So I've been struggling with a code 33 for some time now. The car runs and I don't think it's in limp home mode. I notice a slight hesitation when I let off ... that's all.

Then yesterday it began to start for a second and stall several times before it finally began to run OK. When It began to run OK it throws the codes (now 33 AND 34).

So after replacing both the MAF power and burnoff relays I broke down and bought a new MAF. New MAF produced the following results:

Hard to start unless I revved it.
Still drives with the same hesitation when backing off the throttle.
Throws a Code 33 only.

Got an FSM and time to work on it.

 

I would suggest a data-driven approach.

Beg, borrow or steal an 87-88 $32B or 89 $6E memcal (or better yet, get a G1 adaptor, eeprom and program it yourself) , so that you can easily log data at 8192 baud for test purposes.

From there you can see the MAF signals as seen by the ecm. Start fresh with no codes and record until the error code 33 is set.

Code 33 (maf high) means that the unlimited airflow has exceeded 45 gm/sec under 1 of 2 conditions, either at startup or due to an implausible combination of rpm and tps voltage.

Root cause may just be a mis-adjusted tps or open MAF signal circuit, but let's not jump to conclusions without some data first.

Once a MAF error is set, the maf sensor (voltage-based airflow) signal is replaced by the default airflow calculation which isbased upon tps, rpm and IAC position + an offset value for closed throttle and zero IAC count airflow.

 

So All I need is another memcal to go 8192 baud? No rewiring the ALDL?

 

That is correct. 86 bins are missing a few bytes in the serial data initialization routine compared with the 87-88 and 89 bins. No hardware changes required.

Due to spark advance differences, an 87 bin may be a better fit for a 128 aluminum head car, so I would start there.

 

Mine does this occasionally, which seems to be related to a throttle cable that needs to be replaced. Once I had it adjusted, no more Code 33s showed up. Just something worth checking.

 

I've been told by an ECU expert that the 1989 bin is a much better replacement for my hypertech. I think that's an ARAP $6E bin.

I'll have to disconnect the cold start injector because the '89s do that function with clever programming. I think I have to put a 10K resistor across AB and move the signal wire to get 8192 baud output.

I wouldn't mind having the 160 degree fan temps on and VATS programmed out. I live in florida.

Thanks,
Robert

 

ARAP or equivalent will work. $6E's Highway mode fueling may offer a minor fuel economy benefit compared to the previous bins.

You can see an example of highway mode fueling here where the target AFR steps up (target AFR, WBO2 and injector pw signals shown to illustrate effect):

https://datazap.me/u/tequilaboy/felix-log-0?log=0&data=16-33-37&zoom=5465-5869

Note: you can zoom in/zoom out add and remove display signals as desired and view entire log if interested.

You can see how the fuel control actually improves (less error relative to target AFR) since the integrator is reset/inactive upon entry into highway mode:

https://datazap.me/u/tequilaboy/felix-log-0?log=0&data=5-16-17-33-37&zoom=5465-5869&mark=5752

Hard to show everything at once since the signal scaling changes to fit the max signal displayed.

10K resistor will be needed to connect, but no need to move signal wire. Data is on pin E.

ARAP is a 3.07 gear bin, so things like the tcc lock/unlock speeds and 4th gear n/v ratio max/min values will be a bit different than your original 2.73 gear bin. From what I recall, your Hypertech was based on a 3.07 bin, so you probably already have these (minor) issues now.

Spark advance may be a bit more aggressive than before, so consider running a 91-93 octane fuel if you're not doing so already. Edit: Disregard. See spark advance comparison in post #8 below.

I've re-written a couple 86 bins such as BUA and BUB to improve 8192 baud connectivity. These are intended for those that really need or want to run an 86 bin in their 86 car, like an iron head 4+3 car with it's unique switch wiring and control logic.

For an auto trans aluminum head car, I think it makes more sense to just run a newer bin as proposed.

