nick9004

Hi Guys, I recently got my TBI swap running. It runs and drives great. But I have 2 issues and I don't know if they are related nor how to fix them even with all of the searching I have done on this amazing forum. First some background info.

81 GMC Jimmy, Fully rebuilt 350, TBI installed with stock freshly rebuilt TBI heads, Flat top pistons, Mild RV Cam, Edlebrock Performer TBI Intake, All sensors hooked up except VSS. I’ve been running it on premium fuel which here is about 91 Octane. ECU is a 7747. The donor vehicle is somewhat unknown. I bought the TBI parts off of a friend who had it running on a 377 de-stroker without changing the EPROM. I am using the same EPROM. My SES light is working but is not on while I’m driving. it only comes on for a few seconds when I turn the key. I am assuming this is a test to show that the light is working.

Problem #1: Ever since the first start-up it has had a very high idle. I don't have a tach but when I shift into gear it’s a lot more shock to the drive train than there should be. Also the idle does not change after the engine heats up.

Problem #2: I have a knock under load. Only under load and regardless of if the engine is hot or not. If anything, it gets more noticeable as the engine gets warmer. During conservative driving it is nonexistent. However, conservative driving is no fun especially when you want to see what your new setup is capable of. It is mainly noticeable if I'm rolling up a slight grade and want to accelerate. The RPM begins to climb and it knocks but if I keep it in 1st gear and get the RPMs up high it disappears completely. Then drop to 2nd still on an incline and give it more gas it knocks again until the RPMs get up. Also I can make it do it if I am in drive and stand on the brake while holding the RPM up. I understand the concept of detonation/pinging but am not sure of how it sounds. The distributor is currently set at 0* and it seems to be slightly more noticeable than when I have it set at 4*. I would like to test the knock sensor but when I follow my Haynes book directions for testing the knock sensor both the sensor I’m using and a brand new sensor fail. The way I’m testing it is testing the resistance between the block or and engine ground and the pin on the sensor. I’m using a digital multi-meter and its telling me there is no connection between the pin of the sensor and the block.

Does anyone have any other ways of checking the knock sensor or any other suggestions for me? As for the high idle I can’t hear or see any vacuum leaks and the throttle body gasket is good and tight the idle screw still has the factory plug over it and I don’t want to play with that before I’m sure there is no underlying problem that it would mask.

Sorry for the lengthy post!

Thanks a lot in advance. This forum is so helpful!

RFmaster

1) Reset IAC. There is a sticky in a technical section (use search). Other possibility is that you have a vacuum leak. But you have checked for that - make sure that base of TB has a complete gasket coverage. Flip it upside down and see that there are no breakouts. Both intake and TB flange should be flat! Based on your description your setup should have about 16 to 18 in-Hg of vacuum and idle at 600 RPM. SES should light on - blink off - stay on until engine fires up. Thats a normal POST sequence.

2) You are (probably) using high impedance KS (around 100k) and you may not have the range set correctly on DVM or have high contact resistance. The other possibility is that SA tables in your current EPROM are wrong for your engine combination (too much advance for certain RPM/MAP values resulting in pre-ignition. Another real possibility is that VE tables are wrong for your engine and ECM has not had a the opportunity to compensate (BLM), also re- verify your fuel pressure (stock TBI is happy around 13 PSI). My advise is to get very familiar with tuning lingo, tools and procedures - see technical stickies. This way you can make meaningful headway with your combo. (hint: read stickies)

//RF

nick9004

Hey RF, Thanks for the info! I've just discovered thirdgen.org the last couple of days so I havn't had a chance to read all of those stickies but I did see that IAC one. Ill try that along with the vacum test and I was definetly going to check my feul pressure too. Also I forgot to mention I have an MSD distributor and coil. I'll get reading those stickies!

Thanks again!

