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In the vertical part of using Tunerpro. ZZ502 Short block. Brodix BB1 Oval port heads. Long gone Street & Performance TPI intake with EFI electronics based on the 7730 ECU. Chip 27SF512. AUJP V5 XDF.
Been struggling getting the engine to idle. Getting close on that. Last data log produced some reductions in timing above 2500 RPM and above 55 KPA. I have looked through all the parameters attempting to find one that would limit SA about 55 KPA without success. Seems related to some default to the 100 kpa column values.
History and Main SA table sttached
Anyone know the answer to this off the top of their heads.
Something does not seem right. Spark Table shows 16.17 degrees below 1000 RPM, but history table shows exactly 21.797 deg at 45-55 kPa idle, and all values in the range are the same???
16.7 deg for idle seems very low. I have similar setup but with Vortec heads. I have to idle at 21-22 deg. At operating temp, put a vacuum gauge on it. With bypass connected and a dial back timing light, adjust dist until get max idle vacuum. Dial back light will tell you the advance providing that max vacuum. That is the idle spark for the table. Next, disconnect bypass to get advance. That's your base value. Done.
Thanks for the Response. The ZZ502 has a 9 degree overlap cam. Not a lot, but seems to not like low idle rpm. I have messed with Open loop idle, but I live at 7500 feet above sea level, but drive the car to areas at sea level. So, closed loop idle is a goal. I have brought idle speed up to 900 rpm and messed with the timing. I may have a low stall TC in the car (built 25 years ago). In P/N it idles decently. But in Drive, it struggles a bit. So, messing with the timing and the idle timing correction.
See chart of Spark Advance versus TPS. This was done with idle timing at 22 in the table. (BTW, base timing is 10 BTDC)
My earlier question was related to the other end of the Spark Advance Table. Above 55 KPA and over 2500 rpm, the Spark advance actual reverts back to 29.88 versus what's in the table. The 29.88 is the value in the 100 KPA column.
Very difficult to determine what's going on with only a history table. Please post an exported .csv file from a log that reflects the data in the history table. Also provide altitude at which log was made. Sea-level and 7500 ft. will provide significantly different results in many areas, especially MAP.
I found some interesting posts relative to SA tables created by you. I also found the excel spreadsheet that allowed the construction of a preliminary SA table. Since it appears your engine is somewhat similar to mine, I have copied and pasted the advance table from your excel spreadsheet. I have not had a chance to run a data log on this table. The specs for the zz502 call for maximum advance at 32 degrees with a base of 10 degrees. I read some other posts that the ZZ502 runs well with higher advance rates, but feel that I need to see a log on this table before further changes. I thought I could also watch the knock rate for clues.
Current spark advance table waiting for testing. attached
I am doing this testing at about 7,500 feet above sea level. According to the online calculators, Sea level is 100 KPA. 7,500 feet ASL is about 76 KPA.
1. Should I be concerned about that during the preliminary settings for VE and SA
2. What does this barometric table do (see attached table)
Think the CSV was too big. I sorted on Column for SA and you will find that 29.88 advance between lines 284 and 14636 (with the sort high to low on column DQ
Several things:
1) The spark table in the bin is different than that in Post #1 here. Did the csv file come from the provided bin? Why the difference?
2) Logs shows Err 24 (No VSS signal) and Err 45 (o2 Rich). I'm surprised your tune is as good as it is with 90% of samples being rich and thus the error. Your o2 swing point and boundaries are pig rich.
3) The VSS error is important because cannot determine MPH or TCC lockup (and your post show AT 4L60), and thus can't determine whether in or out of Hwy mode. But if in Hwy mode, it only lasts for 60 seconds at a time where 3.87 degrees are added to total spark from the table at 0x1AB=Highway Mode, SPARK ADV .vs. MAP. But will disappear after 60 seconds until Hwy mode reentered. But again can't tell due to lack of VSS signal.
