corvair_nut

Background: I used at 1227747 ECM for a couple of years and I constantly chased the magic 128 BLM and got a really good tune, but never had a great idle and knock sensor was never really that great. Looking here, I made the change to the 16196395 ECM (OD) and installed a WB02. My Corvair runs a dual TBI-700 and runs pretty good, but only because Ive used the Wideband to tune this thing... kinda.

Car runs great, but I get eractic PW when in closed loop because I know the BLM are lying to me. I get 128 and on accasion I get a 127 on long term. The INT is bouncing around as normal, once it went down to 60 and start a lean pop...but the LT BLM stayed at 128. Ive checked about everything. Sometimes I run open loop and it hangs in the 13.5 to 15.5 range which is OK, but I want to tune this baby in. I spent a fortune getting here and really bummed I cant get the LT BLMs to move around. I know its not tuned that well as it runs smoother in open loop than closed as the PW is not jumping all around.

Ive used tunerpro, RT tuner and both show the 128 or 127 as the LT BLM and again the INT is moving around as expected. I changed out the ECM and nothing. Im open to suggestions

HELP

Ted
Anderson, SC

The_Punisher454

14.7:1 isnt necessarily where an engine will want to run at, especially at idle.

Post pictures of your EFI conversion. My dad and I were contemplating retrofitting a dual TBI to his corvair, but have instead decided to run a 4.9 Cadillac on a 4T80E transaxle. I hope to run $0D MAF MPFI on it.

corvair_nut

The conversion pics are located on my website: http://www.corvairnut.com/corvairTBI.htm

I'm know that 14.7:1 is not perfect for all engines. My point is I think that my ECM is lying to me. I can overly rich or lean this engine up using fuel BPW and it remains at 128 or just changes a point or 2 eitherside. INT changes all over just as I would expect. My INT can get so low (60) that the car starts to skip, but the LT BLM stays at 128. When I ran my other ECM, I constantly chased the 128 as it moved all the time.

Im thinking Ive got something checked or wrong. Im using a USB Cable that I bought (made my last one). I started with a bnbh bin, changed it to 6 and made all my changes for the corvair engine. I just dont understand why the BLM wont work and I wont be able to tune this engine properly until I get this working. I can post the bin on my website if anyone would please look at it.

Thanks

Ted

Ronny

iTrader: (1)

The fact that your BLM is not updating is very strange. Seems every time I datalog I see changes to BLM in range of 124-133 or so. I suspect you are not in CL as BLM is steady at 128. The few times it moves from 128 may suggest it is in CL then but falls our soon after.

Is it possible the BLM is locked at 128? some will do that and instead tune by INT.

Does your datalogger have a flag for CL? winALDL does that.

JP86SS

iTrader: (1)

Could also be that you have set the update rate for too long of a delay and it just never stays in the spot long enough to update.

93V8S10

See if the closed loop flag is set in the data logs. Also, check the closed loop temperature settings.

1tpi

Why would the int go down to 60?

corvair_nut

Brain surgery is simple for a brain surgeon. It was a simple setting as Im glad it is that simple, but it has cost me many hours of research and thought (which is good for me and my hobby).

"Max Temp for AFR Lookup in closed loop" was set to 151c, so it was always looking up and not reporting the BLM. I set it to 45c and it starts reporting. Tunerpro difference checker was a valuable resource!!!

Now I can tune and quit guessing based on my WBO2. Of course I like this thing to make sure no more "lies" are being told.

Thanks Guys.

Ted

EagleMark

I've converted a lot of engines but never a air cooled. What did you do with the CTS?

corvair_nut

This was one of the most challanging problems I faced, but finally got it. I placed it in the head near the cooling fan and then used resistor to get it where it closely matched Fluid cooling. (pic on website above)

My problem with the OD$/6395 right now is surging. The PW is moving around so much that it causing surging. the MAP/SA/IAC are all stable at 1/2 throttle, but the PW is moving all over. The WBO2 is going from 14 to 15.5 to 17 then back and forth. It also goes lean (16.5) at part throttle and the desired is 14.7, but I figured I better get the sensor under control first. I have also changed O2 sensors and used the WB analog side with the same results.