RFmaster

Is MSD distributor ECM compatible (i.e. has a four wire interface connector to ECM)????

nick9004

Yes it is the proper one.

nick9004

Hey RF, so I tried finding that specific stickies about reseting the IAC and i couldn't. Is it just like setting for base idle? Jump A and B on the ALDL, turn key on, wait 30 seconds, disconnect IAC, run engine, turn off, pull jumper wire, reconnect IAC?

RFmaster

https://www.thirdgen.org/tpimod2

nick9004

So I attempted the minimium air adjustment. I backed the screw out and the idle went down slightly then stopped. Looks like the butterfly flaps are holding it open to that point. When I continue backing off the screw the throttle no longer bottoms on the screw. Is there a way of adjusting the butterfly flaps?

nick9004

Well I took a look at mine... Looks like maybe my PROM is programmed for that idle speed. The miniumum air screw is about where It started which is all the way backed off. My IAC is functioning properly. And my TPS voltages come out right. I have 19 in-Hg of vacuum with no leaks. Sound like the PROM to anyone else?

RFmaster

What is your minimum idle speed?
Also, can you determine what is your idle timing (both with EST connected and disconnected)?

7747 ECM was used C/K trucks and vans. Typical truck base timing was set at 0 degrees with EST disconnected. Once base timing is set, and after clearing EST code, timing at idle (normal operating temperature) should be around 18 to 21 degrees and idle speed around 625 to 650 RPM. Again, these numbers reflect a typical truck calibration - ASDU, ASDZ, etc.

Since you do not know what EPROM changes were done to make 377 work I would get going with EPROM burning equipment and software (TunerPro). The best place for hardware can be found here:

http://www.moates.net/

Moates also has a collection of stock (and not so stock) EPROM image files. I am not going to kid you, but there is a learning curve associated with EPROM tuning. Suggest that you read tutorials here and on Moates (G2-0.60 socket adapter allows use of modern flash memory instead of circa '80 UV 2732 EPROMS used with 7747 ECM). Ask questions before making final decision.

If you feel that all of this is EPROM burning, modification is way above you then contact Brian at TBI chips.

//RF

nick9004

Hey RF, Ive been reading all day and most of last night on here. I think I'll be able to learn it. I've got a laptop and aldl cable on the way. As for a programmer would one of these 2 work? they are sold just a few hours away so less shipping no brockerage fees...

http://www.mcumall.com/comersus/stor...idProduct=4225

http://www.mcumall.com/comersus/stor...idProduct=4282

Also for flash chips is there anything that you need to change in the ECM to make it read the flash chip? Besides the adapter?

Thanks Again,

RFmaster

Do you mean this EPROM programmer???




It works very well with Atmel AT28C256. It worked very well for me before I switched to EBL. For starters it is an excellent, economic EPROM programmer - reader. Which brings a very good point - you can read contents of your current EPROM. Since you have 7747 ECM - it runs a very well known $42 mask.
To get you started you'll need is to download a copy of Tunerpro (a donation gets rid of nag screen, I still use v4.14)
http://www.tunerpro.net/downloadApp.htm

$42 XDF bin file definition - This tells TunerPro how to interpret BIN file contents into something that us humans can readily understand:
http://www.tunerpro.net/download/bindefs/GM/42.xdf

If you get TunerPro-RT (RT stands for real time) you will need ALDL data stream definition file (.ads):
http://www.tunerpro.net/download/datastreams/42.ads
With TunerPro-RT you can do real time sensor data acquisition - albeit at a very slow data rate (this die to ECM). But it gets you going.

Firstly get EPROM reader - programmer going and download EPROM contents into a BIN file. Then use TunerPro compare functionality and determine differences between EPROM image and a factory calibration for example ASDU. This should be a good first project and indoctrination into tuning. It becomes very addictive once you begin to see what you can do. However, keeping track of changes becomes a full time job! You have been warned!

