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Stangrcr1

New Member
My good friend recently bought a 98 civic hatch thinking he could use it for a commuter. One of the cv's started clunking, so he called me over to help him change it. Sent him to get another axle from NAPA while I looked over the car. Hmm. B16A2 w/ VTEC. Lots of harness connectors not used. Header. Full SS exhaust. Cylinder head is PR3-3 with 99 date stamp. Look farther and find P28 ECU with OBD1-2 adapter. He gets back with the shaft and it is loose in the diff. Me thinks he needs to swap it for a 99si axle and send him back. While he is gone, I open the ECU and find an SST 27SF512 chip. Look more and find S4C trans(non-LSD). He gets back and the 99 axle fits. Got it back together and then he starts asking why the power is down and mileage sucks.

That is why I am here. How do I get codes from an OBD1 computer adapted to an OBD2 harness without the two wire(black/brown) connector? I was considering hooking up my Snap-On scanner to the OBD port, but not sure what would happen with the adapter, or happen to my scanner.

We did not do this swap, it was already done before he bought it. Now trying to figure out how to make it run right. I think the TPS is bad as he says the throttle is not responsive and will stall sometimes when he hits the gas.

PCM: 37820-P28-A52-761-761684 with SST chip and adapter OBD1-2
B16A2 with 99 date stamps
S4C trans
All in a 98 Civic non-Si.

Any help appreciated.
 
:wave:

Not sure what the SST chip is- it could have any program on it. You should probably get a program based on the factory fuel/timing map for the B16 and burn that to a new chip. Quite a few harness connectors get left off in the OBD conversions, so that's normal- hopefully the car was wired correctly.

As far as pulling codes- maybe trace the jumper wires from the ECU and pull them? I don't have an ECU pinout handy, but they're not hard to find.
 
Since this is a 99 Civic Si engine and trans in a 98 Civic non-Si, would it be easier to just put a stock ECU from another 99 Si into it and then go from there? Sure it would have a lot of codes, but it would be a starting point.

The wiring all looks good and the splices are shrink wrapped, so someone took the time to do it right.

I understand the benefits of going the OBD1 and custom chips, but since this is primarily a commuter for him, what is the best way to go?

He said it ran better when he got it and has recently started acting up, which makes me think a sensor has gone bad, but I can't pull codes easily. He is very adept at the mechanics, but not good with the electrical side. Trying to make it easier for him.

The car is 40 miles away from me right now or I would check pinouts. Maybe this weekend.
 
The last Honda I owned was a 91 Civic DX, so it has been a while since I have really dug into a Honda, and while I know of these conversions, I have never had my hands in one. Til now.
 
Since this is a 99 Civic Si engine and trans in a 98 Civic non-Si, would it be easier to just put a stock ECU from another 99 Si into it and then go from there? Sure it would have a lot of codes, but it would be a starting point.

The wiring all looks good and the splices are shrink wrapped, so someone took the time to do it right.

I understand the benefits of going the OBD1 and custom chips, but since this is primarily a commuter for him, what is the best way to go?

He said it ran better when he got it and has recently started acting up, which makes me think a sensor has gone bad, but I can't pull codes easily. He is very adept at the mechanics, but not good with the electrical side. Trying to make it easier for him.

The car is 40 miles away from me right now or I would check pinouts. Maybe this weekend.

That would probably be the best way to go, especially with no mods inside the engine- but you'll have to take the wiring back up to OBD2b standards.
 
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