4) But even more importantly, without VSS signal, many important code decisions cannot be properly made. This really needs to be fixed despite likely not directly affecting spark.
5) You have this not set indicating optical sensor: Switch 18 (0x018) - Bit 6 - VSS Type: Magnetic=0; Optical=1. Is that the correct setting?
Sorry none of this address spark question, but data are clouded with no VSS.
Lot's of information. And, I am very grateful for your expertise. This engine ran fine for 20 years with the early GM 502 from 1995, until I sucked up a lifter. Put in the ZZ502 short block and have been struggling since getting it tuned.
1) The spark table in the bin is different than that in Post #1 here. Did the csv file come from the provided bin? Why the difference?
The first post was from an earlier BIN. The BIN provided and the CSV log are related.
2) Logs shows Err 24 (No VSS signal) and Err 45 (o2 Rich). I'm surprised your tune is as good as it is with 90% of samples being rich and thus the error. Your o2 swing point and boundaries are pig rich.
I would appreciate recommendations on adjusting the 02 swing point and the boundaries. Driving in cruise control, very minor changes in rpm will just to a different BLM cell with huge swings in BLM.
3) The VSS error is important because cannot determine MPH or TCC lockup (and your post show AT 4L60), and thus can't determine whether in or out of Hwy mode. But if in Hwy mode, it only lasts for 60 seconds at a time where 3.87 degrees are added to total spark from the table at 0x1AB=Highway Mode, SPARK ADV .vs. MAP. But will disappear after 60 seconds until Hwy mode reentered. But again can't tell due to lack of VSS signal. 4) But even more importantly, without VSS signal, many important code decisions cannot be properly made. This really needs to be fixed despite likely not directly affecting spark. 5) You have this not set indicating optical sensor: Switch 18 (0x018) - Bit 6 - VSS Type: Magnetic=0; Optical=1. Is that the correct setting?
I am not sure I have a VSS signal. The Transmission is a 4L60 from GM back in 1995. It is really a 700R4 configuration, not electronic shift, Cable shift. The engine, injection system, wiring harness, etc came from Mark Campbell in Mena Ark. Now he and his company are sadly gone. Street and Performance (Mena) had some aftermarket Torque converter lock up they provided. It's been 25 years since I built this car and I am thinking the only VSS signals I have are for the speedo and the cruise control. The cruise control and the ECU are adjacent to each other under the passenger seat. If I can determine what pin(s) on the ECU need the VSS signal, I can probably share the Cruise Control VSS signal with the ECU. I am absolutely sure that if I do have a VSS it is not optical. Perhaps that setting (which I didn't know existed) is the cause of no VSS.
Without changing anything else, change the VSS sensor selection to 1=magnetic and see if you register MPH/lockup. If not, then obviously need to do 2 things:
1) Chase specs on the VSS as to type
2) The 7730 ECM accommodates the 700R4 and 460 so need to google for connections required. Don't have details handy, but if you have wires to ECM pins B9, B10, and B11, it's wired, albeit maybe not correctly.
Before changing o2, curious to know how your values got to be so rich because they don't match anything the 7730 supported.
Verified there is a VSS sender and wires to the ECU. Took a test drive. Switched parameter related to the VSS back and forth. No vss speed indicated. I did run a short new log. The changes here were to lean the idle a bit in Open loop and raise the idle to 950. Changed the Idle SA to 19.50 but doesn't seem to matter.
I had a spare VSS from someplace. It's some setting in the ECU, the wiring or the 25 year old VSS sender that has been submerged in oil. Put the new sender on, but will have to test it later.
Something does not seem right. Spark Table shows 16.17 degrees below 1000 RPM, but history table shows exactly 21.797 deg at 45-55 kPa idle, and all values in the range are the same???
.
Hey 84Elky, at closed throttle, would table 0x1FD (SA Closed TPS) take over Main SA table? That could explain his history being higher around idle (800-1000rpm / 40-50kpa). Or maybe CT SA correction 0x13B?
