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Discussion Starter · #1 ·
So we have confirmed in my introduction thread that I have a 2005 si with the k20a2, with k20a2 head swapped from the rsx type s. 5 speed Trans, and stock type s ECU. Doesn't have any aftermarket ECU additions and isn't tuned, etc.

So far I have the following codes.
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I had brought it to a shop recently and he said he replaced the canister. I do have to say I think the fuel smell doesn't exist anymore, but the code hasn't turned off. Even after disconnecting the battery (which I'm assuming would soft reset the codes), they remain. I haven't tried physically deleting the code, but I assumed the shop mechanic would have done that anyway.

The map sensor one seems to not come on unless I rev close to the red line area (~7k+ rpm). It currently doesn't show, but I haven't reved it real high recently. I'm curious if I can reproduce this.

Otherwise as some other person suggested, I have taken some readings from the live OBD2 data, at idle (not including wide open because I don't think I did it right, and I don't want to get yelled at O'Reilly's).

Here's video of OBD2 at idle:


Any help pointing me in a right direction or helping me understand these issues is appreciated.

Thanks!
Matt
 

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are you using the MAP sensor the ECU expects?
Besides electric issues this is the only way I can see how such a code can be thrown for a naturally aspirated engine.
 

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Discussion Starter · #3 ·
That's one thought I've had before, I suppose I could check if the sensor has a part number I can lookup. On this note however, I'm assuming my throttle body is for the type s motor, but haven't been able to confirm the part.

Could a slightly different throttle body assembly mess anything up, or would it generally be the same between k20a3 vs k20a2?
 

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This is the K20a2 OEM MAP sensor.




I have read somewhere that all K-series use the same MAP sensor.
if so, then your ECU sees a voltage at its input higher than what it expects.

In your video, indicated MAP seems fine art 9 inHg or 300 mbar. This is normal. The rest of the data also look plausible. What it did show is a TPS value of 7.8% assuming you are at idle. This is not correct. Its should read 0%.
Did you remove the TPS at some point?

Here is what the manual says on your errors:
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The EVAP system test is much more laborious.
 

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Discussion Starter · #6 ·
To be fair, I think I've seen the map sensor reading to be above 11 inhg, but not sure if that was at idle. From that description above and my procedure I remember doing at O'Reilly's the other day, maybe this checks out for a bad sensor.

Btw sometimes the idle rpm goes up and down, so these pictures could be at idle? I can't remember.

I haven't touched the tps since getting the car, unless the mechanic did something when doing other work. Should I check this component too? I haven't seen any tps error codes so far
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the TPS value either indicates that the throttle cable is under tension at idle leaving the throttle slightly open or the TPS got turned on the shaft. It can be adjusted. Or someone fiddled with the throttle stop screw, e.g. to compensate for a non-functioning IACV.
Unless this is fixed, you cannot expect a stable idle.
 

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Discussion Starter · #8 ·
I did end up plopping a new map sensor in just to see if it would do anything thing, and I haven't seen the code go away.

Also I have in fact gotten a new code: P0420 Catalyst system efficiency bellow threshold.

It's also worth noting (I didn't mention this in my original post) that once in a blue moon my car will not go into 1st or 2nd gear (low speeds). It's like it just doesn't get any power and will want to stall when trying to put it into gear (manual car). This is resolved by simply turning the car off and back on again, then it behaves normally.

This is probably related to all the above.

Otherwise I haven't yet played around with diagnosing any problems with the IAC valve (as per your previous comments), that might be next on my list unless there are any different ideas?

Also worth mentioning, the idle once the car is warmed up is very stable around 800, it's only variable when cold starting. The more I think about this, this behavior may be normal?
 

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P0420 Catalyst system efficiency bellow threshold is most likely just that. The secondary lambda sees too large oxygen level swings pointing towards a loss of oxygen storage capacity of your cat = dead cat.

stalling etc is not normal. The VSS sensor of the 5speed box won‘t provide the signals the ECU expects I guess. The PRB ECU expects a 6-speed VSS signal. There are gear depended parameters in the ECU.
It also applied certain RPM limits based on speed.
 

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Discussion Starter · #10 ·
stalling etc is not normal. The VSS sensor of the 5speed box won‘t provide the signals the ECU expects I guess. The PRB ECU expects a 6-speed VSS signal. There are gear depended parameters in the ECU.
It also applied certain RPM limits based on speed.
Is this reason to get a hondata kpro ecu? Can a tune help with any of these items?
 

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The idle regulation requires a proper VSS signal. There are idle speeds and there are rolling idle speeds.
There are also lower speed limits on when VTEC can engage and there is a lower idle rpm limit.
With a KPro or a Doctronic ECU you can adjust these settings.

See: KPro Help
Gear Compensation Parameters
Misc Parameters for VSS set-up.
 

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Discussion Starter · #12 ·
Thanks for your help on this, I think this makes a bit more sense to me now. I still have the ep3 stock ECU from previous owner, so from reading other forum posts it looks like converting the ep3 ECU into k-pro is the way to go.

Any caveats? Looks like I loose reverse lockout (can be modified to add back in), and can I still utilize the immobilizer? I thought I saw somewhere that certain ECU's support the immobilizer and some don't. I would like to keep the immobilizer if possible (working fine with type s ECU).
 

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Both Doctronic and KPro support the reverse lock-out.
I use a Doctronic ECU based on a PRA ECU on the corresponding PRA loom on the K20a2 and it works as it should.
 
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