Just get adapter - no ECM changes required. (you still have to remove old EPROM)

//RF

nick9004

Hey, so I finally got my laptop and ALDL cable. Still waiting on the programmer and chips. Anyways I did some datalogging. Now im lost. I fully understand how to change .bins and burn chips. I found lots of good reads on that. I can't seem to find any information on how to read my datalogs. Like actually interpret the data. Does anyone know of any articles or good threads on it. Would anyone be willing to take a look at my datalogs and give me a few pointers on where to start? I'll post my datalogs if anyone does feel like helping. The first one is normal driving on reasonably level terrain. Second one is driving up a hill trying to maintain my speed or slightly accelerate. Just change the file extensions to .adl had to change them to .txt for uploading. Thanks!

nick9004

Also my base timing is set at 0*

RFmaster

Let me take a look at them first...

//RF

RFmaster

Nick

I took a look at your first log (tomellors). See both CSV files by importing them into EXCEL.

Initial Observations
1) No VSS input - that's not good - need to get VSS working.
2) A handful of bad data packets (i.e. PROM ID <> 201D and bat voltage <> 14.1 volts) that I had to delete.
3) During first 73 data samples ECM is operating in open loop BLM=128, INT=128
4) During drive (I assume since there is no VSS data) a) data sample 80-108 - light throttle, ECM is adding fuel over base line VE tables as indicated by BLM>128. This could be due to a) low fuel pressure or b) incorrect VE tables.

5)Late IDLE, sample #256-294, TPS V=0.45, CTS=54C???, IAC =102 Too High!, Engine is running rich as indicated by BLM =119. I have suspicion about your CTS unless ADS definition is incorrect (your initial start indicated CTS reporting 90C (is it correct?) and dropped down to 55C, which is inverse of what it supposed to be. Which CTS do you have????? Measure CTS cold, at room temperature 20C it should read about 3.4Ohm to 3.5 KOhm and at 80C it should read about 340Ohms!

6) Reset IAC - there is a published procedure.

7) Do you have EGR disabled???

87) Do not give up. CSV files uploaded

//RF

nick9004

Hey RF, Thanks for helping show me a few things!

I am in the progress of hooking up the VSS. Had to get new speedo gears to make it more accurate. Now I'm just waiting on the speedo cable. So its comin soon.

What causes bad data packets? I notice my voltage would randomly drop on the scanner but not on my dash. As well as my RPM on the scanner would crash when the volts dropped. Is that just somthing that the old computers do?

I did some testing on the CTS. Cold (-3C) it read 9280 Ohms. Normal operating temp (85C) it read 210 Ohms. Not quite the figures you gave me... As far as I know its just a stock replacement sensor. Looks identical to the rest of them anyway.

I reset the IAC. Managed to get the idle down to the 450-475 range. Plugged the IAC back in. Went for a drive and data logged a short trip. My IAC steps are still above 100! When I first started they were low and climbed to 100-110... Any Ideas?

I installed the EGR on the engine. When I get the programmer I'll be able to verify wether or not it is disabled in my chip. It's a stock chip so I would assume it is enabled.

Thanks Again!

RFmaster

Hey Nick

Definitely progress, but there is a bit of work that must be done. Since you have 1227747 ECM get a copy of WinALDL:

http://winaldl.joby.se/

Looking over logs the 1227747_42ads definition file does not have correct conversion factor for CTS. This can be easily fixed by editing conversion formula used to convert binary ALDL stream data to engineering units.

Your CTS resistance values are within range of the Delphi CTS data for P/N 12146312:
-5C 12,413 Ohm +/-8.97 Ohm
0C 9,516 Ohms +/-8.57 Ohm
85C 287Ohm +/-4.08 Ohm

