I'm attempting to tune my friends '90 T/A (Autogon350). He already has an Ed Wright chip.
The reason I'm messing with it is I built the dual 160/8192 baud scanner interface, and we hooked it up to his car and his BLM is at 108 and INT runs a steady 90 (Thanks Craig, I got to use your software!). We also cannot keep it from pinging at anything past half throttle above 3000rpm. On quick shot out of a parking lot and his knock count went from 5 to 12 to 21!

Can someone re-explain the theory of the BLM cell thing. I don't have them so I never really paid any attention.

Will turning down the fuel tables help this, or will it not run at all like before (due to the huge cam and heads)?

 

The huge cam/heads lowers the vacuum signal at all RPMS, causing the ECU to use a higher MAP fuel value, which is usually higer, thus the rich condition you are seeing. You need to re-tune the entire PROM to fix it properly. A fuel pressure change LOWER will help drivability (from BLM's) at lower rpm/highway cruise, BUT will RUIN THE TOP-end from it now being lean. You are stuck with having to get a custom PROM!!!

What, exactly, are the cam specs??? ie, Lobe Center and intake/exhaust duration at .050" lift? Flat tappet or roller? Hydraulic or Solid lifters? Overall lift and head type??? In general, to run bigger cams on OEM PROM, you need 112 Lobe center for cams from 204-214 intake valve duration and 114+ for 214-224 intake duration cams. This is to just get the car to run half-way decent with the OEM PROM that is... You can tune around most anything, of course, but just trying to let you know what you are up against.

 

The first thing you need to do is remove the extra timing. If you can hear it knocking it has at least 6 degrees too much. Based on the knock counts I would guess it has 10 degree too much. Is the base timing advanced as compared to the recommended setting?

BLM is best viewed as a percentage(BLM/128) This percentage is multiplied by the base pulse width to get a corrected base pulse width. In your case the corrected amount of fuel is 84% of the programed value (way too rich) Check the fuel pressure it is probably higher than the recommended value(recommended by the chip writer)

Turning down the tables will help in areas controlled during closed loop. Before you do this get the WOT stuff settled by adjusting spark and fuel pressure and PROM fuel values.

HTH

John

Heart of Texas Power and Performance

 

He's already got an Ed Wright custom chip. He's got SVO injectors, I know they are calibrated for 24# at 30 something psi. So To keep the stock 42 psi fuel pressure, what should I set the BPW for, 22#'ers?

 

I am no TPI expert, either, but if your BLM is CONSISTANTLY 109, a BPW constant change is exactly what you need. I don't have a clue to help ou but it sounds REAL easy.

BUT, some injectors don't like higher than spec'd fuel presure so it may be more beneficial to injector life to just get an adjustable regulator and turn down the fuel pressure. I don't have much experieince with SVo injectors but some TBI and TPI injectors will prematurely wear/fail under even moderately higher fuel pressures, as you have here... Just be careful and ask questions before you keep that FP, IMO.

 

Have you checked the fuel pressure? 108 is the lower BLM limit. A 90 int tells me that you are rich beyond the self tuning capacity of the ECM. What is your constant now? Something seems very wrong. Your fuel is more than 15% off. Also if the constant is 24 then 26 will make it leaner. If the ECM thinks that the injector is larger then it shortens the pulse to deliver the required amount of fuel

John

 

Hotpowerandperf is correct about being extremely rich. In fact, you are very close to triggering a SES Code 45 (Rich O2). I would also agree with Hot's recommendation of raising the injector constant to lean out the mixture and then "fine tune" via the VE Tables.