New project Corvair rail buggy, TBI, $0d, 7427

Hi guys, helping a buddy install a TBI on his corvair rail buggy. This buggy has been built longer than I have been alive. Until recently he flipped it and had to totally redo the roof of the buggy. Cut the old bent roof off and fabricated a new one. Also made some small doors.

Anyway here is what I put together for him. Thought some of you might like to see it.

Got it running but have a lot of tuning to do.

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I'm just now getting to read this thread. What a neat project! I'm guessing the EFI is a new addition? Nice job on the minimalist harness. It must be a blast to drive.

Cool Project!

Thanks. It needs a lot of tuning. Turns out this engine has pretty low vacuum. It idles at like 60-65 KPA. I have been wondering if there is a way to know for sure which VE and Timing table you are using. I know there are a few tables that use TPS and MPH to change to the off idle VE, and open throttle spark tables. I am trying to make this as simple as possible. It seems like its going lean on part throttle and WOT throttle. I am wondering if its even moving into the off idle VE table. It using stock 350 injectors so I know there should be plenty of fuel.

There is no VSS so I have that disabled.

If I get it somewhat lined out, i was going to try running it in closed loop. I have an 02 wired in, and also the engine temp is connected to a remote oil filter. Right now its in open loop only.

he is getting ready to drop it off at my house so I can take my time with it. I have been running out to his house for a couple hours a night and just cant get anything done.

He made the distributor. Its a Corvair and 4.3 V6 hybrid. I will try and get a picture of it.

$0D has an idle flag in the datastream. You can separate the data using this flag to know which VE and which Spark table it is using. You can also set the TPS % to switch between idle and off idle tables since you are not using a VSS. If needed, I can send screenshots.

Brian

Quote:

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Originally Posted by sturgillbd

$0D has an idle flag in the datastream. You can separate the data using this flag to know which VE and which Spark table it is using. You can also set the TPS % to switch between idle and off idle tables since you are not using a VSS. If needed, I can send screenshots.

Brian

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I started over with a fresh bin, which fixed a few of the goofy issues I was seeing. I also watched the Idle flag and it seem to be working correctly. So, it looks like I am moving into the off idle VE and timing tables.

One of the issues I am having at idle, which has been the same between two different bins, BJLF and AIXZ. I can start the buggy, starts good, and idles good, then I can rev the engine and when it returns to idle something noticeably changes becasue it will idle a tad bit leaner than it did right after startup. After running for about a minute or so the injector pulse width drops from about 1.2 to .4 usecs, it goes lean and dies. I have the closed loop temp setting maxed out, all o2 sensor bits are off and the o2 sensor is unplugged. I am having a hard time figuring out what is causing this. It only happens a minute or so after you rev the engine up. If I start it and do not rev the engine, it will idle fine. There is some kind of timer or setting that I am missing.

I am also wondering if it is temperature related. The buggy is air cooled. I have the temp sensor installed in a line that would allow the sensor to read the temp of the engine oil, instead of coolant. The engine oil gets pretty hot, 212-220 degrees F.

I have also tried to run the buggy in closed loop. Which is not working becasue the o2 sensor is not switching. The BLM's head up to 140, and the
engine goes way rich. I see the same effect happen on cars with headers and big cams.

I also tried the trick of forcing PE at idle, which you can see in this log, but it still goes lean and dies at idle.

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Ill download and look at the datalogs etc in just a few mins

Ok, when in closed loop with O2 enabled, does the O2 switch when engine is held off idle? IE held at 1500-1800 RPM? Disable CCP and and Turn up EGR ON temp to max. See if that helps. You may need to play with spark table quite a bit too. Seems like those engines idle with a high map (low vacuum).
See if disabling CCP and EGR helps

Brian

Quote:

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Originally Posted by sturgillbd

Ok, when in closed loop with O2 enabled, does the O2 switch when engine is held off idle? IE held at 1500-1800 RPM? Disable CCP and and Turn up EGR ON temp to max. See if that helps. You may need to play with spark table quite a bit too. Seems like those engines idle with a high map (low vacuum).
See if disabling CCP and EGR helps

Brian

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I thought I had those disabled. I will go back on look. I will also try and see if closed loop works off idle.