Poor Cold Idle (Yes I searched)

[fixem2]

SO you lowered your injector latency from what voltage segment? By lowered you went from 1.0 to .9 for example? Sorry just trying to clarify, as want to take a look at this.

[biggie5252]

fostytou how do you go about rescaling if your trims are perfect? I havent touched any maf tables cuz I still run stock intake with an apexi filter.

[Appauldd]

Well, looks like I will be changing over to V7 and starting from scratch. Oh the joys of re-tuning. : (

I think I will re-enable the EGR stuff and remove my EGR block plate. I don't think the "negligable gains" are worth the hastle of cold start and drivability issues.

Anyone think that by not having the coolant flow through the throttle body could cause issues???

I looped the coolant line back into the engine, thus avoiding the throttle body.

[fostytou]

Originally Posted by biggie5252

fostytou how do you go about rescaling if your trims are perfect? I havent touched any maf tables cuz I still run stock intake with an apexi filter.

By changing the latencies you change how long the ECU assumes the injector needs to be on. A lower latency will result in less "on" time regardless of how long it actually takes the injector to open and deliver fuel. This in turn will reduce your fueling. Obviously different amounts of RPM/airflow/etc.etc will require different amounts of fuel per pulse, but in general these are very similar across low to mid throttle ranges.

If you have a positive LTFT Mid and a negative LTFT Low there is either a problem/%error with the calculations of the system overall, the mechanics of one part, or the values you are feeding it. Perfect latencies for injectors with perfectly linear flow vs latency rates would result in perfect 0% fuel trims that do not fluctuate, but that is not the case. Even a "perfect" fuel trim will probably move up and down with temperature changes, but might be "perfect" for the conditions in which you tuned it.

Then things like non-linear flow rate vs latency come into play. Larger injectors can actually flow more fuel at slightly lower pulse times when you are very low in their duty cycle... etc etc. Fueling requirements are vastly different, but still strikingly similar at cruise and low throttle conditions. If one of your trims fluctuates alot with temp changes your latencies are very likely to be off... but if it doesn't that does not mean that they are correct.

All I'm saying is, it is something to try and it worked for me.... very well.

I posted the differences in the injector scaling and latency thread, but they are ~0.14ms less now (about ~17% change) and I made sure the curve followed the stock curve pretty closely. Graphing this in excel helped alot, and I think I also posted a sheet for comparison that might help you out.

In the DSMLink days it was as easy as changing the assumed dead-time which was applied globally to latency. With that I always saw a marked reference of change between the ltft low/mid. They would always move in the opposite direction. In ECUFLash I never saw that same correlation, even though a few people suggested it was better to use that than MAF scaling. In the end I wound up applying it differently by using scientific guessing, but it worked well.

Worst case, keep the stock curve to the latency chart, make sure that you have the scaling XML correct (so you can change it at the correct intervals by using the increment keys, this is still broken in the ECUFLash included definitions), set your injector size to your expected value and then tune latencies to it. It is a different method for doing things, but it would have gotten me where I am today with less of that scientific guessing.

Originally Posted by Appauldd

Well, looks like I will be changing over to V7 and starting from scratch. Oh the joys of re-tuning. : (

I think I will re-enable the EGR stuff and remove my EGR block plate. I don't think the "negligable gains" are worth the hastle of cold start and drivability issues.

Anyone think that by not having the coolant flow through the throttle body could cause issues???

I looped the coolant line back into the engine, thus avoiding the throttle body.

I really don't think EGR is your problem. Why don't you just try zeroing the advance table and living with the CEL for a day while you confirm that it is not the case?

[fostytou]

Also, appauldd... these maps might give you a band-aid that at least solves your problem:

http://forums.evolutionm.net/7603188-post271.html

[ViscoS2000]

Try hotter plugs. I was running range 7 at 30psi with no issues on E-85. Switched to 8's and started having cold start issues.

[nothere]

I found that with pretty close fuel latencies an adjustment of the maf scaling (compensation on v7) allowed me to alter the warm up idle afr. Don't touch the cells above fifty unless you want to rearrange your fuel map.

If you have something other than the stock type air filter it might help.

You may need to alter the chart as per the thread on maf scaling.

