coyoteboy
|
| posted on 28/5/11 at 09:11 PM |
|
|
MS1 misfire...odd one on me
Been working on MS's for a while but got an interesting one on my own car. Managed to log it once, a 0ms PW at full boost.
0 pw?! by j.buckle, on
Flickr
Misfire seems to have done some damage unless I've a coincidental escape of oil from the dipstick. 
|
|
|
|
|
matt_gsxr
|
| posted on 28/5/11 at 09:21 PM |
|
|
You haven't got overboost protection turned on do you? That will force a miss-fire.
Also what is the blip in the PW on the left-hand side of the trace?
|
|
|
matt_gsxr
|
| posted on 28/5/11 at 09:22 PM |
|
|
post the whole log up if you like, I always enjoy a poke around.
|
|
|
Dusty
|
| posted on 28/5/11 at 09:27 PM |
|
|
Coincides with map hitting its peak. You haven't got a funny value for map there possibly? Or exceeding input parameters and defaulting to
something silly.
[Edited on 28/5/11 by Dusty]
|
|
|
BaileyPerformance
|
| posted on 28/5/11 at 09:29 PM |
|
|
Hi,
Are you using low res injectors?
Mite sound daft, but have you set a boost fuel cut?
Only other thing is chk injectors duty cycle, your log says 92% odd things can happen when you approach 100% duty (never go over 80%) Looks like you
need bigger injectors, i use 450cc on my 2.0L turbo zetecs upto 280BHP, 625cc over that.
If the injectors went straight to 0pw, then the engine should just stop firing (not go lean) so i see no reason why the engine should be damaged.
On the other hand if your engine has stock pistons 1 bar of boost is pushing your luck, the stock cast pistons are limited to 12PSI (240BHP), if oil
is pissing out/breathing you have ether melted a piston (lean) or cracked a ring landing (piston failure)
Under boost you MUST run 11.5AFR, no leaner, or meltdown!
Hope that helps!!
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
coyoteboy
|
| posted on 28/5/11 at 11:59 PM |
|
|
Could indeed be overboost that I've not spotted, but I didn't think I'd enabled it yet. That said, forgot I'd enabled IAT
related timing and that tripped me up last week!
It's going to be lean for a fraction of a second or so before it loses the wall-wetting in the intake, that's what concerns me. Stock
pistons in this engine are good for notably more than 12psi (12psi is pretty much stock on this engine), that said this one is running forgies and a
metal HG. However the violence of the cut is pretty shocking (worse than the stock overboost protection which is also fuel cut), so I'm off to
toddle through my msq again! I do still seem to have the odd rpm spike that's not explained and has just started to happen randomly too (never
had it before) so I'm not confident on that having done no damage either. I'll not be a happy bunny if I've trashed a piston.
Oil isn't peeing out, it's just being burned off the inside of the dipstick by the /looks/ of it. A compression test may be needed, but it
still idles fine and at 1500rpm removing the oil filler cap I see suction rather than vac, so I'm hoping the news isn't too bad!
That said, it was running a tad lean (12:1ish) at peak as shown in the log - I was trying to spot and nail that last bit of the map and thought
I'd richened it up enough to be over-rich before starting this run, seems not!
|
|
|
coyoteboy
|
| posted on 29/5/11 at 12:06 AM |
|
|
Scanned back through the logs and the peak DC was triggered due to a false accel enrich due to using mapdot and a somewhat unstable level of boost.
92% was AE on top of a 255VE cell. I am indeed pushing the limits of the injectors, I agree and I'm looking for some replacements already!
Overboost is enabled at 200kpa but according to the logs I only ever reached 196, which either means the logs didn't display the actual peak
reached/read by the MS or it's something else.
|
|
|
matt_gsxr
|
| posted on 29/5/11 at 08:02 AM |
|
|
In your log it peaks at 196kPA, but the log refresh time is about 70ms. If the boost goes above 200 for even one injection cycle (<10ms at
6000rpm) then it will cut. Remember that there is always some "noise" on the map signal (especially with MS1) and this can be seen from
the high frequency structure in the MAP curve which isn't being driven by the MAP or TPS.
If it cuts the sparks then from the driving seat it is brutal. When mine came in at 9kRPM for the first time it was like being shot (massive back
fire, stuttering power, nasty).
Probably easier to test this in practice.
|
|
|
coyoteboy
|
| posted on 30/5/11 at 01:23 PM |
|
|
Still working on the miss which seems to have partially cleared up with raised overboost, cheers for the heads-up!
Dipstick spitting cured by unkinking the pcv hose. phew!
|
|
|
