jardon
Monday 24th September 2012, 23:37
Hi all,
I have had a hesitation at ~5000 rpm in 3rd at WOT. I upshift and it doesn't seem to happen in 4th. My thoughts initially were that it could be a misfire due to increased boost (17psi actuator spring) so change plugs OR the ECU doesn't like it and is doing something like retarding ignition.
My first thought was what does the ECU pulling timing feel like - I'd have guessed at flat performance rather than "kangarooing".
I have some new standard plugs to fit so that may be all that's necessary. I've got iridium NGK plugs in at present - I took them out to inspect and they seem ok. I notice they are gapped to 0.8mm which seems a lot compared to 0.7mm stock.
I logged the car with DiCE this evening (ambient 12C) and typically it was spot on and didn't miss a beat (no hesitation). I made screenshots for your viewing pleasure. Each square = 19ms injector opening, 6.6 degrees advance, 1108 rpm and 0.277 bar.
The first is a 3rd, 4th, 5th pull peaking at ~6300 rpm in 3rd. There is an ignition wobble between 4400 and 5500 rpm which isn't replicated in 4th under the same (higher?) load. That wobble was not felt in the drivers seat. At 6300 rpm I have 1.17 bar and 27 degrees advance. In 5th boost peaks at 1.4 to 1.45 bar so I think my boost gauge is probably over-reading a bit. Injector opening time peak at 17ms but 14-15ms at 5900 rpm means duty peaks at ~70% ie: using 455cc/min of the available 650cc/min. The latter confirms my concerns about greens (405cc/min) and indeed VXR injectors (470cc/min) on the P2 cars (not P2.5):
17114
Second is an uphill followed by a downhill run (3rd, 4th, 5th). Uphill there is a big but very short duration retard at 5000 rpm - again in 3rd but not 4th (odd?). No repeat downhill:
17115
Last is a run in 3rd gear to 6900 rpm and that has an ignition wobble between 6400 and 6800 rpm - again didn't feel it:
17116
My thoughts so far are that I was feeling ignition retard the other day - ambient was lower so maybe higher cylinder pressure. Also, that episode may have helped the ECU learn how much advance is OK at that point and so now it's not shooting for such an optimistic ignition value? At 6900 rpm I have 32 degrees advance and 1.13 bar. I'll monitor the situation - any thoughts?
I have had a hesitation at ~5000 rpm in 3rd at WOT. I upshift and it doesn't seem to happen in 4th. My thoughts initially were that it could be a misfire due to increased boost (17psi actuator spring) so change plugs OR the ECU doesn't like it and is doing something like retarding ignition.
My first thought was what does the ECU pulling timing feel like - I'd have guessed at flat performance rather than "kangarooing".
I have some new standard plugs to fit so that may be all that's necessary. I've got iridium NGK plugs in at present - I took them out to inspect and they seem ok. I notice they are gapped to 0.8mm which seems a lot compared to 0.7mm stock.
I logged the car with DiCE this evening (ambient 12C) and typically it was spot on and didn't miss a beat (no hesitation). I made screenshots for your viewing pleasure. Each square = 19ms injector opening, 6.6 degrees advance, 1108 rpm and 0.277 bar.
The first is a 3rd, 4th, 5th pull peaking at ~6300 rpm in 3rd. There is an ignition wobble between 4400 and 5500 rpm which isn't replicated in 4th under the same (higher?) load. That wobble was not felt in the drivers seat. At 6300 rpm I have 1.17 bar and 27 degrees advance. In 5th boost peaks at 1.4 to 1.45 bar so I think my boost gauge is probably over-reading a bit. Injector opening time peak at 17ms but 14-15ms at 5900 rpm means duty peaks at ~70% ie: using 455cc/min of the available 650cc/min. The latter confirms my concerns about greens (405cc/min) and indeed VXR injectors (470cc/min) on the P2 cars (not P2.5):
17114
Second is an uphill followed by a downhill run (3rd, 4th, 5th). Uphill there is a big but very short duration retard at 5000 rpm - again in 3rd but not 4th (odd?). No repeat downhill:
17115
Last is a run in 3rd gear to 6900 rpm and that has an ignition wobble between 6400 and 6800 rpm - again didn't feel it:
17116
My thoughts so far are that I was feeling ignition retard the other day - ambient was lower so maybe higher cylinder pressure. Also, that episode may have helped the ECU learn how much advance is OK at that point and so now it's not shooting for such an optimistic ignition value? At 6900 rpm I have 32 degrees advance and 1.13 bar. I'll monitor the situation - any thoughts?