Adding IAC to a downdraft setup

[mwarchut]

Thanks. I actually stumbled on that one after I replied before. Ill install everything after work today and see what happens.

[mwarchut]

I am going to run the synchrometer on my ITB's tonight. I did yesterday and they were everywhere.. From less than one to as high as 7. What do you think would be a good setting for them at idle. I used to know this for webers but its been a while since I have done it.

[pkm123]

set them all at 6 or 7. Get them all balanced, start by setting the two control throttle bodies. The others are driven by them. Then start reducing the main two control throttle bodies until the idle settles down. My setup idles well at 6 without the IAC and I can go lower with the air flow supplemented by the iac flow

[mwarchut]

I suppose it doesn't matter if the IAC is flowing or not to do the balance. But once I dial all of them down I suppose I have to reset the TPS to 0? I only assume this because a negative TPS can cause another whole bucket of issues.

[mwarchut]

So I have all of the ITB's balanced now. I set them up at around 6 with the IAC plugged and the car ran pretty good. I then dialed them down as a whole to about 2 with the IAC opened up. The idle is good around 800-850. However the weirdness is the O2 readings. At first they were both at a solid 12.0. Then they would start to jump around all over the place. Even with the auto-tune running. Then once the motor got up to around 180 or so if I shut it off it would not start back up. the only way I could start it is to remove the fuel relay and then it would start for a moment. Then I would put the relay back in and it would start. So it must be flooding when its warmed up. I am adding a datalog and my current tune.

2015-08-15_13.40.55.msl.zip

2015-08-15_14.56.22.msq

[mwarchut]

So after some research and looking at the logs it seems my IAT sensor is soaking up heat and is sending an unnaturally high reading. Right now it is mounted into the manifold between the ITBs and reads the air coming in via the IAC line. It would seem to me that it might be better served if I moved it up the line away from the manifold to a point right after the air filter I have on the line. This way its temp is not being skewed by the heat from the engine manifold since it will be isolated by the rubber hose and nearer to the source air. That said should I put the IAC line air filter outside engine bay so it gets its air from a cooler source?

[pkm123]

I had the same problem with the warm starts. Engine would start cold fine, would not start warm. I found that the engine was flooding. Reduced my priming pulse near zero and reduced the cranking pulse. Engine starts easily now, cold or hot.

[mwarchut]

Thanks... I moved my IAT sensor out away from the engine closer to the temp of the air that comes through the scoop. That helped drop the IAT temp by 20 degrees. Although its been 100+ out here lately..

Ill try what you did and see how it fairs. Overall I am making great progress. She's bound for the road by the end of the week. Ill post a video when I am done.

[mwarchut]

Thanks for your tune. That was incredibly helpful. I exported the dialog for your cranking pulse and priming pulse and my hot start problem went away.. It starts every time now. Now my last issue seems to be idle RPM. I can't seem to get it any lower than 1000-950 RPM. I've closed the throttle plates all the way, adjusted the TPS back to 0 but no good. Im not 100% convinced that FIDLE is controlling the IAC valve properly. Or I have something setup wrong. It's a Bosch IAC from a mercedes. 2-wire. I assume its PWM. But I could be wrong. When I turn on the power it opens wide open. I assume that suction from the motor attempts to close it? Is there an easy way to test it to see if it works ok and whether its the MSII or the valve?

Thanks.

[mwarchut]

Unfortunately I had to take a break from this project to rebuild the Automatic transmission in my daughters car. Fun times..

Anyhow I took my car out tonight for its maiden voyage with the MS2. Overall it went pretty well.. However there were some issues with backfire on decel and a lag from the lower RPM to when I hit it with WOT. I am running the ITB algorithm. Here is the latest tune and a datalog from my drive. It's only a couple of miles but very hilly so a lot of up and down..

2015-09-04_18_modified.msl.gz

2015-09-04.msq

[pkm123]

I see some errors/problems in your tune. First, you should be in single table in general settings. If you want to use dual table then the load values (y axis) don't overlap.
Second, your injector deadtimes seem a little high. Usually they are 0.6 ish. Check the manufactures specs.
Third, your tps threshold in accel/enrich is 200. From your log you should set it between 25 and 50. Presently you aren't getting any accel pumpshot.
Hope this helps

[mwarchut]

I was under the impression that I wanted to use dual table since I have two distinct seperate exhaust paths and wideband 02 sensors. One for the left bank and one for the right bank. That's how it is currently setup. Would a single table be able to support that setup sufficiently?

[mwarchut]

I checked on my injectors and it seems that they should be set to .8 at 13.2V. So Ill try moving them down a bit. I also adjusted the Accel TPSDot down to 35 for starters. Ill be taking her out for a test drive here shortly.

Thanks for the input. Much appreciated. I have a lot left to learn about this it seems. But you guys have been extremely helful.

[pkm123]

I recommend you run Single table for tuning. Both injector sets will run off one table. After you have a good tune (VEAL) with EGO correction off, turn on EGO correction with "Dual wideband". This will let each wideband trim each bank,

[mwarchut]

Ok.. I'm game. Ill switch it to single table and see how it fairs out. Thanks.