I just got my datalogger to work on my 88 running a the gm 1227747 ecm and the blms are running about 108 ave I know by reading that this is rich, but just how rich is it? And would anybody be scared to guestimate how many mpg's it's costing me right now? Or an Idea of what I might can expect to pickup with a good tune? I'm trying to learn as much as I can so I can economy tune this thing cause right now it's really killing me, right now it's averaging 13-14 mpg's on my daily commute to and from work which is about a 30min drive with about 1/3 of it being on the highway the rest city. Any ideas please comment,

Thanks,

 

Well ideal stoich is 14.7 which is 128 BLM so if you are at 108 you are about 16.5% rich. You want to subtract fuel to move your BLM's toward 128. This is done by adjusting the VE tables (VE1 and VE2) by the amount you need to move the fueling, in this case by 16.5 %. since you want to subtract fuel, decrease the VE tables by 16.5% Actually you need to be a little more precise, since your 108 blm is probably not at all RPM's or MAP readings. Fortunately, the 7747 ECM has fairly small VE tables, so you won't have too many to adjust. Good Luck

 

Thanks that's what i was thinking, i made me a spreadsht to do the calcs for me so i can just copy and paste from the data logger over into it then the convert no's straight into tunerpro rt. Oh yea has anyone tried tunerpro rt v5 beta with a windows 7 x64 laptop? I can't get my flash and burn 2 to read my stock chip, so i had to go online to find a bin that would work for me. also has anyone had problems getting windows 7 x64 to recognize their use to serial adapter? I've tried all weekend and can't get it to work, but i did get it to work on the wifes 10" acer ;aptop with windows xp. Anybody have any Ideas?

 

Higher FP (fuel pressure), then set up in the calibration will cause rich condition, it easy noticeble at idle.

 

Good catch, I did do some mods and knew that it would effect it but I just didn't think about it at the time. I changed the 305 injectors out with a set of 350 injectors after porting the tbi as well as modifying the fp reg to an adjustable type and increasing fp to 13 psi. That along with a full highflow 2.5" dual exhaust. I did all the math and found out that my BPW was way off, the stock L03 bpw was 148 and after my mods it needs to be 110 so I know it's way out, I just need a dry day now to recheck my fp then make the changes to my bpw then start from there.

 

It is probable your control of A/F or stoich is compromised. BLM 108 means it is maxed out and can no longer pull fuel. So you should make the VE table values lesser by a factor of .84 as previously stated. Likely you will be globally at 108 or close to it.

 

Well I got out there and checked my fuel pressure and it was 13.5lbs, so I reworked the math to get the appropriate bpw stock was 148 my new is 106 and it really helped the blm table, now it's reading from 113-116 range with a few exceptions throughout the table where it still dipped down to the 108-110 range so i made the corrections and will find out what good I did in the morning, thanks for all the input

 

You may find some other things that need to be adjusted, by adding fuel supply.
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