ULTM8Z

Can't seem to get rid of this stumble between off-idle and 2000 rpm. I've checked to make sure the two VE tables match at 1600 rpm. Here's my Accel enrichment vs delta TPS values

0.0 .75
3.1 .75
6.3 .75
9.4 .47
12.5 .28
15.6 .28
18.8 .28
21.9 .28
25.0 .19
28.1 .19
31.3 .19
34.4 .19
37.5 .19
40.6 .19
43.8 .19
46.9 .19
50.0 .19

What do some of your tables look like? My engine combination is in my signature and I'm running a 7730 ECM.

Grumpy

;-------------------------------------------------
; ASYNC FACTOR vs DIFF TPS
; \(PUMP SHOT\)
; TBL = 128 * MULT
;--------------------------------------------------
ORG $0543 ; MULT %TPS
;----------------------------------
L8543 FCB 128 ; 1.000 0.0
L8544 FCB 128 ; 1.000 3.1
L8545 FCB 128 ; 1.000 6.3
L8546 FCB 80 ; 0.625 9.4
L8547 FCB 48 ; 0.375 12.5
L8548 FCB 48 ; 0.375 15.6
L8549 FCB 48 ; 0.375 18.8
L854A FCB 48 ; 0.375 21.9
L854B FCB 32 ; 0.250 25.0
L854C FCB 32 ; 0.250 28.1
L854D FCB 32 ; 0.250 31.3
L854E FCB 32 ; 0.250 34.4
L854F FCB 32 ; 0.250 37.5
L8550 FCB 32 ; 0.250 40.6
L8551 FCB 32 ; 0.250 43.8
L8552 FCB 32 ; 0.250 46.9
L8553 FCB 32 ; 0.250 50.0

;--------------------------------------------------
; MAP ACEL ENRICH FACTOR vs DIFF MAP
;
; DIFF MAP ABOVE MIN
;--------------------------------------------------
; MULT KPA diff
;----------------------------------
L8580: FCB 24 ; 9.375 0
FCB 32 ; 10
FCB 36 ; 20
FCB 40 ; 30
FCB 51 ; 40
FCB 64 ; 25.000 50

;------------------------------------------------------
; DIFF MAP for Acell Enrich Enable
;
; VAL = DIFF MAP * \(16/5\)
;------------------------------------------------------
; Kpa %TPS
;----------------------------------
L859A: FCB 10 ; 3.13 00.0
FCB 10 ; 3.13 12.5
FCB 10 ; 3.13 25.0
FCB 10 ; 3.13 37.5
FCB 10 ; 3.13 50.0



This is the stock ANHT.
What have you tried doing?, and what were the results?.
Often too aggressive of timing, can cause what seem to be AE problems.

ULTM8Z

Grumpy, thanks. What is the ANHT bin?

I'll try putting those values in and see what happens.


My timing is set at 10° BTDC at the distributor. On the tables, the closed throttle spark advance at idle is around 25° to 28°. Think that is too much?

I've gone richer and leaner trying to eliminate the stumble. But I haven't fooled around with the timing all that much. Any ideas?

87_TA

We have already been through this on your car a couple of months ago..
With mini ram you must Lower delta MAP vs AE and/or Raise TPS multiplier usually, Its very common with mini rammed cars.
Fisrt being sure your IAC counts and TPS voltage is correct .....

Also being sure your part throttle/idle blms are pretty close

ULTM8Z

I don't think that was me... it couldn't have been. I was so busy trying to diagnose that idle misfire that I wasn't at all tuning for performance.

I'll try your suggestion too.

BTW, I'm running an LT4 spark timing map. I found the LT4.lt1 file and used Tunconv to convert it to a bin file. Got hold of a $EE tdf and copied the spark map over to my own $8D bin. I figured since the two intake manifolds are nearly the same and my cam in't that much more radical, it's a good place to start.

I'll see if anyone on this board (who is successfully runnign a MiniRam can post their AE tables).

87_TA

https://www.thirdgen.org/techbb2/sho...hreadid=213914


Here is that post..
I happen to be running a Mini Ram.

Do you have any scan files of your car at Idle and low Rpm cruise?

