JohnCh Posted September 21, 2014 Author Share Posted September 21, 2014 Thanks for the additional responses and sorry for the delay, but work got in the way this week. I checked a few things yesterday and the plot has thickened. Additional mapping from cold to hot shows that the injection and ignition corrections are working as expected. The new wrinkles are the WBO2 is now suspect and the issue has started to affect idle. When trying to do a free air calibration for the O2 sensor prior to the test drive, the Innovate went through the normal process, but instead of stopping when it hit the free air target, the AFR just kept climbing. I finally switched it off after a few minutes when it broke the 60:1 barrier. Mapping was consistent with previous sessions with AFR very lean at light throttle, but normal when approaching 1/2 throttle and above, including at higher rpm (ran to 5000-5500rpm a few times). My gut tells me the readings are directionally correct, but may the numbers themselves may be off by some percentage. About 1/2 way through the drive, the engine started hunting at idle, and sounded like random misses. Fuel pressure check shows it's correct and stable when revving the engine with the car stationary. Given how the car sounds at idle, I'm beginning to suspect the ignition system. I've had to change the coil pack in the past (similar idle issues) so may try that next. If I have time today, I'll also check engine compression and perform a leak down test to make sure something more ominous isn't at play. -John Link to comment Share on other sites More sharing options...
xcarguy Posted September 21, 2014 Share Posted September 21, 2014 Thanks for the additional responses and sorry for the delay, but work got in the way this week. I checked a few things yesterday and the plot has thickened. Additional mapping from cold to hot shows that the injection and ignition corrections are working as expected. The new wrinkles are the WBO2 is now suspect and the issue has started to affect idle. When trying to do a free air calibration for the O2 sensor prior to the test drive, the Innovate went through the normal process, but instead of stopping when it hit the free air target, the AFR just kept climbing. I finally switched it off after a few minutes when it broke the 60:1 barrier. Mapping was consistent with previous sessions with AFR very lean at light throttle, but normal when approaching 1/2 throttle and above, including at higher rpm (ran to 5000-5500rpm a few times). My gut tells me the readings are directionally correct, but may the numbers themselves may be off by some percentage. About 1/2 way through the drive, the engine started hunting at idle, and sounded like random misses. Fuel pressure check shows it's correct and stable when revving the engine with the car stationary. Given how the car sounds at idle, I'm beginning to suspect the ignition system. I've had to change the coil pack in the past (similar idle issues) so may try that next. If I have time today, I'll also check engine compression and perform a leak down test to make sure something more ominous isn't at play. -John The 'FIND' is goinng to be interesting. :rofl: . . . . . . . . . :lurk: Link to comment Share on other sites More sharing options...
JohnCh Posted September 21, 2014 Author Share Posted September 21, 2014 It gets better. I decided to play with the fuel and ignition maps. The plan was to rev the engine into the lean zone and then start adding/deleting fuel and ignition timing via the Live Map screen to see what happens. Well guess what? The car is once again operating perfectly. This marks the second time it's fixed itself. I love intermittent issues... -John Link to comment Share on other sites More sharing options...
BusaNostra Posted September 22, 2014 Share Posted September 22, 2014 (edited) Well, when you change a map you enter a value and update the value. How will it fixes itself? The value in each cell (fuel & ignition maps) will not mysteriously changed without someone changing it.....unless you still have the "lucas prince of darkness" virus. Edited September 22, 2014 by BusaNostra Link to comment Share on other sites More sharing options...
JohnCh Posted September 22, 2014 Author Share Posted September 22, 2014 Sorry, poor writing on my part. To clarify, I was planning to play with the map yesterday. However, when starting the car, the symptoms had once again disappeared. It was fine when cold, when warming up, and when driving a short distance. Therefore, there was no point in adjusting fuel or ignition tables since there was nothing to "correct." -John Link to comment Share on other sites More sharing options...
BusaNostra Posted September 22, 2014 Share Posted September 22, 2014 Oh ok.... That will come back then --- has to be one of the sensors acting up: o2 - ait - map - coolant temp ????????? Link to comment Share on other sites More sharing options...
coffee break Posted September 22, 2014 Share Posted September 22, 2014 If you have been unplugging and replugging connections, you may have cleaned up some corrosion build-up. Checking for poor ground also. FWIW Link to comment Share on other sites More sharing options...
xcarguy Posted September 22, 2014 Share Posted September 22, 2014 It gets better. I decided to play with the fuel and ignition maps. The plan was to rev the engine into the lean zone and then start adding/deleting fuel and ignition timing via the Live Map screen to see what happens. Well guess what? The car is once again operating perfectly. This marks the second time it's fixed itself. I love intermittent issues... -John Gee, John. Thanks for blowing my very narrow concept about thermodynamic laws, entropy and bla, bla, bla. Now I have to revisit the whole evolution vs. creation thing just because your car 'fixed' itself . . . . . . :svengo: Link to comment Share on other sites More sharing options...
