o.k. so.... from the top my sister in laws 1994 honda accord ex spun a rod bearing a month ago... i replaced the original block ( f22b1 ) with one from a junk yard ( f22a1 95,xxx on the clock only 80 bucks) changed the front and rear main seals , new head gasket and then put the head on....put the timing and balance shaft belts on and set the timing. hooked up all hoses , connectors , fuel etc. double checked the timing and on the first try started right up, and idled smooth. only code it thru was a code 6 (ECT) and a code 17 (VSS) shut it off and checked the wires and somebody had taken the plastic case of the harness and the ECT and the condenser fan switch were backwards fixed that and then no more cels. took it for a spin and it bogged or stumbled if i gave it to much gas but if i eased into it, it would pull fine to 5k rpms and then hit the rev limiter at first it would only do it from idle to about 2200-2600 . when i got back check engine light code 41 ( o2 sensor heater.... would the o2 put it in limp more???) tested the o2 and it seems to be fine, did a compression test all 151-155 with a leaky gauge, cleaned the EGR ports in the intake manifold (all but one were cloged). checked the TPS and the MAP both fine, got new plugs, checked the cap rotor and they look fine, took a known good set of wires and tried that. checked the coil and it checked out. basicly anything i could think of to check with a multi meter i did. cat is good took it off just incase...nothin. no air leakes at the throttle body or intake mani. IAC valve is good. ummm...the head feels like its getting hot but the temp. gauge is were its to be. could it be the grounds??? the car did not do this before. its like its not getting either enough fuel or enough spark. vtec pops fine it i feather it. its been like this for two weeks and i've searched and searched and fixed other problems (like the EGR ports) PLEASE any help or thoughts would be greatly apprecaited. thank you in advance PLEASE any help....

 

I thought that a bad O2 sensor would just set the fuel maps to some default level. I would check and clean the O2 sensor wire harness. Also measure the resistance in the heater circuit.

I would check that all of the vacuum lines are routed and connected properly.

All this information is available from a 94 shop manual that you can download from links in the Online Manuals thread in the DIY section.

 

Code 41 but how did you test the sensor? I think 1994 should have 10 to 40 ohms resistance between the 2 heater leads.

If the sensor is OK but you still throw code 41, the problem is in the sensor circuitry. That makes me suspicious of other problems in your wiring harness...

 

well last night i broke down and bought a set of wires and it fixed most of the issues. but it still hits the rev limiter or fuel cut or something at 5000 rpms and the only code its trowing is code 41 (o2 heater). i double checked all the vacuum lines....they are all good. i know the o2 is bad but would that explain why its hittin the rev limiter so early??? i know its runing in limp mode but my brother had a b18c crx that he ran without a o2 for like 6 months and it would pull to the red line everytime. i checked the ohms on the o2 and its just got coninuity between them... does that mean its grounded somewere??? would cleaning the clip for the o2 help??? and the clip is broken off on the corner if that matters.?. i just dont have money now to fix the o2 cause from what i hear only a oem one will do. but now i just wanna find out first if the code 41 will put the ecm in limp mode...and if not why would it be in limp mode if they are no other cels???? and by sensor circuitry you mean the harness or the ecm????

 

oh yea .....you can def. tell that someones hacked at this harness.... the TPS has been cut and spliced (well more like twisted and taped). could the grounds be why its going into limp mode???? thanks

 

I have ben told on multiple occasions that a bad o2 sensor could throw the car into limp mode but never experienced it first hand. Just my $0.02

 

thanks, anyone else running a 94-95 f22b1-2 accord obd1 with no o2 sensor? if so does it pull all the way to redline? ( 6500 ish rpms )...or like 4500-5000 rpms? and also does anyone know of a cheap place to get an oem o2 sensor??? i just cant imagine the o2 putting the ecu in limp mode, i get that it would dump more fuel but why would it hit rev or fuel limiter at 5k ??

 

..... just a thought when i reset the ecu and put the jumper wire back in it and turn the key into the on position..... my code 41 (o2 heater) shouldn't come until i start the car right????

 

I checked the 94 book for the o2 heater circuit, could not find it for the life of me... looked in my 99 book and the heater is driven by a transistor in the ECM. So you're saying you checked the heater and only shows continuity... well, that's not good. You may want to double check this, make sure you id the correct heater wires of the o2 sensor. Because if you only show continuity that means the heater is shorted out - I've never seen this before personally.
If you're correct that means the o2 sensor shorted out the driver in the ECM... not sure that's protected in some way not having the schematics of the ECM.
Let us know. You're correct on your last question, however if the cause is still present you'll get the same result.

 

If no O2 sensor, car would have to be in open loop mode. This may limit rpm, but I don't think this is same as "limp-home" mode. Manual doesn't provide any guidance on this issue.

Code 41 says to check O2 sensor heater resistance is in range of 10-40 ohms. If outside that range replace the sensor. You can get a universal for <$40 on ebay including shipping. I've used a couople and they worked fine.

good luck