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Old 09-22-2007, 04:24 PM
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What is this?

On my 90 Si with the B20A5 engine, on the thermostat housing I find 3 sensors clustered fairly close together. one is the temp gauge sending unit which is obvious. The question deals with the 2nd & 3rd, one of which is the Thermosensor (I beleive that to be the lower one), which has the grn/wht & yel/grn wires attached. But what in the world is the other one? and by the way, the connector plugs for the thermosensor and the other are interchangeable.
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Old 09-22-2007, 09:37 PM
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New info. I went to my favorite auto parts shop to get a new muffler, and while there, one of the guys who works there (who is also a mechanic) took a look at the installation. He recognised it as a later generation design for the B20A5 cooling system, probably from an Accord (I do know that this engine was a replacement for the orig one). The unknown switch is a cooling fan switch. It seams that I have two of them, both wired in. which is faulting out the engine cooling fan.
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Old 09-23-2007, 02:49 PM
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Quote:
Originally Posted by dllang777 View Post
New info. I went to my favorite auto parts shop to get a new muffler, and while there, one of the guys who works there (who is also a mechanic) took a look at the installation. He recognised it as a later generation design for the B20A5 cooling system, probably from an Accord (I do know that this engine was a replacement for the orig one). The unknown switch is a cooling fan switch. It seams that I have two of them, both wired in. which is faulting out the engine cooling fan.
Pictures, FYI, our engines are totally different from any accord engine.
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Old 09-23-2007, 09:20 PM
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I tried to load some pics, but had trouble doing so.
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Old 09-23-2007, 09:24 PM
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see if this works
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Old 09-23-2007, 09:26 PM
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next photo

here is another
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Old 09-23-2007, 09:27 PM
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the lower right one is the thermosensor. I think the upper most one is the extra (or maybe should be primary) fan switch.
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Old 09-23-2007, 09:43 PM
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I'm looking at the online manual chapter 5-66. The one closest to the bleed bolt is the Temperature gauge sending unit. The other is the thermosensor, which you were both correct...which other 3rd one are you talking about?


...for future reference, your car is 2.0Si, not Si. You got me confused too many times thinking you had an Si with PK3 stuff
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Old 09-24-2007, 07:12 AM
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what is it

this pic shows the bleed port, then down to its right is the temp sender. the one in question is the switch paralell to and to the right of the bleed port. In the 1st pic, above, it has a blue colored connector. when its cold, it gives a resistance reading of infinite, but when hot it read about 1 to 2 ohms (i think it is deffective). Also, if the connector is pluged to it, the post shutdown fan does NOT turn on. If I leave it unplugged, the switch on the lower r/h corner of the radiator then turns on the fan at shutdown. Thats why I think its an extra (or later generation) cooling fan switch.
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Old 09-24-2007, 07:18 AM
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BTW, I went thru the PGM-FI control system trouble shooting flow chart from the online manual (thanks again Prelude13) page 6-156 thru 6-157, and it points to an ECU fault. Sugestions on where to get a good ECU at an affordable price?
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Old 09-24-2007, 02:00 PM
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Quote:
Originally Posted by Prelude13 View Post
I'm looking at the online manual chapter 5-66. The one closest to the bleed bolt is the Temperature gauge sending unit. The other is the thermosensor, which you were both correct...which other 3rd one are you talking about?


...for future reference, your car is 2.0Si, not Si. You got me confused too many times thinking you had an Si with PK3 stuff


Right..

Isn't PK3 Si?

I may have a working OBD0 ECU for your B20A5
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Old 09-24-2007, 05:46 PM
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Cool. Meanwhile, I may check the salvage yards around here as well. And I shall check the part number on the ECU. It will help in the hunt.
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Old 09-24-2007, 06:14 PM
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Quote:
Originally Posted by team123luder View Post


Right..

Isn't PK3 Si?

