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Honda B20 Starting/Cranking Issue - Possible Trigger Issue?


gorto88
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Hi guys,

Having a bit of trouble getting my car to start on its new HC92X Link G4X plugin ecu.

If anyone is able to take a look and offer some insight it would be greatly appreciated. I believe there may be some kind of trigger issue has rpm appears to cut in and out while cranking. It is using an OBD1 factory distributor. The base timing/trigger offset has been set to line up with the 16BTDC mark on the crank. What I find odd is the car managed to start once when I played around with a heap of the cold start settings, and seemed to run as expected for an engine yet to be tuned. Went for a quick drive around the block to try rough in the fuel map, but after turning it off we haven't been able to get it started again. I also noted after the drive that there is a lot of trigger errors.

I will attach a datalog, trigger scope, map, and some example images. If anyone is super keen, I will attach the log of the drive too incase there is anything interesting or of note there.

Cheers,
Ryan.

Datalog - Cranking.JPG

Trigger Scope - Cranking.JPG

B20 Vtec NA 1000cc TEST.pclx PC Datalog - Cranking.llgx TriggerScopeLog - Cranking.llgx PC Datalog - First Drive pt2.llgx

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You've got a little spike of noise coming through on trigger 2 and this is being in interpreted as an extra tooth.  Since the ECU didnt see 24 crank teeth since the last cam tooth it causes it to lose position and start counting teeth again.  

nXpy9Yr.png

 

Since it happens in exactly the same spot every rev I would say it is probably ignition noise or a spark jumping inside the distributor rather than to the distributor post.  Assuming it has resistor spark plugs?  You could try setting ignition mode to off and if you then get stable RPM when cranking that will confirm it is related to ignition/spark.  You could try increasing the trigger 2 filter level.  You could also check rotor phasing as per the help article below.  

9vChtQZ.png

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42 minutes ago, Adamw said:

You've got a little spike of noise coming through on trigger 2 and this is being in interpreted as an extra tooth.  Since the ECU didnt see 24 crank teeth since the last cam tooth it causes it to lose position and start counting teeth again.  

nXpy9Yr.png

 

Since it happens in exactly the same spot every rev I would say it is probably ignition noise or a spark jumping inside the distributor rather than to the distributor post.  Assuming it has resistor spark plugs?  You could try setting ignition mode to off and if you then get stable RPM when cranking that will confirm it is related to ignition/spark.  You could try increasing the trigger 2 filter level.  You could also check rotor phasing as per the help article below.  

9vChtQZ.png

Thanks Adam, super helpful response. Turned ignition off and rpm signal was smooth. Bumped trig2 filter up one at a time, as soon as it was on 4/high it fired straight up. I will pull apart the disi now and check phasing to see if I can correct and then move trig2 filter back down.

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Now its running check base timing also.  If base timing is a long way off it could cause that.  Typically if the distributor is somewhere near the middle of its adjustment range the phasing will be correct, but wont hurt to check.

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16 hours ago, Adamw said:

Now its running check base timing also.  If base timing is a long way off it could cause that.  Typically if the distributor is somewhere near the middle of its adjustment range the phasing will be correct, but wont hurt to check.

Base timing has been confirmed. So to get it to start I needed to set arming voltages to the following, and set trig2 filter to 4/high. Once running I can reduce the filter to get a trigger scope. I'll attach the scopes and the tune file. Still getting noise spikes. I have installed a brand new distributor rotor and cap. I don't think I mentioned this in the OP, but the car runs perfectly fine on the chipped ecu that the Link is replacing. I have spare distributor parts I can use to test if needed. The wiring loom is custom and non-oem, a friend suggested possibly getting noise interference through that (unsure how well shielded)?

I don't understand why the noise spikes aren't causing a trigger error while idling with the low filter when they appear to be above the arming threshold? What does it mean/is there anything to take away from the fact that with the low trig2 filter the spike effects with trig1 and trig2? I thought perhaps grounding issue, so I connected a thick jumper lead between engine and chassis to confirm, but rpm signal still drops in and out while cranking even with the high trig2 filter.

