Software recommendation please
Thread Starter
Racer
Joined: Apr 2011
Posts: 367
Likes: 7
From: Congupna Victoria
Software recommendation please
Guys,
I have ordered the moates cable etc for my 1987 corvette.
Some may have followed my problems trying to resolve an error 36, MAF burn off error code.
I need to know what the ECM is seeing once I switch off the engine.
Which software in your opinions will make it easiest to see the data coming from the MAF after engine shut down?
Obviously it needs to have the facility to keep logging data AFTER the engine is shut down.
All advice welcomed.
At present I'm looking at Datamaster, but no real knowledge as to why....I don't need to make changes to the ECM, right now
I have ordered the moates cable etc for my 1987 corvette.
Some may have followed my problems trying to resolve an error 36, MAF burn off error code.
I need to know what the ECM is seeing once I switch off the engine.
Which software in your opinions will make it easiest to see the data coming from the MAF after engine shut down?
Obviously it needs to have the facility to keep logging data AFTER the engine is shut down.
All advice welcomed.
At present I'm looking at Datamaster, but no real knowledge as to why....I don't need to make changes to the ECM, right now
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
No data will be collected once the ecm is turned off from any software. Datamaster is the most user friendly.
Here's a flowchart for error code 36.
http://www.chevythunder.com/maf_code_36.htm
Here's a flowchart for error code 36.
http://www.chevythunder.com/maf_code_36.htm
Thread Starter
Racer
Joined: Apr 2011
Posts: 367
Likes: 7
From: Congupna Victoria
No data will be collected once the ecm is turned off from any software. Datamaster is the most user friendly.
Here's a flowchart for error code 36.
http://www.chevythunder.com/maf_code_36.htm
Here's a flowchart for error code 36.
http://www.chevythunder.com/maf_code_36.htm
There's a thread in Tech section that I've been posting to.
Everything checks out in the flowchart and I've seen the burn off occur, thus I need to verify that the signal getting to the ECM is within the range it expects - as it appears that this is the only reason the code 36 is being set.
I understand the ECM does not turn off, when you turn off the engine, so its still collecting data.
I need to see what the burn off data is being sent the ECM so I can understand whats going on.
I imagine Datamaster allows you to turn off/on data collection?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
From what I've seen (as posted in the other thread), the ECM stays alive about 11 seconds after ignition-off. That time might be shorter if the ECM is in open loop mode because it doesn't do the MAF burnoff. I'm pretty sure it still resets the IAC, though.
As far as I know the data coming out of the ALDL port stops immediately. My laptop is in the car and connected to the ALDL port, so I can test that...
Datalog during ignition off, engine running (non-essential stuff edited out -- I stopped logging before the ECM turned off):
We see the RPM drop to zero and the BATT_VOLT also goes to zero. This is the voltage from the ignition switch. The AIR_FLOW (MAF output in grams/second) drops off until the MAF power relay de-energizes. Then it jumps up to 59 gm/sec, which is caused by the ECM pullup resistor. Since the fuel pump relay supplies power to the MAF power relay, it's voltage goes to zero as the MAF gets turned off.
We see by this that the ECM DOES put out data after the ignition is turned off.
We have to go into the ECM program code to find out the relationship between MAF output voltage and air flow. It's a series of tables with various scalars, but here is the table where our 59 gm/sec comes from:
So 59 gm/sec comes from a MAF voltage of 2.47 volts, which is what my oscilloscope trace showed in the post in the other thread.
I only ran the engine for a few seconds, so it never went into closed loop mode and therefore did not do a MAF burnoff. I'll try to capture a MAF burnoff tomorrow.
As far as I know the data coming out of the ALDL port stops immediately. My laptop is in the car and connected to the ALDL port, so I can test that...
Datalog during ignition off, engine running (non-essential stuff edited out -- I stopped logging before the ECM turned off):
Code:
RPM AIR_FLOW BATT_VOLT FP_RLY_VLT 850 10 13.7 13.9 1000 10 13.7 13.9 1000 9 0.0 13.0 0 8 0.0 12.7 0 6 0.0 12.6 0 5 0.0 12.6 0 4 0.1 12.6 0 4 0.0 12.6 0 4 0.0 12.5 0 3 0.0 12.5 0 3 0.0 12.5 0 3 0.1 12.5 0 2 0.0 12.5 0 2 0.1 12.4 0 0 0.1 12.3 0 0 0.0 12.3 0 0 0.0 12.1 0 59 0.0 1.1 0 59 0.0 0.1 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0 0 59 0.0 0.0
We see by this that the ECM DOES put out data after the ignition is turned off.
