I have been attempting to tune my MAF/MRIII system but I am having issues, much like those that have already been mentioned, i.e., backfire through the intake, and poor part throttle driveability. I managed to get rid of the intake backfire by adding a hell of alot of initial timing (approx 18deg.), of course I am not attempting any WOT runs for now!
How can I increase the "pump shot" to prevent this lean backfire and possibly set the initial timing back to 10-12 deg.? I have the $32B code and there don't seem to be any AE tables specifically, I have BPW fuel vs. Load, Open loop F/A ratio%change vs Load and Open loop F/A ratio%change vs. coolant temp tables. These are AE essentially aren't they?
89 vette if you happen to read this, I would really appreciate your input since it seems that you have already dealt with this problem.
Thanks for your help!

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1987 383 cu.in. IROC-Z: TPIS MiniRamIII / GM FastBurn heads / Strange 12Bolt Diff./ Neil's Home-Built BulletProof 700R4+Vigilante 2800 stall converter
MSD Billet Distributor, Dig 6+, & Blaster coil / Hooker Supercomp Long tube headers

 

Neil, I feel for you. I have been suffering since last fall with this stupid Miniram. So much so that I wish I never installed it. The Super Ram has much better street manners than the ignorant Miniram. I am going to convert to speed density since most people seem to have better luck with tuning.

Anyway, there are 4 tables in the $32B code that affect AE or what I call pump shot.
AE factor vs delta LV8
LV8 AE mult. vs coolant temp
AE Enrichment decay vs coolant temp
AE Enrichment vs BPInj pulses

With the stock settings there is a dead spot when you goose the gas like the pump shot is missing. The problem I am having is that to get rid of the dead spot the motor runs lean AFTER the initial opening. For example: stating out in first, the car starts rolling fine then about 3 seconds later O2's drop to near zero for about another 3 seconds and the it recovers. Shift to second and the scenerio starts over again. You can actually feel the car running lean. This is especially evident while driving very slow in fourth gear with a high load on the motor. I had my decay values up to 90% at one time. So in essence I have not found that magical AE fuel table. It should not be this hard.

Since MAP will most likely be a winter project, I am still going to play with the AE fuel. I installed a ZIF socket in the memcal yesterday and I ordered the 29C256 flash proms so changes are not a 20 minute affair. You really need a working emulator for tuning like this but the flash proms will help a alot.

So after all this rambling, I would set the AE vs coolant temp to 25% where it currently has all zero's. Then play with the AE factor to put the fuel where you want it. The first two values seem to affect the backfire problem more than the upper ones. Email me your bin and I'll show you where to change the values.

As for very light throttle driving at low speeds, mine is rough also, like crawling through the grocery store parking lot. It's probably due to the Minrams poor low speed air distribution and/or the fact that the MAF is reading reversions. Trax claims that MAP systems are easier to tune and are more straight forward.

Let me know if I can help anymore.

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89 Six Speed FX3 coupe
More Performance 396cid specs:
Callies 4340 crank 3.875 stroke
Lunati Pro-Mod 5.85" rods
SRP Pistons 14cc dish
Comp Cams Custom cam 550 lift 220/229 duration
10.8:1 compression
AFR 195 competition ported heads
Miniram and TPIS 1 3/4" headers

[This message has been edited by 89vette (edited May 08, 2001).]

 

89 vette --Jason, am I right?

Thanks for your help, I will e-mail my bin to you tonight.
As for part of my driveability problems I found one. My intake gasket (intake port#1) is leaking. So, I humored myself and pulled out the roll of DUCT tape and amazingly it helped out, the hesitation is not as severe.

BTW what is your e-mail address?
Sounds like your MR problems are more of a headache than mine, so check out my bin when you get it, maybe it will help?

Thanks again

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1987 383 cu.in. IROC-Z: TPIS MiniRamIII / GM FastBurn heads/ 10.6:1 compression
Comp cams custom grind: Dur'n 224/236 Lift .536/.555
Strange 12Bolt Diff./ Neil's Home-Built BulletProof 700R4+Vigilante 2800 stall converter
MSD Billet Distributor, Dig 6+, & Blaster coil
Hooker Supercomp Long tube headers

 

If you really want to make it run like it should and have good street manners save up for a speed pro. There is no substitute for actual a/f readings with a wb O/2. You can have a near perfect program in a couple of days.

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87z 383,afr 190's, comp hyd roller(242/248-.540/.562,114 sep),Ported and polished mini ram, 30lb inj, 3.42 gears, tremec 5spd, , 1,3/4" slp headers, speed pro bank to bank-wb02.
"Just remember children, no man can beat you once youv'e found the cliterous." 'chef'

 

Jason is correct. Email is jwn@sgi.net

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89 Six Speed FX3 coupe
More Performance 396cid specs:
Callies 4340 crank 3.875 stroke
Lunati Pro-Mod 5.85" rods
SRP Pistons 14cc dish
Comp Cams Custom cam 550 lift 220/229 duration
10.8:1 compression
AFR 195 competition ported heads
Miniram and TPIS 1 3/4" headers

 

Tell me what one item a SP does that a gm doesn't. The WB is just a crutch. Or would you care to explain to how having it relates to an AE problem.
11.4 or 11.8 doesn't make a tinkers damn, those are numbers for humans. The engine responds best to what makes it happy.

Pulling some timing out faster for the transistion (to WOT) might help. Especially if at near the stall speed of the converter.

 

18d ain't excessive, some cars do well at 24.
Might try some more fuel pressure.
If you can find a set of 30#/hr GN injectors might try them.
Also, a LONG, intake tract pre TB might help. they aren't as performance robbing as you might think.

 

When you say 18* inital timing are you saying 18* BASE timing?

