Gents...

I have a 99 Honda CRV, B20B JDM swap, 5SPD AWD. I love this thing and it's a wicked car/truck. I use it non-stop to haul things and it's my daily driver which gets 1000kms a week of driving.

Recently the stock engine sprung a major oil leak from the rear main seal and head gasket. Oil pump seals were already shot so I costed out the job and it was cheaper to replace then rebuild. I used a JDM B20B to make it easy on myself.

Right before I pulled out the stock motor, it started to hiccup. I just assumed it was something else going wrong with the stock motor seeing as it had 320XXXkms and was already beaten up/in bad shape.

The swap went fine. But like most JDM swaps the TPS sensor and IACV had damage so I had to reuse my original ones. I replaced the timing belt/water pump and did a full tune up on it (this was 2000kms ago now). I didn't check valve clearance but it doesn't make a noise/tap when idling. I thought replacing the engine would fix all it's operating issues but some still linger. And I'm running out of ideas so I'm asking others what they think/have had happen before.

Under heavy loading in low RPM range (say 2000RPM and I floor it to keep up with traffic) it will hiccup/sputter/backfire (I think backfire). It's nothing major, and it's doing it on and off. But I'm afraid it may cause damage to my newer engine which I just installed. It also tends to hesitate when initially clutching out, and it will make everything rock back and forth until it picks up normally. What a PITA.

It also idles at like 2500-3000 RPM when I do a cold start up. Super annoying, it's way too high and that's so hard on a cold engine (We are dipping into the -20C this week).

I haven't done much other then check for leaks/vacuum. All seems well. The TPS was adjusted to .50V at idle and gets 5V at WOT. I fear it may be worn out, and is giving a fluctuating signal or have a dead spot. What's the best way to check?

Also, is there a way to rebuild/clean out a IACV safely? I cleaned mine out with brake clean when I first bought the car 40XXXkms ago and it ran fine in my old engine. But the new engine cold start is so high I think something may be wrong with it. It seems to idle fine when it's warm, at around 800rpm. Sometimes I can see it fluctuating so I fear the IACV may be shot.

I haven't tested my fuel system at all. I want to take out my injectors and scrub them clean, maybe even flow tested if I have the time/resources. I'm thinking my fuel pump is getting weak too like most older Hondas. It's been ran dry a few times (my low fuel indicator didn't work at first and it caught me off guard a few times). So it may be a fuel delivery issue?

Any help is appreciated. Ask away if I missed some info. Please help, I want my CRV to drive like a champ like it did when I bought it. I love this thing it's awesome for my lifestyle.

Cliffnotes:
- Previous engine had issues, ran rough, replaced with JDM B20B
- Did tune up/timing belt no issues. Didn't check valve clearance.
- Reused TPS and IACV from old engine.
- Car hiccups/hesitates (did this with old engine)
- Idles high when cold (didn't do this with old engine)
- Suspecting fuel delivery issue?!
- Ran out of patience/wit. Please help!

 

What about plugs cap rotor wires?

 

Part of a full tune up is to replace plugs/wires/cap/rotor. And to buy a JDM swap and not do those things is ridiculous in my opinion. Since they stack engines the caps/wires/outward facing sensors get dinged up hard. I just do the investment up front and gain peace of mind and reliability.

I'm leaning on the fact that I used my old IACV which might be fluctuating a bit. At warm idle I can see the needle move about 100-150 rpms or so. And in light throttle/steady rpm in low gear the rpm will go up and down causing the car to jerk/bounce. It's super annoying!

Does anyone know the operation of an IACV? So I can properly diagnose. I don't have a spare B20 IACV. I see that the orifice are larger on the B20 then the B18 or B16. I'm sure it has to do with the displacement. When I first bought the CRV the IACV was in rough shape. I took sensor safe brake clean to clean it up, but it only did so much. I'd like to tear it apart, clean and lube it. But if someone knows any tricks/diagnoses it would be awesome!

Also, the CEL is on for crank fluctuation sensor (JDM swap didn't come with one) and an EVAP fault, which the car had before hand. I doubt an EVAP can have such adverse effects. And the crank fluctuation sensor I will be doing the bypass trick this weekend. Maybe it's to blame? Who knows...

Please help, any info is good info!

 

did you do the basic setting off the idle speed by disconecting the iacv valve?Are you sure that nobody turned the bolt where you set the idle speed?

 

Did not set idle speed by disconnecting IACV. Ran out of time when I was doing the swap and had to get the car on the road ASAP. I will do it this weekend when the warmer weather is here.

As far as I know the Idle screw hasn't been adjusted and still has the factory seal/Loctite. I was hoping to not mess around with it. I am also going to pull voltage out from TPS sensor.

The sputter/hiccup is very consistent under low RPM heavy loading. In between 1800-2500RPM is will do it every gear, every time.

I will be investing the proper time soon to resolve this, just need as much info now so I can properly diagnose and resolve the issue.