His history is most recent samples (10 latest) which is useless IMO. Also the history function does not allocate using the same boundaries as the ECM does.
Cheers
Last edited by SbFormula; Aug 19, 2021 at 07:31 PM.
I am not sure what I am seeing on the monitor tables. When under heavy acceleration, the spark advance moves into the 32 plus degree range. If you step through the log using the dash board in 10 sample steps, you can watch the minute the MAP and TPS (like MAP 68 and TPS 55 %) indicate heavy acceleration, the SA drops from above 30 degrees to 29.88 degrees. Not always, but generally, the AE MAP flag is set. I am at 7500 Feet ASL,
Seems weird to me that under heavy acceleration, the timing would drop to some prescribed level like 29.88 degrees.
Hey 84Elky, at closed throttle, would table 0x1FD (SA Closed TPS) take over Main SA table? That could explain his history being higher around idle (800-1000rpm / 40-50kpa). Or maybe CT SA correction 0x13B?
His history is most recent samples (10 latest) which is useless IMO. Also the history function does not allocate using the same boundaries as the ECM does.
Cheers
Sharp-I initially noticed this CT table had very high values. While not contributing to your constant spark value (still thinking), for an AT, it's generally best to set 0-800 RPM CT spark at idle spark used in Main Table ,and then above that something like 70% of the 0-800 RPM value. This will provide same idle spark as main table, act like a brake when decelerating above idle and, will not cause any hesitation upon adding throttle while coasting. Can also help MT cars, but not much effect felt since gears are in play. Not so with AT.
Shazaaaaaam . . . . Spark problem solved but several others to address. Will do that once you confirm and report back that this issue is fixed.
Remember when I said that the VSS controls many items in the code? Well Launch Control (LC) is one of them. If you carefully review the items below and the log, you'll note that LC is to be RPM Staged if RPM >= 2500, and LC will be activated when TPS% is >= 50%. Car launches at >= 50% TPS.
Further, the LC logic correctly assumes that MPH=0 before launch. After all, it is "launch from a dead stop" control. So when MPH continually =0, LC thinks you're waiting to launch with RPM >= 2500, and then launches (LC ACTIVVE) when TPS reaches 50%. Code just doing what it's instructed to do.
Also note that the LC Spark Table below has been set with all SA-REF values =20.04, and with a 10 deg base (actually 9.84 rounded), bingo you get:
SA-TDC = 20.04 + 9.84 = 29.88 deg, the magic number
And as long as LC is active that's what you're going to get. Now, why all values are 20.04 is another mystery and is grossly incorrect, but that's for another day.
To correct the spark problem until the VSS is reporting MPH, uncheck this Flag:
Can't use LC until have MPH recorded.
This is an excellent example of how important it is that the VSS be reporting MPH!
No VSS signal from the sensor that has run for 20 years. I installed the new VSS sender. The VSS wiring is at the ECU and the sender. I drove with both the box for type checked and the box unchecked. I have the speedo on the dashboard. I got no speed indications from having the box checked or unchecked. I will confirm the wiring in the AM, but rather doubt that the wiring is the issue.
The attached explanation of VSS types, etc. is the best I can do for now. Perhaps googling for other details will provide insight because there are certainly those using a 7730 in other than the car for which it was originally intended. Please post results. Then we can address some other issues.
Photo of VSS sender attached. This is mounted on the Transmission. There is a secondary cable from this sender to a second sender that operates the Cruise Control and the Classic Instruments speedo. The CI speedo and cruise function fine, so the speedo cable is turning.
I also attached a section of the CSV file There are three columns that respond to a VSS search. Two are error columns. Speed sensor error 24 and VSS Failure. Both error columns say 'OK". This other column is "1st VSS Pass" and it says "yes". What ever that means.