 

Spark Advance table comparison: 1987 ABTD vs 1989 ARAP for reference. A little tough to read in this format, but values appear to be identical.

So no need to worry about spark advance differences. Sorry if my previous post was misleading.

TABLE: Spark Advance Table ABTD

RPM Load Variable LV8
32.00 48.00 64.00 80.00 96.00 112.00 128.00 144.00 160.00 176.00 192.00 208.00
4800.00 47.11 47.11 47.11 45.00 40.08 39.02 37.97 35.16 35.16 35.16 35.16 35.16
4400.00 47.11 47.11 47.11 45.00 40.08 39.02 37.97 33.05 33.05 33.05 33.05 30.94
4000.00 47.11 47.11 47.11 45.00 40.08 39.02 37.97 30.94 27.07 27.07 27.07 27.07
3600.00 47.11 47.11 47.11 45.00 40.08 39.02 37.97 30.94 26.02 23.91 23.91 23.91
3200.00 47.11 47.11 47.11 46.06 41.84 41.13 37.97 30.94 26.02 22.85 22.85 22.85
2800.00 48.16 48.16 48.16 47.11 47.11 43.95 43.95 37.97 29.88 27.07 24.96 22.85
2400.00 48.16 48.16 48.16 47.11 47.11 46.06 43.95 41.13 35.86 30.94 27.07 24.96
2200.00 48.16 48.16 48.16 47.11 47.11 46.06 43.95 41.84 36.91 30.94 28.13 27.07
2000.00 48.16 48.16 48.16 47.11 46.06 45.00 43.95 41.13 37.97 30.94 28.13 26.02
1800.00 46.06 46.06 46.06 46.06 46.06 43.95 41.13 41.13 39.02 28.83 24.96 23.91
1600.00 43.95 43.95 43.95 43.95 41.84 41.13 37.97 34.10 31.99 28.83 24.96 23.91
1400.00 41.13 41.13 41.13 41.13 40.08 39.02 37.97 35.16 34.10 28.13 22.85 21.09
1200.00 29.88 34.81 40.08 40.08 40.08 37.97 35.86 31.99 29.88 26.02 22.15 20.04
1000.00 20.04 29.88 40.08 37.97 35.86 34.10 34.10 28.13 26.02 23.91 20.04 20.04
800.00 20.04 20.04 29.88 29.88 29.88 29.88 27.07 26.02 23.91 20.04 20.04 20.04
600.00 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04
400.00 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04


TABLE: Power Enrichment Mode Spark Advance ABTD

RPM Degrees

4800 1.05
3200 9.14
2000 1.05
1200 1.05
400 0.00

TABLE: Spark Advance Table ARAP

RPM LV8
32 48 64 80 96 112 128 144 160 176 192 208
4800 47.11 47.11 47.11 45.00 40.08 39.02 37.97 35.16 35.16 35.16 35.16 35.16
4400 47.11 47.11 47.11 45.00 40.08 39.02 37.97 33.05 33.05 33.05 33.05 30.94
4000 47.11 47.11 47.11 45.00 40.08 39.02 37.97 30.94 27.07 27.07 27.07 27.07
3600 47.11 47.11 47.11 45.00 40.08 39.02 37.97 30.94 26.02 23.91 23.91 23.91
3200 47.11 47.11 47.11 46.06 41.84 41.13 37.97 30.94 26.02 22.85 22.85 22.85
2800 48.16 48.16 48.16 47.11 47.11 43.95 43.95 37.97 29.88 27.07 24.96 22.85
2400 48.16 48.16 48.16 47.11 47.11 46.06 43.95 41.13 35.86 30.94 27.07 24.96
2200 48.16 48.16 48.16 47.11 47.11 46.06 43.95 41.84 36.91 30.94 28.13 27.07
2000 48.16 48.16 48.16 47.11 46.06 45.00 43.95 41.13 37.97 30.94 28.13 26.02
1800 46.06 46.06 46.06 46.06 46.06 43.95 41.13 41.13 39.02 28.83 24.96 23.91
1600 43.95 43.95 43.95 43.95 41.84 41.13 37.97 34.10 31.99 28.83 24.96 23.91
1400 41.13 41.13 41.13 41.13 40.08 39.02 37.97 35.16 34.10 28.13 22.85 21.09
1200 29.88 34.81 40.08 40.08 40.08 37.97 35.86 31.99 29.88 26.02 22.15 20.04
1000 20.04 29.88 40.08 37.97 35.86 34.10 34.10 28.13 26.02 23.91 20.04 20.04
800 20.04 20.04 29.88 29.88 29.88 29.88 27.07 26.02 23.91 20.04 20.04 20.04
600 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04
400 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04

