ULTM8Z

EDIT - please skip to post #41. This thread has gotten too long for it's own good. #41 has the short-story summary.

ULTM8Z

WTF? The fan is on at 65 mph? I have it set to go off at 35 mph.

What am I missing here? Is the ECM going bad or something?

Dominic Sorresso

Don't forget that what your scantool is showing is what is commanded, not necessarily what's actually happening. Bad injector perhaps?

ULTM8Z

Understood. Yeah this all taking about commanded AFR. The commanded AFR is what's fluctuating around.

RBob

iTrader: (1)

In $8D there isn't a MPH off for the fans when they are on due to high coolant temperatures. The MPH values are for when the fan(s) are on due to the A/C system being active.

Place this byte into the data stream:

L0040 EQU $040 ; DIAG MW1
; b7 = map low error in effect, malf 34
; b6 = map high error in effect, malf 33
; b5 = tps high error in effect, malf 22
; b4 = aldl blink out mode
; b3 =
; b2 = tps low error in effect, malf 21
; b1 =
; b0 = mode 10 cmd cleared errors

See if any of the MAP or TPS bits get set. If so that can cause the ECM to drop out of PE mode.

RBob.

ULTM8Z

Edit... double post.

ULTM8Z

RBob, thanks for the reply. Dumb question, but how do I do this in Tunerpro? I'm hex ignorant.

As it stands, the real time data doesn't show the MAP and TPS voltages dropping out when the AFR switches back and forth between stoich and PE.

The data stream does currently read out TPS Low and TPS High (22 and 21, respectively), and I don't see those getting set.

The bin I have loaded into Tunerpro has all the sensor diagnostics enabled in the switches, including MAP High (33) and MAP Low (34). So I'm curious why Tunerpro isn't already reading those out in the datastream.

I switched out the ECM for a spare, then drove the car into work today. It didn't solve the problem.

I can feel the car lurching forward under PE when the AFR goes to the commanded value. On an open stretch of road I put my foot into it and glanced back and forth at the AFR on the Tunerpro dashboard watching it jump from 14.7 to ~12.95 and back again every second or two or three.

I will say this though....the Inv MAT Lookup and TPS scale factor improvements are working fantastically... For the brief moments when the AFR is correct, I've never felt it pull that hard before. When this PE drop out thing is fixed, this car is going to be a rocket (at least relatively speaking)...


Regarding the fans, that is very curious. I went back and looked at the data stream. When I'm speed and the coolant temp hits the fan ON temp, the fan does indeed get requested. I'll have to raise the fan temperature I guess to where I don't hit that temp while at speed.

RBob

iTrader: (1)

Need to add it to the xdl file, how to do that I don't know. Don't use Tuner Pro for logging.

The data stream will only show a code that is stored, which can take 20 to 30 seconds of malfunction time before it does. So an intermittent issue won't set the SES or set the code.

The bits above in DIAG MW1 are usually set immediately upon the ECM thinking there is an issue. And, the ECM uses those bits to decide what to do. Here is where you lose dTPS AE on a TPS error:

The test for high MAP, code 33, is also dependent upon the TPS error bits being clear. If either are set, no test is done for a high MAP malfunction.

Here is where PE mode from the TPS% is disabled on a TPS error:

The ECM will still check the manifold vacuum for PE mode, but if the vacuum is too high the ECM won't enter PE mode. Note that the pseudo baro read will affect this if it isn't correct.

RBob.

ULTM8Z

One thing that dawned on me just now is the pick up coil and how the ECM reads the engine RPM.

I recently had to put a filter on my tachometer due to the needle bouncing around above 3500 rpm. Autometer had told me that they were receiving complaints about erratic tachometer operation and they think it's due to aftermarket pickup coils generating noise that's affecting the electronics.

I'm wondering if somehow the pickup coil is degrading over time and now it's affecting the ECM as well. The PE issue does seem to impact the same RPM range as my tachometer...

I have another pickup coil I'm going to try to swap in this weekend.

RBob

iTrader: (1)

I would suspect that a pickup coil issue would show up in the RPM value. It too would jump around some.

RBob.

ULTM8Z

Probably right... I'll go back and take a look at the data.

