end.
IMO this is 100% an AFR problem; the engine is either misfiring in this circumstance or the mixture is pre-igniting, fired by something hot in the chamber. And, because of what preceded it, namely the long cruise period; if it was a carb I would be blaming it on hot plugs.
But since it is EFI, it could be your O2 sensor is giving the wrong feedback to the computer on account of the 230* cam. If you can turn it off during deceleration, that is the first thing I would try. Ok no, second thing. The first thing I would do is prove that the headers are sealed to the heads, and to the exhaust pipes, and that the exhaust valves are sealing. That cam has a lot of overlap, I mean a lot! I'll guess close to 70*.
During closed throttle, the pistons are gonna put a heavy pull on the plenum.
During the overlap phase, BOTH valves of every cylinder are gonna be open, each pair in turn, and the headers are ALSO gonna pull on the intake.
So; if there is fuel in the plenum, the headers are gonna yank it out and pull it down to the O2 sensor, and the O2 will do it's job and tell the computer that something is waaaay messed up, and the computer will try to lean the mixture out, cuz at the high manifold vacuum, the programming should have been set quite lean.
However;
If your headers are pulling in air from another source, like the flanges, then the O2 could be reading who knows what.
Therefore, I say; prove the headers then put the ECU into open-loop during decel; see what happens.
Click to expand...
Being a retired mechanic, by this point in the conversation I would have already said" I cant tell you, bring it to the shop and ill look at it." Sitting on the bench diagnosis only goes as far as opinions. I cant tell you how many times in forums Ive seen guys advise the most in depth "tear the engine down" advice , in the real world it never goes like that its too expensive. You troubleshoot, pinpoint and then repair.
 
Having to drive it a while before the problem begins, I think temperature related. Something getting too hot. Engine? Trans/fluid? Sure grip? Check them all. Good luck
 
Ben Ainsworth said:
Warning... My knowledge is weak with trans/driveline tech.
I was told it's a cone type when I got it, but I have not verified myself and the seller was a bit of a yahoo -- he could be wrong.
Click to expand...

Very easy to verify and really it's a good thing to know anyway.
Look at driver side of third member for casting number.
If it ends in 489, it's the cone type sure grip.
If it's 742, then rebuildable clutch type.
Could also be 741, weakest of the three.
 
KosmicKuda said:
Very easy to verify and really it's a good thing to know anyway.
Look at driver side of third member for casting number.
If it ends in 489, it's the cone type sure grip.
If it's 742, then rebuildable clutch type.
Could also be 741, weakest of the three.
Click to expand...

It's a 489, so cone type. Thank you KosmicKuda!
 
AJ/FormS said:
disappears if I accelerate or brake.

Com'on guys;
I'm no genius but Ben says
"the problem disappears when I accelerate or brake."
I don't know how you come up with some of the ideas you do.
Clearly this has something to do with coasting down, which is a closed-throttle situation. In this situation, enertia is driving the engine against compression braking. So the engine is pulling very hard on the "closed" throttle blades.
Ben, if you were to shut off the engine at this time, having EFI, no more fuel could find it's way into the engine. If the lurching stops, badaboom, it proves my Transferslot/ hot plug theory.
With EFI the solution is a lil different.
If you have an AIS motor, I would work on the synchronization between that and the closed throttle stopper, together with the fueling. 1100rpm is what roadspeed? 25/28 mph? And you are slowing from hiway speed right? By this time, if you have the right speed-O gear for the rear end, the trans, if it had an automatic lock-up TC, it should have outshifted a long-time ago; unless your Line-Pressure has been boosted by way too much Throttle Pressure via the KD linkage.
Since you say the problem goes away with application of throttle this pretty much absolves the trans of any wrong-doing. Since you say the problem goes away with the application of the brakes this also rules the trans out.
But it simultaneously also proves the brakes have nothing to do with this problem. And to top it off it rules out the rear end.
IMO this is 100% an AFR problem; the engine is either misfiring in this circumstance or the mixture is pre-igniting, fired by something hot in the chamber. And, because of what preceded it, namely the long cruise period; if it was a carb I would be blaming it on hot plugs.
But since it is EFI, it could be your O2 sensor is giving the wrong feedback to the computer on account of the 230* cam. If you can turn it off during deceleration, that is the first thing I would try. Ok no, second thing. The first thing I would do is prove that the headers are sealed to the heads, and to the exhaust pipes, and that the exhaust valves are sealing. That cam has a lot of overlap, I mean a lot! I'll guess close to 70*.
During closed throttle, the pistons are gonna put a heavy pull on the plenum.
During the overlap phase, BOTH valves of every cylinder are gonna be open, each pair in turn, and the headers are ALSO gonna pull on the intake.
So; if there is fuel in the plenum, the headers are gonna yank it out and pull it down to the O2 sensor, and the O2 will do it's job and tell the computer that something is waaaay messed up, and the computer will try to lean the mixture out, cuz at the high manifold vacuum, the programming should have been set quite lean.
However;
If your headers are pulling in air from another source, like the flanges, then the O2 could be reading who knows what.
Therefore, I say; prove the headers then put the ECU into open-loop during decel; see what happens.
Click to expand...

Thank you for the in depth thoughts here!

