EFIDynoTuning Forum

I'm going to start off by saying I am very new to tuning cars. I used to be an f-16 engine specialist, I now do vehicle calibrations and programming. So I have mechanical knowledge and an understanding of how it works. I've been hung up a few days on why my 98 GT won't enter closed loop. I've had my QH for about a week. first thing I noticed I had a bad B1S1 o2 sensor which I promptly changed out. I have a basic knowledge of how the Closed loop system works and I've read through most of the files, reverting bins back to stock, shooting wires and chasing acronyms that have nothing to do with my build. (I can't remember acronyms or terminology to save my life so I'm working on making a list to define most of it. If anyone has something like that it would be very beneficial to me) I tried everything I could think of and wasted a lot of time messing with the FHA3.bin file. I noticed in lists there is a faut on Injector 4. I tested continuity, was good. I swapped injectors still INJ4. fault. Tested voltage. it was fine but the data wire did not pulse to ground when running. I Shot the data wire to ECC harness, wire was fine so i figured i had to crack open the ecc. But i really didn't want to do that yet so i unplugged my QH and let it run for a bit and, voila! it enters closed loop. I'm stumped at this point. I feel like I'm missing something crucial. I archived everything, reinstalled TP, redownloaded all adxs, xdfs and bins. After all of that on a bone stock FHA3 bin I still have the same issue. Im gonna keep digging, Ill figure it out eventually but some insight would be much appreciated. Ill take all the help i can get to understand this system better. Also one thing on dashboard is fpump DC x2 is reading 2 with a red alarm. shouldn't that be correct on my stock return style system?(could be wrong) just wondering if thats throwing something off

I dont think I have injector faults logging on crai8.

something doesnt aound right with what youve got happening.

Post your stock tune and the tune you were running and a datalog and ill take a look.

98 is return fuel and doesnt have a fuel pump duty cycle so thats normal.

im going to put together an acronym quick search for you but the datalogging write up should cover most everything

I was poking around and found the data list view, that's where I saw it. the only thing I edited datalogging.

FHA3 is a forced open loop tune from the factory.

Attached FHA3-B which allows closed loop. Load this in and post back a log driving around to verify all is well. Be sure to copy over your PATS code from your stock tune read out.

btw, thats not your stock tune readout that the fha3 file from the downloads.

Yea, that's what I've recently figured out. It's been throwing P0135 since I bought it, so I didn't pay attention to CL/OL until I swapped that sensor out. But thank you very much! I've been searching for a while and no dice. I'll give it a shot here shortly.

Looking good! Thank you very much

Very nice, your fuel looks perfect.

Enjoy.