We have to go into the ECM program code to find out the relationship between MAF output voltage and air flow. It's a series of tables with various scalars, but here is the table where our 59 gm/sec comes from:
Code:
;----------------------------------------
; Mass Air Flow TABLE 3
;
; TABLE = gm/sec * 3.08
;----------------------------------------
LC6B3: FCB 83 ; TABLE SCALAR
LC6B4: FCB 8 ; 9 LINE TBL
;----------------------------------------
; gm/sec BIN VDC lb/hr
;----------------------------------------
FCB 147 ; 47.7 768 2.19 368
FCB 158 ; 51.2 800 2.29 395
FCB 170 ; 55.1 832 2.38 425
FCB 182 ; 59.0 864 2.47 455
FCB 195 ; 63.2 896 2.56 488
FCB 209 ; 67.8 928 2.65 523
FCB 223 ; 72.3 960 2.74 558
FCB 238 ; 77.2 992 2.83 596
FCB 253 ; 82.0 1024 2.93 633
I only ran the engine for a few seconds, so it never went into closed loop mode and therefore did not do a MAF burnoff. I'll try to capture a MAF burnoff tomorrow.
Last edited by Cliff Harris; Jan 20, 2015 at 01:26 AM.
Thread Starter
Racer
Joined: Apr 2011
Posts: 367
Likes: 7
From: Congupna Victoria
Cliff,
thanks for the info...
When i get to the bottom of the error code and fix it, I'm coming over there and buying you a beer!
Would love to see the data showing the burn-off taking place as this is what I will be looking for once the cable arrives.
Cant wait to see what it looks like.
What software are you using?
What is the time period between data points as shown?
thanks for the info...
When i get to the bottom of the error code and fix it, I'm coming over there and buying you a beer!
Would love to see the data showing the burn-off taking place as this is what I will be looking for once the cable arrives.
Cant wait to see what it looks like.
What software are you using?
What is the time period between data points as shown?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Code:
AIR_FLOW FRAME_NUM 56 3720 101 3721 64 3722 26 3723 25 3724 25 3725 25 3726 25 3727 25 3728 25 3729 25 3730 55 3731
Using the data section of the ECM program code (edited for length):
Code:
;----------------------------------------
; gm/sec BIN VDC lb/hr
;----------------------------------------
FCB 119 ; 22.3 512 1.46 172
FCB 133 ; 25.0 544 1.55 193
FCB 147 ; 27.6 576 1.65 213
Diacom logs at 8192 baud which gives a frame rate of about 10 records per second, or roughly 1/10 of a second per frame. There are 63 pieces of data in a frame/record plus some other bytes for checksum and identification.
Thread Starter
Racer
Joined: Apr 2011
Posts: 367
Likes: 7
From: Congupna Victoria
My Moates cable arrived today and have downloaded the DATAMASTER software.
Will be giving it a go this weekend.
The setup looks simple enough...just need to work out how to correctly start/stop the data logging so I can see what I need to see...
Fingers crossed!
Will be giving it a go this weekend.
The setup looks simple enough...just need to work out how to correctly start/stop the data logging so I can see what I need to see...
Fingers crossed!
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Thread Starter
Racer
Joined: Apr 2011
Posts: 367
Likes: 7
From: Congupna Victoria
I got the Moates cable and data logger software working.
Was sooooo easy
Did a run, saw that it was in closed loop (software tells you, very convenient)
Turned off the engine, watched the burn off take place, then stopped the data collection.
Looked at the data, doesn't look like the ECM saw it happen??
I checked the resistance from the maf to the ECM..... It was 0.1 ohms...so fine...
Post up the data later, but now at least I know the burn off is happening, it's just the ECM isn't seeing it....
Actually really like the data logger software
While I was pulling the ECM, if found a vacuum connector that was loose - plugged that back in and now have vent control!!!!!!!
At least I fixed something!!!!!
Just overheating and the code 36 to fix now (and a small oil weep)
Was sooooo easy
Did a run, saw that it was in closed loop (software tells you, very convenient)
Turned off the engine, watched the burn off take place, then stopped the data collection.
Looked at the data, doesn't look like the ECM saw it happen??
I checked the resistance from the maf to the ECM..... It was 0.1 ohms...so fine...
Post up the data later, but now at least I know the burn off is happening, it's just the ECM isn't seeing it....
Actually really like the data logger software
While I was pulling the ECM, if found a vacuum connector that was loose - plugged that back in and now have vent control!!!!!!!
At least I fixed something!!!!!
Just overheating and the code 36 to fix now (and a small oil weep)