I had the pulse count at about 9k during the drive. I suspect it needed to be 4k. I expected to see a Vehicle speed indication on the dash board of Tuner Pro, albeit incorrect due to the pulse rate, but it remained zero.
Without MPH, may be chasing rabbits looking at VSS 1st pass. You verified that you had purple and brown on b9 and b10 respectively. And you indicated that cruise control works. That's a 2K signal so something's working. But you did not mention anything about b11. That's generally a brown wire with the 4K signal to the ECM that will register MPH. Where does the b11 wire from the ECM go?
Also, on one of VSS flags, you mentioned it only had "Set". Right. Set=1, Not set=0.
The cruise control and the speedometer in the car have a separate VSS sender. The VSS sender mounted on the Transmission (photo above) has a purple and yellow wire that goes to the ECU. There is a stubby speedo cable that has a second VSS sender about a foot away. The second VSS feeds the Dakota Digital cruise control and the Classic Instruments speedometer in the dash.
According to my schematic. The VSS input to the ECU is pin B9 and B10. B11 is output to the speedo (not used in my installation)
I checked my last BIN and the pulse rate was about 9000 for VSS input (not 4,000). Would that cause the ECU not to see the VSS signal?
I checked my last BIN and the pulse rate was about 9000 for VSS input (not 4,000). Would that cause the ECU not to see the VSS signal?
Yes, pulse rate must be 4K but you must have 2K for Cruise Control which I assume is working. What happens at 9K I don't know. If you're not going to wire b11, I would recommend talking to CI or search for what others have done installing a 400/460 tranny to a 7730. Been done many times but I don't know the exact wiring other than what's already been discussed. Maybe someone could chime in or perhaps a search.
Well, I am running out of ideas here. Took the car around the block. Speedo in dash working fine about 25 mph. Vehicle Speed in Tunerpro sat at zero.
Confirmed that Pulse rate in the BIN is set at 4000. Yes
Confirmed that the check mark is present for type of VSS. Yes.
I checked the Original VSS with a AC volt meter. It came with the wiring harness from Street and Performance. Spin it with a drill and the AC voltage ramps up the faster you go with the drill. Conclusion the Sender should be ok.
I removed the ECU. Unplugged the cables from the ECU. Unplugged the VSS at the other end. I tapped into the purple twisted pair for the VSS at Pin B9. Supplied 12v. Crawled under the car and confirmed the 12v was present at the VSS end of the twisted pair on the purple wire. Conclusion the Purple wire is good
Did the same test on the yellow wire from Pin B 10. Confirmed 12 Volts was present at the VSS end of the Yellow wire. Conclusion the yellow wire is good.
What else is there? Is there something in the BIN that could cause this other than the Pulse rate and type of VSS? Could the ECU be bad?
I too am out of bullets. I do however believe you need a 2-output VSS buffer which is the middle item in in the pic on page 2 of the doc I provided in Post #30. Is the Scalar below now set to 4000:. It was 3608 in the bin you posted.
If changing that to 4000 does not fix it, I would contact CI, jagsthatrun.com or TPIParts.com to determine what you need. My belief is that the buffer is needed to get the 4K required. Others here may know.
Tuned Performance is well respected and very knowledgeable and the ECM may well be faulty; but IMO, before replacing the ECM, it would seem appropriate to talk to others or research what is required to interface a 400/460 tranny to a 7730 before replacing the ECM. My experience with the 7730 is that it takes a bomb to make one go bad. FWIW.
The VSS sender appears to be ok.. Two tested and neither one works. Wiring from ECM to VSS appears to check out. What is left is hardware or software. Kinda doubt it is software, but you never know. A new ECM for $100 eliminates that variable. There are not answers to this on the web.
I saw previous logs, some tunes Vss was there others no signal. Not sure if drive or driven gear could be damaged. Another test would be to see if anything registers on tp dash with a log started and a drill spinning the Vss.
