Hey guys, been working on the car a bit more and got the "Pump shot" / AE issue sorted it seems through increasing the "AE Factor %BPW Inj" to 0.64 across the board and "Async Accel Enrich if Neg Diff TPS > 3.9%" changed from 3.91msec to 2.73msec. Wide band has WOT around 12.8-13.1 (other tables) right now and tip in is solid without backfiring or stumbling at least at low RPM, still working on smoothing things out but it is getting there. Thanks again.

BUT now there is a new (old) issue:

Drove the car today, Friday, to enjoy it since it is finally coming along. I have taken a couple of 20 minute drives on the current tune and all was good. So I am driving to work today....in about 4 blocks I get the SES light... bucking, surging, backfiring like crazy, wideband gauge is reading 19-20 (max is 20)....I believe this is limp home mode...and for my 383 it is super lean.

Code 33, which I had before and replaced the MAF and relays and it fixed... but I also bumped the max airflow table at low RPM so a larger engine would not falsely set it off, so I really believe this is a wiring problem.

I don't think this is a pump or filter issue, as I had it before and replaced the MAF and it seemed to fix it and also really giving it throttle >40% seems to dip into PE or something in limp home mode, and it gets down to 14 AFR and seems to run much better...I just can't stay at that much throttle without speeding the whole time....

So, since this is the second MAF, it just randomly started with a tune I have 60 minutes+ of driving time on, and it gets more fuel when I give it more throttle, I think it must be wiring or a bad ECM (ugh!) however since after replacing the MAF and relays fixed the problem previously (code 33 and 34). I'm thinking/hoping it is a wiring issues at the relay connections OR at the MAF. So frustrating. I'm going to go out during lunch and try to check the connections and just unplug and plug them in and see if it clears it. Once the code showed up, restarting did not remove the code/running issues.

Any thoughts on this?

Finally, the big thing here too. Is can I mod the tables so they at least better fit my engine so when it does have issues it isn't running ridiculously lean?

 

You can tune the code 33 MAF high diagnostic parameter which is 45 gm/sec by default. Raising this value may be sufficient to avoid setting the code.

You can also tune the default airflow calculation so that the car will run acceptably when the MAF is faulted. Kopbet89c4 (or kobbledvette) ran this way for years with my help.

Which mask?

For $32 here are the relevant parameters:

LC213: FCB 167 ; If TPS > 65.2%, then use for MAF Default
; CALIB = Arg * 2.56
LC214: FCB 21 ; Gms/sec Scale factor
; gms/sec/IAC Count
; CALIB = Arg * 256
LC215: FDB 1024 ; 4 Gms/Sec default air flow offset
;CALIB = Arg * 256
;--------------------------------------------
; DEFAULT AIR FLOW OFFSET PER PCT TPS VS RPM
; Value = Gms/Sec * 100 pct, (Offset)
;
; TBL = Arg * 100
;--------------------------------------------
ORG $0217
LC217: FCB 8 ; Table Value
;
; Gms/Sec RPM
;------------------------
FCB 30 ; 0.30 400
FCB 90 ; 0.90 800
FCB 110 ; 1.10 1200
FCB 135 ; 1.35 1600
FCB 150 ; 1.50 2000
FCB 175 ; 1.75 2400
FCB 210 ; 2.10 3200
FCB 225 ; 2.25 4000
FCB 230 ; 2.30 4800
;--------------------------------------------

Also the max air vs rpm still comes into play to serve as an upper limit.

;--------------------------------------------------
; Max Air Flow vs RPM
;
; 17 LINE, 0 -> 6400 RPM
;
; TBL = Grams/Sec
;---------------------------------------------------
ORG $06EC
; gms/sec RPM
;---------------------------
LC6EC: FCB 23 ; 23 0
FCB 23 ; 23 400
FCB 30 ; 30 800
FCB 48 ; 48 1200
FCB 68 ; 68 1600
FCB 89 ; 89 2000
FCB 111 ; 111 2400
FCB 141 ; 141 2800
FCB 170 ; 170 3200
FCB 200 ; 200 3600
FCB 220 ; 220 4000
FCB 236 ; 236 4400
FCB 245 ; 245 4800
FCB 247 ; 247 5200
FCB 247 ; 247 5600
FCB 247 ; 247 6000
FCB 255 ; 255 6400
;---------------------------------------------------

 

1986 so 32... right?