ECM primarily uses IAC to maintain commanded idle speed. In other words it is a controlled vacuum leak so as to maintain (about programmed value) idle speed. This is where it gets tricky. If you have a cam with wide overlap some of the intake charge gets drawn in into exhaust stream. This increases detected O2 levels which ECM tries to compensate by adding more fuel which engine does not need at idle resulting in a richer mixture. Richer mixture does not burn well and unburnt fuel along with excess O2 end up in the exhaust stream where excess O2 is detected by NBO. Thus NBO detects more O2 in the exhaust which ECM treats as a lean condition (which is false) further adding more fuel which gets ugly very quickly as engine speed drops!
Getting back to IAC with pintle position controlled by ECM in steps. One step moves the IAC pintle a small amount. The full range is typically from 0 to about 160 steps. Zero steps is a park position when the pintle is fully extended, closing off all IAC bleed air flow (minimum idle speed).
As the ECM increases steps, the pintle opens air bleed through orifice, allowing more air to bypass the throttle blades. This increasing the engine RPMs and a stock TBI engine will happily idle with an IAC count of 35 to 45. Engines with wilder camshafts may idle closer to 0 to 5 counts. As long as idle speed falls with in specified window ECM will keep IAC at a given position. However, once idle speed falls outside idle window ECM will move IAC to a new position compensating engine RPM.

Can you provide camshaft parameters for your engine (if known)?

//RF

nick9004

Hey RF,

I have a copy of WinALDL. I just started using TunerPro RT because it does both things. Should I only use WinALDL for data logging? Did you mean I could use WinALDL because it would use a difrent .ADS which means I don't have to bother changing the .ADS in TunerPro?

The cam I installed is a Melling MTC-1. Specs are at this link, Just search MTC-1 and it'll jump to it.

http://www.mellingselectperformance....haft-specs.pdf

I'm going to PicknPull tomorrow for a speedo cable so by Sunday ill be able to data log again with VSS input.

Thanks!

nick9004

Hey RF, So I have a new data log. I got the VSS hooked up and I think my speedo is pretty close to accurate. The knock under load is like 75% better. I can't believe there are so many people running without a VSS. Its clearly very important. Anyways I think I understand how to begin tuning the fuel tables. I can follow the Prom Burning guide on here. The problem that you were talking about with the IAC opening due to readings from my O2 sensor... Will that be resolved after I work the VE tables? What is the proper way to deal with that?

Would the steps suggested here be a good place to start now that I have the truck drivable without bad knock? (VE/Load Tuning - Spark Advance) https://www.thirdgen.org/forums/diy-...ack-magic.html

Here's the new log. Its in .xls and zipped this time.

Thanks!

RFmaster

Hey Nick

I had a chance to look over your log tonight. With VSS connected ECM now has control over EGR and CCP. From reading DIY tune articles the first thing to do is disable EGR by setting its enable temperature to maximum = 151C or $FF and similarly CCP function by increasing enabled speed to 255 MPH. By disabling EGR you side step EGR fault codes - ECM will never test EGR functionality since it can never (we hope) reach threshold temperature.

MTC-1 cam is a mild RV cam with calculated LSA of 112deg - it appears to produce adequate vacuum levels at idle (16 to 19 in-Hg at 650 RPM). This is important as MAP sensor will govern amount of fuel being looked up by ECM. Are you still using custom 377 chip? Do you know what your BPW constant is set to???? This may explain your knock - get a copy of ASDZ bin as it should provide you with a good baseline tune configuration for your 350.

1) Idle (332-349) - still have a problem with IAC stuck at 76-85 counts and idle RPM at 1250. BLM is showing slightly rich at 125. You have mentioned that you set base timing 0 deg. Get your timing light see if you are getting about 20-23 degrees while idling. A very common cause for high idle is a vacuum leak - check usual suspects (I know you did this before). In previous post you have reset IAC and were able to achieve 450 RPM idle with EST disconnected. Another reason for high idle (surprise) is a low fuel pressure.

2) Under Load (278-290)
BLM are high plus KS counts are increasing - this may be an indication of a low fuel pressure (lean condition). A low fuel pressure results in high KS counts and very high BLM values (ECM is adding fuel)! Can you verify your Fuel Pressure????

