I am doing an F20B swap in my 90 Prelude using a chipped P28 ECU. The dizzy is OBD2B and Im going to OBD1 (i know obviously). I found all the diagrams and information to go along with it so I have that covered. I was speaking to someone on another page about my setup and was told I needed to swap to an OBD1 dizzy or ill have issues running, which contradicts information I have seen. Before I rewire I want to just be sure that as long as I wire everything properly at the plug, and the wire off the ignitor for the tach, that I wont run into issues with how it runs. Im assuming not as this seems to be common? Or does perhaps it differ from ECU setups? Thanks in advance.

 

OBD-1 and OBD-2 distributors have the same internal trigger counts for the TDC, CKP and CYL sensors. Their function is the same... they just have different plugs. The real question is what are you doing at the ECU end of the '90 Prelude since it is OBD-0 ???

 

Thanks. Thats what I had seen and wanted to confirm before I bought a new distributor.

I have a Wireworx OBD1 harness for all the engine stuff. Included jumpers for various plugs. Only had like 5 wires I had to tap into myself.

 

does the f20b have a crank sensor on the actual crank mounted to the oil pump?
does the distributor have 9 wires total? or only 7 wires total?
and is your car originally b20 (obd0) or b21 (obd1)?

 

The crank sensor is inside the distributor, and there are 7 wires coming out. The tach lead isnt on the stock plug as it originally draws its signal from the ECU. So i have to add the tach signal myself by placing an extra wire on the ignitor. My car is originally OBD0.

 

I think we're both a little confused here. 7 wires total would mean the crank sensor is not inside the distributor. 9 wires total would be if the ckp is inside the distributor.
internal coil/igniter with all 3 sensors would have wires for: 2 wires per sensor (6), coil/igniter 12v (1), igniter trigger (1), tach (1). 9 total.
if there are only 7 wires TOTAL coming out of the distributor, then the ckp is on the crank and not in the distributor.
if the distibutor does not have a tach output wire (which I find nearly impossible), it would have either 6 or 8 wires total coming out.

 

Then perhaps it has 8. Ill have too look at it again. The plug is only an 8 pin. Also there is no crank sensor at the oil pump. Everything I have looked at states this distributor includes the crank sensor and there is no tach lead as it gets the signal direct from the ECU. Here is my dizzy, one plug 8 pin and im pretty sure one is missing. Ill get a better pic when i get home.

 

The seven wires would suggest that you have three sensor pairs (CKP, CYP, and TDC) and the ICM wire. These would be found in the 8 pin (2 rows of 4 wires) that you have pictured. The lower 2 pin plug in your photo has the 12v+ wire and the tach lead in it... but it does not appear to be connected to the distributor. If this is part of your distributor adapter harness, you need to let us know how your distributor is getting power. The 8th pin in your plug would normally have the 12v+ black/yellow wire in it to power your distributor. Does the distributor plug have matching wires on both sides of the plug ???

H22 engines are set up differently than "B" series or "D" series engines... there are only three positioning sensors used in all H22 applications. Early OBD-1 type applications, as well as most JDM/EDM engines, have all three housed inside the distributor. USDM OBD-2 engines have one sensor in the distributor and the other two are housed on the oil pump housing. OBD-2 "B" and "D" series engines differ in that ALL have three sensors in the distributor AND one additional (for a total of four sensors) called the crank fluctuation sensor. OBD-1 engines do not have this additional fourth sensor.

 

I looked again. It is an 8 pin with only 7 wires. 2 for each sensor (positive/negative) and one ground. I have to move the 12v from the second plug to the big one. Then I will add the wire for the RPM directly to the ignitor.

 

Worked too. Car starts now.

 

cool, glad you got it figured out

 

Yeah. Now I just need to figure out why it only runs for like 10 seconds. Its like the fuel just cuts out. So thats the next thing to figure out. Also I have a 3 wire IACV and my harness is a 2 wire. I have seen conflicting answers to this. Am I able to convert it to 2 wire and run it, or do I need to swap the upper manifold and run an actual 2 wire IACV?