ULTM8Z

Well the pickup coil wasn't it.

I'll need to figure out how set those bits you were mentioning...

If it's the MAP or TPS, it isn't showing up in the real time voltage data...

ULTM8Z

Here's a sample of my data...


Note how the inj pulse with is completely incongruous with the commanded AFR... Sorry about the scrunched up columns...

The engine RPM looks a little erratic, but swapping out the pickup coil didn't seem to make any difference. But I did feel lurching during this PE test...

1.) Engine Speed RPM

2.) Injector BPW (ms)

3.) Target AFR

4.) %TPS

3875 5.28 13.24 32.03
3925 6.55 13.24 34.77
3850 6.32 14.73 41.8
4175 8.06 14.73 44.92
3950 6.84 13.19 44.92
4050 8.03 13.19 46.88
3950 7.22 13.19 48.05
4200 7.22 13.13 50
3950 8.36 14.73 53.13
4150 7.48 13.13 55.86
4075 8.07 14.73 66.8
4375 7.71 13.05 67.19
4175 7.78 13.13 67.97
4175 9.02 14.73 68.75
4125 8.97 14.73 70.31
4225 9.03 14.73 71.88
4175 7.81 13.05 72.27
4475 9.11 14.73 72.27
4225 9.08 14.73 73.05
4200 7.86 14.73 73.05
4325 9.08 13.05 73.05
4175 9.08 14.73 73.83
4300 7.81 13.05 73.83
4250 9.25 14.73 73.83
4375 9.19 14.73 73.83
4300 9.09 14.73 73.83
4575 7.78 14.73 73.05
4250 7.83 14.73 72.27
4375 9.12 14.73 72.27
4350 9.23 12.95 71.88
4475 7.83 14.73 72.27
4425 9.17 14.73 74.22
4475 9.28 12.95 79.3
4475 9.34 12.95 81.25
4575 9.37 12.95 83.98
4700 9.43 12.95 85.94
4425 9.43 12.95 86.33
4600 9.43 12.95 86.33
4550 9.43 12.95 86.33
4600 9.43 12.95 86.33
4625 9.52 12.95 86.33
4600 9.51 12.95 87.11
4625 9.43 12.95 87.11
4625 9.43 12.95 87.11
4650 9.57 12.95 87.89
4900 9.57 12.95 87.89
4725 9.43 12.95 87.89
4725 9.41 12.95 87.89
4650 9.43 12.95 87.89
4675 9.51 12.95 87.11
4775 9.48 12.95 87.11
4725 9.41 12.95 87.11
4700 9.37 14.73 82.81
4675 7.83 12.95 73.83

Dominic Sorresso

I can see where it drops in and out of PE. Do you have the associated MAP readings?
Also, what's the TPS% for PE set at. You have PE at ~ 30% TPS?

ULTM8Z

I'll check when I get home tonight. But I believe it's set to 30% above 3500 rpm.

Also I don't recall seeing anything anomalous in the MAP data. I'll look again.

ULTM8Z

MAP looks pretty stable.... This would be the column lining up with the others...

The time differential between one value to the next is only about 100 msec... So unless something is invisibly happening in between every sample, I'm not seeing how the MAP is causing this.

TPS is rock solid, MAP is rock solid, I'm completely stumped here... What else could the PE depend on that we're missing?

69.39
73.08
79.73
84.15
84.52
85.63
86.74
87.47
89.69
91.16
93.75
94.12
94.86
94.49
94.12
94.86
94.86
95.22
94.86
94.86
95.22
94.86
95.22
94.86
95.22
94.49
95.22
94.49
94.86
94.49
94.12
94.49
95.96
95.59
95.96
96.33
95.96
96.7
96.33
96.33
97.07
95.59
96.33
95.96
96.7
96.33
96.33
96.33
95.96
95.59
95.96
95.96
95.22
93.75

ULTM8Z

Ok, one thing I'm noticing is that the Learn Control is becoming enabled during PE. In past data logs, it remains disabled during PE (which I think it's supposed to be).

Does that mean anything significant here? Though it doesn't correlate with incorrect AFR values.