The black magic post is a classic read - it covers basics and give you a good flavor of things to come. But get a good known baseline BIN to work with.



//RF

nick9004

Hey RF, I just reveived my BURN2 and chips in the mail. I installed the adapter in the ECM last night. I'm about to burn 2 chips with the EGR dissabled. I will try one with my stock ANTY.BIN and one with the ASDZ.BIN both with the EGR disabled. I'll see which one runs best and go from there. Havn't been able to verify my fuel pressure yet. But I will buy a gauge next time I get to town. I'll keep you posted!

Thanks again!

nick9004

Forgot to mention... My BPW is 134 on the ANTY and 135 on the ASDZ.

nick9004

Hey RF, I took the ASDZ for a drive and it idles fine but once I start driving it surges and it keeps getting worse until it dies. I'm probably better of sticking with the ANTY.

RFmaster

For the sake of discussion it is the same.

RFmaster

I am going to take a swag here - stock ASDZ has EGR enabled and your copy of ANTY has EGR disabled. You'll have to load both BIN files into Tuner Pro and do a compare. On the other hand, after a quick search BCC ANTY comes back to 7.4L calibration. There are some differences between BBC and SBC IAC circuit implementation which may explain why your engine dies once you go for a drive drive.

Do me a small favor - take a look at left front corner of your TB - there should be bunch of numbers stamped (p/n should start with 17xxxxxx). I have a hunch that you have a BBC TB installed. IAC in BBC TB (for some BCC) has a pair of its control lines swapped. In other words ECM running ASDZ calibration instead of closing IAC is opening and in reverse. This may explain engine shutdown.

//RF

nick9004

Hey RF, number on the TB is 17087101. I searched and looks like it is a 350. Would have made sense though. When I was doing the wiring I remeber seeing a note about switching the 2 wires for a 7.4L. Any other ideas as to why it would surge?

Thanks!

nick9004

Hey RF. I started working on my Main VE Table. When you have a chance could you have a look at what I've done. I think I'm on the right track but just to be sure? I put 3 examples of numbers I used below the tables in the attatched .xls file. Any suggestions?

Thanks!

RFmaster

Not knowing complete history of your TBI pieces forces a bit of a guess. The 17087101 come back to a 350 SBC TB. The ANTY calibration was used with BBC applications. I pulled up the other two known L19 (aka 454) vin "N" calibrations ANTZ and AZFT. Both BCC use 3.87 degree initial timing and BPW=134. Interestingly enough both calibration have a rather conservative timing curves when compared to SBC!

Use google and search for antz8364 and azft9503 and you'll find these two bins. If you flash these two bins and your engine is running ok (idle and otherwise) then the most likely explanation is that IAC wires were flipped to accommodate BBC calibration with SBC TB - go figure! One way to verify this theory is to force IAC reset. With everything off remove IAC from TB and see if IAC moved pintle into a fully extended position. If you repeat this procedure with ASDZ and pintle is fully retracted - then the difference between BBC and SBC calibrations is clear. It is a bit of experiment.

https://www.thirdgen.org/forums/diy-...i-iac-7-a.html

Back to your operational ANTY bin file. You can use it as foundation, but save all subsequent files under different names. In Tuner-Pro you can copy SA tables from ASDZ bin into your new master file. Burn and verify.
Keep notes. In TunerPro you can compare two BIN files and transfer differences. Aside from Main SA and VE tables PE added spark and intial timing advance jump at me right away. In other words if you want to leave hardware alone this will be the way to morph the differences. For initial tuning stages disable EGR by setting Temp on =155C


//RF

nick9004

Hey RF. I Verified my fuel pressure today. It stays at 13PSI regardless of how much throttle and rpm there is. I had thought it might be leaning out due to low fuel pressure. Reason I thought that... I changed some values in the VE table and I'm still running lean in the same areas that I've changed. What would cause this? Once I correct it shouldnt it give me 128? Am I missing somthing? I double checked my injector size... They are stock truck injectors. the 55lbs/hr. I ran the ANTZ bin. It didnt run well but it idled okay. It ran way better than the ASDZ. Tommorrow I will check my ECM pinouts to the IAC and I'll take it out and verify that it closes(extends) with A and B jumped.

