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detonation pinging pinking at minimal load - not at high load


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#1 HONDALEO

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Posted 03 July 2019 - 08:36 AM

This one has me baffled.

 

Any suggestions welcome.

 

The car will start to pink on a slight incline, at 15% throttle, 1800 RPM, IAT 35°C for example.

 

I acn't be too sure about the ingition advance as I have no reliabale way to measure it.

 

This car is one of those with a 5 pin OBD connector so it's difficult to get it to communicate withany decent scan tool.

 

I did get it to connect to an Autel but the be honest the data logging feature doesn't have very good resolution so it's a bit difficult to post process the logged data.

 

I have:

 

fitted official NGK lambda sensor.

done a fuel pressure test. - perfect

did an injector balance test - all identical

ran a can of Moly injector cleaner through the system

checked the function of the air bypas system

done a bore scope cylinder inspection

fitted new plugs / leads just as routine service

fitted new exhaust

measured TPS voltages 0.4 -> 4.59 (I guess 0.4V is okay ? but my next task is to recalibrate this to begin at 0.5V)

checked MAP sensor voltage output with reference pressure - spot on

checked IAT termistor output with reference temperature - spot on

checked vacuum hoses for leaks with Mityvac - spot on

checked valve clearances

replaced knock sensor

measured crank position sensor out and tdc sensor output - look fine

taken a feed directly from the coil primary and logged it in my Picoscope, checking phase shift with respect to tdc sensor

 

I did wonder if the car has had its head skimmed before I bought it. (It has had this problem from day one about 8 years ago !!!)

 

However, I would guess giving it more gas would make the problem worse if it was a too high compression issue.

 

I've probably done a few more tests but can't remember right now.

 

I've used both standard and ultimate fuels but with no improvement.

 

I think it is worse on hotter days. (Somedays the IAT sensor is about 60°C !!!!)

 

I even replaced the IAt with a potentiometer so I can dial in any IAT I like, but I still can't dial out the pinking.

 

Likewise I created a resistor arrangemt to let me mimic the MAP sensor, so to fool the ECU to read any value I want.

 

All I have on my list left to try is to put a thermcouple into the plenum to measure the actual air temperatue independently.

 

Also to measure the compression ratio, but I think I am clutching at straws.

 

I even tried putting the cam beather pipe into a catch tank instead of back into the plenum.

 

I hope I have been an idiot and missed something really simple?

 

Any ideas ???

 

Here is another thread I found, but which didn't help me, as no conclusion was arrived at.

 

It could almost have been written by me, it is so similar.

 

https://www.ericthec...r-load?start=20

 

Thanks

 

PS I should have said, the lambda voltage are fluctuating as normal, and the STFT is between fluctuating between about 0% and -7%

 

The LTFT is fixed at 0% and has never ever changed from 0% no matter what I do. Maybe it should be called a VERRRYLTFT :-)


Edited by HONDALEO, 03 July 2019 - 08:53 AM.


#2 skhell

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Posted 03 July 2019 - 08:56 AM

I also have this problem. I have it for a couple of years, did almost everything you did, and got no success.

 

I have mine running on LPG, but this only happens when running on Petrol. Although LPG have a higher octane value, which helps with detonation/pinging, I suspect this can be related with the petrol feed system. One thing that occurred to me is that it could be related to the fuel pressure regulator. If the fuel pressure is too high I think it can make this happen. I never had the chance to test this or try another fuel pressure regulator.

 

Mine also has the 5 pin OBD connector. I have found the hondash (https://www.hondash.net/) which apparently work in our cars. I have never tried it, but have exchanged some emails with the guy and it really seems to work. The only problem is that you need to use their own application, but I guess that is ok.


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#3 HONDALEO

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Posted 03 July 2019 - 10:50 AM

Thanks. I tested my fuel regulator and it was spot on to the Honda spec at both vacuum levels. I do have the Hondash already, thanks to you I think. (I think it was you who recommended it to me). It's money well spent. It would be nice if it would allow the data to be exported but that isn't available yet, although you can save the info you need then recall it. I synchronised the clock of my Hondash android tablet, with my Picoscope laptop, to within a second, so between the two I can correlate some information. It's all a bit clumsy but better than nothing. I just find the spark advance and knock retard numbers a bit weird in the Hondash. I did contact the bloke who designed it and he said it was a bit confusing to him too.

