All right, here's the deal. I swapped the B16 into my car last July or so, and unbeknownst to me, the ecu I was given was a P72. Everything was running fine (though the fuel was rich and vtec kicked in at 4700 rpm), but after a few months, I got a check engine light. Turns out it wasn't just one, it was 4 codes. I would throw the cel about 98% of the time I would drive the car. The car still ran the same as before the cel was thrown, so my friends and I attributed it to bad wiring.

Fast forward to the present. I was able to swap the P72 for a P30 from the place that got me the swap, and I was still getting the codes for about a day. Now that the fuel is leaned out and vtec kicks in at 6k, it just makes me want to stay in vtec all day, but even though I kinda beat on it often, I haven't been getting any cel's since the first day that I swapped the ecu.

Now my question is, is it possible that it was the gsr ecu that was throwing the codes, but now that I have the correct ecu, they will be all gone. I just found it wierd that I got the cel for just one day, and now it is gone (coincidince, I think not, but that's what I am here to find out).

Thanks!

-Shane

 

Both ECUs should throw the exact same codes unless the GS-R ECU was defective somehow. The only codes caused by the P72 might be from running it so rich that it threw an o2 code, but that's kind of doubtful.

The only extra features a P72 ECU has are the secondary butterfly controls, which are not connected with any CELs at all.

 

Yes, the ECU will throw differant codes per differant computor. The P72 is looking for more sensors due to the GSR's intake manifold. The B16 is not looking for some of those sensors, therefor eliminating the CEL and codes. But you arent throwing any codes now? And what were the codes you threw before the change, and what was the code you threw for one day?

 

Correct, I am not throwing any codes now. Like I said, every day since the first time I threw a code, it had been throwing them with the P72). But since after the first day (about a week and a half ago) I swapped the [P72] ecu out [for the P30], I have not thrown a single code.

Thanks for the replies. If you can all think of anything else I would be happy to hear from you!

-Shane

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMJoelEK &raquo;</TD></TR><TR><TD CLASS="quote">Yes, the ECU will throw differant codes per differant computor. The P72 is looking for more sensors due to the GSR's intake manifold. The B16 is not looking for some of those sensors, therefor eliminating the CEL and codes. But you arent throwing any codes now? And what were the codes you threw before the change, and what was the code you threw for one day?</TD></TR></TABLE>

WRONG

Name the sensor or extra sensors that a P72 would look for that a P30 does not.

<FONT SIZE="7">**CRICKETS CHIRPING**</FONT>

As I already stated the P72 doesn't look for any extra intake manifold-related sensors.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Correct, I am not throwing any codes now. Like I said, every day since the first time I threw a code, it had been throwing them with the P72). But since after the first day (about a week and a half ago) I swapped the [P72] ecu out [for the P30], I have not thrown a single code.
Thanks for the replies. If you can all think of anything else I would be happy to hear from you!

-Shane
</TD></TR></TABLE>

What codes were you throwing before though? again the only codes I can think of that an OBD1 P72 would throw vs. an OBD1 P30 *might* be an o2 code if the P72 is running it too rich or if the lower VTEC point was messing with the fuel mixture, but again that's a stretch.

 

just wondering , what codes did you throw on the p72?

 

#3 - MAP
#7 - TPS
#21 - VTEC solenoid
#43 - Fuel Supply System

as per https://honda-tech.com/zerothread?id=682412.

Thanks again for the replies.
Forum mod, why o why do you treat me like sh*t always. Oh, and I never got your pm back about who did your side moldings. Either you really do hate me or I just lost the pm somewhere. It looks awesome anyway.

-Shane

 

Oh, and also, the car doesn't overheat anymore. I know there is a difference in pin A12 (fan output on P30, engine coolant temp switch on P72). Everything just seems to be running perfectly since I swapped out the old ecu. Not complaining, it just seems so odd that this ecu would cure all of this. Thanks anyways everyone!

-Shane

 

those ecu's share the same pinouts and sensors. the only thing i can think of is the P72 ecu might of been bad.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nighttrain33 &raquo;</TD></TR><TR><TD CLASS="quote">#3 - MAP
Forum mod, why o why do you treat me like sh*t always. Oh, and I never got your pm back about who did your side moldings. Either you really do hate me or I just lost the pm somewhere. It looks awesome anyway.

-Shane</TD></TR></TABLE>

Huh?

How am I treating you like ****?

And my anti-pop-up software at work sometimes owns my IMs here when my boss changes the settings constantly. If you need something, re-IM me.

 

Oh well. its fixed anyway. Thanks you guys!

-Shane

 

My bad, but I know the P72 looks for the intake air bypass, while the P30 does not. Its located on pin A17 in the P72, so i thought that may be a problem. So I wouldndt say the IAB caused it for sure, but at least you got the probelm fixed. BTW, I believe this fills in for the crickets chirping, not to be a dick, but you did start it. Didnt mean to give you false info, sorry.

Name the sensor or extra sensors that a P72 would look for that a P30 does not.

So I say IAB. Is that wrong? becuase I would like to know. You seem to be seasoned in this stuff, and always want to learn something new. So please let me know if I'm still mistaken. Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMJoelEK &raquo;</TD></TR><TR><TD CLASS="quote">
Name the sensor or extra sensors that a P72 would look for that a P30 does not.

So I say IAB. Is that wrong? becuase I would like to know. You seem to be seasoned in this stuff, and always want to learn something new. So please let me know if I'm still mistaken. Thanks</TD></TR></TABLE>

Okay I should have been more specific. What sensors that will throw check engine lights does a P72 look for that a P30 doesn't.

I just assumed that we understood that we were talking about check engine light inducing sensors since the root of the topic was why the P72 threw a CEL and the P30 did not.

Sorry to come across as a dick, but I've seen a lot of misinfo lately and I am trigger happy when it comes to correcting misleading posts. I apologize for being overly abrasive to you.

 

Thanks for the heads up. And an apology wsnt in order,but appreciate it. I just find that the GSR with that mani. runs so much smoother with that ECU so I jumped the gun and said that was the problem. Thanks for the info.

 

Well, here are the differences in pinouts:

A12 - P72 has engine coolant temp switch; P30 has fan output.
A17 - P72 has IAB; P30 has nothing.
B9 - P72 has starter signal; P30 has clutch interlock switch.

-Shane

 

P.S.

These are the only differences between the two according to http://www.hybridgarage.com

-Shane

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nighttrain33 &raquo;</TD></TR><TR><TD CLASS="quote">Well, here are the differences in pinouts:

A12 - P72 has engine coolant temp switch; P30 has fan output.
A17 - P72 has IAB; P30 has nothing.
B9 - P72 has starter signal; P30 has clutch interlock switch.

-Shane</TD></TR></TABLE>

Again these differences should not cause a CEL either way.

I've swapped out a P72 and a P30 in my old B18C1 hqtch and my wife's B16A hatch and aside from each engine running like **** with swapped ECUs, there were no CELs for either car.

 

1. Did the B16 run better (in your opinion) with the P30 (and vice-versa)?
2. I just can't figure out what would make such a difference with the CEL's and the overheating problem. Not so much for my info., but for someone else's. Although it would be nice to think that this ecu has cured my prob's. Like I said, I have been driving it extra hard (you know that the 6k vtec feels so much better in the B16 than the 4700 [not to mention the mid-range power]), yet still no CEL's.

-Shane