I need help from the wiring gods

GLAMIS WEATHER

ecbug

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After finally getting a j35a from (supposedly) 2001 honda odyssey wired and installed into the back of a 1969 baja bug I've run into 2 issues

1. I have the obd2 code p1753. Its an open circuit for a solenoid in the oem auto transmission. Im pretty sure there's nothing I can do about that.

2. The engine won't rev past about 3000 rpm.

The "trick" is to jump the TDC signal to the VSS signal to get the ecu to think the vehicle is in motion but for the life of me I cant find the pinout for my ecu

One answer that I found was to bridge C20 to D10

I dont have a D plug. I can get one or maybe pop the lid and solder if this is the right solution

To add to the confusion, I had to replace the throttle body with one from ebay.I accidentally bought

"Throttle Body LX Fits 02-04 ODYSSEY"

And the sensors fit the wiring harness without modification

The ecu has the sticker code "37820-P8F-A64" which is supposed to be an OBD2B ecu for a 2000-2001 odyssey

Here are some pictures of the ecu/plugs

Hopefully this is a quick fix, everything else has fought me tooth and nail. Thanks in advance for any guidance or help

20260503_120049.jpg20260503_115941.jpg
 
1000054685.jpghere's another image of the ecu. It doesn't really match what ive seen for OBD2B pinouts
 
That ECU is '01 only. It's not what people typically use. I stay away from them, so I'm not help off the top of my head. I can look a the wiring diagram when I get home tonight.
 
1000054725.jpg20260504_200958(1).jpg

I designed the wire from plug C carefully and got it into plug E

Unfortunately its too late to crank the motor and confirm the fix.

Thanks again for your knowledge and help.

I'll update tomorrow morning.
 
I got home today and gave the motor a go. Still had a rough idle and it seemed to rev a little higher. Went and started double checking everything and noticed that because I'm using a newer throttle body, its slightly bigger. Well, the bottom edge has some of the gasket exposed and was allowing unmetered air in. Could that have been the whole problem? I had some extra milled flat aluminum plate from Industrial Metal Supply and cut out the pattern of the throttle body with a 2.5 inch hole in the center. Used sealant on the throttle body side and gasket on the intake side. works great. Tested by spraying brake cleaner and no change in rpm. FIXED, that at least.

Now, i plugged in the OBD2 scanner and I'm up to 4 codes from 1. FML

P0335 - Crankshaft Position Sensor
P1298 - High input voltage from ELD - electrical load detector
P0141 - o2 sensor heater circuit bank 1 Sensor 2
P1753 - open circuit for a solenoid in the auto transmission

Ordered up a new o2 sensor and crank position sensor. they're from 2001. weird they got out at the same time but they're old and I'd rather deal with it in the backyard versus in the dunes or on the road.

Edit: sensor 2 is the post cat sensor. definitely don't have that sensor installed on the 69 manx. but that shouldnt have any bearing on being in limp mode.

I'll have hopefully good news when the parts come in
 
Sorry for the long delay. Im going back to school and I had to shift my focus to studying for my finals. 5 classes All A's

Now, back to the problem...stupid mistake. Went back through all the wiring and connections. Well the ground lug for the fuel injectors was loose. Problem 1 solved. The surging/oscillating revving was apparently caused by having air in the coolant lines. Me thinks the temp coolant temp sensor that goes to the ECU wasn't getting a proper reading. ALSO, because I opted for a remote thermostat thats basically floating, the housing 'isnt grounded'. I also added a ground cable from the roll cage to the sensor and everything seems to be working fine.

As for the vdo tachometer, I ended running the engine and did trial and error with the toggle switches on the back. "All off" works for my setup
 
I had an issue with my father in law’s buggy where the tach was set for a 4 or 8 cylinder. Confirmed with an OBD2 scanner it was hitting actual rev limiter (6500 or whatever)
 
I had an issue with my father in law’s buggy where the tach was set for a 4 or 8 cylinder. Confirmed with an OBD2 scanner it was hitting actual rev limiter (6500 or whatever)
Building, running and maintaining a home brewed buggy is truly a labor of love
 
Building, running and maintaining a home brewed buggy is truly a labor of love
Yessir. Nothing beats a buggy in the dunes…

Assuming it made it to the dunes
:ROFLMAO:
 
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