Timing errors what is the logic | AEM
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scoobydo123
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Timing errors what is the logic

Hi,

 

Running AEMv2 on a nissan KA24DET nissan people carrier. This version  runs the dizzy on the back of the cam like the 4 cylinder Nissan Altima so running the CAS disk. Car has been running decent since fixing the various issues caused by the previous owner. The cams were never set to specification of the cam card including valve timing and also valve lash. I have resynched the ign timing as after the cam timing it was 13 degrees out (remember that the dizzy runs from the back of the cam). Used a degree wheel (stuck on the crank sound hillbilly but works for me) and dial guage to get absolute TDC  and made a new marking and done the sync uig the AEM wizard. Also change the plugs from NGK 8's to NGK 7's and gapped them as per what everyone is running.

After this used the car locally and everything seems fine, took it out or a longer run just before lockdown and was getting breakup at 1 bar of boost, maybe faulty new plugs or spark blowout. Gapped the new NGK7's less than the 8's and still had the issue. Got it home and changed the plugs back to the 8's and then lockdown came. Here are two logs showing the errors. I have other logs before these that show no errors. I do wonder if the tidying of the engine bay HT leads may be my issue could this cause the problem (maybe now routed near the wiring for the CAS pickup)? Have also ordered new HT leads, but am interested in what logic AEM uses to report timing errors? BTW it is a faff to get to the engine as it is mid engined so front seats need to come out, centre console etc.

 

Help very much appreciated.

 

05i_graham_22psi_12 timing errors.02v02.daq

2020-06-06 1645 ECU Log.daq

k24det nissan largo mpv.02v02.cal

scoobydo123
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Ok so my leads came, ordered

Ok so my leads came, ordered new ones on Monday night and got here from the states on Friday morning :-) Have stripped the interior and put the leads on and made sure the routing of the HT leads was not near anything else. Took it out and still some timing errors. Had a read up on here and zero'd out the 2 tables Load Accel Factor" and "dLoad Accel. Have now done a log in the ADV pickup tabs as per other instructions with battery voltage and Tper2  (pc logs). Logs are here also included the triggered ECU log during the attatched PC logs, for completeness also included is the calibration during these logs.

Maybe relevant seeing that I dont know the logic of when a timing error is reported is that the car is an automatic, I am now running full line pressure as I need to upgrade the trans as I think it slips a bit on gear changes.

Also included is a PC log on the ADV tab during a start

 

Thanks

Load Accel FactordLoad Accel zeroed calibration.02v02.cal

timing erros during pull adv pick up tab PC Log.daq

timing errors during pull ECU Log.daq

just start with zerod adv pick up tab pc log.daq

 

 

 

scoobydo123
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**UPDATE**

**UPDATE**

So might have this fixed. Would really appreciate an explanation if this could cause the issue or if it indicates another issue. So back in Feb this year I double checked the ignition sync and IIRC pressed the small retard button 4 times.

IGN sync

4.281 teeth (gives errors)
4.313 teeth (no errors) just loaded this and drove around with no errors when I adjusted it to this setting in the calibration I attatched on this thread.

scoobydo123
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**UPDATE**2

**UPDATE**2

So looks like spoke to soon went out in the vehicle today and still have errors being logged. Have gone back to an old tune in Jan this year and couldnt get that to throw a timing error. Is it possible that as I get more agressive with my timing errors are appearing as that what it seems like now. Help with what the logic is for a reported error would be very much appreciated and any advice. The main differences between the logs are different spark table and the idle wizard fixed setting was changed from 15 to 19.9.

 

 

AEM_NS
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If you want to learn more

If you want to learn more about engine position signal processing, I suggest reading the PDFs here: https://www.aemelectronics.com/forum/ems-4-diyfaq-look-here-first

Timing errors mean either extra crank teeth are sensed (signal noise on crank input) or a cam signal is missed.  Unfortunately PC logs of Adv Pickups tab aren't all that helpful with such a slow data capture rate.  Get as many of the pertinent channels loaded into the internal logger and capture data that way.

From what I can see, it seems you're most likely picking up noise on the crank signal.  This is observed by the fact that you're accumulating Timing Errors plus where the errors occur, engine speed jumps up thus the ECU is probably sensing false crank teeth which would most likely come from noise.  The problem with engine break that's associate with Timing Errors is that you don't know which is the chicken or the egg.  Sometimes ignition break up due to a weak ignition can cause Timing Errors since combustion seems to provide some level of spark absorption and without combustion, you get a full strength burst of EMI which can then get picked up on senstive inputs like the crank/cam signals.  Or sometimes low level noise can cause Timing Errors which may result in physical ignition timing deviation (timing jump, etc) which will result in misfires/break up.  But which one of those is happening is hard to tell from logs.  

