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CRX ECODiesel Ram
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Discussion Starter #1
i have had an off and on code 9/p0340 (as shown in the smanager software).
The distributor has been tested multiple times and replaced several times (new, used and reman), it has no known issues. The engine wire harness has been replaced with new oem honda wires. The ecu has been replaced with a HA refurbished ecu.

The ONLY common factors left are the engine (which has had the cam gear reset to 0 and ignition timing reset) and the Hondata s300.

I am really at wits end right now. Does anyone have any suggestions where to go next?
 

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Classic Man
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When does it usually come on? Beating it? Idle? Hot idle? Cold idle? Right when the engine idles down when warm? etc?

Do you have any skills with a oscilloscope?
 

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Discussion Starter #3
If I recall correctly it never came on with the stock cam, but it has been quite a while. With all electronic aspects changed EXCEPT the s300 i am starting to really wonder if there is some sort of mechanical issue that might cause this, though ruling out any sensor problems with the scope is worth it.

If i let it sit at idle for over 5 minutes from a cold start it will often appear, it will appear in any driving condition (once warmed to operating temp) usually preceded by several minutes of random missing (steady state light or heavy throttle makes no difference) and the misses are randomized with no discernible pattern or time spacing. Once the code comes on, missing immediately stops, though it almost always drops out of closed loop.

I do not have immediate access to an oscilloscope though i am asking about to see if anyone I know can let me come use it. I know enough if I know what leads to hook up to (assumably the CYP sensor) and then set the scaling and read a pattern. Similar in some ways to an EKG itseems.
 

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Discussion Starter #4
I MIGHT try and let it idle on a stock p06 (the h22a4 injectors, compression and cam might make this hard) and see if the code pops up there too, if that is the case I suspect the s300...
 

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Discussion Starter #5
would a cheap diy style oscilloscope be effective? looks like a 2 wire reading is pretty easy and i see some build it yourself units (as well as pre assembled ones) for under $50, obviously they are not going to be great but for reading a single 5 volt signal would they be adequate?
 

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the DIY scopes are pretty slow reacting, but should work okay as long as you know it can be off a bit.

could try it on the O2 sensor circuit to see how it sees the normal sway of the signal

EDIT how have you been positioning the distributor? the code coming on and the missing disappearing makes me think the ecu is pulling timing out and enriching the AFR
 

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Discussion Starter #8 (Edited)
well just for the hell of it i went back and did all mechanical and ignition timing from scratch, with base timing set at 18 btdc at idle. verified tdc on piston 1 with a rod down the spark plug hole, visually verified the cam position, visually verified the distributor position. then warmed it up and get the timing light out. to get to 18 btdc i had to max advance the distributor out. While everything was apart i also pulled the distributor plugs out and inspected the male and female pins, the females are brand new having been put on with the obd1 plug. I also took a few minutes and gently pushed the lower surface of the pin to be tighter fitting to the male pin.

I have not been able to get a dtc all day...

i am not seeing timing being pulled at all on the hondata app, but i can see that closed loop is off, and the wideband display shows it running significantly richer.

also noticed that until the distributor was advanced i was seeing -13 at idle, after advancing it was back to the -19 or better (still hits -22 to -24 when coastingdown with closed throttle soi know the engfine is good and tight).
 

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one trick you can try to get a bit more wiggle room out of the distributor is make sure the car is fully warmed up, loosened the distributor mounting a bit, and retard the distributor slightly.

With the service jumper NOT used, the ecu should attempt to correct for the timing difference of the disty being rotated slightly.

Depending on how it SOUNDS, you will know if it cannot correct anymore.


This is something I have had to do for a lot of people who buy ebay distributors. Those distributors are often made with F or B series locations for sensors, and that is why you sometimes have to max the goddamn things out.


Just make sure the engine has been running for at least 30 minutes, as we all know a colder engine will not react well to an accidental detonation or missfire.


Its a small risk, but something Ive gotten away with. Im not saying do it so your distributor is perfectly centered, but extra wiggle room is always handy!!
 

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Discussion Starter #10
I'm going to give that a try as a next step. Going to drive as is for now and see what happens. I recall a while back having a similar experience with the stock cam and gear.

I really need to keep a diary on what i have done.
 

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Classic Man
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So how the CYP sensor works, its a mag pulse or AC generating signal.

If there is a short to ground or missing shielding, it can cause the amplitude to drop and the signal to be lost and the ECU throws a code.

Could also come down to a bad connection/connector, or a cracked magnet at the CYP pickup.

Something to consider, since all these sensors are on the same shaft, the car has no idea if the cam timing is out since theres no crank sensor at the crank, its on the same damn shaft as the cam sensor! lol. So the ECU is throwing that code because the signal is not correct. Not because of the timing being incorrect.
 

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Discussion Starter #12
Retarded cam timing from 4.75 degrees advanced to 0, advanced ignition timing to full advance and 18 BTDC....haven't seen a code 9 since then.

All connectors are brand new with less than 250 miles on them, distributor(s) are brand new as well (though chinese made).
 

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be wary of the china distributors

they LOVE not getting screws tight inside the case, adn they love "forgetting" to add thermal paste or padding to the ICM.

Many years back, I was having a repeatable problem of the car loosing ignition power over an hour of driving. Taking apart the distributor and following advice of thermal paste removed the issue. WAAAY back in 2004 or so
 

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Discussion Starter #14
I have 3 of the chinese ones, i have a used Honda one, I have a "reman" one, all have various brands of icms, and each has been opened and had arctic silver put on them. I also have 4 or 5 spare used icms as well. The worst distributor i have is the reman factory one though the bearing did start to fail in the used oem one and every bearing i have ordered that is supposed to be the right one is far enough off spec to unusable.
 

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Classic Man
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Also dont call it a P0340. thats an OBD2 trouble code and your car is OBD1, and has no crank sensor on the crank. Unless Hondata cracked the OBD2 code. That would be cool.
 

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Discussion Starter #16
Hondata s300 indicates it as a p0340 as they use the obd 2 codes for USUALLY greater specificity as well as bluetooth compatibility. Even then the fine print states that it is a CYL code rather than CYP...
 
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