Thanks again!

RFmaster

Hey Nick

ANTZ calibration was designed for BBC (454). You have 350 which requires a completely different SA tables to run. Take a look at the 454 combustion chamber which is huge when compared to SBC - SA tables are different to make it work.

If you are using 55lb/hr injectors on your 350 that may explain your lean issue! With stock fuel pressure (13PSI) you should use GM 5235206 *RPD orange/black injectors which are rated at 61 lbs/hr. The 55 lb/hr injectors can be identified by the 5235279 *RPD, green/white color code and used on LO3 (305) engines.

//RF

nick9004

Hey RF, I will have to take another look at that. I only assumed they were the Org/Blk because I didn't see any other colored material on them. I now relize that all of the injectors have an Org colored insulator around the electrical connector on top. I wasn't able to see any numbers on them. I'll have another look in the morning. It was kind of dark out when I was looking. I'll post up in the morning!

Thanks for all the help!

RFmaster

Yea, 1 am on cold winter night (morning) is no better time to look at injector numbers! Good luck and take one step at a time.

//RF

nick9004

Hey RF, I cleaned out the tops of the injector and found those tiny little faint numbers. They are the 5235206 injectors. I'll go back out shortly and have a look at the IAC.

nick9004

PROGRESS! FINALLY! Well... Sorda...

RF,

I managed to run and drive the ASDZ again. This time for a little longer and under the same load conditions where I was having problems before. The problem is completely better!

...However now that surging is still giving me issues. While driving, about 1-2 minutes in, the engine starts surging. Not just an idle surge but if its revving high it will surge very high also... Once it starts it just keeps getting worse until it dies and I pull over. If I turn off the key for about 15 seconds and start up again I can drive another few minutes before it starts again.

Another note, when I first started the engine with the ASDZ chip in I sat idling for a few minutes and the SES light came on. It stayed on for a few minutes and went off for a minute then came back on. After I drove a little while it stopped coming on. I pulled a code 43 from it. I believe its a ESC error? Low voltage from the ESC to the ECM?

Checked my IAC and compared the movement between the 2 bins. With the ANTY and A+B jumped, key on the pintle fully extends. Repeat with the ASDZ and it also fully extends the pintle. This would mean my IAC is wired correct for a 350 right?

Any suggestions?

Thanks!

RFmaster

Hi Nick

Great progress. It is also a good feeling to turn a corner.

1) Code 43 is related to ECM test as it did not detect a knock signal during near wide open throttle operation with coolant temperature above 90C or the knock signal was present for 5 seconds or more during normal engine operation. Check your log for knock counts. Code 43 can be disabled - set bit. (Use search function to find how to do it).
https://www.thirdgen.org/forums/dfi-...help-code.html

2) IAC is wired and functioning correctly.

3) Surging relates to proportional gains which can be sometimes difficult to dial in. Also Close Loop CL surging can be related to the type and position of O2 sensor. C3 ECM proportional gains and CL algorithm were optimized with AC-DELCO O2 sensor characteristics in mind. In your original post you did not indicate your exhaust compliment nor if you are running heated or un-heated O2 sensor. You can verify that PG by disabling CL (increase
Start with getting idle dialed in by data logging from cold start well into CL idle. Since you have stock 7747 ECM you are a bit at disadvantage since ECM data stream is very slow. Before hand make sure that base timing corresponds to BIN value. Use timing light and disconnect EST connector to set correctly. Do not forget to clear Code 42 afterward. Collect enough data before making any adjustments to VE tables. For sake of experimentation you may try ASDU.bin - it was reported to be one the forgiving of all 350 calibrations out there. At the beginning of VE table tuning you'll need to disable EGR (EGR Temp On 0x1B3 by setting it to maximum).