Im thinking its too much gain from the O2 sensor, but I dont which to adjust. I have adjusted everything I can, but I didnt want to play with this if someone else know the answer.

Ted

EagleMark

Surgings number one cause is a vacuum leak! The only method I have found to work is starting fluid in small bursts anywhere there is vacuum. REMEMBER THIS IS DANGEROUS!! Very flamible. It has found vacuum leaks where carb and choke cleaner, brake cleaner have not.

What about vacuum reading at idle? Is it steady? Will go up and down with RPM and surge but is it shakey? Cam specs?

corvair_nut

No... MAP is dead nuts steady. I think im having a o2 swing problem. The car runs almost perfect in OL, but when I go into closed loop, the PW starts bouncing. I didnt have this problem when I was using the 1227747, so Im betting its a setting in the 9365.

The PW is changing for example 1.20 to 1.60 and back to 1.20 while at a steady cruise going down the road and that is where I get the surge/jerking. Its not a major jerk, but I know its not near right and makes adjusting cells for BLM almost impossible. This is why I'm wanting to figure out how to "tone" the PW down so the changes are not so drastic. When In OL, the PW is steady and the MAP/SA/TPS is also until I step on it and then it moves to the next settings.


Ted

xch3no2

Is IAT available for your .bin/xdf to replace/blend w/CTS?

Minimize/disable/zero proportional gains to help settle mixture variances if you don't have converters to heat cycle.

93V8S10

Good point xch3no2. Also, disable CAT Overheat Protection if it's not needed.

corvair_nut

Which proportional gains?. In the OD$ xdf I have
PG-Unstable,
PG-Stable (These are for Idle I think).
RPM-PG,
MPG-PG
Proportional Flow Gain Factor vs MAP and RPM
Proportional counts vs slow o2
a few others are also listed.

I dont have have IAT. I did cut Pro Flow Gain Factor by 1/2 and things seem to be working better, but wanted to do it the right way.

Running this WB has given me more information than I know what to do with, but I know Im not melting pistons.

Thanks so much.....Im trying to be "schooled"
Ted

hotrod9168

Corvair,

I have the 730 ECM, it has a function called highway mode, if the parameters are right this mode will kick in and push your timing and fuel curves to strange places if not set correctly. Your issue sounds familiar to this because the highway mode cycles on and off to keep from over heating the CAT, so I have read in a post somewhere in here. Mine was dissabled at the factory.

EagleMark

Lean Cruise

corvair_nut

I'm dont think have lean cruise issues. The desired AFR is 14.7 and bouncing around 2 points on either side. In the OD$ I think you use CL AFR lookup tables for cruise AFR, but thats not what Im after (right now). Which Proportional do I adjust to "tone" down the AFR swing in the OD mask.

Ted

EagleMark

I just looked in the TunerPro 5 OD_tpv5_v225.xdf and there are 4 paremeters to set O2, this seems to be what your after.

93V8S10

Actually there are 20 Scalars and 14 Tables. Admittedly the O2 setting are one of the areas of tunning that I don't understand completely, but I believe these are the items you need to work with:
L4940 Rich Idle O2 Voltage Threshold
L4941 Lean Idle O2 Voltage Threshold
L4942 Mean Rich/ Lean Idle O2 Voltage Threshold
L4CE0 Mean Rich/Lean O2 Voltage Threshold vs Airflow
L4CE9 Rich O2 Voltage Threshold vs Airflow
L4CF2 Lean O2 Voltage Threshold vs Airflow
With this being the table xch3no2 was referring to:
L4D2A Proportional Flow Gain Factor vs. MAP vs. RPM

Lean cruise can be activated at L48C7 Maximum Temperature for AFR Lookup in Closed Loop.
If temperature less than setting, table at L4BB4 "Open Loop AFR vs. Temperature vs. Vacuum" will be used for closed loop fueling instead of L48DD "Stoichiometric AFR", but only if L400D Bit 0 "Open Loop AFR Enabled" is enabled.
Also, I think that the EGR has to be enabled as well, but I'm not sure about that.

Ronny

iTrader: (1)

Does it surge as you stated above when in open loop?

As a test disable CL by setting coolant threshold high(max) and see if surge reappears?

