Engine Cranks but hunts for an idle

[webb1624]

Working with a MS3 with MS3X expansion board. Ford 347 ci, AFR 185 heads(ported), Holley systemax intake(ported), Ed cutis cam, 75 mm TB, 36-1 trigger wheel from Explorer, 42 lb injectors, sequential injection, Ford factory coils from 1998 Explorer. I am able to get the engine to run but it struggles to stay running. It is hunting for an idle. I have used several fuel tables from the fuel table generator and I have to take ALOT of fuel away from it at idle to keep it running and when you try to rev the engine it will cut off. I messed with it some and got it to where it would rev but it would die when coming back down to an idle. I'm sure there is something wrong with some of my settings, I just don't know what. Timing has been verified and I messed with the timing table alittle but it didn't make much difference. I have to idle it at 1200 rpms to get it to stay running and when I take some fuel away I can bring it down to around 850rpms but then the engine will die when you try to rev it. I'm pretty sure the issue is fuel related seeing as that makes the biggest difference when I change it.

I am also using 2, LC2 widebands and they are all over the place on my Tuner Studio gauges while the engine is running. I have double checked the wiring and re calibrated them and they show a solid green light after turning on the power. Not sure whats going on there. I even disabled them and it made no difference in the way the car ran.

I have uploaded a msq if anyone has any ideas as to where I need to start fist.

Thanks

Chris

[ashford]

id start off by turning off alpha-n and using speed density.4 years ago i had a nearly identical engine, if im lucky i may be able to find an old msq.

[webb1624]

I'm not running a MAP sensor. I don't think I can run Speed Density without one. Alpha-N uses the TPS so I was under the assumption it would react faster anyway. Is that not correct ?

[billr]

You already have a MAP sensor there on the mainboard, right? Why not try using it and speed-density?

[webb1624]

Your right !! I forgot about that. Ill give it a try next time and see what happens.

[webb1624]

I was able to play around with the car a little today. I changed from Alpha-N to Speed Density. It didn't make any difference. I left it on Speed Density and changed some settings. If I input what the engine should make HP & Torque wise in the fuel table generator, the fuel table is way rich. I tweaked the Fuel table some using the Fuel Table generator and got it to idle around 950-1000 rpms. If I lowered it anymore than that it would not idle. It stills hunts for an idle. One thing I did notice is that I don't have a dot moving around on the fuel table. I have one on the 3d table but not the regular fuel table. I can make slight fuel adjustments up or down and the engine will die. I did notice when I fixed the timing around 15 degrees it would idle pretty steady. That was just to see if it made a difference, I am using the timing table though.
I messed with the Accel enrichment and got it to rev pretty darn good from idle. It stll struggled to run when it came back down to an idle but would eventually stay running.
Any thoughts on where to go from here ??

Also, I can't seem to figured out how to get a log while its running. Can someone help me with that as well ?

Thanks,

Chris

[ashford]

making a log is easy goto datalogging and hit start logging(ctrl-l is a shortcut)
in the 3d tables tuning is easy, move the cursor around with the arrow keys hold shift then up or down for small incriments or ctrl-shift up/down for larger incriments.
your iac appears to be closed when warm.
your timing also moves around too much on the table in the idle area.

[webb1624]

Any reason I can't see the dot on the regular fuel table? Is it a setting I have turned off?

Is the fuel causing my timing to move around? What would cause my timing to move around using the 36-1 wheel? It should be steady with that, right?

How are you seeing the iac position, and my timing moving around from the msq?

Thanks,

Chris

[webb1624]

Here is a log of the car running I did today. I fixed the IAC so it would not shut off 100 %. The idle was surging from 900 rpms to 1100 rpms. My LC-2 widebands are acting weird too. One is working but reading way off it seems, and the other is not working at all. You can see that AFR 1 is reading 22.3 all the time, but after I rev the engine and its coming back to an idle it does reads 14.4 for just a second then goes back to 22.3. This makes me think that the sensor is working but the engine is just rich. AFR 2 is reading 7.5 all the time. The red light on AFR 2 controller is also flashing 8 times, indicating a sensor timing error ???? The manual says typically a damaged sensor. These are brand new !!! I have calibrated them and I'm not sure what is going on. Under AFR control I have it set to "No Correction" until I figure out what is going on with them. The AFR table shows around 13 - 13.5 when idling. Not sure where its getting its reading from. I tried messing with the fuel table some but its hard when the dot isn't showing up to let me know where to make changes. The dot was there when I first started the car but disappeared. I think its disappearing when I use the fuel table generator. Anyone else had issues with not seeing the dot ???

So if my AFR is rich, why does the engine die when I take fuel away from it ?? I can't take enough fuel away to get the AFR down enough without the engine shutting off.

Thanks,

Chris

[elutionsdesign]

You will have to sort out the O2 issue to be able to tune.

Notice its running at very high MAP for idle, you're up in the top of the load range and it's going to be difficult unless you can get more vacuum at idle. Any chance you have a big leak somewhere? Maybe shut the throttle plate further at idle?

[webb1624]

I'm going to get a new O2 sensor and see if that's the issue with the one that's not working at all. Kinda strange though, because they are both brand new. I haven't started the car but on 3 different occasions.

I will check my vacuum again just to be sure I don't have a leak. I am using the 3 ports on the Holley Systemax intake just behind the TB. There is one big port that goes to the vacuum tree, and one small one that goes to vacuum tree, and one small one that goes to map sensor on MS3. I can also just use 2 vacuum ports off the intake, one for the fuel pressure regulator, and one for the map sensor, then plug the third one, just to eliminate anything with the vacuum tree and the lines going to it and see what that does.

I did notice the high map at idle. I'll check my throttle blade position. I've moved it around so much I'm not sure where it is. I finally got the IAC working so the throttle blade may be open to much.