Enabled 13.24
Enabled 13.24
Enabled 14.73
Enabled 14.73
Enabled 13.19
Enabled 13.19
Enabled 13.19
Enabled 13.13
Enabled 14.73
Enabled 13.13
Enabled 14.73
Enabled 13.05
Enabled 13.13
Enabled 14.73
Enabled 14.73
Enabled 14.73
Enabled 13.05
Enabled 14.73
Disabled 14.73
Disabled 14.73
Disabled 13.05
Disabled 14.73
Disabled 13.05
Disabled 14.73
Disabled 14.73
Enabled 14.73
Enabled 14.73
Disabled 14.73
Disabled 14.73
Disabled 12.95
Disabled 14.73
Disabled 14.73
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 12.95
Disabled 14.73
Disabled 12.95

RBob

iTrader: (1)

The PE mode loop is running at 80 times a second, every 12.5 msec. This is why you see at times the cAFR & drop in PW not always lining up. See this graph of the first post of data.

RBob.

ULTM8Z

Does the enable/disable toggling tell me anything about cause? Or is merely a symptom?

RBob

iTrader: (1)

I don't understand the toggling you are asking about. The bits in DIAG MW1 will tell you what the ECM is doing. If you see either of the TPS or MAP bits being set, there you go.

RBob.

ULTM8Z

It's the Learn Control toggling between enabled and disabled as shown in the datastream. It seems that it should stay disabled during PE, but for me, it's toggling to enabled.

Was just curious if that's a clue to the cause or a symptom of it.

Any rate, yeah, I'm itching to see what these TPS and MAP bits have to say...

RBob

iTrader: (1)

Going into learn mode is a symptom of dropping out of PE mode.

RBob.

Dominic Sorresso

Just curious but have you looked at what's going on w the NB O2?

ULTM8Z

There are leaner areas than others, but I always here people say the accuracy diminishes the farther you are away from 450 mV, so I'm not reading a whole lot into this piece of the data... All I'm taking away is that I'm not going "lean" during PE...

919.36
937.04
945.88
937.04
897.26
875.16
839.8
848.64
923.78
910.52
910.52
884
888.42
861.9
879.58
870.74
879.58
861.9
853.06
879.58
870.74
879.58
853.06
879.58
866.32
884
875.16
866.32
879.58
870.74
848.64
897.26
937.04
928.2
923.78
914.94
914.94
910.52
923.78
910.52
914.94
914.94
914.94
914.94
1025.44
919.36
919.36
914.94
914.94
910.52
914.94
914.94
906.1

Dominic Sorresso

True. I was curious to see if maybe the NB was causing u to fall out of PE.

ULTM8Z

The data seems to indicate that things are going awry above 3500-4000 rpm. THat's when the Inj BPW and commanded AFR seem to start doing funky things.

ULTM8Z

Dug up a spare TPS sensor and put it on. Still not solved.

Edit: Just put a vacuum pump on the MAP sensor and pulled almost 1 atmosphere on it. Monitoring it on the ALDL, it drops by ~2 millivolts every 5-10 seconds (likely some leakage in the test set up), but nothing that would indicate a problem by any means.

So, it's not the ECM (replaced with another one), not the pick up coil (replaced with another one), not the TPS, and not the MAP sensor.

Color me stumped...


Nonetheless, many kudos and thanks to RBob who's been helping me via e-mail the last couple of days. Folks like him are what make this hobby even possible for folks like me....

ULTM8Z

Very curious thing this morning...

As I was telling RBob in an e-mail exchange...

Having essentially ruled out the hardware (though he's not 100% convinced of that yet), I started thinking it's in the calibration. So I undid the last known major change- the BDZL Inv MAT Lookup table. Put it back to ANHT.

Did three WOT runs and now there's no indication of dropping out of PE (either in the data or in seat of the pants feel for the lurching). AFR holds at commanded value and the learn control stays disabled. The only problem is I'm down on power... the car REALLY liked the values from BDZL at non-PE/non-WOT operation.

So WTF is going on here? Question of the day... how does MAT relate to engaging or disengaging PE mode? Anyone familiar with the ANHT hac can take a stab at that?

ULTM8Z

Ok, so here's a WTF for the record books...