Each individual step of adjustment in Ignition Sync is 0.12°.  Going from 4.281 to 4.313 got you 8 steps of adjustment which is 0.96°.  I personally find it pretty hard to believe that the threshold between having or not having Timing Errors is a difference of 1°.  I'd start by taking a very close look at your ignition system.  Fresh plugs are one thing and having them gapped tighter than the old plugs is fine, but what it that actual gap value?  Perhaps whatever they're gapped out is too big.  Are you using a stock ignition coil?  You may have to start making coil dwell adjustments to get more spark energy especially now that you're forced induction.  Seems like a common mod for KA motors that go boosted is to convert to COP ignition and eliminating the HT wires.  You can keep the distributor for crank/cam inputs but add in wiring for individual coils.  

I'm not as familiar with Nissans as I am other vehicles (and especially not People Carriers) so I don't know if the crank/cam signal wiring is bad like a Toyota that doesn't use any kind of shielding or twisted pairs or if it's good and uses shielded cable.  If not shielded cable, you might think about changing to it.  You could also potentially have an issue with the distributor itself however it doesn't seem to be the case from what I can see right now.

 

scoobydo123
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Not sure I have a crank input

Not sure I have a crank input think it is just cam sensor only. Could you kindly let me know if the below is the correct channels forthe internal fast logging channels and slow? The coil is a MSD blaster. Have never seen any timing errors on any other logs that I have collected in the 4 or so years of owning the vehicle. Plug gap is .018 is there any chance of it being transmisison related as I feel like I seem to get them on gear changes (remember it is an auto) and unfortunately the engine is producing more torque than the current transmission can hold, this I have improved by increasing the line pressure by creating a dummy load for the line pressure solenoid and changing the dropping resistor so there is no dither. Would you also expect timing errors be generated if you rev the engine as I have not managed to produce any like that. Thanks for help. BTW also put new plugs in that I gapped down to .015 as that is what alerted to me that something was wrong orignally installed at .018. BTW just to be clear the vehicle was factory ka24de and the previous owner installed a turbo.

 

(fast channels)

Engine Speed

Cam Count

Crank Count

S Tooth

A Tooth

MX Sync Count

S Sync Tooth

(slow channels)

Sync Errors

Timing Errors

Stat Sync’d

Battery Raw

Run Time 

AEM_NS
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Yes you have a crank input.

Yes you have a crank input. The CAS in the distributor outputs both a crank and cam signal. Look at a picture of the AEM Nissan CAS wheel. There are 24 windows for crank and one window for cam.

Normal behavior is to not get any Timing Errors while the engine is running. Knowing that either an extra crank tooth is sensed or a cam tooth is missed will cause a Timing Error, it's more likely to be a direct result of some engine load and rpm threshold and not specifically that a shift is occurring.

Here's a better log list:

FAST
Engine Speed
Crank Tooth Period
T2 PER
A Tooth
S Tooth
d Tooth Time
Sync Tooth

SLOW
Timing Errors
Sync Errors
Crank Count
Cam Count
Miss Time
Stat Sync'd

scoobydo123
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Will get onto that thanks a

Will get onto that thanks a lot for giving me the list. Whilst going over previous logs and compairing what I have been doing with the van I may have found what triggered it. On an old ecu log dated 26-01-2020 I had 9 errors. On the 25-01-2020 fitted the 5ohm 40watt dummy load to bypass the line pressure solenoid this involved me taking the signal wire for the line pressure solenoid at the TCU and running it through my dummy load with that going to ground. I done this a the TCU maybe that is causing some issues. Take it the EMS4 instruction apply to the AEM V2 that you linked to? So maybe some additonal filtering required since I done the line pressure mod? What wattage resitor required. Or maybe just coincidence. Here is the log from the 26-01-2020 against a couple before including  a 3rd gear pull with no timing errors. 

Possibly on the right track?

2020-01-26 1506 ECU Log.daq

05g_graham_22psi_20_01_2020_ecu.daq

05f__22psi_graham_ecu_18_01_2020.daq

 

 

scoobydo123
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Ok so here is a log with the

Ok so here is a log with the internal log settings changed. Certainly does feel like it is around when the transmission changes up. Also included is the calibration I was running whilst this log was took.

If you need anything else then let me know

BTW this was done after I had changed the ground for the dummy load that I have in place to run maximum line pressure. As I had gounded the dummy load at the chassis rather than TCU so now that is grounded there.

