When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Thanks Mike. Ya I'm real happy to finally get this sorted out. I'm sure I will be adjusting the tune for quite sometime but at least now its all setup, working and driveable.
I think it was both changing the location and changing to the 4 wire NB that helped.
Changing the location of course lets it read all the cylinders on one side rather than just #7. (The WB monitors the other side) so that proabbly makes it more accurate. Of course since I have headers the sensor is a bit farther away from the head than would be ideal so the idea with the 4 wire is that it keeps the NB O2 sensor hot enough to read properly at all times, thus allowing it to work even though its a bit farther down the exhaust tract.
I could have tried just moving the 1 wire NB and see if it would work but, I was getting tired of messing around with it and wanted a solution that would work for sure.
Here's a couple picture I grabbed today of the work that was done on the corvette recently.
We tied into the MAF circuit that the relay on the left in order to get 5v reference wire so the heater on the NB only runs when the engine is running.
Here is the new 4 wire NB heated O2 sensor installed on the driver's side exhaust pipe just behind the header collector.
I spent a a short time today playing with a few things in the tune to help the car run a little better. The next step will be a road test, and trying some VE learns while driving, hoping to get a little time this long weekend.
So I spent a few hours driving the corvette and working on the tune.
I am not a pro at this but I think I got the high speed VE table about as good as I can get it. Including WOT. The AFR at WOT is a beautiful 12.5:1 pretty much from idle to 6000RPM. The engine is very strong at low and mid range and seems to make peak power around 5400 RPM then the power gradually drops until 6000RPM (redline). The BLM when driving seems to be around 128-130 which seems ok. I found it super useful to watch the wide band gauge, then just maunally adjust the VE table.
I also managed to get the low speed VE table about 90% done. I also did VE learns until they were only 1 or 2 point adjustments.
The only 2 remaining iasues are I have it idling real nice but when forst starting or coming to a stop it surges a bit with the RPM flucutaing about 3 times before settling down. I also seem to have a rough spot at low MAP around 1700-1800 but I can't see a reason for it on the VE table and the VE learn isn't correcting it. Other than that the car runs wonderfully now.
I have to say for a little bit I was worried I wouldn't get the tune/wiring sorted out, so its nice to finally have it almost done.
Congrats! Glad to hear that you have gotten an opportunity to drive the car, get some tuning done and that things are working out! I have copied and pasted exactly what is recommended by Bob on dynamicEFIs website (Introduction to tuning part 2). Hopefully this helps! As for your other issue, i'm guessing it is the same issues that is causing the surging. I would raise the VE table in those 800-1800 rpm ranges and see if that helps both surging and rough spot. Although I know when mine was running to rich, it seemed very rough. Take a look at the parameters that control when VE learns take place. Should be named BLM-MAP learn threshold and BLM-RPM learn threshold. You may need to adjust them to allow for VE learns to take place in those 17-1800rpm range. Let me know how you make out, as I'm still learning too! Bet the car runs much better now than before with your old ECM!
"Deceleration:
At times deceleration can be troublesome. If too lean the engine can start to surge. As the vehicle slows to a stop this surging can carry into idle mode. Which can result in the engine stalling. Best bet here is to manually increase the VE in the low MAP areas of the RPM being used. This is usually in the idle to low RPM range of the engine.
You can un-check the forced open loop during decel option to do a VE Learn. However, since prop gains will then be active and the AFR will get leaned out some. It is easy to get surging during decel. This surging is why the decel is open loop in the provided calibrations.
Another issue is that during decel the PW gets small. Very little fuel is required. So it is easy for closed loop INT/BLM to rise and fall while being unable to control the actual AFR. This time it will start to buck as the fuel comes in and out.
Increasing the injector compensation offset will help in this regard. Which is required for proper control of the injectors. But it doesn't always correct the surging.
An aspect of decel is that the air/fuel density in the chamber is very low. Which is difficult to light off. So a little extra fuel goes a long way in preventing misfires. And it isn't really a lot of fuel.
This extra fuel also helps when the engine drops into idle. Otherwise idle can start to surge before either settling down or stalling (it's usually one or the other)."
Thanks so much for your help MikeP84, it is much appreciated. I will definietly try raising the VE table in the low MAP area and look into the VE learn settings.
Ya after a few hours working on the tune the car is already running much nicer than last year.
So I spent about an hour today driving the car and working on the tune. I tried using the WB O2 for the VE learns, it worked well and seemed to more or less get most of the minor rough spots fixed that I noticed today.
