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Thread: Missing when cold

  1. #21
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    Ok, checked the air filter, it looks pretty good. Was replaced Jan last year, so guess it would be a good idea to replace it, but I don't think that's the issue atm.

    Re measuring blocks, is this what you are expecting to see?

    Missing when cold-20191028_232549-jpg

    Thanks

  2. #22
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    I do a lot of kays and generally do my filter before any track events. I couldnt have been longer than 2 months interval and it started basically kicking over into cold start and after the initial burst where it fired to life it would splutter for a second or two like it had a miss, and then come good again until the cold start routine was finished and the idle settled. Filter had every kind of insect/dust etc, blew it out and problem gone. bizarre. It could be that they are running them very specifically at cold start for emissions reasons that the slightest unexpected flow through the maf or whatever and it chucks a wobbly. Maybe the dirty filter has it run richer than it wants for that first fire up so it quickly tries to pull fuel out resulting in misses? - not sure but thats all it was with my car. I'm up to about 30 miss free cold starts when previously every second or sometimes all the cold starts being bad. You could just make sure the airbox is clean and do a test start with the filter removed to test the theory.

  3. #23
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    oh and RE the vcds stuff, block 031 should be updating constantly even at cold start. Block 032 though will only start showing STFT trim changes when the cold start/warm start routine finishes I think. Its long term fuel trim LTFT usually needs the coolant temp to be greater than 75 degrees + some other conditions before you'll see it appear and getting it to update can take sometimes a long drive in cruise mode ie closed loop. If your block 032 trims dont eventually appear/update, let yus know cos there's a couple of simple things that can cause that other than say a dud 02 sensor.
    You could also monito block 091 I think it is - it'll say 0.00 or 20.0 degrees cf. That shows inlet cam advance. It advances to 20cf = 20 crank degrees only at cold start up. If its not doing that then you might have a weird cold start because the cam is all over the place due to a dud chain tensioner or the cam advance solenoid isnt moving the cam.

  4. #24
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    Quote Originally Posted by sambb View Post
    oh and RE the vcds stuff, block 031 should be updating constantly even at cold start. Block 032 though will only start showing STFT trim changes when the cold start/warm start routine finishes I think. Its long term fuel trim LTFT usually needs the coolant temp to be greater than 75 degrees + some other conditions before you'll see it appear and getting it to update can take sometimes a long drive in cruise mode ie closed loop. If your block 032 trims dont eventually appear/update, let yus know cos there's a couple of simple things that can cause that other than say a dud 02 sensor.
    You could also monito block 091 I think it is - it'll say 0.00 or 20.0 degrees cf. That shows inlet cam advance. It advances to 20cf = 20 crank degrees only at cold start up. If its not doing that then you might have a weird cold start because the cam is all over the place due to a dud chain tensioner or the cam advance solenoid isnt moving the cam.
    Sam, sorry for the delayed response. Finally had a chance to to it for a decent drive with VCDS. Regarding block 091, I had taken the car for a drive about 2 hours earlier and it's a 25 degree day here, so although the temp gauge was at the bottom, it may not have been completely cold. The CF reading I had then was -2.0. During my 40km drive that moved up to +1.0. Doesn't really line up with what you say above but maybe it wasn't cold enough?

  5. #25
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    Regarding the other blocks, if you are implying I should be seeing those empty fields with data in, well this is what it looks like after 40km of driving...
    Missing when cold-20191130_154223-jpg

  6. #26
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    no those bin bits field dont matter. But maybe a bit of concern re the block 032 lambda (multi) value. -20.3% means its pulling a lot of fuel. Have you made any mods that would be over fuelling it recently?

  7. #27
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    Dunc, what's the performance like. Any chance that you have a boost leak? Most of the time I see fuell removed at idle and LTFT.
    Try logging 003 115 and 118 from 1500 revs to say 6k. Then message me the log

  8. #28
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    Quote Originally Posted by sambb View Post
    no those bin bits field dont matter. But maybe a bit of concern re the block 032 lambda (multi) value. -20.3% means its pulling a lot of fuel. Have you made any mods that would be over fuelling it recently?
    Nothing I can think of. SAI delete was the most recent engine related mod, but I was having this issue prior to that. Bear in mind I'm running a catless DP with Gav's stage 2 tune...would that impact those figures? It's not going to be unhappy on the 98 RON E10 fuel I feed it? Thanks for your help.

  9. #29
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    Oh ok yeah it could be the tune. My tuned cars have always been out of the expected multi % ranges. 98 RON E10? Our E10 is only 94RON here. Our 98 RON is pure pure petrol 98.

  10. #30
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    Quote Originally Posted by sambb View Post
    Oh ok yeah it could be the tune. My tuned cars have always been out of the expected multi % ranges. 98 RON E10? Our E10 is only 94RON here. Our 98 RON is pure pure petrol 98.
    Yep 98 E10. Force 10 >> Gull NZ
    We can get 98 RON pure petrol too (probably comes from your side) but its a bit more expensive and I figure some E is good for our boosted cars... They do E85 in some select locations...I've not tried it.

    Any more thoughts on why my car is running so poorly? Cheers

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