2020-06-16 1356 ECU 7 errors with new ground Log.daq

ECU Calibration with AEM log settings for timing errors.02v02.cal

Thanks

 

AEM_NS
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Log data shows that Timing

Log data shows that Timing Errors are a result of noise on the crank signal.

In upper plot, green trace is Sync Errors and lite blue trace is Timing Errors.  In the lower plot, white trace is Crank Tooth Period and yellow trace is Cam Tooth Period.  Notice that there's a downward spike in the crank tooth period when sync/timing errors occur.  A downward spike means that the time between sensed crank teeth has gotten shorter and you can see that it's much shorter than the general trend from the other normally sensed teeth.  This is the result of noise falsely triggering the crank input making the ECU see more crank teeth than expected which temporarily makes engine speed spike up and also results in sync/timing errors.

So the question becomes what is causing the noise?  There's a possibility your trans wiring mod may be suspect.  You might try un-modding it to see if the errors go away.  But honestly if the dummy load ground is far away and not at all shared with any wiring from the CAS/distributor, then it's a little less likely to be the culprit.  You might try running new twisted pair shielded cable from the distributor to the ECU to see if that makes a difference.  You might also try shielding your HT leads.  Maybe try wrapping them in foil with a bare drain wire going to an engine ground away from the distributor.

scoobydo123
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OK thanks a lot will remove

OK thanks a lot will remove the modification and see if that clears it up. Unfortuntely it has just poured down with rain here in the UK and we have a thunderstorm so need that to clear. Will also try and source some cables. Looking at the FSM it looks like it is 4 wires and there is a shield If I replace and re-route with the twisted pair looks like I need a 4 core cable and shield. From what I read I need to ground the shield at the ecu only and leave the shield loose to stop the shield becoming a source of interference? Would I need 2 twisted pairs and how would I arrange the conductors please ie each twisted pair for simplicity can I buy 2 cables and pair up the shield. The attached is from the FSM from the altima as there is not one for the Nissan Largo. Thanks

altima dizzy wiring.doc

scoobydo123
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Ok so removed the dummy load

Ok so removed the dummy load and still got errors, they seemed to be more frequent and obviously my flare between changes is now worse here is the log.

Regards

2020-06-16 1833 ECU without dummy load Log.daq

 

AEM_NS
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Well if the FSM shows

Well if the FSM shows shielding already in place, there probably isn't a reason to replace the crank/cam wiring. Do you happen to have a spare distributor you could try? Also converting to COP ignition to eliminate the HT wires may help.

The spark plugs you're running are not non-resistor racing type plugs are they?

scoobydo123
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Ok so trans back to default

Ok so trans back to default so no dummy load or modified dropping resistor and still it does it on gear changes when at around half a bar or so 2nd to 3rd. I thought I may have found the issue as my dropping resistor modification I had wrapped it around the loom which carries the signal wire I have removed this and gone with the standard 12ohm droping resistor but still it does it. I have now confirmed that the factory wiring is twisted and shielded I guess as it is inside a thicker pvc jacket but will need to check at the ecu end that it has been put to the ecu ground (the AEM was installed by the previous owner). I also found that the bolt for the ground on the head I had not tightened properly when I done the headgasket (so was hoping it was that but no luck)

My plugs are NGK BKR8EIX I think (engine covers back on again so cannot check). I might have a spare dizzy will do that as last resort. Next thing on my list of possibles is perhaps the rebult transmission that cannot hold the torque perhaps that has a noisey solenoid as that was done in January this year. 

2020-06-16 2122 ECU trans mods off Log.daq

 

 

 

 

scoobydo123
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Here is what I thought it

Here is what I thought it might have been as you can see I didnt consider interference.

My dropping resistor mod that is now gone.doc

dizzy wiring.doc

 

scoobydo123
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Gone through the wiring as

Gone through the wiring as best I can (havent got a factory FSM)and found a strange arrangement.Coming from the + on the MSD 2 blaster coil is a aftermarket wire that I have traced to the idle PWM solenoid could that create a problem? My plugs are gapped at .024 took that down to 0.20 and still the same issue. Just to be clear the timing error seems to be as 2nd to 3rd is grabbed via the autobox. Does my signal look decent apart from when the single timing error occurs. Thanks

AEM_NS
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The crank signal does look

The crank signal does look fuzzier than I'd expect but that doesn't really have anything to do with a noise problem. If wiring is suspect, then maybe it would be a good idea to re-wire the distributor with fresh shielded cable and supply the distributor with dedicated clean power and ground. It also might be a good idea to try a different distributor. I really can't guess what impact some wiring that's done one way or another is going to have on your setup. You're going to have to keep making small changes and see if they make a difference.

