Ony- I assume you have done some tuning on your 4.3 V6. Would you let me take a look at your bin file? It's ok if you don't want to- don't want to overstep the bounds
thanks
Ony- I assume you have done some tuning on your 4.3 V6. Would you let me take a look at your bin file? It's ok if you don't want to- don't want to overstep the bounds
thanks
probley should start your own thread, here is a bin for a standard shift that is a sync bin, my truck is a std trans I am running a 288 ecm right now this bin is for a 7747 it has lean cruise employed in it. you might use the timming and ve tables as a starting point.
Thank you Ony!
Just when you guys had thought I had dried up and blown away, I'm back. I saw the thread taking a different direction and that made me feel a little better about nagging you guys with my problems. It seems the discussion has helped others!
As I had mentioned, the solenoid idea was a lot better in theory than in reality. So that's history. BTW I have a really powerful 12V push type solenoid for sale really cheap :)
Someone here had noticed in my data that my BLM value was way off. Way too lean. The first thing I did was plug up one side of the duals and force all the exhaust through one muffler. BLM value dropped quite a bit. Then I went on to adjust the fuel pressure. Last time I checked the BLM value was about 133 or so, down from 150. I haven't tried to drop it any more because I think I'm out of adjustment on my home-modified OE fuel pressure regulator. Enriching the A/F ratio has been the most significant improvement in the idle quality since the truck has been on the road.
Still looking for the Holy Grail of pre balance shaft Chevy V-6 idle, I decided to try the 0 or near 0 IAC count approach, except I didn't do it by zeroing out the IAC with the computer. I simply raised the minimum air stop slightly until I found a sweet spot in the idle while in drive, which turned out to be 600 RPM. somewhat less than what I had asked EagleMark for initially because when he burned my PROM, I hadn't addressed the BLM issue yet. I wasn't even aware of the problem until it was pointed out to me. BTW I'm running the stock PROM again. Of course on the next restart, the IAC simply throttled the engine down a little to defeat the change I made. So, another little tweak of the minimum air screw was done, again to get me back to 600 RPM in drive.
I have been kicked in the ass often enough by this engine to be very wary of declaring victory over the General and his legions of software engineers, however, the truck is now idling rock steady and quite smooth at 600 RPM in drive and it climbs to 750 in park. The idle quality is close if not equal to my 2012 4.3 Sierra. Now all i need to do is unplug the 2nd muffler and see if my BLM value and idle quality hold.
Last edited by 1great40; 05-10-2015 at 08:28 PM.
Have you had any changes made to the VE and spark tables, or any other parameter for that matter?
Sure sounds like you are trying to force the ECM to operate out of it's programming by mechanical adjustments.
I don't know everything about the programming, but I think you are eventually going to have to make some changes in the programming.
Its a completely stock PROM that came out of the Astro van I got the engine out of. Forcing the ECM to operate outside of it's programming is exactly what I'm trying to do and from what I understand about how the ECM controls the idle, this is possible. Time will tell. I have already spent money on a failed attempt to fry up a new PROM since I didn't even have my A/F ratio in the ball park when I asked EagleMark to start changing stuff for me. I think from what I have read on other forums and my personal experience that a mail order PROM will require multiple iterations and multiple disappointments. This EFI thing is very likely something I wouldn't incorporate into my next project although, while I'm still a flaming rookie, I have learned a bunch of stuff that would certainly put me way up on the learning curve if I were to do it again. I guess my main frustration is that my initial intent was and still is to do a simple transplant of the EFI engine into another vehicle and get it to run as stock. This has proven not to be worth the time it has taken me to get there. I have no intention of buying a bunch of hardware and spend my free time burning PROMS in my garage, just to get 1 engine to run reasonably well.
glad to hear you making progress. another member was having fueling issues after putting on custom duels last year I don't remember the thread.it was on a v/8. when you open the other muffler up the blm will proble go up, have you got a heated o2 sensor?
No, it's just a 1 wire 02 sensor
Originally Posted by 1great40
Here is my learning curve, I've installed a TBI on a GM 3.4L 60 degree V6 that never came from GM installed with TBI in any GM application. The TBI system came from a GM 2.8L engine.
I can tell you from my personal experience that one iteration of programming will not fix everything. Watching my logs, any minor changes in the VE and/or spark table, the effects aren't immediately seen in the first few minutes of driving after changing the PROMS, especially if you completely disconnect the ECM. I've got a ZIF socket installed, so I just swap the prom and drive. I'm still making changes, especially into areas of those tables that I don't touch too often. I'm also going to have to watch and make changes as summer takes full effect because I started tuning while not having to run the A/C. I don't expect to see much though.
I don't believe I'm the only one that would tell you that minor environmental changes do affect the BLM/INT values. I see it in my logs. I've had EagleMark remind me of this when I first started out because I was so focused on having the BLM's running 128 exactly regardless of environment. Just ain't going to happen.