Additional references:
https://www.thirdgen.org/forums/tbi/...ark-table.html
http://www.diy-efi.org/gmecm/papers/747spark.txt

//RF

nick9004

Hey RF, I just did some reading on BPW. I was just double checking what mine should be at. In your previous post about the injector flow rates you said the 5235206 was a 61lbs/hr and the 5235279 were the 55lbs/hr. Isn't the ...206 the 55lbs and the 279 40lbs? Also arn't the 55lbs ones right for a 350? I think the next size up is 65lbs and looks like they are the 350 "cop car" injectors and have the number 17084327. Does that sound right?

Thanks!

RFmaster

Nick
This subject has been discussed extensively in the past and there is a lot of incorrect data posted out there - just be aware. To clear up the confussion I refer you to the following.

Read post #9 by Fast355 in the following thread:
https://www.thirdgen.org/forums/tbi/...tor-specs.html

The 'cop' car injectors 65 lb/hr flow a bit more compared to plain vanilla 350 truck injectors 62 lb/hr. 305 use 55lb/hr injectors.

GM issued numerous service numbers - the best way to cut through nonsense is to flow test suspected injector and verify its flow rating. For your application 350 truck injectors should do the job.

If you need additional fuel (i.e. your VE table maxed out at high RPM, low MAP area) a small increase in fuel pressure can solve that problem. You are not even close in to that point as you need a lot more drive data captured.

First things first - you need to make that engine idle in close loop (it should as you have a mild cam) and get that surging under control (o2 sensor /single wire or heated, possibly headers). Once you get idle under control you can venture out. It would also help to know your engine / exhaust / intake configuration as this affects tuning.

//RF

nick9004

Very interesting. There are so many inccorect tables on flow rates. Thanks for pointing that out.

I am about to go out and datalog a cold start on the ASDZ to try and figure out whats going on with the surging. After I'll test the ASDU just to see if the surging is the same with that one.

My intake is an Edelbrock Performer TBI, with an open element air filter. I have stock exaust manifolds, eventually will swap to headers but not yet. I have a single wire O2. Dual 2.5" pipes with mandrel bends. Mufflers are slightly better than stock replacements.

Thanks Again!

nick9004

Hey RF, I think I've made some progress with my .bin. Heres what I've done..

I reset the IAC to get my idle into a reasonable number.

The ASDU drove good but would'nt idle when cold. The ASDZ Idled well but surged as soon as I shifted into drive. I took the ASDU.bin and copied the Main SA table along with the Mean R/L Threshold, Lean o2 threshold, and rich o2 threshold tables from the ASDZ.

I have EGR and PE disabled.

I seem to be getting an awful lot of bad data samples... Do you have any idea what kind of things cause them. With so many bad samples it is hard to see what is actually going on.

On my log there is a column "Temp - Loop Status" what does this mean? When it reads 0 does that indicate open loop and anyother number mean closed loop?

From this log, where is the next place that I should be looking at? I see that I'm rich while idleing but I also see lots of Lean BLMs during driving also I am experiencing a bog when I give it gas. After a second it recovers. The same sort of feeling that happend when my carb used to flood when i gave it gas. Can that be due to leaning out? Or do I need to get some more data at an idle and perfect that first?

Thanks Again!

RFmaster

Nick

I took a look at your latest log - too many bad data packets. I would swap out lap top to see if laptop's serial port has an issue. As you have mentioned it is tough to see, but you can use autofilter (from menu) function and filter bad packets. Basically any packet that reports voltage other than 13.5 to 14.3 (6 or 7volts for example ) is a suspect packet. There can be half a dozen reasons for bad packets - bad cable, loose header contact, bad I/O card in laptop, flaky ECM, etc. Once you resolve communications errors there is a neat VEPHD program that can calculate corrections for VE tables

https://www.thirdgen.org/forums/diy-...ng-e6-ecm.html

You should nail comm errors first.