The VSS for the ECU is mounted directly on the transmission. Feeds only the ECU. There is a 12 inch stubby speedometer cable that runs from the ECU VSS to a second VSS supplied by Dakota Digital That second VSS runs the cruise control and the speedometer in the dash of the car. Since the speedometer in the dash of the car is functioning correctly, I know that the mechanical parts are working.
I am going to closely check the wiring today. Was thinking that the pin could be pushing back when I install the connectors on the ECU.
What appears to be missing is the 4K signal needed for MPH. You have the 2K signal or cruise would not be working. I believe it's the buffer that provides the 4K.
@84Elky are you referring to the internal Vss buffer of the 730. Sounds like it’s not being used for cruise but
the 2k could goto c6 of the ecm and optical flag set .
For the sake of redundancy. I took my spare VSS. Connected it to a drill. I plugged it into the cable at the transmission When turning the VSS with the drill, I confirmed AC voltage at the Connecter Pins B10 and B9. From the ECU connecter to the transmission is ok
I plugged in the ECU. Connected Tunerpro. Turned on the car (did not start) and hit the acquire data button in TP. Dash connected (all at base levels. ) Powered up the drill. No Vehicle speed indication, zip, zero.
@84Elky are you referring to the internal Vss buffer of the 730. Sounds like it’s not being used for cruise but
the 2k could goto c6 of the ecm and optical flag set .
Tuned-Yes this may work because it absolutely certain the ECM is not seeing a 4K signal.
Sharp - Below are some bits and pieces you may find helpful and Tuned Performance may have the answer.
VSS to lp, 4K Pulse per mile (ppm) Pin B11 Brn Voltage key on12 Voltage running 13.9
The 730 ECM (speed density) uses a VSS that does 4000 PPM that goes to the the ECM. Then the ECM sends 4000 PPM to to the speedometer. The ECM also sends 2000 PPM to the cruise control.
I found the problem. After taking it all apart a dozen times and running tests, it was programming.
When I added the WBo2 and changed BINs, somehow the Setting "VSS MPH Lag Filter Coefficient" reverted to zero percent. All the WB BINs had the zero coefficient.
I returned it to the default of 50% and I have Vehicle Speed. And, pretty accurate, within 1 mph of my GPS.
I found the problem. After taking it all apart a dozen times and running tests, it was programming.
When I added the WBo2 and changed BINs, somehow the Setting "VSS MPH Lag Filter Coefficient" reverted to zero percent. All the WB BINs had the zero coefficient.
Am glad the problem is resolved, but I believe a clarification is in order to ensure correct information is being posted and read by others.
Specifically, you posted 3 bins (Posts 11, 17 and 19). The bins in 11 and 17 had the VSS Lag Filter Scalar you reference at 50%, not 0. Further, the log posted in #12 was confirmed by you to be associated with the bin in post #11. This BIN did NOT report MPH, but did report WB AFR, which means WB would have already been added contradicting the statement: When I added the WBo2 and changed BINs, somehow the Setting "VSS MPH Lag Filter Coefficient" reverted to zero percent. All the WB BINs had the zero coefficient.
It was not until the bin posted in #19 that the Scalar =0.
Something is either misstated or there is another explanation as to why MPH began being reported, because with a 50% coefficient in BIN #11, MPH should have been in the log in post #12, but it was not.
Ok
There were multiple versions taken off BIN 11. The last BINs that had all three factors properly entered were the Narrow Band O2 Bins. Once we went to WBO2, one or more of the three factors requiring vehicle speed was off.
Coeff Pulse Check for Magnetic
NB BIN 11 50 4000 Yes
NB BIN 12 50 4000 Yes
WB BIN 11 50 4000 No Post 17
WB BIN 12 50 3608 NO
WB Bin 13 50 3608 No
WB BIN 24 50 3608 No Post 11
WB BIN 25 0 9020 No Post 19
WB BIN 26 0 9020 No
WB BIN 27 0 4000 Yes
WB BIN 28 (today) 50 4000 Yes