You kind of contradict yourself when you state,
"I guess my main frustration is that my initial intent was and still is to do a simple transplant of the EFI engine into another vehicle and get it to run as stock. This has proven not to be worth the time it has taken me to get there. I have no intention of buying a bunch of hardware and spend my free time burning PROMS in my garage, just to get 1 engine to run reasonably well."
If the engine you are transplating the TBI to is the same as the engine the TBI came from, I can see the frustration, but dropping a TBI system on a different engine, it's just not going to be that simple.
The programmers and eprom erasers can be had for less than 75 bucks. You might find tuning a lot easier and less frustrating if you had your own or more frequent access to them. If you lived near me, I'd volunteer to help you on that.
I'm not trynig to be an a55, but it seems that you are looking for the easiest mechanical kluge to force them ECM to do things that it will always continue to fight doing when you could be reprogramming it with all the hassles you are having.
I have forgot what type exhaust you have,if it is true duals 3cylenders would have a hard time heating the o2 sensor at idle to keep it in closed loop.thats why I ask if it was a 1 wire.
yeah, I guess I wasn't clear... 1989 GM Safari (Astro) Van 4.3...take it out of one vehicle with the ECM and bolt it into another. The differences I quickly learned were fuel pressure, even though the guys I bought my fuel pump from swore up and down I was good to go, I had to modify the internal TBI fuel pressure regulator to get the fuel pressure into acceptable (9-13 psi) range and then I had to adjust the fuel pressure to compensate for reduced backpressure at idle. That's why I kept mentioning the stock aspect. I was hoping to do minimal engineering to get the engine to run the same way it did in the donor vehicle. I wouldn't consider adapting TBI to an engine that wasn't running TBI to begin with, at least not for my first rodeo. I don't think you're trying to be an a55, you're right, I am looking for the easiest mechanical kludge and I may have found it :) Lets put it this way: when all you have is a hammer, everything becomes a nail.
Let me ask you this, If I'm going to run a TBI engine, with it's stock ECM in another vehicle, what would make me think that the ECU would have to be modified to get the engine to run the same way it did the day before I took it out?. I would think that since it was determined the fuel pressure and back pressure were wrong, the best thing to do would be to address the fuel pressure and backpressure, not change values in the PROM. I'm not sure where you got the impression that I'm looking for a rock solid 128 for my BLM come hell or high water. I never understood it to be necessary. All I said was that it was pointed out to me that the engine was running excessively lean, and I set out to address that issue by tuning the exhaust to more closely resemble the exhaust system the engine was initially calibrated around and adjust the fuel pressure towards the higher end of the factory specification, which results in an enriched mixture without changing the injector pulse width. Around here, we call it fixing what you know is broken before you try to fix anything else.
Ony,you make a good point about the 02 sensor. The exhaust is true duals with a crossover pipe. I believe I have noted only one instance where I saw the engine drop out of closed loop and that was after an extended period of idling. The exhaust is going to be changed to single soon. That's the way I'm running it right now by plugging one muffler anyway.
This is where I am kind of confused because even though the engine and ECM came together, and then installed into a different vehicle, technically, I would not call the setup, "stock", as a whole.
Apparently there are enough differences in the fuel supply/return system, and, the exhaust system that have caused the issues you are having.
For my truck, it just so happens that the fuel supply line and return line are the same diameters, and honestly, I'm not aware of what my return line backpressure is. I just know that I'm running about 13 psi at idle and that my BLM's in the areas that I drive the most are pretty close.
For me, I took a 3.4L out of a camaro, installed it into my S15 truck. S15's never came with those. GM never mated TBI to the 3.4's either, but I did. A few others have done the same, but I know they've not done any tuning either.
In any case, over the course of a year and a half now, I've made more modifcations that have affected the blm/int tables.
One of which was adding Edelbrock long tube headers. Then, I went from a 2.8 throttle body with 1 3/8" bores to a 4.3 throttle body with 1 11/16" bores. Those changes alone caused me to have to up the fuel pressure a little bit along with adjusting the VE and timing tables.
If I may suggest, dump that single wire O2 sensor and get a heated 4 wire.
Hi Guys, I don't get back to Gearhead too much, and I know you all have nothing better to do than hang out and hope I'll post. I have been driving the truck for a few hundred miles now since I pushed it to the "0 IAC count" mode. I was only seeing an IAC count of about 10 or so anyway, so the change I made only really involved less than a half a turn on the minimum air setting. I have not logged any data yet since just about a hundred miles or so ago, I made a hard piped change to a single exhaust and then I had to disconnect the battery to do some electrical work, so I need to put a few miles on it. All in all it seems to be running well. It will be interesting to see where the BLM value falls, I just want to be sure it's still not running lean. The lack of cold hesitation I was initially experiencing along with a little blackness in the tailpipe are a seat of the pants indicator that it's richer than it was before I started fooling with it.
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