 

I just have the throttle body almost removed. I have hit it quite a thump with aluminium drift, but it is pretty tight. Doesn't want to come off easily. Gonna have an early lunch and ponder it a while longer.



#4 HONDALEO

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Posted 03 July 2019 - 02:26 PM

Ah well. There's another two hour wasted. TPS calibrated and theres no change at all ....



#5 skhell

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Posted 03 July 2019 - 02:39 PM

Glad to know Hondash is working for you!

Didn't noticed you had already tested the fuel pressure. There is also the fuel pressure damper. Don't know if it has any influence and have no idea how to test it.

 

I see that you have used a bore scope to inspect the cylinders. Were you able to check if there is a significant amount of carbon deposits on the pistons? I have already done the same, but I couldn't get to a conclusion. The image quality was not good enough....

 

I have tested the cylinder compression, and they were all good. It was almost too good. All 4 cylinders presented compression values as if the engine was new. This could mean two things: 1) the engine is in really good condition; or 2) there are carbon deposits in the piston will increase the compression values. 

 

If the problem is really carbon deposits, that would mean take of the engine head and give it a clean. Something that I will not do...

 

I bought BG44K (https://www.bgprod.c...system-cleaner/) to clean the carbon, but I messed up when I was pouring the stuff into the petrol deposit and most of it went straight to the floor... Dind't tried it again, but I have read good things about it. Maybe worth a try if you can easily find it...



#6 HONDALEO

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Posted 03 July 2019 - 05:16 PM

SKHELL, you should try one of these ebay scopes if you have an old android phone or tablet available.

 

They're so cheap and the picture quality is pretty good.

 

I've used a Snap On borescope that a friend has and it is useless compared to this Chinese cheapo.

 

https://www.ebay.co....h=item442432668

 

Compression test is next on my list, but I don't expect it will help me. I'm just doing it to gather more info.

 

The carbon build up was negligible, although I did run a can of cleaner through my tank anyway.

 

I wonder is this a mapping issue, and no amount of changes elsewhere will ever cure the problem.

 

 

One point that might be relevant is that I once wanted to make up a break out cable to let me T into the O2 sensor wires.

 

I went to the breakers to get the plug from the wiring loom which connects to the O2 sensor.

 

While I was at breakers I just decided to buy the O2 sensor as well just to have as a reference.

 

I think I got it from a CR-V, but I didn't care as I was only interested in the connector and it was identical to mine.

 

However, I did try this old O2 sensor in the car, and it immediately performed like a racing car!!!

 

It was quite a surprise.

 

However, it was very short lived, and after just a few minutes running, the IML would come on and the car start to run erratically.

 

This does suggest that if the fuelling was different, the problem might go and stay away.

 

I did try tampering with the O2 output, using a voltage divider, but it seemed that once I tried to fool the ECU, it just changed the STFT to undo my changes.

 

I began to read up on bias voltages and got completed confused and ended up giving up on that test.



#7 HONDALEO

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Posted 05 July 2019 - 09:39 AM

So here's the latest.

 

I filed out the distributor which gave me the option to retard the timing by about 10°(crankshaft).

 

When I set the distributor to this new position (with the SCS shorted), I strobed the tiiming pulley and it showed to be firing about 2° BTDC.

 

I removed the SCS paperclip and took the car for a drive and it did feel better, and the pinking seemed less pronounced.

 

I couldn't remove any more material from the distributor slot so the next step was to find a way to give even more retard.

 

The easiest option I could think of was to make a new drive coupling, which connects the cam to the distributor.

 

I made the one shown below with the drive pin hole displaced by 7° (camshaft).

 

This would allow me to further retard the timing by another 14° (crankshaft) if needed.

 

I repeated the paper clip procedure, but I didn't apply full retard just yet. I went halfway.

 

The car drove much better, so I then introduced to total retard possible and it got better still.

 

Pinking now appears about 2500rpm, but only if I give her lots of throttle.

 

The engine is much more responsive, even in top gear at about 3000rpm.

 

I suppose now I really need to make another one of these drive couplings.

 

This seems a bit weird. It's almost like the engine, map is wrong.

 

In case somebody thinks what I thought, that could the timing pulley index marks be out sync with the piston position, the answer is no, they're not.

 

I put a TDC gauge into the sparkplug hole and checked.

 

TDC on the timing pulley is spot on with regards to the piston at TDC.

 

I am going to try to accurately record when the spark event occurs with respect to the camshaft sensor pulse, and maybe that way get an accurate idea of when the spark actually occurs with respect to TDC.

