Author Topic: Car with bipolar disorder?  (Read 6695 times)

Offline dnb

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Car with bipolar disorder?
« on: February 03, 2015, 09:41:44 pm »
I found an interesting feature with my new car engine.  It's done less than 50 miles so is not even close to run in or tuned (so I know there's loads of work left to do, including finding the 10% bias in fuelling between the banks) but I did expect it to behave the same way on two occasions on the same day.

Run 1 - half past 7 at night, air temperature around 3 degrees C.
https://dl.dropboxusercontent.com/u/8968424/vems/v3.3_u004371-2015.02.02-19.26.23.vemslog

Run 1 - quarter past 9 at night, air temperature around 1 degrees C.
https://dl.dropboxusercontent.com/u/8968424/vems/v3.3_u004371-2015.02.02-21.14.52.vemslog

in run 1 the car ran quite rich (as I wanted it to do when running in) such that the average EGO correction across both banks was around 95%.  Idle was high for some reason, and the IAC couldn't reach target.  EGO correction maintained good mixture throughout the drive and didn't appear to be biassed by air or coolant temperature.

In run 2, the car ran quite lean such that EGO correction averaged 103%.   This is much less good!  Again, there looks to be no obvious bias from anything the ECU is measuring.

You should be able to see that no tables were changed between the two runs - so why is the car behaviour inconsistent?  What am I not measuring or seeing?

My first thought is that the cam sensor is not working right and the engine synchronised differently, however the cam sensor looked to be reliable when I tested it during installation.

My second thought is that fuel temperature has a much bigger effect than I thought - the car was warm for the couple of hours between runs, so the fuel would have become hotter, and there would have been less fuel for the same injected volume.

Any thoughts?
Thanks

Offline jeanno

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Re: Car with bipolar disorder?
« Reply #1 on: February 04, 2015, 08:03:21 am »
MAT is higher on run 2.  ;)
Project : Peugeot 106 Xsi 1992
Member page : http://www.vems.hu/wiki/index.php?page=MembersPage%2FJeanno
Engine is a tuned 1.6 litre 4 cyl / 8 valves (TU5J2) with 220 cc/min injectors fired individually+ wasted spark

Offline dnb

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Re: Car with bipolar disorder?
« Reply #2 on: February 04, 2015, 09:50:07 am »
Initially yes, but it drops off over the run.  In the first run mat increases.

Offline fphil

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Re: Car with bipolar disorder?
« Reply #3 on: February 04, 2015, 10:47:20 pm »
I had only quote that the battery voltage is about 14V+ in one run , 13.65V in the other. However with your injector settings this could not make a difference more than 3% in case that setting is  unecessary

Offline dnb

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Re: Car with bipolar disorder?
« Reply #4 on: February 05, 2015, 12:25:08 am »
Looking like I have an ADC problem on that ECU.  I can't get any life out of the analog inputs. :(

Offline fphil

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Re: Car with bipolar disorder?
« Reply #5 on: February 05, 2015, 08:30:18 am »
I would also have a look at the wbo2 sensors. Have you already swapped the two of them by banks?

Offline dnb

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Re: Car with bipolar disorder?
« Reply #6 on: February 05, 2015, 01:49:19 pm »
Yes.  Done the bank swapping thing.  It makes no difference.

Offline dnb

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Re: Car with bipolar disorder?
« Reply #7 on: February 07, 2015, 02:10:01 am »
ADC chip replaced.  I now have proper ADC signals again on all channels.  Hopefully this will make a difference to some of the funnies and I'll be able to monitor fuel temperature too.