corpi
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| posted on 14/7/09 at 09:06 PM |
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What could cause these pauses in MSnextra?
On starting the engine, it runs fine for a few moments, then "misses" irregularly, as you can see from the attached log file the pulse
width drops to 0, the revs too, but the engine keeps running. MegaTune shows NO restarts/reboots!
When this happens I can hear the fuel pump relay clicking. So it looks like MS decides is does not need to power the fuel pump etc. It happens so
briefly that it's difficult to measure current. Besides when you wait for it, it does not happen.
It's less (obvious?) when driving but still very worrying!
any suggestions are welcome.
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MikeRJ
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| posted on 14/7/09 at 09:10 PM |
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Are you definitely getting a good signal from your crank sensor? The signal amplitude from an inductive pickup is proportional the engine speed, so
it could easily be marginal at low engine speeds and get better at higher RPM.
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omega 24 v6
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| posted on 14/7/09 at 09:20 PM |
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You're profile says your running webbers?? So why Msn extra?? and why pulsewidth if there are no injectors??.
I'll have a look at your datalog now but we'd need all the current relevant info on your setup.
When you load your rpm into the graph it follows directly the dip/drop in the pulse width.
Also at this low point the "run" light goes out which would lead me to believe the crank signal was the problem
My Xe was a nightmare to get right ( but it seems to be ok now)
[Edited on 14/7/09 by omega 24 v6]
[Edited on 14/7/09 by omega 24 v6]
If it looks wrong it probably is wrong.
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robocog
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| posted on 14/7/09 at 10:41 PM |
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Just had a quick look at the log and the reason for the fuel pump cutting off is because run goes to No right where those spikes are - in otherwords
it is turning off- hence fuel pump cutting
Also it looks like the spark advance is jumping to 20 degrees at those points
(cause or effect?...not a clue as I say it was only a quick glance through megalogviewer)
Whats the advance set to on the first bin (no load and low rpm?) or crank RPM?
also
Looks like there is a correlation in voltage spikes at 3 of the "events" - but not all so could be a red herring, and they don't
look menacing looking at the numbers alone
Will have another look when I'm less tired and have thought about it :-)
Post the MSQ and what config you think your running as it may reveal something in the configuration?
Regards
Rob
[Edited on 14/7/09 by robocog]
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corpi
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| posted on 15/7/09 at 07:17 AM |
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I've converted an XE on Webers to MS2 using GSXR 750 TBs and injectors at 4 bar which seems to flow enough. 85% injector duty.
I'm using the standard XE VR pickup. Driving a single coil from MS2 using the standard distributor.
I ran this for a while using standard MS2 firmware and speed density. but could not get it to run properly.
I've done 2 things since. changed the VB921 to BIP373 (number from memory) to increase reliability, and I have moved to MSnExtra 2 and Alpha N.
Before I made these changes, in never had any missing etc. (OK it would not idle properly when cold so I kept my foot on the throttle until it was
warm enough to idle by itself. so possibly I circumvented the issue.
On the advise of this this forum (FBB especially) i have upped theidle with the idle screw and moved the advance to 3 degress to get it to idle
properly. there is one extra RPM box at 500 RPM with 20 degrees advance so when it idles lower that it's supposed to the advance goes up to
compensate. this works a treat!
this morning i drove it to work about 55Km mixed motorway and main roads: At cold idle it missed a couple of times again, but for the rest it behaved
properly (needs some more mapping at motorway speeds. but nothing serious.
Except for the last bit where I gave it some, and it died for a moment or 2 twice under high load and about 5500 RPM. a very quick look at the log
showed: voltage drops and a resultant reset. also i noticed that the IGN LOAD value goes from 0 to 65555 sometimes. what does ignition load
show/measure??
all help appreciated! going to the Alps starting Saturday. So I a bit of trust in the car would be nice...
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omega 24 v6
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| posted on 15/7/09 at 11:21 AM |
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3 degrees advance at idle??? Seems way to low. Mines is 10deg
Not familiar with ms2 myself but you could post your msq for us to look at as well.
If it looks wrong it probably is wrong.
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MikeRJ
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| posted on 15/7/09 at 11:45 AM |
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Probably worth taking the MS PCB out of the housing and looking over the solder joints with a magnifying glass.
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fatbaldbloke
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| posted on 15/7/09 at 12:17 PM |
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quote:
3 degrees advance at idle??? Seems way to low. Mines is 10deg
It's the subject of another post, but it's all to do with not letting the throttle butterflies on the GSXR TB's get too shut at idle
to avoid a little flat spot just off idle. For sure, if you don't get this problem 10 deg is a good timing idle, but retarding the ignition and
compensating with increasing the idle throttle stop is just one neat way of getting away from the flat spot.
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corpi
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| posted on 16/7/09 at 09:55 AM |
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Update:
I've rerouted the cable from the VR sensor, which ran through the chanel between the camshafts where the Spark plugs are. (it is the way
Vauxhall/Opel run them??) and I believe the missing just after starting is now gone :-)
Remains the other problem, but I believe that is more an electrical than and injection problem.
I was "lucky" that it died completely and utterly on the way to work this morning. Nothing works: lights, engine, horn, immobiliser; so it
should be easier to diagnose, than an intermittent fault. I live in hope...
I'll post an update when I have found the cause
So far thanks for all the advise!!
[Edited on 16/7/09 by corpi]
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corpi
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| posted on 16/7/09 at 09:15 PM |
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i promised an update when I found the problem. I did: loose connector on the alternator on the cable to the fuse box....
Nothing to do with MegaSquirt. just a coincidence that it started playing up just after I changed something on MegaSquirt...
Me: very relived, of to the Alps on Saturday! :-)  
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MikeRJ
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| posted on 16/7/09 at 09:19 PM |
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Hope the car runs well! I'm off to the 'ring tommorow and then next week going down to the Alps to do the Stelvio etc. for a bit of a
road trip with a friend. Sadly not in a very interesting car, but will still be fun.
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corpi
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| posted on 17/7/09 at 06:02 AM |
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Never been on the Ring myself. Stelvio is impressive!! just try to go there very early, or another quiet time other wise you will thing you are on
the M25 during rushhour, albeit with a better view
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