[biggie5252]

I misunderstood you. I thought when you said you rescaled, you actually changed the scaling value. This is the method I used to set my latencies originally. I always check them every few weeks to a month and adjust if necessary (not usual). They're pretty much always less than +/- 2%. Sometimes less than 1%. I've found that the Ecuflash increments are too big and I can't adjust one way or the other to get any closer.

1. Choose a global setting (ECUFlash injector scaling number)
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to increase your global fueling, or in terms of ECUFlash, you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to descrease your global fueling, or in terms of ECUFlash, you need to raise your injector scaling number.
5. If idle trim is more positive than cruise trim, then you need to increase the dead time, or in terms of ECUFlash, you need to increase the latency value.
6. If the idle trim is less positive than the cruise trim, you need to decrease the deadtime, or in terms of ECUFlash, you need to decrease the latency value.

Where can I find the correct scaling xml? If it's in the scaling/latencies thread don't worry about it, cuz I'm about to read through it again.

[Fast_Freddie]

Originally Posted by nothere

I found that with pretty close fuel latencies an adjustment of the maf scaling (compensation on v7) allowed me to alter the warm up idle afr. Don't touch the cells above fifty unless you want to rearrange your fuel map.

If you have something other than the stock type air filter it might help.

You may need to alter the chart as per the thread on maf scaling.

I did this today as well... I still need to work on the trims a bit and see how the car starts when it is completely cold...

[nothere]

Where can I find the correct scaling xml? If it's in the scaling/latencies thread don't worry about it, cuz I'm about to read through it again.

well since you are a IX I'm not sure. It might be in the latest ecuflash download?

if not you will see it in V7
How-To: Rescale your MAF (without pics)

[Jorge T]

I did the tb coolant mod and had to put it back on due to cold start problems.

the only way I was able to fix my cold start was to change the lower load/rpm fuel map cells.



I still haven't been able to figure out why when temp is below 60 rpm jumps to 2100 with the clutch in and as soon as I release it the rpm goes down to 1400.

Originally Posted by Appauldd

Well, looks like I will be changing over to V7 and starting from scratch. Oh the joys of re-tuning. : (

I think I will re-enable the EGR stuff and remove my EGR block plate. I don't think the "negligable gains" are worth the hastle of cold start and drivability issues.

Anyone think that by not having the coolant flow through the throttle body could cause issues???

I looped the coolant line back into the engine, thus avoiding the throttle body.

[Appauldd]

WOW...Everyone has tons of different ideas which is great.

Seems like we are still trying to shoot fish in a barrel. We are close to the problem, but there still isn't an exact fix.

My car will start no matter the temperature, and does so almost instantly. The issue lies in the few minutes it takes to warm up. It will idle high until I press the gas. Then if i try to drive (with the engine still cold) it bogs badly and AFR goes pure lean.

I've been busy the last few days with my Anniversary so the car had to sit. I will try going back to square one and change one thing at a time unitil the problem reveals itself. This will be a long process, but I don't think there is an "easy" fix. Until the exact problem is isolated the ideas you have all come up with will be methods to attempt to fix the issue.

Thank you everyone for your concern and assistance. I truely appreciate every one of you for your efforts.

[l2r99gst]

You may want to experiment with the IPW delay tables, since they seem to control exactly what you are looking for...warmup AFR.

mrfred mentioned that they are Maf scaling multiplier factors during engine warmup. Try increasing the multiplier at the engine temps that you are seeing your issue and see if that helps.

Maybe ask if mrfred found any kind of load/tps/rpm checks for it as well to be sure they are deactivated under certain conditions, like the cold start ignition trim is deactivated over a certain load.

[Appauldd]

Originally Posted by l2r99gst

You may want to experiment with the IPW delay tables, since they seem to control exactly what you are looking for...warmup AFR.

mrfred mentioned that they are Maf scaling multiplier factors during engine warmup. Try increasing the multiplier at the engine temps that you are seeing your issue and see if that helps.

This is a new one....

Is this the "MAF Adjustment" table? AKA MAF Compensation?

If not, I am not familliar with the IPW delay tables.

[l2r99gst]

No, they are part of the IPW adder tables. They are defined currently as IPW cold start decay #1 and #2.