OK Craig, I need some help

[Reggie West]

FAST is installed.

Car starts OK when it is cold.

Idling is the problem. The best idle speed seems to be 900 rpms.
The biggest concern is that the motor is running very rough at idle to 1500 rpms, after that it smooths out and runs nicely.

Took it out around the block and it stumbles around until you rev up some. Same problem it sounds like to me.

I have tried changing the VE values at and around idle, it helped but did not solve it. E.G. value in cells at idle( bottom left corner was 43 changed it to 26, it did help.) Any lower and the car would die on us. A/F ratio is 13.3 in corresponding cells.

I am getting a backfire every now and then. Dont know if it is exhaust or intake.

Now here is the other problem. Crank Reference Angle. As I understand it this allows for any mechanical timing that has been setup on the crank.
So here is where we are. The crank sensor is set at 24* BTDC. I have tried the Crank reference angle setting at 14 BTDC. According to the book you are supposed to allow 10* for the ECM to make its calculations prior to the timing event. No help, it is still running rough and we have a stumble at low rpms. I tried the default setting of 10, no help. Tried 24 that did not help either.

Suggestions anyone?

I am having a beer and trying to ponder all of this.

Thanks in advance.

 

[HighPSI]

Originally posted by Reggie West
FAST is installed.

Now here is the other problem. Crank Reference Angle. As I understand it this allows for any mechanical timing that has been setup on the crank.
So here is where we are. The crank sensor is set at 24* BTDC. I have tried the Crank reference angle setting at 14 BTDC. According to the book you are supposed to allow 10* for the ECM to make its calculations prior to the timing event. No help, it is still running rough and we have a stumble at low rpms. I tried the default setting of 10, no help. Tried 24 that did not help either.

Suggestions anyone?

Why are you changing the referance angle? Have you put a timing light on it (raise the rpms above idle) and verified what it needs to be? Once it is set, leave it alone. If we are talking about a Buick with DIS and a stock balancer, it is USUALLY 10, with a BHJ, start at 6 and check it. Next thing to setup is the idle parameters. If you have the IAC completely closed, the timing is going to retard a lot to try and lower the idle.

I don't know where you bought the system, but I would ask them for a start up program and some customer support.

 

[Reginald West]

OK update here. I figured out the crank reference angle and the crank and the timing map have now become one. Thank God for that.

My idle is still rough but I attribute that to the 242 cam in motor. It seems 1000 rpms is a good compromise. I have noticed the the MAP never reads higher than 40 kpa at idle until I get up above 1500 rpms.

I datalogged a couple of runs I made on the street and so far things are looking pretty good.

I wanted to data log O2 correction and it did not do that. I think the closed loop throttle limits are not right. I have to check that.

Geno has been nice enough to send me a file to look at for reference as far as timing and fuel. Craig can you please tell me what Non Public File Mismatch means? That is driving me up the friggin wall......

All in all the day was good, car starts now, idles pretty good and I am learning.

Thanks for the help Gene and Craig.

Cal your advice did not go unused either.

Updates to follow

 

[bobc455]

Reginald,

What is your timing at idle?

-Bob Cunningham
bobc@gnttype.org

 

[Reggie West]

Timing is 40*

 

[bobc455]

That seems very high. Does a lower timing setting smooth the idle out?

-Bob Cunningham
bobc@gnttype.org

 

[Reggie West]

No I tried that and it did not help.