What's next
Ok I have now had my FI up and running for 2 weeks and around 140 miles in various conditions. Hopefully this link works for you to see the data log and you can tell me how everything is doing and if I need to change anything.
https://1drv.ms/x/s!AtllmUWFvoeUghnufW2c-ClxMwWX
This was idling after warm up (actually after a 6 mile drive)
If it matters it's a
1972 AMC 360
TH400 transmission
Fitech 39001 (2 barrel)
a Fitech 40102 fuel pump mounted in the fuel tank, (not in a fuel command center)
No timing control
No fan control
Thank you
Some things that seem odd to me.
Your IAC steps are really high at 82. Was this log with it in gear?
Your fuel learn is adding approximately 29% fuel in order to meet your target AFR. Possible vacuum leak?
It was in park and all settings are as it came out of the box.
What should AIC steps be? Is that something I can change?
I'm pretty sure there are no vacuum leaks but I did use the existing connection on the manifold for both the transmission and heater actuator vacuum. The transmission if a hard line connected to the runner to the #8 cylinder and heater vacuum is off the #1 runner. Fitech said that shouldn't be a problem.
To lower your IAC count, you need to turn the throttle linkage screw in with the key off. Small movements at a time. I would start with maybe 1/2 turn (assuming it is making contact with the throttle linkage) since your counts are very high. You want to be around 7 to 15 IAC counts at idle fully warm in park.
As for the system adding fuel to achieve target AFR, what is your fuel pressure?
This being a 2 barrel system, what is the fuel pressure requirement for the throttle body?
I have a way for you to check for vacuum leaks, but lets take a look at other areas first before going there.
Thank you TTA Perf
It took a lot of adjusting but I got the IAC count down to around 18. Here is the new data log
https://1drv.ms/x/s!AtllmUWFvoeUghxAu-n1flsFrCvd
For some reason it didn't seem to have recorded as much data. If necessary I'll do another tomorrow after it gets run down the road more.
I don't know what my fuel pressure is, I don't yet have a gauge for that. Fuel pressure for this system is supposed to be the same as the others, 58ish PSI but I noticed when I did initial setup that the PWM was set to 80 when it seems it should have been preset to 74.9. On their website they say that setting is for the frame mounted fuel pump but if you are using the fuel command center you should reset it to 40. I don't have the fuel command center or a frame mounted pump but I am using the same pump used in the command center just mounted in the gas tank. This all got me to thinking that at 80 my PWM is probably too high and I wonder if that could be causing the problem with the AFR target.
I finally got the IAC step down. It's around 8 ish although it did drop to zero for a bit. The adjustment for that is very touchy. I'll adjust it more if you think I need to. Here is today's log.
https://1drv.ms/x/s!AtllmUWFvoeUgh7Q3qfucs_g64hv
Before I left work this afternoon I also adjusted the PWM down to 74 to see what that did. I see it dropped the idle fuel learn to 121.9 from the 129 it had been. I don't know if that is a good thing or not.
Thank you for the help on this, I feel so lost when it comes to this stuff.
PWM of the pump shouldn't have much effect on the AFR unless you drop pressure considerably and it goes lean.
Going from 80 to 74 should not effect it at all.
Looking at your logs now, the IAC looks good.
The system is still adding fuel and the AFR is still a little lean from target.
I look at the AFR % and the AFR Learn not the Fuel Learn numbers.
Your AFR Learn is showing 21.9. The max is 50 that the system is set to. To me, the computer is still adding fuel to reach target.
I would try to double check your fuel pressure.
Got a gauge and fitting ordered. I'll let you know when I get some more info on fuel pressure.
Thank you for your help.
I got my fuel pressure gauge the other day, I took it to my work and had our people who certify instruments verify it reads correctly. The fuel pressure being put out by the pump is right at 58-60 PSI like it should be. I looked for any possible vacuum leaks and can find none, all vacuum lines are new or capped with new caps. It may not matter but it's worth noting that I adjusted the PWM down just a little bit but not enough to effect fuel pressure and have a new log for you guys to have a look at
https://1drv.ms/x/s!AtllmUWFvoeUgilbCwv7JgXBjFUy
So, what do you think? If there are still issues do you have any suggestions? Is there somewhere to go that explains exactly what all those numbers should look like?
The log looks great to me.
When I look at an idle log, the data I pay attention to are:
Target AFR
Actual AFR
Trim %
Trim Learn
IAC counts
TPS
I always compare Target AFR to Actual and see how close they are. If they are close, I look at the Trim % compared to Trim Learn. Trim % is short term adjustments the computer is making to the fuel to achieve target AFR right away. Learn is stored data the computer uses the next time the engine is at that parameter. Negative number means it is pulling fuel. Positive it is adding. The system will add up to 50% and remove up to -34%. If your Trim % or Learn are close to those numbers, your tune is off and the computer is maxed out trying to compensate. The IAC in the 5-15 range helps steady the idle.
Next step is to log while driving.