2002 Accord EX 5 speed, 2.3L.

OK just finished dropping in a used motor with 77K on it. The old motor had been over heated and #2 cyl was pumping oil.

Motor in ECU/PCM reprogrammed after eng change. Tried to drive it and as soon as I came up to a stop, idle surging, IACV was my first thought. Back to the garage, cleaned IACV. Still Hunting at idle. What I've found is that if I warm the car up, 3000 RPM until the radiator fans come on, then pull the air cleaner tube and cover the vacuum port to the PCV valve, idle immediately drops to normal. So I popped the PCV valve out of the valve cover and goosed the throttle and it went right back to surging. stuck my finger over the PCV valve, idle dropped instantly. Now this is a new AfterMarket PCV valve. So I pulled the one out of the pile of parts that I took off the yard motor, plugged it in and it too was experiencing same problem.

Now the question that I have, is it possible that the engine is pulling to much vacuum? I understand that any after market part is questionable. However this after market valve functioned fine for 2 months on the old motor before I pulled the engine out. So I'm hesitant to say that I have conclusively identified my problem. I found a problem, just not sure that it's the only problem. Could I be pulling in to much air? Is there something else that is causing it to completely open 2 different PCV valves?

Need some tech savy folks to help this mess in my brain!!! Any suggestion would be extremely helpful!!

Motor pulled out, 160K bad #2 cylinder, new motor 77K for what ever thats worth. Thanks in advance!!

 

Engine can't produce "too much vacuum".

If pinching the PCV flow drops the idle, the PCV may be allowing too much air to flow (see below). Pinching the pcv should cause the valve spring to close the valve and you hear a click. Clean PCV w/ throttle body cleaner to be sure the action is free. You should be able to shake PCV and hear a rattle.

It may be possible that you have an intake air leak elsewhere and closing off PCV simply reduces air leakage to a tolerable level. Check all vacuum lines and intake manifold seams for air leaks. Spray throttle body cleaner and listen for a change in engine speed as cleaner is pulled into leak.

good luck

 

I intend to. I prefer to use bottle torch for vacuum leaks, safer and no flammable residue! I just found it off that it was holding 2 different PCV valve fully opened! Obviously the valves we both bad! Or not correct valves for the application.

Thank you for the reply!

 

PCV valves should be open at idle. They require a minimum level of intake manifold vacuum to open. They close when vacuum drops to a low level (?).

good luck

 

After PCV valve change little to no change with the idle surging. I then sprayed Carb cleaner around the throttle body, leak there was solved by tightening TB bolts. Now it's Ilde is fine and I can operate throttle 8 out of 10 times idle will return to normal, 2 or the 10 time it will go back to surging. Now when it does surge, if I load the engine with A/C or lights. Idle will stabilize. I have got P0505 code several times, and have cleaned and swapped out IACV with another.

The TPS sensor Plug is it the Blue 3 pin plug, or is it the Grey plug that is TPS. Both will fit. It's getting progressively better. I have checked the remaining Intake area with Carb Cleaner and have not found any additional leaks.

Is it possible that the IACV actually be faulty with out setting a CEL/MIL code?

 

The map is "on top" of the TB.

The tps is on the "back side" of the TB.

If memory serves me - the blue plug is the tps......wire colors are....GRN/BLK RED/BLK YEL/BLU

 

OK off to the Stealership! here's what they found 1) throttle cables to tight (I checked these, seems normal and the butterfly was closed) 2) Idle screw was backed almost all the way out! (ok same throttle body was on the off motor and worked perfectly, I never touched the throttle, doesn't mean that some one before me didn't)

Now although it idles smooth as a babys butt, now there is a HORRIBLE 1st gear stumble when it's cold! Won't take accelerator hardly at all. Is Perfect once warm! I'm puzzled! Stealership still has it and I'm waiting for a diagnosis!

Any thoughts would be tremendous!! Oh they gave me a CIVIC to drive 2010, Uh Yeah I'll keep my 12 year old Accord thank you!!!

 

Suggest examining all the sensor inputs for something a bit off; IAT, ECT, MAP, etc.

good luck

 

Thanks TexasHonda, Oh Girlfriend is from Conroe!

Now let me add, the engine I installed is out of a 2002 Accord, Auto. I installed it in 2002 Accord, Manual. I've checked that the A/F O2 sensor on the two are the same part number. Can you tell me if there are any MAP, ECT, IAT sensors that are different between Manual, and Auto's? I just got it from the Dealership, they pulled Egr off and it was clean, the new motor has 77K on it, I don't believe that it has any major problems. Once it's warm it's run like a new car. Some sensor isn't reading something. If I can't come up with something, I'm going to start with, Coolant temp sensor and swap off the old motor on to this one, one at a time. Old motor ran great, just blowing HUGE amounts of oil out of #2 cylinder.

Engine harness was off the old motor, the Throttle body was off the old motor and the knock sensor was swapped over off the old motor, both motors are 23A1 motors. All other parts and components came on the Automatic motor. If that helps.

 

I checked all component location diagrams and none had any differences for manual vs. auto.

good luck