Trigger Settings.JPG

Triggerscope - Idle (High Trig2 Filter).JPG

Triggerscope - Idle (Low Trig2 Filter).JPG

TriggerScopeLog - Idle (High trig2 filter).llgx

TriggerScopeLog - Idle (Low trig2 filter).llgx

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If it starts and runs ok with the trig 2 filter at 4 then leave it that way, it is of no consequence when there is only a single tooth once every 720 deg.  But I suspect its only going to get worse at higher loads when ignition energy increases.  

The noise is definitely spark as you can see 4 spikes with 180deg spacing between every trig 2 tooth.  

Im not hugely familiar with the honda ign system, is this one of the distrubutors that has the coil and ignitor inside?  Does the coil and ignitor just ground through the distributor body?  Confirm the ground is good.  Diagram I found below suggests the ignitor has a noise condensor built in, have you got a spare one you can try?

Does it have resistor spark plugs and good suppressed HT leads?

k52Unel.png  

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17 hours ago, Adamw said:

If it starts and runs ok with the trig 2 filter at 4 then leave it that way, it is of no consequence when there is only a single tooth once every 720 deg.  But I suspect its only going to get worse at higher loads when ignition energy increases.  

The noise is definitely spark as you can see 4 spikes with 180deg spacing between every trig 2 tooth.  

Im not hugely familiar with the honda ign system, is this one of the distrubutors that has the coil and ignitor inside?  Does the coil and ignitor just ground through the distributor body?  Confirm the ground is good.  Diagram I found below suggests the ignitor has a noise condensor built in, have you got a spare one you can try?

Does it have resistor spark plugs and good suppressed HT leads?

k52Unel.png  

Okay so went for a decent drive. It gets the odd trigger issue around 2.4-3k rpm 20% throttle (cruise). It hasn't done it once under WOT or at high rpm, but likely just due to minimal time spent there. Yes it has resistor spark plugs (BKR6E-11) and OEM leads (have another set I will put on to rule them out). Distributor has internal coil and ignitor. This issue definitely seems hardware and platform specific, so speaking to a few Honda guys this is a pretty common issue when going to an aftermarket ecu. Most seem to go aftermarket trigger kit and COP ignition. I did have one guy say it's possible to grind a tooth off the factory 24 tooth ref sensor and then set it up as a 24-1 and not use a sync. Or alternatively, keep the 24 tooth sensor as is, and cut 3 of the 4 teeth off the factory TDC cranking sensor (currently not used) and use that as the sync rather than the single tooth CYP sensor which is known for noise issues. There is a good image on Haltech's site, I'm out of attachment space so can't insert image: https://support.haltech.com/portal/en/kb/articles/b-series

24-1 would be the simple solution and I have spare parts that I can try it on. Do you see any flaws with this idea Adam? Going to give it a try after work this afternoon. Before I do that I will try a replacement ignition control module in the distributor and also adjust distributor angle and trigger offset for correct phasing (needed someone to hold the timing light to reset so left it in the centre and timed correctly for now).

 

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On 1/19/2022 at 1:39 PM, Adamw said:

You can see the same spike on both trig 1 and 2 so I dont think 24-1 is going to solve the problem if that spike gets larger as ignition energy increases.  

So I ended up trying 24-1 as I had little to lose (spare distributor in parts). All worked well without a second trigger and still sequential injection, but the issue was basically unchanged. I bumped trig1 filter up from 1 to 2 and never had another trigger error. Unsure whether this would've been the case or not had I just tried a higher trigger 1 filter without modifying the tooth. Was so worried about playing with trigger 2 settings I completely forgot to try playing with trigger 1 filter.

Anyway, it seems to work with no immediate downside. RPM trace is a little noisy when in vtec, but I assume this is just a case of a cam mounted engine speed sensor with lots of vibration. I'll do a bit more work on trying to reduce noise in general, I'll add another engine ground, confirm distributor phasing again, etc. Here is a trigger scope of the current setup: https://drive.google.com/file/d/1YgPIYMQ3e-5eCB-sTOxqCrU4TtfqU3Zo/view?usp=sharing

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