 

34j2gxu.jpg


Edited by HONDALEO, 05 July 2019 - 09:59 AM.


#8 skhell

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Posted 05 July 2019 - 10:57 AM

Wow, that is a really nice hack  :)

I have a cheap ebay bore scope but the quality is not that great. It already has a couple of years, maybe the new ones are better.

 

About your new findings, as you say, it really seems like it's a mapping problem. But that doesn't makes any sense, unless there is an issue on ECU...

 

When I tried to solve the problem, I tried to understand what controls the advance of the ignition and what sensors can influence the advance, but was unable to reach a conclusion. It seems that the ignition advance is not being correctly calculated.

 

There is a chip/module inside the distributor, but I am not sure if it related with ignition advance. 

 

Also, when we put the clip in the SCS, it seems that whatever controls the ignition advance is ignored, which makes sense to understand if the base ignition advance is ok. 

 

Considering the amount of sensors replaced and tested, could it be a bad ECU? I am not sure... That is a pain to test. I think it would have to be paired with the immobilizer...

 

Also, since I replaced my distributor a couple of years ago, that chip inside the distributor was also replaced, but the problem remained the same... I guess this would be another item to exclude.

 

I also tested the ignition advanced with the clip in the SCS and a strobe light and it was spot on.

 



#9 HONDALEO

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Posted 05 July 2019 - 03:58 PM

Unfortunately the better performance was short lived.

 

The car began to become very lumpy at idle, then went I went into the motor shop, when I came back out it didn't start immediately.

 

I had to crank it about 5 seconds which is completely not normal.

 

Regarding that module in the distributor, I already did a swap on that one too.

 

I think it is purely the igniter though, so all it does is control the dwell time and limits the current once the coil is charged.

 

In my case the igniter change made no difference at all.

 

I think I'm getting ready to give up.

 

I've ran out of ideas.

 

I wouldn't simply do an ECU swap.

 

It would be too much hassle and I don't have enough confidence to believe it would make a difference.

 

I did some tests where I logged the crank TDC sensor output, at the same time as the firing kV at the coil primary winding.

 

I paused the Picoscope when the pinking began, and the spark advance was 8° BTDC !!!!

 

This is very strange. I don't believe it.

 

I don't know what triggers the TDC sensor, but it is internal. I guess it is a machined notch in the crankshaft?

 

If it was actually a trigger bar / disc which bolts to the crankshaft internally, then my question is, could it come loose, and possibly be experiencing some angular displacement?

 

That's the only way I can explain that pinking occurs at 8° BTDC spark advance.

 

In other words, although I am recording that the spark kV takes place 8° BTDC, if the trigger bar / disc can float around, then dear knows where it is really firing with respect to true TDC

 

I would love to solve this before sending it to the crusher :-)



#10 skhell

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Posted 07 July 2019 - 09:04 AM

The crack position sensor and the top dead position sensor are located near the crankshaft.

I (myself) have replaced the timing belt twice, and I think the sensors are triggered by the pulleys.

 

Take a look at the following picture. You can see the sensor on the left which points to the smaller pulley, and the sensor on the right which points towards the back of the other pulley.

I don't believe that what triggers the sensor can suffer any displacement. 

 

BTW: it's time for me to fix that oil leak :)

 

 

P1260549.jpg

Edited by skhell, 07 July 2019 - 09:05 AM.


#11 skhell

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Posted 07 July 2019 - 09:08 AM

After a closer look on the image, I think the left sensor is triggered by that metal plate behind that pulley that have a notch. I think that plate is attached to pulley.



#12 HONDALEO

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Posted 08 July 2019 - 08:57 PM

Thanks for the photo. It makes a bit more sense now. But does that imply that the sensor on the left actually detects the pulley right  through the rubber belt? I am going to have to connect my scope again to help clarify this. From what I remember there were 12 crank sensor pulses for 2 TDC pulses, however the pulley in your photo has 20 teeth, so now I'm guessing I must have counted something incorrectly. I will upload a few photos once I capture them.

 

P.S. on your image in the previous post, the sensor to the left seems very far away from the pulley teeth. These type sensor normally have a gap of 1mm or less. I find it hard to understand how it could work so far from the teeth.

 

P.P.S

 

I just came across this civic photo below, so now it makes sense again if the Accord is the same. The plate on top of the pulley has 12 lobes and is close to the sensor.