Turns out $8D doesn't like the specific value .102 for 240 and 256 gm/sec on the Inv MAT table that the $DA3 has. Other than that, my car absolutely loves the $DA3 table.

Any rate, I recalled that I had run GrimReaper's MAT table in the past with .07 as the value and had no PE drop out issues.

So I put that back in and PE holds solid as a rock with commanded AFR's matching the calibration exactly.

Then I went up to .09, then .100.... same thing, no dropping out.

I put .102 back in and boom... intermittent PE drop outs!

What's the deal with .102?

Maybe someone with an ECM bench can see if they can duplicate this because I don't @#$%-ing get it.

Overall, substantively it doesn't matter really since the car really likes the new values .09 @256 gm/sec and .1 at 240 gm/sec.

I'm just super curious after that huge headache I went through...

Hopefully in the next few weeks I'm going converge on an updated Miniram start bin I can release.

Dominic Sorresso

I had one of those. ECM would go closed loop BUT LEARN would never activate.
Finally narrowed it down by trial and error. The O/L AFR v CTS values had to be > or = the Coolant Compensation Bias value. Thank goodness I had an Ostrich.

norcalz28

iTrader: (13)

Great info!

ULTM8Z

Well, this thing has reared it's ugly head again.... except repeating the solution I used last time in post #29 doesn't seem to work this time. The car runs excellent (I really don't feel it, but just happened to be running Tunerpro and noticed the commanded AFR bouncing around...

Basically the commanded AFR osicllates between stoich and the PE value every 1/2 second or so while I'm in PE.

But the learn control seems to bounce around randomly at various times between enabled and disabled, no apparent rhyme or reason, even when I'm not trying to be in PE.

I don't see any fluctuation in MAP or TPS voltages...

Also pulled up the SAUJP_V5 xdl and looked at all the error bits. Everything looks ok.

Not sure what else helps the ECM determine to go into PE...(and stay there)...

Now, the WB doesn't seem to be picking up this oscillation. But it may not be reacting fast enough? It's not hooked into Tunerpro (yet). But just glancing at it while I'm driving.

I have the log file if anyone would be kind enough to take a look at it...

ULTM8Z

Maybe I'll try disabling the map and tps high and low error flags and see what happens.

ULTM8Z

Question... so I went into Tunerpro to start disabling the MAP and TPS error bits. I'm using the SuperAUJP_V5 xdf file...

Is it the case that if I go to bits for ERR21, ERR22, ERR33, and ERR34, and then uncheck the "set" in those, that it'll disable them?

If not, then what is the other approach?


One curious thing that seems like it could point to the MAP error bit being the culprit...

There's a scalar entitled ERROR QUAL 22, TPS Voltage-Min Qual Time, which is set to 1/2 second. The 1/2 second is interesting because it seems to match the oscillation period in which the commanded AFR is bouncing between commanded PE value and the stoich value. It'll be interesting to see what happens when this error bit is disabled.

RBob

iTrader: (1)

Masking out the malfunctions doesn't prevent the ECM from using default values. It only prevents the SES/CEL and stored code.

Check the value at this location and then check the TPS voltage itself:

L8260: FCB 246 ; IF TPS A/D VAL > SET ERR 21A

If the TPS voltage is higher then it the ECM will start to set code 21 (TPS Hi).

But you need to look at the mode word I posted above to see this.

Can also set the TPS timer to 3 or 5 seconds to see if that changes things.

RBob.

ULTM8Z

Looks like there are three mode words for 21A... not sure how they all play together, but in using the SAUJP XDF file, and looking at what's in my bin... I'll say this... everytime I encounter one of these wierd problems, it does force me to dig deeper into the code (so I guess one positive aspect about encountering them).

ERROR QUAL 21A, TPS Voltage-Max A/D Value - set to 4.82V

ERROR QUAL 21A, TPS Voltage-Min A/D Value to Enable - set to 2.51V

ERROR QUAL 21A, TPS Voltage-Min Air Flow To Enable - set to 15 g/sec

Looking at my tunerpro data, my TPS voltage hits 3.8V and considers that to be 100% TPS, even during periods where the PE dropout is occurring. So, it doesn't appear that my TPS is tripping the error...

