Where's a good starting point for cold idle surging

[99LS1SS]

One other question, if I up my Idle Airflow, will that allow me to up the Open Loop EQ table some? In my mind, it seems like if I add more air at startup I can add more fuel. Is that the wrong way to look at it?

[Omega]

One other question, if I up my Idle Airflow, will that allow me to up the Open Loop EQ table some? In my mind, it seems like if I add more air at startup I can add more fuel. Is that the wrong way to look at it?

I'm battling idle issues also.

I would think that getting the Idle Airflow closer to what is actually entering the engine, the computer will be able to more accurately hit the OL EQ table. Anyone? Anyone?

[Ben Charles]

99LS1 go to Startup airflow and make the table look like this 2, 2, 2, 1.50, 1.50, 1 (replace what you have with this) next on startup airflow delay set it too 100, 100, 100, 50, 50, 50. Crack Throttle blade or open up the hole in the TB (what size is it now?)

Next report back with good results.

[Ben Charles]

One other question, if I up my Idle Airflow, will that allow me to up the Open Loop EQ table some?

Just get fuel right and leave it alone.

BTW the RAF table will change once its in Gear vs Park/neutral. Gear values are typically 1-2.5 g/sec more.I'd make your OFLA table roughly factory from 32-140 degrees anything above that set it 1.00-1.02

What size is your cam? Timing looks low to me at idle

[99LS1SS]

Just get fuel right and leave it alone.

BTW the RAF table will change once its in Gear vs Park/neutral. Gear values are typically 1-2.5 g/sec more.I'd make your OFLA table roughly factory from 32-140 degrees anything above that set it 1.00-1.02

What size is your cam? Timing looks low to me at idle

Ben,

I will change my Open Loop EQ to match roughly stock numbers up to 140 degrees.

I feel like this will continue on with the surging.

My mods are:
Fast 90/90 intake/throttlebody.
The cam is a Torquer V2 232/234 .595"/.598".
The heads are Patriot 64cc.

I'm confused and conflicted about timing. Some people say lower is better and others say higher is better. I adjusted the timing while it was running and this cam it "seemed" to like 16.5 degrees at idle. It made the most Delivered Torque at that RPM. If I'm missing something or if that isn't a good way to tell let me know.

I logged and adjusted my VE again this morning after the car was warm and in the lower RPM's it wasn't off by more than 1%. There were some other cells in the upper regions that were off and needed to be changed but the idle area seemed to be fine.

I will log another VE run later today and then re-tune my MAF just to be safe.

Outside of that, I'm still struggling.

[99LS1SS]

I might have a culprit to my woe's. At lunch I started the car and it wouldn't stay idling. It's in VE tuning mode so I didn't think too much about it until I saw the check engine light on. I looked at the DTC's and there was one for an O2 sensor.

Could this be the root of my problems or just a contributing a factor?

[Ben Charles]

I would look at map, adjust the VCM controls and find your lowest map then take than Timing and subtract 3-4 (make that your idle timing) overspeed and underspeed tables will make it swing in and out around your base timing.

What was your DTC? Did you make the changes I asked?

[99LS1SS]

I would look at map, adjust the VCM controls and find your lowest map then take than Timing and subtract 3-4 (make that your idle timing) overspeed and underspeed tables will make it swing in and out around your base timing.

What was your DTC? Did you make the changes I asked?

I forgot to save the DTC (unless it's stored automatically). I made your changes but the car wouldn't start at all this morning. I don't know what was going on with it. I have to believe that the O2 sensor had something to do with it. This car has never not turned right over and at least attempted to run before this morning. I've got a replacement O2 coming for free and it should be here Thursday.

I don't fully understand what you want me to do regarding the VCM controls and the timing. Can you explain a little more for me?

Thanks.

[edcmat-l1]

I forgot to save the DTC (unless it's stored automatically). I made your changes but the car wouldn't start at all this morning. I don't know what was going on with it. I have to believe that the O2 sensor had something to do with it. This car has never not turned right over and at least attempted to run before this morning. I've got a replacement O2 coming for free and it should be here Thursday.

I don't fully understand what you want me to do regarding the VCM controls and the timing. Can you explain a little more for me?

Thanks.

The O2 has nothing to do with cold start. The computer could care less if they're even in the car at that point.

You need to get the fuel trims in range first. The last log I looked at, your trims were way off. If that's the case, you'll have too much fuel when it's cold. Need to get them dialed in first thing. I would put it in SD, dial in the VE, then MAF mode, and dial it in. After that is all done, you may find that is starts just fine. The OLEQ table I set up for you should work perfectly with that size cam.

[99LS1SS]

The O2 has nothing to do with cold start. The computer could care less if they're even in the car at that point.

You need to get the fuel trims in range first. The last log I looked at, your trims were way off. If that's the case, you'll have too much fuel when it's cold. Need to get them dialed in first thing. I would put it in SD, dial in the VE, then MAF mode, and dial it in. After that is all done, you may find that is starts just fine. The OLEQ table I set up for you should work perfectly with that size cam.

I have dialed the VE and MAF in multiple times. Unless I'm dialing them in incorrectly, they should be close.

[99LS1SS]

I am using your OLEQ settings. I've bumped up my idle air and startup air. We will see if it starts in the morning.

[edcmat-l1]

I have dialed the VE and MAF in multiple times. Unless I'm dialing them in incorrectly, they should be close.

Post another log please.

[99LS1SS]

I have a hot start log from a few minutes ago. I went into a restaurant to get some food and came back out and logged the drive home. It stumbled pretty hard on startup in this one. Once it's leveled out, it runs solid.

[99LS1SS]

It started this morning. I stumbled a little on initial startup but it didn't cut off and I didn't have to give it any gas. It did the surging but for a much shorter time. So, I think we're moving in the right direction.

Here's my tune and cold start log from this morning.

[edcmat-l1]

Try this one out.

Attachment 32799

[99LS1SS]

I think I need to add a couple of grams to the 104 idle airflow area and the cold start surging will be gone. The only thing left is the initial stumble at startup.

[99LS1SS]

So, you think my idle airflow is ok?

[edcmat-l1]

Try this one instead of the last one I posted. Plot your base idle airflow. Copy and paste it into your cal. Make sure the units are the same. Either metric or imperial.


Attachment 32800

[99LS1SS]

Try this one instead of the last one I posted. Plot your base idle airflow. Copy and paste it into your cal. Make sure the units are the same. Either metric or imperial.


Attachment 32800

I used your tune. Here's the log from my lunch trip startup.

[edcmat-l1]

Still too much fuel. Give this a try.

Attachment 32811