Yeah, is bumping the max airflow/RPM table the same as bumping the diagnostic? I did bump that up to 100 or so (I'll check the chip when I get home.)

Default airflow calculation sounds like where I need to go, I don't want to run that way permanently, but I don't want it to run >20AFR when it does have an issue.

Thanks!!!

 

If you're using one of my old $32B bins (that was adapted for 86 4+3 use), then you'll need to use the $32B addresses instead:

LC220: FCB 167 ; Use this when TPS > this for MAF Default
LC221: FCB 21 ; Gms/sec Scale factor, gms/sec/IAC Count
LC222: FDB 1024 ; 4 Gms/Sec air flow offset for MAF default (Arg * 256)
;--------------------------------------------------
; DEFAULT AIR FLOW OFFSET PER % TPS vs RPM
; Value = Gms Air/Sec * 100 (Offset)
;
; TBL = Arg * 100
;--------------------------------------------------
ORG $0224 ;
;
LC224: FCB 8 ; 9 LINE TBL
;
; gms/Sec RPM
;--------------------------------------
FCB 30 ; 0.30 400
FCB 90 ; 0.90 800
FCB 110 ; 1.10 1200
FCB 135 ; 1.35 1600
FCB 150 ; 1.50 2000
FCB 175 ; 1.75 2400
FCB 210 ; 2.10 3200
FCB 225 ; 2.25 4000
FCB 230 ; 2.30 4800
;--------------------------------------------------

 

Thank you so much!

Since I swapped in a zf6 I am now using the 32.xdf from moates and an older bin which I believe is 32 based.


A couple of questions:

1) If TPS > 65.2%, then use for MAF Default
Does that mean I am using the MAF Default tables right now when in PE? Does fixing it for limp home mode (increasing MAF Default), also mean that I am going to have to rework PE then?

2) It looks like this is what I need to change:
I don't see this listed in my definition file, does this mean I need to find it in the code? Add it to the definition file then?

Thanks again and congrats on the SC #'s!

 

The 65.2 % value is used as a tps limit for calculating the default airflow only. No effect on PE.

What it means is that once the throttle exceeds 65.2 % the flow value that is obtained from the defalt airflow calc will not be further increased by tps position. It will only be increased by rpm according to the values in the table.

I typically reset this to 100 % so that throttle position will always contribute to the calculated flow and so that the table will roughly represent the flow at 100% tps.

Example 230 at 4800 rpm. 100 % tps would result in 230 gm/sec + the base offset + the IAC position based value then the total will be limited by the max flow vs rpm table.

Ideally you want the calculated default airflow to roughly equal the real MAF flow for given rpm and tps position. Takes some datalogging and trial and error to establish the correct relationship between flow tps and rpm.

If not in your *.xdf, you will need to add.

 

Ahh, that makes much more sense. I also agree, 100% throttle seems logical.

I'm going to start with just trying to add the definition for Default Air Flow. It looks like I added it correctly as a table. Using TunerProRT I put it in as a new table with a start point of 0217 it read:
Gm/sec; RPM
8 ; 400
30 ; 800
90 ; 1200
110 ; 1600
135 ; 2000
150 ; 2400
175 ; 3200
210 ; 4000
225 ; 4800

Changing the start point to 0218 made it:

30 ; 400
90 ; 800
110 ; 1200
135 ; 1600
150 ; 2000
175 ; 2400
210 ; 3200
225 ; 4000
230 ; 4800

So I think that is right? This is my first time adding a new definition.

I also didn't put anything in the equation section, I'm hoping this is right. I'm going to try it out and I guess we'll find out...

Thanks again!

 

It was the relay connector that was the problem. I made some changes however shortly thereafter my hydrualic TOB blew out. Awesome... I'll try to update this when that gets fixed in a month or more... blah

Thanks for all the help.