In fact, just for information sake, here's all of the TPS and MAP error MW's... with what I believe are the facotry settings

0x264 ERROR QUAL 21, TPS Voltage-Default TPS% if Error 21 - set to .94V

0x262 ERROR QUAL 21, TPS Voltage-Min Qual Time - set to 3 sec

0x260 ERROR QUAL 21A, TPS Voltage-Max A/D Value - set to 4.82V

0x261 ERROR QUAL 21A, TPS Voltage-Min A/D Value to Enable - set to 2.51V

0x263 ERROR QUAL 21A, TPS Voltage-Min Air Flow To Enable - set to 15 g/sec

0x265 ERROR QUAL 22, TPS Voltage-Max TPS Value - set to .23V

0x267 ERROR QUAL 22, TPS Voltage-Min Qual Time - set to 12 sec

0x283 ERROR QUAL 33, MAP Voltage-P/N HI MAP/BARO Ratio Thresh - set to 0.85 MAP/BARO Ratio Threshold

0x284 ERROR QUAL 33, MAP Voltage-In Gear HI MAP/BARO Ratio Thresh - set to 0.85 MAP/BARO Ratio Threshold

0x285 ERROR QUAL 33, MAP Voltage-Min TPS% to Set Error - set to 1.95%

0x286 ERROR QUAL 33, MAP Voltage-Min RPM to Increment Timer - set to 500 rpm

0x287 ERROR QUAL 33, MAP Voltage-Error if Time > - set to 0.5 sec

0x288 ERROR QUAL 34, MAP Voltage-HI/BARO LO Ratio Thresh (calc ??) - set to .15

0x289 ERROR QUAL 34, MAP Voltage-Min RPM for Error - set to 1200 rpm

0x28A ERROR QUAL 34, MAP Voltage-Min TPS% to Enable Test - set to 10.16%

0x28B ERROR QUAL 34, MAP Voltage-Min Qual Time to Enable Test - set to 0.050 sec

0x28C ERROR QUAL 33/34, MAP Voltage-Default MAP kPa Error - set to 90.8 kPa

0x28D ERROR QUAL 33/34, MAP Voltage-Default MAP Coefficient - set to 28.1 kPa %

ULTM8Z

Well I set ERROR QUAL 21 and 22 to 25 seconds each, but no change. Not sure if that tells me the TPS is not the issue?

Maybe I'll try the MAP stuff next...

Anyone have any suggestions?

ULTM8Z

I played around with the MAP Error 33 and 34...

First, I set ERROR QUAL 33, MAP Voltage-Min TPS% to Set Error to 99%. No effect... That should have delayed the MAP Error 33 test by the ECM until I get to 99% throttle, but I can get to part throttle PE well before 99% TPS, so it seems to indicate that it's not an Error 33.

Then I set the ERROR QUAL 34, MAP Voltage-Min TPS% to Set Error to 99%. Again no effect...

I also started a brand new bin to see if it was some corruption of my current bin... again no effect.

At this point, I don't know WTF is going on... I don't even know when this even started.

Something is causing the PE to cycle in and out every 100 to 200 msec. I thought it was a 1/2 second just from watching the digital dash, but the data is showing about 100 to 200 msec.

Anyone have any ideas? I'm going bonkers with this damn thing...

ULTM8Z

Had a chance to play around a little more. I can't freaking figure this out.

The damn thing is still cycling in and out of PE every 200 milliseconds. WTF?

What is significant about 200 ms in the code? The data shows rock steady MAP and TPS values while in PE. No signs of fluctuating values.

No codes being set, no bits being set for high or low MAP/TPS values. Different ECM didn't make any difference.

I don't want to start throwing parts at this thing... does anyone have any idea? Anyone mind looking at the data?

MrWillys

I'm not going to read threw this entire thread. Do you realize that that if TunerPro sees a lean condition it calls for a richer AFR? Look at your O2 Voltage and not AFR. .860 to .900 at WOT is where you want to be. Also look at History table averages. Scott

ULTM8Z

It is a long thread.... Here's a quick summary...

For some reason, when I enter into PE mode, the ECM is basically cycling in and out of PE mode every ~200 ms. I'll see the commanded AFR cycling between say 12.5 and stoich every ~200 ms.