ThEWhitebirD

iTrader: (1)

I looked at your website.. you set up the pcm with a DIS ignition system? you just needed a crank trigger wheel? I've read you need to change the timing too something weird like 64 degrees.. are you running a v8 bin and memcal on a 6 I believe the firing rate may be different its physically different in the memcal you might need a 4.3 bin or memcal, I know the proportional gains and o2 tables are different from v8 and v6 bins.

corvair_nut

Found it...but dont know exactly why. (This is a little long, but posted for edification of others)

This car ran decent in Open Loop, but when going into CL, I got a stumble at light cruise and noticed lean WBo2 readings, while the BLMs where rich being reported from the NBo2. I wanted to tune this car against the BLMs and get a real good starting point for the future. So to sum it up... I had a NBo2 sensor saying it was rich, pulling fuel out and making the mixture lean to the point of poping and surging. At this point I didnt understand what the sensors were telling me.

First... I checked for vac leaks, exhaust leaks, etc. I also replaced both injectors, MAP, TPS. Then I replaced the O2 sensor with a known good one... same results... then a new one....again. I then added a heated o2 sensor (which I knew was the solution).... nope...try again. I was almost to the point of running in OL and tuning off wideband and let it go, but I knew something was up.

I had my o2 sensor located where the 2 banks meet. I later added another bung so I could run my WBo2 sensor and is how I found out all this. This WBo2 sensor was farther down the exhaust (about 5 in) from the NBo2. The depth of the sensor into the exhaust is the same, so Im not getting better stream from one than another. I could run off the analog side of my WBo2 sensor and all was within limits and I was able to tune using BLMs, but as soon as I went back to the NBo2, all hell would break loose.

Since I had replaced everything on the car, I switched the WBo2 and the NBo2 and the WBo2 started reading lean and the NBo2 started switching in the 500mv range instead of the 800-900 range. My BLMs were back inline with the analog side of the wBo2 and everything is running good. So it appears its like real estate... location...location...location.

Im not sure of why 4-5 in closer to the "Y" that the sensor reads so rich (full 1 to 1.5 AFR rich), but reads fine in the other location. PROBLEM SOLVED, but Im going to do a litte more research to find out why... unless someone knows right off the bat here.

Thansk
Ted

corvair_nut

Yes... Im running DIS instead of a Distributor due to the space limitations of the Corvair engine. I also wanted DIS for dependability and its COOL. I drilled trigger holes in the Harmonic Balancer to simplify the install and I didnt have to relocate the oil filter.

The V6/V8 memcal doesnt make much difference since I have to use timing offset to make the DIS work (60 degrees). If the ECM shuts down, its not going to run anyway, so I can run either with the same results (it wont run in ECM limp home mode). Bill Hamilton on the IH site figured this one out and I might be still running a Distributor if not for his guidance.

I'm back on top of the world now that my baby is running great. The difference between the 7747 and the 6395 is 2 different worlds and glad I made the change. The idle and knock control is amazing and I can tune around the wide temp swings of the Corvair Air-cooled engine.

Thanks

Ted

Fast355

iTrader: (2)

V6 and V8 memcal make a HUGE difference. I would actually look into finding a V6 memcal. The V8 memcals fire the injectors at a different rate.

corvair_nut

Maybe....Ive got my terms wrong. Im using a romulator to emulate the 512 chip. I cut the 512 chip out, desoldered and soldered a ZIF. I plug my romulator into that. The existing part (silicon feeling covered circuits) I thought was called the "memcal" that provided limp home and knock sensor info. I also have a LC-1 for monitoring AFR which is how I kept from burning this thing up when I first started running in CL.

I have one from a V6 and one for a V8 and neither seem to make any difference when I use one over the other. Before I went to DIS on the 1227747, the V6 one would run the car in limp home, but the V8 one would not. I assumed the same was true for the 6395. The car ran great before, but would run lean in CL which is how this whole thing started.

I have posted the latest 6395 OD mask bin that Im running on the Corvair. It would be great if a couple would look and the bin and give some advise. Its located at http://www.corvairnut.com/Injection.htm and select "Latest 6395 ECM Bin File"

Thanks

Ted