scoobydo123
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Ok I have some new high

Ok I have some new high quality shielded twisted pair that I am going to run separate to the rest of the loom. The power and gnd I have de pinned and pinned into my new connector the shielded cable I have terminated into the new connector. Now reading the install instructions on the 30-6600 am I correct in saying that pin 22 and 30 are commoned and 31 and 40 are commoned? So I planned on tracing back the signal wires as they currently stand on the factory loom and replace with my new 2 core twisted pair at whatever terminal they trace back to. The shield I understand leave unterminated at the engine end what pin(s) do I terminate it at the ecu end please. Thanks in advance. Will of course up date with the outcome :-) BTW treated the car to a new AEM wideband 30-0300 and that is so much more responsive than the old one and calibrated perfectly to the ECU also have on order a 9 inch AEM brute force air filter to bin the stupid HKS mushroom.

AEM_NS
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Yes, the cam & crank inputs

Yes, the cam & crank inputs pins are common with each other. Nissan felt it necessary to have spare inputs - in case one breaks down apparently. Shield can just drain to a clean (unshared) chassis ground at the ECU - doesn't need to drain into an ECU pin.

scoobydo123
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Ok thanks, what I have

Ok thanks, what I have uncovered is almost like a piggyback arrangment the AEM V2 is located on top of the factory ecu with the original AMP connector splicing to both the Factory ECU and the AEM V2. When I was buzzing back the pins from the CAS pin 22 on the AEM I found it spliced to both the original amp connector (factory wiring) and also the original ECU. I can only guess that it was done this way as the car is an automatic so some of the information is shared between factory ECU and the TCU. These shared wires are just standard automotive cable and not screened, wonder if this is part of the issue. 

By clean unshared chassis ground is this just a bolt (obviously paint rubbed off etc) located near where the ecu lives?

Thanks in advance

 

AEM_NS
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Piggyback arrangement can

Piggyback arrangement can definitely throw some wrenches in the gears. Stock ECU will definitely not be happy with the AEM CAS wheel pattern that's 12 & 1 crank/cam. You might need to put the stock CAS wheel back in and send it only to the stock ECU and add on something aftermarket to the crank to send to the Series 2.

Clean, unshared ground would just be a good ground new the ECU that isn't connected to anything else BUT the shield drain and doens't have any high current grounds grounded near it.

scoobydo123
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Just to be clear the vehicle

Just to be clear the vehicle is a build that has had 1000's of miles (build started around 2013) put on it by the previous owner drives fine but I am sorting out minor issues that presented themselves when I started to get familiar with the vehicle after purchasing it. The major issue I had was headgasket failure that the previous owner tried to fix with mechanic in a bottle! These timing errors are very intermittent I took the car 100 miles and got a total of 3 and this included a roll on throttle pull to 120mph from 70mph. So just wanted to make it clear that it is not a new build with issues with diveability and errors flagging up all over the place. Currently trying to work out why it has been set up as piggyback as didnt think the TCU had much interest in what the CAS was doing. I thought the TCU only took inputs from TPS but maybe there is more to it than that.  Here is a log of cranking on my new wiring 

2020-09-09 1040 ECU new wiring for cas Log.daq

AEM_NS
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I'm pretty confident that a

I'm pretty confident that a trans controller would probably need to know engine speed which it gets by communicating to the stock ECU thus the Series 2 has been put in in parallel with the intent that the Series 2 can run the engine and the stock ECU/TCU can manage the trans. But, and this is a big but, there's no way the stock ECU will be happy with the completely different crank/cam pattern of the AEM CAS wheel so it's pretty much guaranteed that the stock ECU isn't reading or reporting RPM and the TCU is likely running in a failsafe mode and just getting by. Probably not an optimal arrangement but perhaps it "works" well enough.

scoobydo123
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Yes agree, I dont have a

Yes agree, I dont have a factory wiring diagram for the vehicle. When I look at similar Nissan's of that era with AT certainly the re4r01a takes a signal from the CAS also the rear window demister and power steering pump and neutral selector. The transmission seems to change and respond perfectly for my application so left with is this shared connection cause of my timing errors. Did the attached log during cranking look ok? I looked to the best of my knowledge and it seemed like it missed a couple of events ie had counted to 142 it increments of 1 but skipped 143 if I was reading it correctly. Tks

AEM_NS
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A log of the engine running

A log of the engine running and running in the area that typically creates errors would be better for comparison.