So searching/reading through here I see that the E40D/Torque Converter interacts with the reverse sensor and brake lights. What I can't seem to determine is why.

I can feel that reverse seems to be more direct then 1st or 2nd forward gears (pressure increase maybe). But the brake lights I don't understand at all.

Anyone care to elaborate?

Bob

 

Not an expert but the system needs to know when the brakes are applied so that it can unlock the torque converter (if it`s locked).

 

I have no idea why it looks for the reverse, but Lazy K is right on why it looks for the brakes - if you floor your brakes and the converter don't unlock you may end up damaging the converter as on one end you have the engine trying to turn it, and on the other end you have the driveline trying to stop it. This is exactly why I wired up an interrupter relay when I installed my manual lockup switch, this way the moment I touch the brake pedal the converter unlocks and I can then stand on the brakes if I want to and no damage occurs. Now why the PCM looks at the brake lights, and not the BOO switch on the pedal, that I have no idea about, seems to me it's a pretty dumb idea as when a brake light goes out it sometimes throws the PCM into failure management (limp-home) mode - my lockup interrupter relay is triggered by the BOO switch, so as far as converter is concerned I couldn't care less if the brake lights are working or not.

 

I guess my confusion stems from that fact that the converter already unlocks as soon as the throttle is released (which I find most annoying) and sensing the brake lights seems somewhat redundant.

Oh well, sometimes I think understanding the Ford engineers logic must be above my pay grade.

Thanks
Bob

 

And now you know why some of us run manual lockup setups - engine braking is a real good thing when you can actually use it

 

I had an idea a while back to put a foot operated momentary switch on the floor conected to the converter lock up and an exhaust brake for those down hill runs that I seem to do a lot of. Does this sound feasable and is there any damage likley? How hard is it to make a manual lockup.

 

I put my switch on the shifter, and that's also where I moved the OD cancel button (your OD button is already on the shifter), it makes it easier to operate for me. Wiring up a manual lockup is pretty easy actually, I think I posted the diagrams on here somewhere...

 

I have zero experiance with the E40D but woildn't the lockup converter in it's stock confirureation make the exhaust brake useless when you needed to use the brakes.

Besides that how do you like the exhaust brake on the idi motor and does it build boost like a jake.

 

Yes, it would, hence why I have a full manual lockup control. As for the brakes, actually I'd rather have both the wheel brakes an the engine brake, but there's no easy way of achieving that. IIRC David85 programmed his Bauminator to lock up the converter over 30mph and keep it locked regardless of brake use, then under 30 mph it automatically unlocks and stays that way - the latter of which may at first seem undesirable, however under 30mph you really should be in 2nd gear anyways and there the engine braking is better with the converter open (I've tried it).

 

Although the engine braking may be better in second with the converter unlocked it makes a lot of heat in the trans because the converter is doing half the work. With the average summer temps being 40 celcius over here I need to avoid the trans temp increase hence my thinking about the manual lockup. As far as exhaust brake is concerned I dont yet have one but in its stock form the trans would disengage to early and the brake would be useless. What I really need to know is what are the dangers of manual lock ups other than stall outs and does an exhaust brake do any damage to our engines or turbos.

 

I don't know anyone with an exhaust brake on an idi. I can't see why they would damage the turbo or engine though. The dodge guys have installed them forever and now they all come stock with them. some of the cummins big truck motors used them instead of a jake from the factory. the principle is the same just 8 cylinders instead of 6.
They will show you if you have an exhaust leak though.

 

I have a factory exhaust brake on my Dodge. It is a bit different from the typical add on aftermarket EB as it is a design function of the VG turbo. The TC locks any time the brake is on and you let off the throttle. With the converter unlocked, there is little to no compression braking.

I've heard about exhaust brakes causing valvetrain damage on the IDI because of the hydraulic lifters. Yet, if I am not mistaken, there are EB's available for the PSD. If the engine was prone to damage because of increased backpressure, how much damage is being caused by increasing the boost at the other end? I personally don't think these engines are that fragile. The EB doesn't completely shut off exhaust flow, just slows it down.

Jason

 

IIRC the exhaust brake designed for the IDIs runs lower backpressure (6psi max?) than the one for the PSD or the Cummins, not because of the lifters but because of the valve springs (which can be replaced with stiffer ones if needed).

And yes the converter will make more heat descending a hill in 2nd gear but on the way up the hill you're making the same heat if not more, so it ain't gonna be much different than your current heat-generation situation. You need a big cooler for that, not playing with the converter - my trans used to be purely air-cooled through the factory A/C condenser and it worked just fine, now it's back to radiator cooler and then again the A/C condenser for even better cooling when I run up and down the mountains with the converter unlocked. I still need to do the pump mods but I ain't pulling that beast any time soon... Another thought on locking up in 2nd - it's been rumored that it's not a good idea to do so, but I'm not sure exactly why - maybe because in manual 2nd there are different set of clutches applying then when she's in automatic 2nd? I know the factory setup will lock the converter halfway through 3rd and pretty much constantly in 4h, but never in 2nd or 1st...