Hey guys, I have a 1994 Honda Accord Lx with a JDM F22B2 Engine (replaced 3k miles ago). It has a horrible idle surge issue that won't seem to go away. I have been throwing parts and trying to diagnose for about 3 months now, and am at a complete loss of ideas as to what the culprit is

The problem occurs every time when cold cranking and throw a CEL code 14. Once it's warmed up I will shut off and crank the motor back up. The issue will usually stop for about 10-100 miles, then it will come back and act like it’s going in to limp mode all of a sudden. I will lose throttle response every 5 seconds off and on. It will then throw a code 14. What gets me is that I replaced the IACV twice and the pig tail once, but it still is throwing the same code 14...

I have bled the coolant numerous times, thinking it was just air in the system but I notice that air keeps coming into the system after warmed up and cooling fans come on. Below is a list of parts I have replaced or cleaned.
Please help me fix this idle issue, as I have put too much money into it to give up.

Replaced (NEW):
* OEM IACV
* OEM FIV
* OEM MAP Sensor
* OEM Radiator/Thermostat/Water pump
* OEM Timing belt (installed by Honda, Timing is correct)
* OE replacement Dizzy cap
* NGK Spark Plugs & Wires
* NGK 02 Sensor
* OE Replacement EGR VALVE

Cleaned/Inspected:
* TB and the port going to IACV
* EGR Ports
* No Vacuum leaks
Compression Test:
Cyl. 1- 180 psi
Cyl. 2- 182 psi
Cyl. 3- 180 psi
Cyl. 4- 185 psi

 

Check the iacv connector. When starting my car up a few months ago, it started throwing that code upon a restart. Pulling the connector, i could see the connector pins were badly connector and partially deformed. I swapped in another connector pigtail i pulled from the junkyard which fixed it. Until i got around to going to the junkyard i had to spread the pins apart(or closed, i cant remember atm) with a pair of needle nose when it threw the code.

 

I already replaced the IACV pigtail connector. Still no luck there. My issue is that I am getting bubbles in the coolant and dont know how. I have bled the coolant system for over an hour and bubbles still keep appearing... There is no sign of coolant/oil mixture either.

 

It is possible for a code 14 to be a bad ecu. Have you tried another ecu ?

 

bubbles in the coolant after an hour of bleeding. sounds like a headgasket to me. just because oil hasn't mixed with the coolant doesn't mean you don't have a head gasket problem. compression could be leaking into a coolant jacket hence the bubbles. if it was a severe head gasket then you most likely would have oil and coolant mixing along with compression escaping. grab a digital volt meter and do a ohms test on the iacv connector back to the ecu or a continuity test as well make sure the wires are ok.

 

Haven't tried a different ECU yet, due to the continuous amount of bubbles in the coolant system.
I really have been thinking the head gasket is my problem but don't want to go though the hassle of changing untill I'm possitive that it's the culprit...

 

do a leak down test with the radiator cap open and radiator topped off.

 

Can you describe/explain where you aee seeing the bubbles ?

With those compression numbers its unlikely the head gasket is bad.

 

Thanks NerfGunner420 , I'll do the leak down test and post the results.

holmesnmanny, the bubbles are coming out of the top of radiator... I'm using a Spill-Free Funnel to bleed the coolant system. I cannot think of any other reason why I keep getting air in the coolant though.

 

The only way i can see air getting in is if the water pump was leaking or sonething was leaking. In order for air to get in, water would have to be drawn out. Perhaps even the heater core leaking.

 

No leaks or loss of coolant.

 

Then i think your bubbles are normal bubbles from the flow of coolant. Upload a video if you want.

 

If I'm not mistaken , a continuous amount bubbles in the coolant sysyem will cause the car to idle improperly... I have bled the system more than 5 times in the past week and keep getting the same result.

When the issue first presented itself I could get away with bleeding the system every 100-200 miles. Now the car won't idle right untill it's warmed up, then it will drive fine for about 10 miles. Then all of a sudden it will start to idle like crap, loose throttle response every other 5 sec. and throw code 14.
I will try and get a video if I have the time. I'm in the middle of working on my Evo 8 and Montero too... 3 cars down at the same time sucks lol.

I will post leak down test results later today.

 

How are you bleeding the system?

 

You need to test for continuity from the iacv connector back to the ecu connector while jiggling the connections to see if the issue is intermittent. If no connection issues, try a new ecu.

 

i recommend you to try with another ecu if possible

 

I first park the front of the car on a slightly inclined plane. I then fill a spill free funnel halfway up with coolant. Open the bleeder screw (with engine off) untill there is a stream of coolant with no bubbles. Then I start the car with the heat on high and let it run until there's no visible bubbles left in the funnel.

 

I haven't had any free time to work on the car yet.

Forgot to mention when I installed the JDM F22B2 motor I used the original Dizzy because the JDM one wouldn't work. Also using the JDM Exh. Manifold and downpipe, so the O2 Sensor is further downstream than the original location (on USDM Exh. manifold).

 

Sorry for the delay guy's. I've been out of town. Just to clarify, I double checked every cyl. and made sure each one was at TDC and not 180 deg. out of time. Im assuming that my timing is off by a tooth or so... I am going to check the timing today and post my results.
F22B2 Leakdown Test:
Cyl. #1: 19%
Cyl. #2: 80%
Cyl. #3: 35%
Cyl. #4: 58%

 

Has your car ever overheated ? It looks like you got damage. Compression test to verify the accuracy of the leakdown test.

Be sure you check and set mechanical timing first.

 

Replaced (NEW):
* OEM IACV
* OEM FIV
* OEM MAP Sensor
* OEM Radiator/Thermostat/Water pump
* OEM Timing belt (installed by Honda, Timing is correct)
* OE replacement Dizzy cap
* NGK Spark Plugs & Wires
* NGK 02 Sensor
* OE Replacement EGR VALVE

Cleaned/Inspected:
* TB and the port going to IACV
* EGR Ports
* No Vacuum leaks
Compression Test:
"Cyl. 1- 180 psi
Cyl. 2- 182 psi
Cyl. 3- 180 psi
Cyl. 4- 185 psi"

 

holmesnmanny- Enging has never overheated. Compression test came out fine (Listed #'s already), I am going to check timing again and make sure im not off a tooth... Any other ideas as to why my leak down test failed would be great.

 

Sorry for the delay guys...
I just got done checking the timing belt on the engine. At TDC, all necessary marks are lined up perfectly. I rechecked the valve lash and they are all still per spec. Rotated the engine to make sure the valve train was doing its job properly, good there. Finally I preformed another leak down test and I keep hearing a slight hissing/leak on the intake side (all 4 cylinders). The car usually will idle and drive ok for a while when it reaches operating temperature. Thus, my final assumption is that the valves need to be re-lapped due to not seating correctly when cold.

 

yes sir. you found your problem you need a rebuilt head. i just noticed you wrote that all 4 cylinders leak into the intake manifold. how much air is escaping, you didn't tell us % on the gauge per cylinder

 

Defenitaly not what I was expecting from a fresh jdm swap. I will keep posting my progress to let you know how everything turns out.
Thanks guys, for all your help!