Do I need to increase the throttle blade opening?

psikillz

New Member
Joined
Aug 1, 2002
I have a ford mustang with a 302 and a FAST bank-bank w/ wideband.

I have been having a hard time getting the car to run. It will start, then die about 2 seconds later. I finally increased the atfer start enrichement through the roof. The car now starts and barely idles (surges), the idle speed jumps from 700-1500. The IAC target alternates from 80 to 180. I'm thinking not enough air is getting in the engine? Think I should increase the throttle opening.

How important are the VE tables at idle, any idea why I had to almost max out the start enrichment?

Thanks in advance!

Clayton
 
Clayton,

Is this a new startup or was it running fine until recently?

I like to have the throttle blades fairly far open, but others disagree. My car typically idles with the IAC at 10 (about 60 when cold).

Here is has gotten much colder lately, and I have had to play with my starting numbers a bit, and you might have to do the same. But I seem to have a LOT of cranking fuel this cold...

-Bob Cunningham
bobc@gnttype.org
 
Thanks for your reply. This is a brand new startup, just installed the unit a couple of weeks ago.

It is about 65 degree F here. Not too cold.

Clayton
 
I assume your operational parameters are okay.

We might have to do some "blind" tuning until we get the car to start and stay running- I would try the following settings to get going:

- After-start enrichment - about 15%
- Idle Speed set to 1200 RPM (just for now, you can lower it later) at 65 degrees
- A/F ratio set to around 13.5 at 50-60 kPa / 1200 RPM (and surrounding cells)
- VE around 45 at 50-60 kPa / 1200 RPM and surrounding cells

You might also try increasing the "engine revs to run mode" from 12 to 30, to let the engine settle out a bit before it transfers to running conditions.

Once you get the car running and the wide band operating, you can tune these to make the car idle and drive better.

Also, before you get too far into the tuning range, make sure that your RPM range is realistic - if you engine redlines at 5500 RPM, don't have the tables set up for 8000 RPM, you will lose tuning resolution.

Let us know how things go.

-Bob Cunningham
bobc@gnttype.org
 
Thanks Bob! I'll follow your advice!

Operational parameters should be good. I'm thinking a may be a bit lean, I'm going to try and richen up the VE table around the idle. I did make some progress last night, the surging was only about 200-300 RPM, then again by this time the Coolant was warmer.

The other thing I noticed last night, I was basing my tuning off the demo.gct file, I just saw the dakota0.gct file. It looks like this one is for the windows version? The values seem to be a lot closer to what I have had to modify the demo.gct to. I'm going to plug that file in and see what happens.

The other thing I have noticed is that the wideband does not appear to be showing up, will it only show as being present after the sensor has warmed up?

Thanks for your help.

Clayton
 
I finally got the car idling pretty good! I ended up having to increase the V/E tables quite a bit around idle.

Thanks for the help! I'm sure I will have more questions down the road.
 
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