 

ubicacion_del_sensor_de_posicion_de_cigu


Edited by HONDALEO, 08 July 2019 - 09:07 PM.


#13 skhell

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Posted 08 July 2019 - 09:25 PM

That steel plate with the two "ears", one in front of the left sensor and the other hidden under the right sensor makes part of that pulley. I suspect those "ears" are what triggers that sensor. If you look closer, those "ears" seem to be right in front of the sensor. Something like hits:

 

1198312456_w640_h640_shesternya-kolenval

 

P1260549.jpg



#14 skhell

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Posted 08 July 2019 - 09:34 PM

According to the repair manual, the left (front) sensor is the TDC sensor, the right one is the crank shaft position sensor:

 

sensors.png

 



#15 skhell

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Posted 08 July 2019 - 09:40 PM

The other pulley, which i guess is what triggrers the CKP sensor, has 12 notches. That makes the 12 CKP pulses for 2 TDC pulses. You can see it mounted in the engine and in the ground where you can see the rear side:

 

dsc08975.jpg

 

dsc08980.jpg


Edited by skhell, 08 July 2019 - 09:41 PM.


#16 HONDALEO

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Posted 09 July 2019 - 03:14 AM

Excellent. It's all clear now. When I observed the TDC pulse on the scope I noticed the sinewave shape was non symmetrical, and had a slight blip at the start of it. I can now see why. The two lobes on the pulley have a slight ramp before their peak, so that correlates exactly with my scope trace. I should get some time tomorrow to capture some traces. I have a funny feeling mine are out of sync somehow. Did you notice in the manual that it says if you remove the distributor you must attach it when cylinder 1 is at TDC ? That part has me mystified, since it is impossible to fit it any way other than the one way. I cna't see how you can put it on wrong?



#17 HONDALEO

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Posted 10 July 2019 - 09:01 AM

Here are the four images I captured.

Hopefully they're self explanatory.

I just have to try to capture these details when the trouble starts and see if I can make any sense of it.

These were capture while stationary.

The car won't even idle now. I possibly incinerated my O2 sensor with that overly late timing. The car hasn't run properly since.

I've even put everything totally back to normal, although I can't undo adding the fuel injector cleaning additive.

 

 

(The first image is just pointing out the asymmetrical pulse I mention previously - you can see the pulse begins to appear round about the red arrow)

 

 

24e84xy.jpg

 

 

 

23lxjx1.jpg

 

f3e6g0.jpg

 

 

29uvdsp.jpg


Edited by HONDALEO, 10 July 2019 - 09:26 AM.


#18 skhell

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Posted 10 July 2019 - 09:31 AM

Excellent. It's all clear now. When I observed the TDC pulse on the scope I noticed the sinewave shape was non symmetrical, and had a slight blip at the start of it. I can now see why. The two lobes on the pulley have a slight ramp before their peak, so that correlates exactly with my scope trace. I should get some time tomorrow to capture some traces. I have a funny feeling mine are out of sync somehow. Did you notice in the manual that it says if you remove the distributor you must attach it when cylinder 1 is at TDC ? That part has me mystified, since it is impossible to fit it any way other than the one way. I cna't see how you can put it on wrong?

 

I think that you can't install the distributor in other way. They do say to put the engine at TDC in cylinder 1, but they also say the lobe is offset to prevent mounting the distributor 180º out of time...

Screenshot-from-2019-07-10-10-29-08.png



#19 skhell

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Posted 10 July 2019 - 09:33 AM

Those readings are awesome? Try do get them when the pinking is happening to see if we can reach to a conclusion.

BTW, what did you used to get those readings? And where did you got the signals? Straight from the ECU wires?


Edited by skhell, 10 July 2019 - 09:35 AM.


#20 HONDALEO

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Posted 10 July 2019 - 12:31 PM

I got 3 signals at the ECU beside the passengers feet, but you need a rubber neck to get in at them.

 

GREEN TRACE = PIN 20 (green wire TDC sensor) 31 pin connector

BLUE TRACE = PIN 11 (brown wire INJ 1 pulse) 25 pin connector

BROWN TRACE = PIN 29 (yellow wire CAM sensor in distributor) 31 pin connector

 

The red trace is directly from an inductive pickup on the spark plug wire at cylinder 1.

The ECU does NOT send out a dedicated pulse to each cylinder.

It just sends a pulse to the distributor and the distributor sends it to the relevant cylinder.


Edited by HONDALEO, 10 July 2019 - 01:42 PM.