I may have a working OBD0 ECU for your B20A5
Yes, pk3 is Si, OBD I, B21a1


Here is a ECU for you:
http://cgi.ebay.com/ebaymotors/88-89...spagenameZWD1V

PK2 OBD 0
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Old 09-24-2007, 09:20 PM
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what is PK3 Si?
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Old 09-24-2007, 09:27 PM
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PK3 is the ECU for b21a1's, or 90-91 "Si's"

Your car is 2.0Si and uses OBD 0 ECU....hence, PK2 as in the pic:
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Old 09-24-2007, 09:31 PM
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haha*off topic*
iused to race electric rc cars and one of my favorite motors pk2 or p2k2 either way haha random.
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Old 09-24-2007, 09:54 PM
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One thing I have repeatedly said to my co-workers throught this re-build project, when Honda starts to build the Honda Jet, we (Cessna) will have a serious competitor. They know how to clamp things, and they know how to hide parts & make mechanics say not nice things about engineers. I just pulled loose the ECU to check its part number. the tag showed a 37820-PK3-A00. And it otherwise works great with the B20A5.
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Old 09-24-2007, 09:58 PM
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I wish I knew more of the car's history. This B20A5 engine was installed by a previous owner a few years back. I really dont know what it started with. But I do know that a 378020-PK3-A00 is what is installed with that engine. (right or wrong)
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Old 09-24-2007, 10:04 PM
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BTW, I just updated My Avie with a freshly washed and waxed pic of my new toy.
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Old 09-24-2007, 10:04 PM
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Pk3? whoa.

Okay, let's clear this up.
Your car...does it have fog lights?
Do you have power windows?

see, the b20a5 has dual intake runners, which only will work with the pk2 ecu.
Im lead to believe now that you have a Si model, with a b20a5 swap.

...you reused the b21a1 manifolds(pk3) ON your b20a5, then you're good with the pk3 ecu.


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Old 09-24-2007, 10:16 PM
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I wish I could tell you for sure. The block says B20A5, the manifolds fit, but the gasket kit for the B20A5 did not. the ports were further apart and there are 4 distinct tubes (i had to modify it to use it). But that would make sense. the previous owner may have had a B21A1 that died and this was available. yes, there are power windows and fog lights. would having the vin help you as well?

Last edited by 3G-Lude-a-tic; 09-24-2007 at 10:22 PM.
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Old 09-24-2007, 10:21 PM
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Nope. You answered my questions

So to really CLEAR THINGS UP , you got a SI. Former motor in your car was the b21a1. Sorry if i thought otherwise, we weren't on the same page all this time
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Old 09-24-2007, 10:23 PM
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Quote:
Originally Posted by dllang777 View Post
BTW, I just updated My Avie with a freshly washed and waxed pic of my new toy.

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Old 09-24-2007, 10:32 PM
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So then to confirm, (sorry, its what I do as a pre-flight inspector), with this B20A5 powered Si that has its old B21A1 intake manifold and Fuel control Unit, I am good to go with the PK3-A00 ECU? (I wonder how much more of a runner this car would be with a re-built B21).
That sure helps to explain the fan switch and harness differences.
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Old 09-24-2007, 10:39 PM
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Roger that you are cleared for takeoff -----corny i know.




Personally, i like the b21a1 a lot more, even though 85% of them burn oil(including mine)...see this thread to understand more: B21a1 owners hollah at your boy!!
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Old 09-24-2007, 10:46 PM
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Its a relief to finaly get a handle on what I have under the hood.
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Old 09-24-2007, 11:17 PM
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The B21 is a nice engine, though it only makes power up to 5800rpm as opposed to the B20A5, which builds up to 6200rpm.

The B21 makes 140bhp, the B20A5 makes 135

With very little modifications, the B20A5 can make up the lack of 5bhp.
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Old 09-25-2007, 05:27 PM
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So with the over bore I have, I should be about equal. Now for that ECU...
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