TABLE: Power Enrichment Mode Spark Advance ARAP

RPM Degrees

4800 1.05
3200 9.14
2000 1.05
1200 1.05
400 0.00

 

So I found a gentleman that will flash my chip to the 89 ARAP but I don't want to send him my hypertech chip since I want to sell it. Does anyone know what the electronic base part number is to the prom used? Acdelco 16134193 ARAP4194 is the part number for the flashed prom from the factory. What is the part number of a blank prom?

 

I'm not aware that you can buy a memcal with a blank eprom, but you do have several options.

You can buy any compatible (86-89) used memcal and have it erased and reprogrammed with whatever you want. You can have somebody read, erase and reprogram your existing hypertech with whatever you want. You can use a Moates G1 syle adaptor or equivalent with a new eeprom and any compatible memcal (which you already have).

The programming on the hypertech is pretty much worthless. Its nothing more than a stock bin with edited fan on/off temps and maybe a degree or two of extra spark advance here and there. Might be interesting for academic purposes, but that's about it. A serviceable memcal does have some value, so it is what it is.

I would suggest spending a few bucks (about $125 total) on a programmer, a new eeprom and a G1 adaptor. Program it yourself, plug in the old hypertech memcal to the G1 adaptor for limp home and be done. This will also empower you to retune for any future changes should the need arise. Might as well jump in with both feet.

The cheapest route would be simply reprogramming the hypertech or buying a G1 and having somebody program a new eeprom for you (assuming a modest fee to erase, program and ship it figure about $75).

My own approach is a bit different, since I use a socketed memcal in lieu of any adaptors, so I can either plug in a new eprom or eeprom directly to the memcal or use an ostrich for emulation. If you have a spare memcal and soldering skills this is the best option.

 

There's got to be a base chip for such a popular product. It turns out that I found the number 27C128 with a Vpp of 12 V obsolete on most sites I've checked so far.

 

Here's a csv export of an 8192 baud log from a stock BUA_1728 bin recorded in an 86 car with ign on and engine off. Note: this car has too many mods to run correctly on the stock chip, so this was only a static test with key on/engine off to test connectivity.

This log shows that it is at least possible to connect and log an 86 bin at 8192 baud in an 86 car, so give it a shot before you move on to a later bin. Be sure to use a proven *.adx file.

Updated: new information has come to light. The 86 car that was used for this datalog has an 89 digidash but that would not be expected to influence the results, since the dash only receives 5 bytes of 160 baud data from the ecm for control of the shift light, od indicator (or cags) and provides cylinder, injector, fuel and distance info for the mpg display under normal operation (not in aldl mode).

Note: I've never been able to get a stock 86 bin to connect in my own 88 car, so I was surprised by this result.

Bin also attached for reference.

Also attached is a modified version of BUA_1728 with changes that allow it to connect at 8192 baud in my 88. This bin has not yet been tested in an 86 car, but may offer improved connectivity.

 

 

Replaced the MAF power relay & Burnoff relay which cured the codes 33 and 34 but triggered a code 36 and went back to my original MAF which cured the code 36. I guess I need to go back and get a new MAF since I just paid $130 for the one that threw a MAF burnoff 36 failure. Always good to have spares I think.

Thanks All!