Help with vehicle staying running and cold starts without throttle aid...

[sac811]

Been following this and want to make a few comments based on my experiences.
The size cam you are running should not be causing as much problem you are having. One thing I would do is cut the Base Spark back to about 19-20 degrees. Always include spark in your PID's. Your Idle Air numbers are just not big enough for a cam.....do you have a vacuum leak? Would explain all the surging. For better cranking add air in the Startup Friction Air table and then decay it faster. Crack your throttle screw to obtain near 0 IAC counts until you get the surging resolved and then set it to obtain 30-40 IAC counts under normal conditions.

Get what your saying, but pretty much everything you have recommended has been tried. None of it helped unfortunately. Slowly but steadily statesman has gotten me a much better running tune than when I started though. So at least we are getting there, thanks for the help.

[statesman]

Been following this and want to make a few comments based on my experiences.
The size cam you are running should not be causing as much problem you are having. One thing I would do is cut the Base Spark back to about 19-20 degrees. Always include spark in your PID's. Your Idle Air numbers are just not big enough for a cam.....do you have a vacuum leak? Would explain all the surging. For better cranking add air in the Startup Friction Air table and then decay it faster. Crack your throttle screw to obtain near 0 IAC counts until you get the surging resolved and then set it to obtain 30-40 IAC counts under normal conditions.

Hi 67SS509, and thanks for your suggestions. The problem with the cold starts is that the IAC air passage on this aftermarket TB is a bit restricted and he is already maxing out his IAC counts on cold starts so commanding more air in any of the tables isn't going to help because this TB just can't physically deliver any more idle air. The spark looks a bit high for idle, but it was at 35 degrees before and I have brought it down a bit.. and now it seems to be where the engine wants it to be. Keep following our progress... and any more suggestions are always welcome.

[statesman]

Here is a log from today of your mod9.1 tune, but the wife was in the vehicle so had the a/c running most of the time:

At the last couple minutes of the log is without a/c running for sure though if it makes a difference

I've made some adjustments to your a/c air compensation. These adjustments work well on my engine so they should work for yours too. If you don't like the smaller air compensation, you can always put those tables back to what they were.

Okay, here's Mod10. Your small pulse table looked too flat in the area where you surge, so I've made adjustments to it. Without injector data, it really is a guess... but I think this adjustment might help with your idle. You'll have to redo your VE yet again.

Post a non-a/c log after you redo your VE... but also let me know if the a/c adjustments I've made work for your engine or not.

[sac811]

After redoing the VE table here is my most up to date tune:

CLGood_OS_Mod10.ctz

And then here is a log of this tune from today:

LS1B_0569.efi

Sometimes it seems fine, then other times it wants to surge and/or die. But it seems to get worse, the longer the vehicle runs...maybe thats just in my head though.

[statesman]

Your log is showing random spikes in airflow. I think this is some kind of physical intermittent fault, not a tuning issue.

Okay, here's Mod11. This will try to fix the surge/stall when you come off the throttle at low speeds. Log the same pids as last time.

[sac811]

Your log is showing random spikes in airflow. I think this is some kind of physical intermittent fault, not a tuning issue.

Okay, here's Mod11. This will try to fix the surge/stall when you come off the throttle at low speeds. Log the same pids as last time.

I did a full flash with you most recent tune to see if that made a difference with the random spikes, along with unplugging and plugging back in the IAC sensor.

But here is the log:

LS1B_0572.efi

[statesman]

I've looked at your latest log and noticed that you have a large variation in IAC counts for what is essentially the same amount of airflow at the same operating temperature... and I can't work out why.

Frame 1300 has you at 94 IAC counts for 8.28g/s airflow at 81C ECT.
Frame 9600 has you at 63 IAC counts for 8.11g/s at 80C ECT.
Frame 35660 has you at 32 IAC counts for 8.68g/s at 81C ECT.

In all 3 frames, you're at stable idle with similar injector pulse widths... which would indicate that airflow is indeed similar. I would think that there's a problem with either your IAC valve or with your PCM.

If anyone reading this has seen this kind of thing before or has any suggestions... then please leave a comment.

[sac811]

Just an update, I have purchased a new IAC valve and PCM, but have yet to install it.

When I do, Hopefully that will solve the problem. But am waiting on the PCM to be delivered, and then I will need a little spare time, because while I install the new IAC valve I plan on opening up the IAC passage so it is no longer maxing out.

Thanks

[sac811]

Since my last update, I have installed a new IAC sensor, new PCM, opened up the IAC port on the FAST 92mm tb, and worked on an potential ground wire problems.

Here is my current tune:

CL_33WOTSpark_MAFail.ctz

Here are 2 logs using the previous datalog pids:

MorningACoff.efi

I believe the tune is running pretty well without the A/c on, but with the A/c on it is very up and down and wanting to die occasionally. I have a log of this, but the file is bigger than the 2.0mb limit on file size, so I will just log it again tomorrow.

[statesman]

It looks like the adjustments I made to your A/C airflow correction hasn't worked well for your setup so I'm changing it back and also adding a bit of idle air.

See how you go with this.