Do you even have a scan tool?

Because in these two post you have been asked about your IAC counts and BLM and have not reponded to those questions.
I would give you my table values but only after I know everything else is right.

ULTM8Z

Yeah, I was asking about how those AE functions work, not about a noticeable stumble. At that time, I thought I had solved the misfire problem, but it turned out that wasn't the case. I'm actually getting performance data now (without the misfire) which is prompting this question. But anyway....

Yes, I have a scanner. It's an AutoXray so I'm able to record data for future reference. I can post the data for you to review, but I'll have to wait until I get home tonight in order to do it. I also downloaded Moates software, but my attempt at building a cable failed and have yet to get back to that. So far though, the AutoXray seems to be doing the job.

Your comment about the lack of runner velocity makes sense. I do notice it going quite lean in this particular RPM range during normal accleration from a standstill- O2 drops down to about .1 volt or less, which shoots the integrator up to 150-160 pretty quickly. As soon as I hit ~2000 rpm, everything goes back to normal. So I guess I'm just wondering how much additional AE enrichment is needed to eliminate the lean spot. Sounds like a considerable amount is needed, I don't want to just dump in all sorts of extra fuel on the AE circuit when the problem could be more fundamental in another area.

What I still need to do is a steady-state data log crusing at about 1500 rpm. I'll try to do it today and post everything this evening.

The TPS is set at .71 volts and the IAC at idle (in gear) is about 25-30 counts when fully warmed up. Spark timing is per my previous post. My BLM cells are functioning properly as well (something I just corrected last night through some digging in the archives here!). All of my sensors are functioning properly too- readouts on the scanner are all very reasonable and verifiable by gauges and ohmmeter/voltmeters. Fuel injectors are 24 lb/hr and the pressure is set at the factory rating. Throttle body is 52 mm. Lastly, there are no codes being thrown by the ECM.

Would you rather that I e-mailed all of this data to you, rather than post it all here?

87_TA

No need to do so,
I really wanted to make sure you where working at this and had some sort of direction.
Also was a good move at not just throwing all kind of fuel in.

The mini ram requires quite a sustancial amount of A/E fuel, but the biggest problem in my opinion is the -
A/E delta Map enable vs. TPS .
Which means it adds fuel after a given amount of vacuum is lost .

I will mail you my tables..
You really need to get a laptop working in order to tune your VE corectly-
It will take you years to do so with a hand held tool that does not display Map KPA or allow you to view more than 1 value at a time.

Not saying you cannot do it, but I have and it really really sux.
You can get away with a scan tool in a MAF car almost, but not a
SD.

Very well said!!!!

I will not be responsible for vehicle damage as a result of my tables - use at your own risk* and do not use as a crutch.
These are what works in my car with my combo.

*(HP)* is a trademark of 87_TA
Helping thirdgens go faster since birth.


EDIT: Opps , just realized you have that option disabled.
You will have to mail me your address.

ULTM8Z

Thanks! I just want to compare what works for someone else vs. what what I have. I may just inch up to your values little by little rather than everything at once. If it's one thing I've learned, incrementalism works best.

Actually, the beauty of the AutoXray is their PC link such that I can import the data into Excel and graph whatever values I want against any other of the values. In that way, I'm really not even looking at the scanner while I drive- I just come back and view it on my laptop later. Also, I can read MAP voltage and translate it into kPa as required.

87_TA

Well you can do so, and I guess you cold make a spreadsheet to automatically convert to KPA .

But Moates freeware will record data point by 10 per second
while showing everything at once and record for 45 minutes or longer of driving.
My laptop is to small for excel so I must transfer data via floppy,
45 minutes is about all I can fit on one.

But I still use my Auto-x for quick checks and ses lights, its very handy for that.

Greg

I'm running the MAF with my mini-ram but back to what Grumpy said about timing. I think that is a bit much. Mine is right at 20. I would take a little out there first. And then play with AE if you still have problems. With AE, one thing I had a problem with is the %change in TPS to enable AE. I had to lower that value or else the AE wasn't not kickin in until I gave it a bit more throttle(raised TPS). It felt like a stumble when that was happening.

poorboy8

Did you end up increasing or decreasing the values?