This what was binder talking about:



As you can see, its in seconds.

 

loud? like real loud or..>? Can you record the pop?

 

Alright I did some testing today. Here is what I have concluded:

Decel cut is based on APP, not TPS. I know this because I have logged many cases where the Decel cut activates, despite the TPS still reading above 2% (2% is my what my threshold is set to). I know it says "Throttle Value" in the ecu manager but I promise you, it is using APP. If you don't believe me, do some datalogs.

The second thing I have concluded is that my problem is definitely being caused by the "Injection Time Threshold" setting. If I set the threshold to 1.5 ms, the decel cut will activate right about 0.5 seconds after the APP drops below 2%. This is exactly what should happen, because the time "Delay to Fuel Cut" is set to 0.5 seconds.

However, if I set the "Injection Time Threshold" to 0.85 ms (the highest it can go while still allowing the cruise to work) then the delay between 2% APP and decel cut is more like 1.0 seconds. So it seems as though the "Injection Time Threshold" is what is causing the excessive delay between throttle lift and decel cut, because it should take no longer than the "Delay to Fuel Cut" setting, which is 0.5 seconds.

See the attached datalog for a comparison between 1.5 and 0.85 ms "Injection Time Threshold". Notice the time difference. This is repeatable every time.

What it comes down to is that the Haltech needs to be able to recognize when the cruise is engaged and prevent fuel cut from happening. Because an "Injection Time Threshold" of 0.85 ms is not high enough to have a proper decel cut. It sees the 0% APP when you take your foot off the throttle after engaging the cruise, and thinks it is time to go into decel cut - unless you set the "Injection Time Threshold" excessively low (lower than the stock ECU would ever call for when cruising).

At least that's what I believe to be true. What do you guys think?

 

No that's not what binder was talking about. Changing the "Delay to Fuel Cut" time wouldn't affect the cruise, only the "Injection Time Threshold" will cause that problem. Since he mentioned that it affected his cruise, and since he typed "ms" after every number in his post, I think it's safe to say he was talking about "Injection Time Threshold".

That said, he wasn't making any sense.

 

injection time threshold is what i was talking about in ms.

 

i've never had a problem with cruise not working. My problem was when going downhill with cruise on so the TPS WAS actually going below 2% so it has to be tied to the TPS not the APS because it wouldn't work at all when cruise was on since APS is 0% then. In cruise my TPS will go below 2% on downhill which is when my decel has issues.

When i talked to hal on the phone about this as i was driving he told me most engines have an injection time threshold of .550ms and it works fine but mine needed to be bumped up. I bumped it up to .650ms on my vortech and my cruise worked fine even on decel. On my turbo system i had to increase it to .750ms to keep the car from bucking when on cruise and going downhill.

 

binder,

do you even know what "Injection Time Threshold" means? Seriously. Because what you are saying does not make sense.

 

Based on the values I'd venture to guess 'minimum effective injector latency'? On my Uprev I've got it set to 0.4ms which is what my DW injectors specify.

 

Huh? We are not talking about injector latency. Are you talking about the minimum effective pulsewidth? Because you can change that with Osiris.

"Injection Time Threshold" in the Haltech refers to the injection time in ms that the STOCK ECU must fall below in order to signal the Haltech that it is ok to begin decel cut. Don't forget that even with the Haltech, the stock computer still thinks it is in control and still tries to fuel the engine accordingly. The Haltech monitors the injection pulses that the stock computer is calling for. Heck, you can even copy them through if you want, and effectively run the stock computer through the Haltech.

 

how/why does that affect the cruise control if the value is too high?

I assume you dont want the Haltech to trigger the decel cut while using the CC?

 

See the screenshot posted by midz350 above.

There are three conditions which must be met for the Haltech to activate decel cut.

1.Throttle Value - I believe this to be based on accelerator pedal position (APP), not throttle position (TPS). I have seen in my datalogs many instances where decel cut will activate when TPS is still above the Throttle Value setting.

2. Injection Time Threshold - This is the time in ms which the STOCK ECU injector pulsewidth must fall below to trigger decel fuel cut in the Haltech. Unfortunately, the Haltech does not allow logging of the stock pulsewidth. (In fact that just gave me and idea - I could log the stock pulsewidth with Cipher and see if it truly does fall below the threshold when I hit the cruise...)

3. Delay Till Fuel Cut - After both the above conditions are met the Haltech will wait this amount of time before activating decel cut. I am not sure if this time begins when condition 1 is met or when both 1 and 2 are met though.

