AFRs constant 19.0 during cranking, warmup, etc

[Austin Finley]

I apologize if this has been brought up before and solved, but a quick google search didn't resolve the issue, so I figured I'd make a post.

I just completed the installation of my MS3x and LS2 truck coil conversion in my 1997 v6 mustang. It's a stock motor that i'm using to learn how to tune with before I swap in a v8. After fiddling with the VR pots I finally got the motor to catch. However, the engine rpm still "hunts" big time during all of the phases and if I don't give it steady throttle it will die. I tried adding more fuel during these phases but my afrs stay at a constant 19.0 the entire time until right before the motor stalls. I attached a log file and my tune that will hopefully describe what is going on better than I can. And for what its worth I am using APSX V2 wideband sensors.

Thanks,

Austin

[billr]

I'll start with the basics:

Do you have the coils "hard-wired" in correct sequence for your firing order, like spkA=>cyl1, spkB=>cyl4, spkC=>cyl2...?

Have you checked spark timing with a light? Was it a simple light or "dial-back"?

It never hurts to use "wasted COP" at the beginning, that eliminates some problems with CMP sensor phasing or detection.

Try just opening the throttle stop some more for now.

The MAP is slow to respond, any clue why?

Battery voltage is low, that may not be a problem, but won't help any as you first are sorting things out.

Have you flowed the injectors? Just a simple rate for now, with the large "req_fuel" you have dead-time isn't so critical.

Do the injectors and coils all seem to work OK in "Test Mode"?

Keep in mind that a high AFR may not mean the mixture is lean, it may be so rich it is miss-firing and just showing "lean". Or, just miss-firing because of ignition problems.

[slow_hemi6]

Are the sensors calibrated under Tools > Calibrate AFR table?

[Austin Finley]

Thanks for the advice.

The coils are wired correctly because when I was feeding the wires through the firewall made sure to label then one by one as not not be confused later on, and I also labelled the wires coming from the MS3x while I was making the connector.

I have a timing light (Bosch digital from Oreilly) and used it to check that each cylinder was getting spark. I couldn't find any timing marks on the crank to help me with timing so I set it to 10 degrees after a little research on mustang forums.

Do you know how to do that? is it similar to a carb where its a set screw? I'm running cable throttle right now.

As far as the MAP, I honestly dont know. I have the vacuum tube hooked up to a small nipple on the intake that was used for emmissions.

And regarding the battery and injectors: I charged the battery last night and started the car on my break from work and the same conditions were happening, although this time the AFR gauges were changing like I described before (during the first datalog posted the afr gauges weren't changing like that for some reason).

I can only post one of the tunes due to file size restrictions, but both of which I converted to Wasted COP. The car seemed to run slightly better with the wasted COP setting, however it could have been the freshly charged battery as well.

For the second tune (the one attached) I changed the fuel injectors to 19lb/hr (common "upgrade" for v6 mustangs) and received similar results as the stock injector req_fuel.

And lastly, as a reply to slow_hemi6:

I checked before I datalogged this time and recalibrated the afr gauges in tunerstudio. The only thing that really changed was the A/F went to 18.9 instead of 19.0 lol

Again, thanks guys for the help!!!!

Austin

[Austin Finley]

Update:

So i recalibrated the sensors and it seemed to work. However after the motor stalled one too many times the drivers side gauge now reads a steady 9.0 (rich) while the passenger side fluctuates from 10-12 like how i might expect it to do. Any idea whats causing this?

[racingmini_mtl]

I don't know if the APSX V2 is different from previous models but you might want to do a search on the forum for APSX. That might be your problem. And check the actual voltage on controller wire (with a multimeter) to see if that actually matches with what you see in TunerStudio.

Jean