 

Yes, exactly!

 

one item a SP does that a gm doesn't. The WB is just a crutch. Or would you care to explain to how having it relates to an AE problem.
11.4 or 11.8 doesn't make a tinkers damn, those are numbers for humans. The engine responds best to what makes it happy.

Pulling some timing out faster for the transistion (to WOT) might help. Especially
if at near the stall speed of the converter.

[/B][/QUOTE]
Show me one 165 ecm that has a ae vs tps table? Yes I know your beloved 730 has it, but who wants to burn 200 chips to get the tip in right for a miniram? If you have lots of time and no money, than yea stick with a gm ecm. I dont see how a Wb o2 can be a crutch?? If anything its a perfect aid and time saver. Not flaming you but the speed pro is one of the best deals out there. If you have even ore money go with a motec. Tell me a gm ecm that even comes close.


[This message has been edited by 87Z-ya (edited May 17, 2001).]

 

Show me one 165 ecm that has a ae vs tps table? Yes I know your beloved 730 has it, but who wants to burn 200 chips to get the tip in right for a miniram? If you have lots of time and no money, than yea stick with a gm ecm. I dont see how a Wb o2 can be a crutch?? If anything its a perfect aid and time saver. Not flaming you but the speed pro is one of the best deals out there. If you have even ore money go with a motec. Tell me a gm ecm that even comes close.
[This message has been edited by 87Z-ya (edited May 17, 2001).][/B][/QUOTE]

A 165 set up as a 808 or a 730 will match em. Have you noticed tuning has been around long before WB O2s and Knock sensors?. It measuring performance that matters. A 11.8 AFR is meaningless if the engine runs best at 12.5. You have to hunt either way to find where the engine runs best.

Where's the lean cruise in the SP or Motec?.
No where in the US are either legal in a street car.

It takes 200 chips for someone to get clear on what they are REALLY doing, as well as that many changes with a SP. Your kidding yourself, if you think you can do a chip in 50 tries and be perfect.

Look for the timing offsets in the aftermarkets when using with a crank reluctor sensor.

Try and find a SP on a Sat Night.

Have you even read the mission statement of SP?
L8r

 

Who makes Speed Pro? and how much? Just curious.
I don't plan on switching b/c I just spent $$ on all the chip burning hardware and software.

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1987 383 cu.in. IROC-Z: TPIS MiniRamIII / GM FastBurn heads/ 10.6:1 compression
Comp cams custom grind: Dur'n 224/236 Lift .536/.555
Strange 12Bolt Diff./ Neil's Home-Built BulletProof 700R4+Vigilante 2800 stall converter
MSD Billet Distributor, Dig 6+, & Blaster coil
Hooker Supercomp Long tube headers

 

Fel pro carries the speed pro electronics line. However Ive heard rumor that comp cams has purchased this division?? I picked up my complete setup for 1900$

 

On the "200 chips" issue, I have to agree with Grumpy that a LOT of the initial chips is just part of the learning curve to of trying things and seeing how the engine responds to the changes. Also, a lot of it is just "experimentation".

I would say that for any "newbie", regardless of system, there will be a LOT of recalibrations just for learning purposes. The only exception is MAF cars, where if you car is not too radical, it is fairly easy to get a decent (though far from perfect) chip in a few tries. In this respect, I have to agree that I like working on MAF cars. But, in nailing it down PERFECTLY, I still like SD.

I personally enjoy doing all these tests and burning 200 eproms is fun for me. And, a LOT of those 200 burns were strictly experimenting; trying new things and even altering the actual machine code to make the ecm function the way I want it too, instead of the way GM wanted it.

I seriously doubt I could do that (alter the actual machine code) with any other setup as I wouldn't have access to the machine code or all the documentation that is available on the SD ecm. All the available documentation makes using the stock GM ecm very nice if you want to get SERIOUSLY into the ecm and alter it beyond simple parameter changes. Altering the actual instruction set takes eprom programming to a completely different level.

 

Glenn or anyone,

I am having problems in trying to get the car to run not so rich, especially at idle and part throttle (The Integrator fluctuates from 118 down to 95 and back to 128 w/ a light touch of the accelerator).
Just a reminder, I am using a $32 code. Of the tables which are available for me to modify in Tunercat, I thought the BPW vs. load(RPM) table would give me good results. It didn't! The table is setup with Air flow (GPS) vs. RPM and injector pulse width is the variable parameter. I decreased the IPW and did not see any difference in the integrator response. Why is that? Should I also be playing with the Mass Air Flow tables #1-6?


------------------
1987 383 cu.in. IROC-Z: TPIS MiniRamIII / GM FastBurn heads/ 10.6:1 compression
Comp cams custom grind: Dur'n 224/236 Lift .536/.555
Strange 12Bolt Diff./ Neil's Home-Built BulletProof 700R4+Vigilante 2800 stall converter
MSD Billet Distributor, Dig 6+, & Blaster coil
Hooker Supercomp Long tube headers

 

Have you considered converting to the 6E and dumping the cold start injector?

 

Actually, I am using this chip without a cold start injector and start up is not a problem.
Regarding the $6E code, how would I convert to it from a $32B code? Does the $6E offer more in the way of tables and adjustments?

 

The ARAP BIN (6E) is a very nice bin. I found its MAF Scalar tables to be almost bang on. It's high part throttle spark advance necessitates an EGR, but you can easily cut back the timing for your Miniram setup.

The 6E.TDF has more constants and tables defined, and if you see my other post on the "experimental" 6E TDF, there is even MORE constants and tables defined for the 6E.

 

Glenn, that sounds good. Thanks for your help. Also, do you know by chance if I can simply down load the $6E ECM definition file for the Tunercat software, or will I have to purchase this?