My initial thoughts have always been engine related, but at this point I've checked so many things I'm erring to driveline.
I've already changed the O2 sensor, collector flange gaskets and the header manifold gaskets -- no leaks.

What you describe makes a lot of sense to me, and I'm much more familiar with checking/tuning these elements so I do everything I can, but I have yet to solve it by addressing possible engine causes.

I haven't tried an engine shut off on decel though. The Sniper goes into open loop by default at 0% TPS at that rpm, but I'll pull a data log.

I didn't get a chance to warm the Duster up yesterday but today I'll give it a big drive and try out some of the test recommended here.
 
MOPAROFFICIAL said:
Whine in park & drive until 2nd gear and up?
Does it get quieter in neutral?
Click to expand...
Sorry, I should have clarified that...
It only whines on the highway in 3rd at about 2500rpm. The source of that whine is certainly the rear end. I know it's not good, but I understand that's fairly common.
 
Ben Ainsworth said:
Sorry, I should have clarified that...
It only whines on the highway in 3rd at about 2500rpm. The source of that whine is certainly the rear end. I know it's not good, but I understand that's fairly common.
Click to expand...
The whine sometimes they run forever like that its how much it bothers you . my 4 speed whines in first gear...
 
On the bright side I have the holidays off work and I'm not visiting family...
So I have a good 300 hours to figure this one out before 2022.
I'll even go as far as rebuilding the dang engine or trans (i purchased a trans build manual). :|
 
@AJ/FormS he's bounced between 3 fuelers (2 EFI and a carb) and it does it on all. I like the exhaust leak theory, definately plausible with EFI doing it only when warmed up (going to open loop) but hows a carb gonna do that? Interesting.....
 
I'm pretty sure it has to do with the huge overlap cycle of that cam, as the engine comes down in rpm, thru it.
235/249 sounds like a Comp CL20-601-4,
Which is a Thumpr, advertised as
287/304/107, and lifts of .497/.483ex
From those specs the overlap calculates to;
(287+304)/2, less (2x107) =81.5 Oh Lordy that is huge.
As the rpm comes down, it provides more and more time for the headers to do their thing, and it culminates in a very lumpy idle........ because of that overlap.
Well, 1100 rpm is just above idle, as are the other numbers provided. So you know that the headers are really pulling hard and for a long time on the plenum, with a closed throttle above it.
The big picture of that cam, in at 103, is;
287/304/107 in at 103, would be an Ica of 66.5, so
compression is 113.5* and power is 97*
Now with an Ica of 66.5* the piston is ABOUT 1/3 of the way up from the bottom before the intake valve closes, so at these low rpms, the pistons are pushing a portion of their just-inducted mixtures back up into the plenum....... where the primary header pipe of a nearby cylinder is gonna yank it right across it's associated piston, and into the exhaust tract. I'll bet you have a Single-plain intake on that beast; I hope I'm wrong.
So now, this bizarre action has put a combustible mixture into a place it ought not to be. And all it takes is a tiny hotspot to set it on fire........ If this happens while a piston is on it's way up, the pressure of the expanding gasses will try to force the piston backwards the way it just came !
My theory is that you interpret this action as a lurch.
Possible Solutions:
If you have a single plain intake, get rid of it. Get you an Rpm Airgap. This will cut in half, the number of cylinders available for scavenging but even better, it will put the next cylinder in the firing order on a leg of the opposite plenum. This alone should kill your problem, if my theory is right.
You cannot do anything about the overlap, it is part of the character of that cam.
You could install a hi-stall TC which would not change the lurching, only mask it in the hydraulic coupling.
You could eliminate hotspots in the chambers, and my first thought would be cooler plugs, or a richer cruise mixture. But; hang on a sec;
Speaking of cruise-rpm; Do this; install a vacuum gauge on the intake, then slowly rev the engine up to where the intake vacuum peaks, then slowly bring it down to where it begins to fall again. When that happens note the Rpm. IMO you should consider this your lowest cruise rpm, because the engine is gonna rapidly loose efficiency below this rpm.
If you do not have a vacuum advance or it's equivalent timing system in the EFI, this is gonna suck. So I'll give you a tip.
Tip
determine your current cruise rpm.
then rev your engine up to that rpm in neutral/park/ and try to keep it there; While you simultaneously begin to advance it. As you add timing, the rpm will go up, so reduce the rpm back to the cruise rpm. Continue in this way until the rpm no longer rises with increase in timing. Back the timing up 3 degrees. Now read the timing at cruise rpm, and write it down. Return the rpm to idle and the timing to as it was at the start. The number you wrote down is the timing your engine wants to cruise with, or very close to it.
How does that compare to what she is actually getting?
If it is not getting that number, then it is cruising in retarded mode. When that happens, it is impossible for the mixture to complete it's burning in the chamber, but exits still burning and still expanding. Because of this, it destroys the overlap cycle, heats the headers red-hot and puts the temperature of the exhaust valves up to nearly melting............. so those hot exhaust valves could be your hotspots.
If my theory is right.

I went all thru this when attempting to run that 292/292/108 Mopar cam ...... But I did not have as radical a problem as you do because the overlap of that 292 was only ..... 76 degrees, lol. In the end, after just a couple of months, I realized my error in trying to run that big a cam on the street, so I pulled it and sold it to a kid who wanted to go racing. Best combo-decision I ever made.
 
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