Diagnosing Knock Retard Issue

Post 796530 by Dangerous Dave on 2016-02-13 17:35:42

After fitting an MBC and tweaking the ecu on the Blue AWD I ran into an issue with stuttering when accelerating. So to fix it I needed to know what was going on. Time to flash the datalogging ecu map being developed on Volvospeed. So after editing the maps to suit the 2.5MPT I flashed the map to a spare chip and put it in the ecu. I have a small netbook running windows xp spare so connected it to the obd port, started the logging software and went for a drive. From what I gather reading the log is the timing was too high at certain rpms/load and the ecu was retarding the timing. This was only happening at the low rpm/load range, once I stripped the data down to just the knock events the problem area was 2ms to 5.5ms around 2500-3000rpm only. Comparing the 2.5LPT ignition map to the 2.3HPT map the timing was a bit lower in these areas, so I transposed some of the values in that area of the ignition map and flashed it to the ecu. Took it for a drive and the timing issue had all but gone save a few tiny hiccups (the engine management light flashes when knock is detected) so a little more tweaking is needed but there is no more stuttering during acceleration. Now I just have to get the Green AWD started and datalogged :)

Post 796559 by MoleT-5R on 2016-02-14 11:05:12

Nice work Dave looks like you've got your head around that ok then.

Post 796573 by Dangerous Dave on 2016-02-14 16:55:43

Was quite simple to narrow it down, the KRcount is the log of knock detection so just used the filter option in the spreadsheet to narrow it down to the detected knock events.

Post 796784 by Dream3r on 2016-02-18 00:50:38

[QUOTE=Dangerous Dave;796530]After fitting an MBC and tweaking the ecu on the Blue AWD I ran into an issue with stuttering when accelerating. So to fix it I needed to know what was going on. Time to flash the datalogging ecu map being developed on Volvospeed. So after editing the maps to suit the 2.5MPT I flashed the map to a spare chip and put it in the ecu. I have a small netbook running windows xp spare so connected it to the obd port, started the logging software and went for a drive. From what I gather reading the log is the timing was too high at certain rpms/load and the ecu was retarding the timing. This was only happening at the low rpm/load range, once I stripped the data down to just the knock events the problem area was 2ms to 5.5ms around 2500-3000rpm only. Comparing the 2.5LPT ignition map to the 2.3HPT map the timing was a bit lower in these areas, so I transposed some of the values in that area of the ignition map and flashed it to the ecu. Took it for a drive and the timing issue had all but gone save a few tiny hiccups (the engine management light flashes when knock is detected) so a little more tweaking is needed but there is no more stuttering during acceleration. Now I just have to get the Green AWD started and datalogged :)[/QUOTE] You've taken a higher compression map and stuck it on a HPT car, much better lowing timing advance on the stock map imo but you should be able to add more! What is the CR? There was bad knock there man wow, fueling looks off also , probably the reason, add more fuel post spool or re-check your maf setup ;).

Post 796926 by Dangerous Dave on 2016-02-20 12:58:51

Cheers bud :) Sorry, I should have posted more specs. The engine currently has the standard 13G turbo on it and the CR is 9:1. The ignition map was originally the stock LPT map and the fuelling is the stock map for the LPT (which has generally higher values than the HPT). I compared the stock ignition map to the HPT map and it was those areas that were lower on the HPT map so I used them. The other values remain the same as the stock map (as there are no issues at higher load at the moment so leaving that alone for now). The fuelling is all over the place, there may be a problem with the lambda sensor as it wasn't the best before changing the map. I have a new sensor to fit just to make sure.