I tied all of the suggestions on the dynamic EFI site for eliminating surging on decleration and I didn't notice any real difference. Aside from that I think the tune is about as good as I can get it with my limited experience. So not perfect but not bad.
I'd like to try and see if I can do a VE learn with the WB in the open loop deceleration part of the VE table as I think it would help, I just can't seem to figure out how to do that as the VE learn for the WB right now only seems to work in closed loop. If anyone has any suggestions please let me know.
I also spent a little time thinking about where I should mount my WB gauage and decided the driver's side A-pillar would be a good spot so I ordered a A-pillar with a single gauge mounting spot. It will be nice to get the wiring cleaned up and WB gauge off the passengers side footwell!
So I made a quick trip down to the states and picked up the A-pillar gauge pod from my US shipping address.
It seems to be designed to fit a C4 corvette perfectly...
I was originally concerned an A-pillar pod might create a blind spot, but thankfully it seems it was well designed so no blind spot I am planning to perminiently mount the WB gauge in it and clean up all the EBL wiring this week.
Good to hear that your driving your car again. Ya there is always something that you have to adjust. Mine bogs abit on acceleration when the motor starts to get hot (around 200 deg'C)
I run a dual gauge pod on my car. I must of knocked the pod off the pillar a dozen times driving my car, as it get very close to the steer wheel with you hand during fast/quick turns. I run electronic autometer water/oil pressure cobalt blue gauges.
Congrats on getting the computer sorted, I personally would gave up months ago with the factory stuff.
Thanks Mike hope you are doing well. Ya it was a bit of work getting EBL flash all up and running properly but it finally seems to work good now and for the price I can't complain.
For sure I imagine I will be adjusting/ tinkering with the Tune for quite a while, but I think one more day/evening of adjusting it and it should be about pretty close.
That is a good point about the clearance from the steering wheel, I did notice that when I was mocking everything up, but I couldn't really think of a better place to mount the gauge. Hopefully since I have smaller hands I won't hit it too often.
Hey Guys, so I didn't have a ton of time today but I did manage to get started mounting the WB A-pillar gauge pod.
The first order of business was to run all the wiring from the ECM to the A-pillar on the driver's side.
I had to pull the A-pillar trim and the dash off in order to run the wires.
After running the wires I drilled a hole in the A-pillar and ran the wires through the hole then put the dash back together.
All the wires are now run and I just need to connect all the perminent wiring to ECM etc... and remount the ECM under the dash.
I also ran the COM port wiring for the computer/ laptop connection into the glove box, thought it would be a good place to hide it that is easy to acess.
And that's as far as I got today, hoping to tidy things off this week...
I admire your "can do" attitude, David, as well as your willingness to just dive in and do it! 'Glad to see that the car's up and running - maybe bring it out to Dan Ward's place @ Cultus this Saturday for the BBQ?
I admire your "can do" attitude, David, as well as your willingness to just dive in and do it! 'Glad to see that the car's up and running - maybe bring it out to Dan Ward's place @ Cultus this Saturday for the BBQ?
Thanks Loren, nice to talk to you. I enjoy getting to learn new skills. This project took a little lomger than I would have liked due to other life priorities coming first but I'm glad its just about done now.
I would like to bring it on Saturday, but with a new baby I don't think I can get away for that long... However, my wife and I have arranged for some child care on Friday evening so we can go to the 'White Spot Friday' and cruise.
Just as a quick update, Yesterday evening I drove the Corvette to my friends place and we finished up all the wiring and got the WB gauge mounted on the A-pillar.
I did notice a number of small issues with the tune while driving to my friend's and back in addition to the surging on decel issue. I did make some changes in tunerpro as a result but haven't had a chance to test them yet.
I'll try to post a coupe pictures of the mounted gauge tomorrow.
Here is a couple pictures I took this morning of the WB gauage mounted on the A-pillar:
I was a little worried I might knock the gauge with my hand while steering (as mike had noted) But it looks like given the position I put the steering wheel that shouldn't be an issue. (I could see it being an issue with a dual pod A-pillar though).
Well Guys, I will proabbly be tinkering with the tune for a while as I learn more but, I don't think that will be very exciting reading so I think I can call this build completed and wrap things up here as I don't have anything else near term planned for the Corvette other than driving it and tuning.
Since there is still a little summer left I have a few 'events' I plan to attend with the car, the first of which is tomorrow evening, should be fun.
Thanks to everyone for taking the time to read and give me input on this build, I know this thread has been going for 1.5 years (plus my previous build thread) so thanks for waiting while I got eveything figured out. All the best, and see you guys around the forum, or if your local maybe in person.
08-02-2018, 12:04 AM
