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lexcrob98 · Jan 4, 2009, 12:42 AM

OK well just put on a brand new o2 sensor the old one checked out bad and no effect.. the car now no longer throws 43 though.. lets see tried brand new iacv. Tightened fiacv all way down but still sucks a little?. I have also replaced the tps sensor,pcv, and tried a new map sensor replaced the icm and ignition coil. Plugs wires cap rotor. Changed oil lol just throwing it out there... searched and searched with carb cleaner for a vacuum leak and replaced a few hoses for the heck of it. Put back on time and checked with light perfect... also set idle screw multiple times resetting ecu I'm really now about to give up and blow up this car lol...

what it does... now(same as before) when cold it will idle high just like its supposed to no missing nothing take it for 5-10 min drive runs great. Then come to stop and idle / fluctuates between 900-1200 then will randomly drop to like 300 almost stall then back to bouncing I adjust idle screw and it doesn't really change anything.. this is with the iacv disconected. It might just drop a little lower or more often.. I'm so lost if I unplug the tps it will smooth out enven though it's a new one on there now which I thought would be it HELP HELP HELP!! :mad::mad:

KISS · Jan 4, 2009, 01:01 AM

Let me guess. A big vacuum leak once the engine is at operating temp.

Try pull or bypass the coolant sensor, so the car doesn't know it warmed up. e.g. operating in closed loop

TxGreaseMonkey · Jan 4, 2009, 01:00 PM

Replace the Engine Coolant Temperature (ECT) Sensor, which affects fuel injector pulse width. It's located under the distributor. The ECT Sensor is a temperature dependent resistor (thermistor), whose resistance decreases as the engine coolant temperature increases. It provides a richer mixture when cold, leaner mixture when hot.

Here's what it looks like and costs:

http://shop.advanceautoparts.com/Pro...pe=290&PTSet=A

Wrap the threads with Teflon tape, before installation.

lexcrob98 · Jan 4, 2009, 05:12 PM

Wouldn't the coolant temp sensor being bad throw a code? I was throwing a 43 so and I talked to a guy at honda and he said its probably 02 so yea.. but to NO AVAIL!! I replaced the pcv and hose to IM but the pcv hose from that box thing on back of block to pvc is like cracked don't know if this could be it I can't find out where the heck to get it but yea... I'm thinking no since it just pulls a certain vacuum depending by the spring inside the pcv I think. Any more ideas... ill try the cts PRAY FOR ME lol.. :eek:

KISS · Jan 4, 2009, 05:52 PM

PVC normally would do it all the time I would think but it depends on the vacuum logic.

Come to think of another reason is the EGR valve modulation. Have you tried capping that.

TxGreaseMonkey · Jan 4, 2009, 06:38 PM

Thoughts:

. Reset ECM by pulling the Backup Fuse, in the underhood fuse box, for 10 seconds.

. Did you install a Denso oxygen sensor? Many generic oxygen sensors (e.g. Bosch) are problematic.

. Erratic rpm often indicates a failing Ignition Control Module (ICM), which I know you replaced. Did you apply heat-transfer silicone grease to the back of the ICM? If not, they will quickly fail.

. Failing ECT Sensors don't always throw a code right away.

A Code 43 indicates a problem with the fuel supply system or the heated oxygen sensor circuit. My bet is you either installed a generic oxygen sensor, which your Civic is rejecting when it comes out of "open loop" mode, or the ECT Sensor is bad. The answer to your problem is likely with one of the items above.

lexcrob98 · Jan 5, 2009, 11:06 AM

I used a bosch danngit I remember you saying that TX... no heat transfer silicon... OK well I just want to test the coolant temp sens. How do you do it I know you check for 2400 ohms when cold but how do you know mine only goes to 200 then you check for 200-180 hot... I probably should get this but I'm not totally shur how to test it I just want to be shur its bad when I go to replace it I'm runnning out of $ to spend on this thing just trying to sell it! Oyea speaking of parts Don't EVER BUY EXACT FIT PLUG WIRES:(

TxGreaseMonkey · Jan 5, 2009, 11:10 AM

I think you need to replace the Bosch oxygen sensor with a Denso and immediately apply heat transfer silicone grease to the back of the ignitor. After doing this, reset the ECM and I think your problem will be solved.

Now that I know you installed a Bosch oxygen sensor, I no longer suspect the ECT Sensor is failing.

lexcrob98 · Jan 5, 2009, 11:22 AM

Speaking of vacuum if I put my finger over the bottom hole the ficv there is no sucking but if I plug it up for a few sec then pull off there is sucktion... hope that makes sense thanks for the tips I think I'm digging a hole lol

lexcrob98 · Jan 5, 2009, 11:25 AM

Okok I will when I get some more dough... I mean I tested the 02 for ohms on the heater side and it checked out OK but I will go with what you think luckily I work at adv. So maybe can return bosch maybe

TxGreaseMonkey · Jan 5, 2009, 11:26 AM

The Standard Motor Products SG302 Oxygen Sensor ($54.89), available at RockAuto.com, should be a Denso or NTK for a fraction of Honda's price.

lexcrob98 · Jan 5, 2009, 11:59 PM

buddy has an etc sensor (free)im going to try first... we messed with it and he thought for shurr it was the tps sensor not adj. right . When hot while surgine between 900-1400 we pushed on the tb plate to close it a hair I mean a hair and it smoothed out then when we let it go it stayed smooth at1000... lol... we then bleeped the throttle and it went back to surging... we then adj. idle screw and tps trying to get it to 750 by the book setting and it just surged all over and can't fig where to set screw and pressed tb plate and didn't smooth after adjment.. don't know if this helps... also sometime it will just randomly drop to like 300 almost die then go back to surging... Maybe ecu bad?? Or o2 like you said. We see

KISS · Jan 6, 2009, 04:50 AM

Try pulling the cable off the MAF sensor.

lexcrob98 · Jan 6, 2009, 10:26 PM

I tried the coolant temp sensor today. It did change the way it surges it will not even stall now it will even out like perfect right at 750 then it will all of the sudden begin the surging again. I think I'm going to say its not the o2 sensor because I was talking to a coworker and he said that bosch probably makes the oem 02 anyway it checks out to so... Im going to smoke the vacuum system tomarrow and see if I find any I hope it do. Thanks for all the input ill let you guys know the outcome if I fix it.

KISS · Jan 7, 2009, 04:54 AM

So it's something used in closed loop. Collant sensor prevents it from going into closed loop. The O2 sensor has to be warm for it to work. Therfore it's still a possibility. I just got a defective MAF sensor. It worked only for two trips, then engine would barely stay running, but while it was starting, it was fine.