JohnCh Posted July 14, 2015 Author Share Posted July 14, 2015 Revisiting this old thread. It appears this issue is finally resolved so thought I'd post an update to enable people to settle their bets (winners, don't forget to forward my 7% commission). Between my schedule and the intermittent nature of the issue, the diagnosis process was frustrating; on days when I had time to work on the car the engine ran fine, on those days when I only had time for a short drive, it generally ran poorly. Damn that Murphy and his blasted Law! I did get lucky one day though while revving the engine with the air filter off. The car was parked in the shadow of the garage and the engine was running normally for a few minutes before it started acting up. As this occurred, combustion flashes began appearing behind all 4 throttle plates. A little more messing around and the engine started running better, but still not right. Now the combustion flashes were only visible behind 2 throttle plates. The next day I removed the air filter, started it up, and it was running fine -- no combustion flashes were visible. I then did some additional data logging and paid closer attention to the advance readings. Although no corrections were being made, and the advance was consistent (i.e. no jumping around) the actual advance numbers weren't matching the values in the ignition table for a given load and rpm during those periods of poor running. Given the only 2 electrical items I hadn't replaced or already ruled out through previous data logging were the ECU and the Crank Position Sensor, I swapped out the latter for a new one about 2 months ago. The issue seemed to go away, but didn't have an opportunity to use the car extensively until last week. After putting 300 miles on it in various conditions without a hiccup, it appears the CPS was the culprit. -John Link to comment Share on other sites More sharing options...
slomove Posted July 14, 2015 Share Posted July 14, 2015 (edited) Hello John, apparently I missed this thread last year or I would have contributed a few more distracting guesses. As it happened , I had slightly similar (but not as severe) problems forever. Also Emerald and Jenveys on my old Zetec (RIP). I never found a good reason why the AFR in idle fluctuated sometimes between 12 and up to 16 but 90% of the time around 13.5. But I did find the behavior extremely sensitive to a single point injection map change in the cells around the idle area. I suspect, the injector opening time in idle (injector pulse duration minus injector dead time) is so short that the combined drift of TPS and air temperature sensor, battery voltage and the need to interpolate between the neighboring cells can add up to significant fuel dosing inaccuracy. There is a reason that people sometimes use a secondary set of smaller injectors for idle and cruising range. So, I hope that the Crank sensor was the problem in your case. Could be the reason for the jittery ignition timing. For me it did not make a difference as well as upgrading the ECU software to the K3 version did not make a difference. But with careful adjustment I had somewhat stable idle AFR between 13 and 15. Good enough for me but now I am going to swap the engine anyway and I am curious if that behavior will stay with the new SVT engine. Edited July 14, 2015 by slomove Link to comment Share on other sites More sharing options...
JohnCh Posted July 14, 2015 Author Share Posted July 14, 2015 Hi Gert, have you tried the K3s adjustable speed and load sites option? This enable you to add a lot more granularity around light throttle and idle which addresses sensitivity issue you highlight. It made a noticeable difference on my engine. I'm running larger injectors than necessary for my power output, which does affect my idle. I'm toying to make the switch to 8 injectors, and may also go with a sequential setup when I do my next engine upgrade. Hate the added complexity, but it should aid drivability. -John Link to comment Share on other sites More sharing options...
slomove Posted July 14, 2015 Share Posted July 14, 2015 I used the speed and load sites as they came with the K3 software but they had already a finer load resolution near idle than the old M3K software. After all, I had the engine running near perfectly until the valve drop. On the last trip I got to 28mpg cruising at 70+mph, great throttle response and WOT power. Really a shame. After many tweaks, that idle fluctuation was rather a kind of nuisance than a real problem so at some point I just decided to live with it. If I would not have that AFR dash gauge I might not even have noticed. Link to comment Share on other sites More sharing options...
JohnCh Posted August 1, 2016 Author Share Posted August 1, 2016 I hesitate to drag up such an old thread, but given there are two updates, one a year overdue and the other very recent, I thought I'd try to close this out again in case anyone else runs into a similar problem. When I left you last July, the car had been through a full tank of gas with no recurrence of the issue, so things were deemed resolved. Fast forward a few days when I decided at oh-dark-thirty that it was Take Your Westfield to Work Thursday. Much to my chagrin, the engine began acting up before I got down the driveway. After less than a mile, it was clear a U-turn was necessary, and suddenly it was Take Your 993 to Work Thursday. The next several months alternated between long periods of utter despair, and shorter bursts of attempting to figure out what the hell was going on. Based on all the signs, it was an electrical problem that wasn't tied to a specific cylinder. Given several key sensors & parts had been replaced, and that data logging indicated it wasn't the ECU or any remaining sensors, the wiring harness became the prime suspect. The ECU wiring harness was cobbled together from the harness that came with the crate engine mixed in with net new wiring. Looking into it, a few issues were found and fixed including one that matched my best guess of the problematic wire (12V+ to the coil pack). However, the intermittent poor running and idle continued. Finally, I was able to get the problem to repeat/resolve by pressing on the harness as it comes into the engine bay - I had my smoking gun! Unfortunately,efforts to track it down to any particular wire(s) were for naught, so with the post-Brexit Pound in freefall, an order was placed with Emerald for a new wiring harness. It's been in place for a couple of weeks, and so far, everything seems fine. In fact, it's been good enough to make today Take Your Westfield to Work Monday. I arrived without issues, hopefully the same will be true of the commute home. BTW I've forgotten just how easy this car is to rotate and hold with the throttle. Damn addicting -John Link to comment Share on other sites More sharing options...
Croc Posted August 7, 2016 Share Posted August 7, 2016 John - Why Emerald and not Westfield for a wiring harness for a Westfield? Naughty boy - you been sliding around on the roads again? :iamwithstupid: Link to comment Share on other sites More sharing options...
JohnCh Posted August 7, 2016 Author Share Posted August 7, 2016 It's the engine wiring harness that connects the ECU to all the sensors, coil, and injectors, not the car harness. I had Emerald start with the Caterham long loom and add wiring for the Map Selector switch and a VVT controller. I'm toying with an engine upgrade that includes variable intake geometry based on a motorcycle unit I bought a while ago. The VVT option native to the Emerald will allow me to control the actuator based on rpm and would theoretically offset some of the low-midrange torque loss from more aggressive cams Me? Slide around on the streets like a hooligan?? Never!!! That comment was purely for entertainment value. Really. -John Link to comment Share on other sites More sharing options...
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