I'm thinking the ~200 ms has to be some sort of clue...

The tunerpro data indicates that the TPS and MAP values stay rock solid (nothing bouncing around in terms of voltages). No codes being set, no error bits being set.

Nothing I've done has made any difference...

- Gone back to earlier calibrations
- Started over with a fresh calibration
- Disconnected the Ostrich emulator and ran directly of the EPROM
- Tried a different ECM
- Changed the error bit set parameters for high/low TPS/MAP to try to fool the ECM to ignore any potential TPS/MAP issues during PE mode
- Tried a different TPS sensor
- Checked the wiring and grounds

The only thing I haven't tried is a different MAP sensor because I don't have a spare sensor and am hoping to not have to start blindly throwing parts at the car hoping to find the problem.

Any rate, I'm desperate here...

RBob

iTrader: (1)

The major loops (16 of them) run every 100 msec. Some of them run alternately on each call to the routine. IOW, every 200 msec.

You are running SAUJP, correct? If so that is a modified form of $8D, so there is some custom code in there. Try running a y-body $8D code such as AXCN, which is for stick shift cars.

RBob.

ULTM8Z

Actually my base calibration is ANHT. I start from there to do my mods for the Miniram.

I do run SAUJP_V5 for the Tunerpro xdf and adx though, which give a lot of visibility on what the ECM is doing/seeing.

RBob

iTrader: (1)

OK, so it is straight GM firmware, no mods? For some reason I thought you were running a stick trans, with the auto ANHT is a better choice.

Also, I'm not sure about using the SuperAUJP XDF file. SAUJP is a modified version of AUJP, I'm not sure if all of the calibration is still in the same locations. All it takes is a single byte shift and you will be editing the wrong parameter.

A symptom of this is:

If the XDF is incorrect, you aren't editing the correct locations. You are editing something else.

RBob.

ULTM8Z

Yes, no mods. Everything is straight-up GM. Automatic trans.

I actually use TunerCat to do the mods to the chip. Have been since the beginning of time. I only use Tunerpro to take data.

I'm not sure what the Inv MAT table played into it last time. I've tried playing with the values again, but no effect.

One other thing I notice in the data is that the learn control is randomly coming in and out as well, but not corresponding to how the PE mode cycles in and out. When things were running properly, learn control would be on until I entered PE mode, at which point it would go off and stay off until I exited PE.

But I don't know if this is a symptom or a cause at this point...

MrWillys

I would run the $8D ADX and see if it still has the same symptom.

ULTM8Z

Yeah, I've done that as well. Thing is, I can see the AFR going lean on the WB when I get really into the throttle, so it's kind of an independent check that tells me Tunerpro isn't "lying" to me.

I've also taken earlier datalogs (viewed with both a standard $8D and SAUJP adx) which didn't exhibit this problem and exported to excel to see if I could see any differences with the current logs.... again, nothing.

When it's cycling in and out of PE mode as well, the BPW seems to be fluctuating by 1-2 ms, but the peaks and valleys don't necessarily line up with the off an on's of the commanded AFR. Nothing seems to make sense here...

ULTM8Z

Whoa, hold the phone...

Just noticed I have a Code 42 error being set in the log data. It's permanently set in the log data, but the ECM hasn't thrown a code for it (no check engine light). The engine diagnostic option for Code 42 EST Monitor Diagnostic is turned on, so the ECM should be looking at it.

Earlier log data from a while ago that doesn't show the PE drop out also doesn't have the code 42 error set.

Man, I'm hoping this is the problem! Just need to figure out what's causing the code 42 error.

ULTM8Z

Looky what I found on code 42 during a internet search!

The conditions for setting this code are:

System in BYPASS mode but the ignition module is still controlling timing

- or -

Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.


Now I KNOW this has to be connected to my PE problem... Although the spark timing itself doesn't seem to be affected. Seems to be tracking the spark map in the calibration pretty good.


Looks like the EST is on the white wire, circuit 423, going to the HEI module. I'll have to look at it later today...

If anyone else has any code 42 suggestions, please chime in as well!

RBob

iTrader: (1)

Have you tried another ECM or two? It just may be that this one is failing.

RBob.