Corrections based on a stock ASDU table
Sample RPM BLM MAP
849 1475 135 48.73 lean cruise
857 1650 140 58.69 lean
906 1850 140 62 lean
940 1900 139 64.2 lean
980 625 116 41.3 rich idle
1003 1950 133 47.25 lean cruise
1019 2025 121 34.34 rich cruise
1030 2025 133 39.14 lean cruise

In VE as % (FL1) table
Find Column 20, row 40: cell (43.75) -> 44.25 (based on #1030)
Find Column 20, row 30: cell (41.80) -> 41.25 (based on #1019)
Find Column 20, row 50: cell (45.70) -> 46.00 (based on #1003)
Find Column 8, row 40: cell (25.00) -> 23.50 (based on #980)
Find Column 20, row 60: cell (48.44) -> 49.50 (based on #940)
Find Column 16, row 60: cell (45.31) -> 46.50 (based on #857)
Find Column 16, row 50: cell (42.58) -> 43.50 (based on #849)

nick9004

Hey RF, Ive made some good progress. Have a look at my latest log. Ive got all my VE fairly close. I upped my AE Delta TPS and AE Delta Map tables by 10%. Seems to have helped me from going lean during acceleration. That still needs some fine tuning though. The log I have attached I highlighted some rows which Im going to change those VE values tomorrow morning and burn and burn another chip. I think the BLMs look pretty good other than the few that I'll fix. Am I ready to start with some timing or should I try playing with PE without a WB.

I seem to be going rich on deceleration? Isn't it supposed to be opposite (Decel Enleanment)?

One question which I started another thread for but havnt got a reply yet is... I know you shouldnt have a VE value over 100 otherwise it just means your injectors go static but what if I have... 66.00 at 3200 and 60KPA and in table 2 at 3200 I have 39? Would this mean 105 = Static injectors? If so I may have to start over and raise my BPW a bit. Which I don't really mind. Starting to really have fun now!

Also figured out my bad data... All I had to do was jump A+B on my ALDL cable and I hardly get any now. I know there is a table for the ECM to add spark in ALDL which I zeroed. Is there anything else that ALDL Mode does that I should disable so it doesn't scew my data?

Thanks for all the help!

RFmaster

It is always truly amazing to see this - once you start tuning it is tough to let it go!

1) There is no attachment in your last post - so it is tough to see.

2) It is perfectly ok for engine to go rich during deceleration. I had the same concern a short time ago. See post #922 and subsequent responses:
https://www.thirdgen.org/forums/diy-...ng-ebl-19.html

3)Stock 7747 ECM uses a pair of VE tables with one used as a RPM scalar additive. I did not spend too much time playing with 7747 VE tables - just reading how limiting they are made me to look for alternatives (I run EBL board in my ECM). I suggest that you post VE related question in the PROM forum. In a nutshell VE>100 indicates that you are exceeding 100 duty cycle of injector. On the other hand trying to tune with 162 baud ECM is like trying to listing in on a conversation inside a crowded mall! It is possible, but painfully slow!

4) I do not know about ALDL SA data capability in 7747! I do not know if there is patch available or if it will screw up your data, but perhaps that's a good question to post in PROM forum!

You can always increase Fuel Pressure (provided that your fuel pump is capable of delivering higher fuel pressure ) from stock, slightly higher, with a stiffer FP regulator spring. JET makes adjustable FP regulator. This will prevent VE's from going over 100 and provide your engine with enough fuel during PE and WOT.

//RF

nick9004

Hey RF,

Yeah I think most of this thread should have been in the DIY PROM section. Anyways seeing as I've got the high idle and knock outa the way. I might as well post further prom related questions in the PROM section.

I'd like to thank you so much for all the information you've shared with me. Without it I would still be trying to run that 454 chip on my 350... haha. Anyways thanks and maybe I'll here from you over in the DIY PROM section!

Thanks Alot!