I have a 94 Accord ex stock vtec with cold air intake. When I’m driving above 20mph runs like a champion (I think, probably not with all these problems). When it is cold I have a very high idle around 2000, and when warm there really is no normal, but normally idles around 1000-1250. I turn the idle screw all the time warm and cold to try and fix it but the idle is never the same or where it should be. I have very erratic idle speeds. When its cold with the high rpms it takes off great, but when its warm and my rpms get all erratic, and I go to take off it bogs down till it gets what it needs then takes off. Sometimes after I drive it and then let it sit for an hour to 4 hours and then takeoff when I get around 10mph it starts jerking real hard like its stalling and starting really quick. And it won’t stop till I let off the gas and push the clutch/disengaging it. It’s rough. When I drive to school a 45 min trip, and if I have to stop to get food and gas. Half way to school my fuel code (code 43, fuel supply system defective OR malfunctioning fuel supply system) would pop. But if I left and went straight to school, less slow speeds and stopping the code wouldn’t pop. I started there. Without checking pressures or anything and still haven’t. got to get a vacuum tester and the fuel pressure tester I haven’t rented yet, I replaced my fuel filter, then fuel pressure regulator, then at school used an oscilloscope on my injectors, they all threw the same great signal, still getting the code I replaced my fuel pump with a JDM 255 LPH fuel pump. It takes off a little better, but I wonder if that’s just because it’s an upgrade and not OEM. I’m still getting a fuel code and now I’m getting code 41 (oxygen sensor heater malfunction). So that’s 2 malfunction codes. I printed off some diagrams and connecter voltages from Mitchell on demand. In my book it says that my IAC should have battery voltage and my DMM only reads 1.7 volts at the connector. So I got a engine performance diagram and seen that my evap control solenoid which eventually hooks up to the fuel pressure regulator, my heater side of my O2 sensor, the resistor that’s to my fuel injectors, and my IAC are all hooked into this bar (that’s all it shows on the diagram is a bar). Also hooked into this bar is the PGM-FI relay and then from the ECM are 2 wires from pins A25(IGP1) and B1(IGP2). So this bar has 2 wires from the ECM and 5 wires running out to the things I mentioned. All 7 wires are yel/blk. I asked a teacher what that bar was. ((I want to note that one time I hooked the battery charger up to my car without a battery, so I could get a cd out and some stuff made some weird noises but it ran no different than before I done that “I think ??”)) My teacher said that bar is a connector that has 2 wires from the ECM into it and 5 wires out to the sensors, etc. he said the connector is a power distributor for those things. Well I looked and looked for this connector and can’t find it. I have my wire harness from the alternator to the connectors on the passenger side tire well that leads to the ECM out, and still can’t find it. my questions are does anyone know what this bar is that im talking about and where is it. If I was to take a Dmm and stick one lead to ground and one lead to pin A25 or B1 and look for battery voltage, and if its not present I know it’s the ecm. will that mess anything up and /or is there a better way to test this without having a $$$$$ ecm test harness. Or maybe theres something simple im over looking. Not an experienced at all Honda guy. I know what I know from messing with this car and the great access to diagrams and info off mitchell. Thank you for you replys, and sorry its so long. if you go to this link theres the diagram its hard to see for some reason, but if you look in the upper right corner theres the fuel injector resistor, IAC, evap control soleniod and right below those is the bar ive been talking about


http://www.facebook.com/album.php?ai...4&l=fad968c8bf

 

when i went looking for the bar in the wire harness i realized that, that bar aint what it seems. i dont understand what im looking for if that bar ive been talking about is a metaphor for something else that has its own diagram??? but none of the yel/blk wires that i tested for continuity are hooked together the yel/blk wire from the IAC connector runs straight to a big connector that leads to the ecm. its really wierd this bar on the diagram is making me mad. but what ever that bar represents weather its a thing that has wires going to it or just saying in the long run they are all linked somewhere. what i really need to know is what am i looking for, and if i touch a lead from a DMM to one of the pins and to ground will that mess anything up in the ecm. i wanna make sure if i test for voltage at these pins and they read OL on my meter, that i didnt just do that by hooking it up this way.

 

You need to read some of the manual information you have more closely.

Code 43 usually means the O2 sensor is not performing correctly. Code 41 is an open circuit for the O2 sensor heater. Easy to check w/ a VOM. It's either shorted or open. Either way, sounds like you need to replace the O2 sensor. Your manuals should show exactly how to do that.

good luck

 

so what your saying is if i replace my o2 sensor it will cause my IAC connector voltage 2 go back up to battery voltage. i wouldnt doubt if i do need a new one. what im saying is all these things going from this bar thing, im having problems with, which the o2 sensor heater side is also hooked up to all of the things i mentioned. i am pretty sure i have a short or something like that and thats why my IAC is only getting 1.7v. but i cant see my o2 sensor causeing the IAC connector to have low voltage. and can i test the IGP1 & IGP2 pins with a DMM hooking the other lead to ground. will it mess anything up, and if i just skip ahead to this part. wouldn't this tell me if its my ECM or after it.

 

i just realized what you were saying. if all these things are in the long run areb hooked together in some sort of way. then if my o2 sensor is shorted it would also short everthing thats hooked in with it. hope thats it and its that easy thank you, and when i get the money and buy a new one i will let you all know how it went. if it changed anything.

love, peace, & chicken greese

 

Your post is confusing.

I think you may be mistaking a harness connector for a "bar thing". The diagramatic depiction in a circuit diagram looks like a bar, but is simply a multi-pin electrical connector pair. You may notice that one bar wraps around the other at the end. This distinguishes male end from female and each side assigned a different connector number, Cnnn.

The O2 sensor and the IACV don't share the same harness connector. My Honda shop manual shows the O2 sensor connects to ECU via C266 (F) and C131 (m). These are located on the passenger side shock tower.

You can separate these connectors and test the O2 sensor heater resistance at that point. You will need to identify the correct two wires on the male end connector (C131); yel/blk and org/blk. If you have a shop manual look at pages 11-22 and 11-23. The female connector diagram (C266) is depicted so may be confusing.

The IACV ties into a different harness which terminates on driver's side behind shock tower near cowl at connectors C133/C353.

Regarding the IACV voltage, you should check the Blk/Blu wire. Engine may need to be operating for voltage to appear at the IACV. A back probe may be necessary to check voltage.

good luck

 

im not saying your wrong or i wouldn't be here but maybe if you look at this picture i wrote on, on my face book you will see this bar thing i talk about and then my post wont seem so confusing. im not just making words up im saying it as i see it. i traced all the wires that lead to this bar thing. so they can be seen easier. please look at the diagram and see if you can explain what the bar is or is representing

thank you

http://www.facebook.com/photo.php?fb...00001603026974

 

Sorry, I don't have a facebook account.

good luck

 

I was gonna say the same thing after I tried to look at it.

 

My 93 Accord exhibited this EXACT same behavior and I searched for the trouble for over a month before replacing the O2 sensor. No CEL on my OBD1 system ever displayed. I finally decided the driveablity problem had to be related to the air-fuel mix and took the anicent O2 sensor out of there and replaced it with a new one. Problem solved. I felt dumb for never having replaced it previously. Lesson learned.