Cat warm-up - who has had issues and how have you addressed?

[WS6FirebirdTA00]

I am starting a new post to get to the point of my take-off hesitation concern.

It looks like the cause is cat warm-up. Factory is set to 66C in my truck, but some other calibration had it at 43C. Since lowering, the hotter restarts have not been an issue. I still have some issues on warm days but with a cold motor.

I know this is meant to help the cats heat up, but I am curious if anyone has found a better way to deal with it or maybe disabled all together. The timing is negative and it just creates a hesitation feeling until it gets back to normal timing. If it let the truck run and idle for a little it may not happen, but I don't want to wait that long before driving all the time.

I was hoping there was a way to disable over a certain speed, throttle or something and I see nothing in any files I have looked through in mine or the repository. It simply just gives an enable and disable temperature.

[IARLLC]

I just turn it off. It does not bother me if the cats don't warm up quite as fast.

[WS6FirebirdTA00]

Well cold start was much more quiet at least. I disabled it today.

Only problem is the odd hesitation I noticed does not seem tied to this.

Does anyone know of any risks to the cats disabling? I assume not and it is only for emissions?

[IARLLC]

The late spark and double pulse of fuel dumps a lot of unburned fuel into the cold cats to get them up to temp earlier. I guess somebody somewhere decided that getting the cats warmed up sooner (by dumping extra fuel through them) would ultimately result in less emissions. Seems that everybody (even BMW) is doing it in some way or another. I am not sure if Ford is double pulsing the injectors too but they fire the plugs REALLY late cold causing a "rumble" if everything is in good shape and a cold misfire for many. Bringing the timing in that table up several degrees makes for a much smoother morning and less fuel smell in the garage....

One of my clients has over 40 GEN5 in one enclosed area. They don't get that much use so his guys have to run them in the garage every week. The ventilation cannot keep up. These minor changes to the cold start have seriously improved the air in there and since they don't run that long each time they are started I am sure the cold start changes I made will keep the plugs clean much longer as well.

The cats come up to temp as soon as you give it any gas anyway. I honestly can't imagine a negative. If anything, less fuel used, longer lasting cats, and cleaner plugs for those that have a very short morning drive, at least by a little bit.

[WS6FirebirdTA00]

That was my thought too. Cold starts always kill MPG. After disabling, my drive this morning didn?t tank the MPG idling out if the driveway.

[lt1z350]

That was my thought too. Cold starts always kill MPG. After disabling, my drive this morning didn?t tank the MPG idling out if the driveway.

Yes old thread but now a problem as hptuners has removed the ablitly to disable all this. On a 2020 truck with the e90 its causing cold start stalling with heads cam whipple on it. The moment you either give it throttle or its past the 30 second or so mark it will start and run fine. Cold start rpm comes up and its like turning the key off its just pukes. No slow death to tell tale signs other then lots or retared timing as its stalling timing is being pulled more rather then adding it trying to hold the rpm. Its like zero help when in the cat warm up mode. And being a e90 you cannot just open it on older editor as it looks for the mpvi2 and that far back it wont open this file. The removal of these cat tables is hurting the ablitly to fix problems like this unless I am just missing something. Truck runs fine no hunting idles well everything works as it should other then cold start issue in which I have tried a lot of redicilous stuff to make this work out.

[TriPinTaZ]

You may be able to try setting the VE Coefficients for cold start temps either very high or very low. Anything to try and get more timing in it after it starts. It's likely that the cat warmup mode supersedes all other tables maybe and this wont help. I guess my point is to try and trick it from pulling so much timing during cat warmup mode and this would likely help the issue. Does this one have NN?

[lt1z350]

You may be able to try setting the VE Coefficients for cold start temps either very high or very low. Anything to try and get more timing in it after it starts. It's likely that the cat warmup mode supersedes all other tables maybe and this wont help. I guess my point is to try and trick it from pulling so much timing during cat warmup mode and this would likely help the issue. Does this one have NN?

yes very much pain in the ass NN setup. I wont even get into the no NN fueling for boost control as the table only goes to 1.00 Pr ratio. This ecm is a plie compared to e92. Took a lot to make it work on 9 psi and heads cam combo. Just fighting the cold start now. If shop starts log it will either take 6 starts and stalls to run which consumes the start time or touch the pedal when tried to stall and it recovers and timing jumps and it idles fine. I have already messed with the ve correction factor a little to try to make wot in boost rely more on maf vrs that NN crap and that did help my wot fueling as basing it more towards the maf. I was hoping it was like the High RPM Disable and it seems to have worked as no longer have that table. I aslo had to re scale the Maf down low so more resolution in boost which is at 980-1050 HZ. I really hate I cant get this thing to cold start and sucks knowing its 100 percent cat warm up causing it to stall as far as I can tell anyway.

[GHuggins]

Map torque model will sometimes help with this, but you have to lower it pretty good in the idle and 500 rpm regions. It should run on negative or positive timing as long as it's not too negative.

[lt1z350]

Map torque model will sometimes help with this, but you have to lower it pretty good in the idle and 500 rpm regions. It should run on negative or positive timing as long as it's not too negative.

It typically hits -9 rpm starts to drop then -15 or so then it?s like hitting the start stop button. It?s only doing it when sits a long time. Once it?s past around 30 seconds of trying it starts fine. Shut off re start fires fine. This e90 is such a piece of shit and zero range for boost in that NN shop is going to talk to customer see if wants to swap to e92 ecm and harness.
Everything you know and typically apply to any other vehicle and it runs well isn?t working on this ecm. It?s really not responded well to anything. Totally out of fuel at 420whp and when they put the lt4 injectors in it we had even more problems with idle and normal driving and we have done this in a lot of 2018 and down with none of these issues. I read about a few people running e92 with good luck.
Heads cam it?s probably ok but trying to add boost to that it?s become a totally wreck vrs anything I?ve ever had to deal with and I have come across some messes from others and managed to work through it and be happy with the vehicle and have a happy customer.

I appreciate the help as know you know what your doing Greg and glad to see your back around again. We have spoke in the past and you gave me advance on soi a while back for my zl1.

[GHuggins]

I could see it having issues with -15 degrees and lower dynamic compression from a fairly aggressive cam.

[tunerpro]

It typically hits -9 rpm starts to drop then -15 or so then it?s like hitting the start stop button. It?s only doing it when sits a long time. Once it?s past around 30 seconds of trying it starts fine. Shut off re start fires fine. This e90 is such a piece of shit and zero range for boost in that NN shop is going to talk to customer see if wants to swap to e92 ecm and harness.
Everything you know and typically apply to any other vehicle and it runs well isn?t working on this ecm. It?s really not responded well to anything. Totally out of fuel at 420whp and when they put the lt4 injectors in it we had even more problems with idle and normal driving and we have done this in a lot of 2018 and down with none of these issues. I read about a few people running e92 with good luck.
Heads cam it?s probably ok but trying to add boost to that it?s become a totally wreck vrs anything I?ve ever had to deal with and I have come across some messes from others and managed to work through it and be happy with the vehicle and have a happy customer.

I appreciate the help as know you know what your doing Greg and glad to see your back around again. We have spoke in the past and you gave me advance on soi a while back for my zl1.

That's the new world, unfortunately. Emissions targets are so tight that VE coefficient algorithms aren't good enough anymore, so we have the NN.