When you activate the cruise control and take your foot off the pedal, the APP or "Throttle Value" goes to 0. So condition 1 is met. Now the only thing keeping the Haltech from thinking it's time for decel cut is the Injection Time Threshold. Thus, if this value is set too high the stock ECU may command an injector pulsewidth less than this value (when it is regulating the speed of the vehicle) and send the Haltech into decel cut. Once the cut happens, the stock computer sees the deceleration and applies more throttle (more throttle = more fuel) and the stock injection time rises above the Injection Time Threshold again and the decel cut stops momentarily before it happens all over again. That's why when you set the Injection Time Threshold too high, the cruise will cycle on-off-on-off about every .5 seconds.

At least that is what I believe to be true.

 

I know what it is.

I'm telling you EXACTLY what hal told me to do to fix my cruise problems when going down a hill and car goes into decel with cruise enabled.

I bumped it from .55 to .65 the first time and the bucking going downhills on cruise stopped. Then on these injectors i continued to raise it until it stopped. .750ms was the time in which my cruise was smooth going down hills.

If your cruise isn't working in straight and level then something else is going funny. I know hal sets most cars to .550ms injection threshold because he said that is a good starting point and usually it has to be increased slightly for larger injectors. He told me to do steps of .010ms until the problem stopped. That's why i'm saying 2.5ms is way too high. Your injector pulsewidth will probably be lower than that all the time therefore never going into decel cut i would assume. I'm not an expert but i've asked these questions to Hal who is the expert.

Also, on another note i increased my fuel enrich from 5% to 10% and that greatly reduced my lean buck when i touch the throttle after decel. I'm going to go alittle higher and it should fix it completely.

 

Dude, you are thinking of it backwards. Decel cut happens when the stock ecu pulsewidth falls BELOW the threshold. So if your Threshold is too low decel cut will be take longer to activate, as I proved in the datalog attached previously.

I have never heard of anyone raising the threshold to fix a cruise problem. If you had it too low it might cause problems with the cruise as well, but I don't know that for sure becuase I have never tried it.

I am using 2.0 ms right now, and on the highway I can get the cruise to work if I am not going down hill. If I activate the cruise and very carefully lift my foot off the throttle it will stay engaged, but if I try to lower my speed with the coast button or start going downhill, the stock ecu will output a pulsewidth of less than 2.0 ms and the car will go into it's on-off-on bucking cycle.

The best part about using 2.0 ms is that the car NEVER pops anymore, not even on rev matching downshifts. It sounds like stock and the gear changes are still smooth as can be. To me that is more important than a working cruise control, so I am going to leave it as is for now. I am gonig to contact Haltech and see what they have to say. If there was a way to make the threshold adjustable depending on whether or not the cruise "set" light was on, it would work much better I think.

 

email hal, he'll tell you exactly what he told me which is the same thing i posted. he starts tuning at .550 ms and slow raises from there. If a pro tuner starts at .550ms do you think that your 2.5ms is a little excessive?

email hal, he's going to tell you to lower it.

You have something else going on in your fuel table

 

I don't know why I waste my time doing all of this testing, spending hours analyzing datalogs and posting the results on here. I have proven that the decel cut does not work properly with threshold settings that low, and your only response is "well Hal said..."

Maybe this is just a shortcoming of the Haltech?

I paid Hal $100 for my basemap by the way. The threshold was set to .65 ms.

I did email Hal about this months ago telling him about my success with raising the threshold, and the only thing he had to say was "Have you tried using cruise control since those changes? You may encounter trouble there on downhills". He then went on to say "If it is popping it sounds like you have other settings that need to be setup, such as APP cal, start point, decel rpm, etc".

I assure you that my APP and TPS calibrations are 100% correct. The decel rpm table is setup correctly - in fact I haven't changed it from what Hal had set up. I don't know what start point is.

 

Do you have a flash on your stock ECU? I wonder if the injection timing is modified somehow.

 

My Haltech tune from Forged did this like crazy. I actually liked it.

I then had the car retuned and it all went away. I would compare maps and try to figure out the differences but my laptop was stolen from the car with the maps on it

 

I was using Osiris tuner for a short period of time, but I flashed it back to stock before before removing the UTEC and installing the Haltech.

 

Aww man that sucks! I would be pissed.

Have you gotten a new laptop and downloaded your current map since then? If so, would you mind me taking a look at it to compare it to mine?