 

the iacv valve lets more air trough in the intake collector according too the temperature off the cooling fluid. Thats why it's essentiale that the thermostat off the engine is working properly. Thats the way the valve will set the idlle speed. There is also a thermo valve inside too pull op the iddle speed when the enine is cold. You can check if the thermo valve workes .Theire is a hole in the inlet just before the trothle. it sucks air when the engine is cold and schould be closed (no sucking when you close it with your finger) when the engine is warm (themo fan worked at least 1 time). There is no description how to take apart the iacv in the European Honda shop manual sorry

 

Pull the plug wires and check for oil.

This is not going to be an easy problem to track down, just gonna have to eliminate variables.

Also, I'm very sure your iacv is fine. They are an open/close valve. Not constantly adjusted like you would a water faucet for more or less flow. It opens 100%, then closes 100%. To get a high idle it opens more times per second, to get a low idle it opens less times per second.

Have you checked your ignition timing with a timing light?

 

No oil in the spark plug tubes. That's all fine and double checked.

I have set the base idle, it was a little high so I turned it down. This helped a bit, my cold start idle was 2500rpm and now is 2000rpm. But still...a new symptom came up.

When the car is cold (Canadian winter cold) and I start it up. Right at the 1800-2200rpm range there is a high pitch humming. Like an air knife type of high pitch humming. At first I thought it was metal grinding noise but after I evaluated it it's coming from the intake manifold, somewhere. Again, it's way too cold/snowy to actually get any work done. I'm just checking stuff out and googling the crap out of my symptoms. It's driving me nuts! Oh well, can't let my frustrations distract me from what needs to be done.

I have a feeling its a mixture of problems and not just a single issue. The car is a high mileage queen, so I wouldn't be surprised if an older reused component is given up.

I also feel my ELD might be on the way out. It has no idea on how to predict an electrical load. The rad fan kicking on almost stalls it. Turning the wheels will make the idle vary (PS pressure switch). I read this will cause the ecu to try and adjust the idle in the wrong times/never and allows all electrical loads to work against the idle. Thoughts?

 

Have you not ever clean the IACV?

It'll get some heavy carbon buildup. You can take it off the manifold and spray it good with throttle body cleaner and it should clean up the gunk in it.

That metal screen might be clogged up in there.

Also, what check engine lights do you have? Since you have the JDM engine did you do the CKF trick since JDM engines don't have the crankshaft fluctuation sensor or did you replace the oil pumps? I'm not sure if that will affect it at all but it's always worth a try.

 

Did you replace the manifold? I'm not sure why you didn't swap over the crank gear including the oil pump. That would've saved you from doing the ckf/p mod. Hopefully you swapped out all the seals before putting the motor in.

 

sputter also on my engine after running for 20'.found that there was o lot of rust in the distibutor.took it apart, the rust came from the high tension cord.Changed that one and problem was solved.Went looking after i checked the sparks on every cilinder with a strobscopic light.When the sputter began there was no spark on cil nr 1 and 2 .it could not be the icm because when it fails the engine stals completly.

 

Ok. The IACV was cleaned, it's working fine as far as I can tell. My FITV was out to lunch, but that's been fixed. This was causing my whistling/air knife noise. Idles a lot nicer without fluctuations.

I didn't want to swap the oil pumps, so I deleted the CKF sensor. The mod is a lot less work then swapping oil pumps. And who would bother with swapping an oil pump that was leaking like a siv from a 320XXXkms motor to a cleaner/younger/less mileage JDM engine. Waste of time in my eyes. The mod took 10 minutes.

Took my dizzy apart, everything looked ok. I swapped out the ICM and problem solved! the ICM couldn't maintain consistant ignition timing. Would fluctuate back and forth causing wonky idle/spudder/misfire/backfire.

Honvol, when the COIL dies the car quits instantly. I've now had a bad ICM twice on 2 separate Hondas I've owned. Both displayed similar characteristics and I'm embarrassed to say I didn't think of it sooner.

Also, my A/C compressor was seizing, adding to the overall struggle. I removed the belt and tied it out of the way, and it helped the overall cause.

I still feel my ELD is dying. My alternator outputs 14V but my battery never wants to charge over 11.8V. The battery is older but in really good shape and has never let me down on cold start ups. I've seen this before where the ELD is so worn out that it won't let the alternator charge the battery. Also, it doesn't seem like the car can compensate for electric load. Fans kick on, idles drops. Power steering input, idles drops. Turn on the blower fan, idle drops. Pain in the **** this car is getting.

But it felt like a huge win when I fixed the dizzy!!

 

Idk how safe the mod is but I did it anyways because I have a subwoofer and I hate dimming lights. I did a big three upgrade using 1/0 gauge wire. and it helped with the shitty honda power issues on my crv. It still does it but not near as bad and my lights don't dim when my subwoofer is turned up anymore.

you know what I'm taking about when you hit the power windows and your car struggles to catch back up in revs to compensate for the load.

 

i do agree about the engine to qiut instantly when the coil fails but not when it losses capacite ,then you get the prob like i had .My partents had a honda dealership for more than 35 years but they retired a few years ago so they could not help so i am aware off the probs with the icm from when Honda started with them in europ in 1980 .I was a small black box mounted on the chassis extern off the distributor.the engine could not start when it was warm but we only had too let it cool off for 2 hours and it would run fine witout probs.
what your charging off the battery concerns. i had a 8 years old battery and even in cold conditions the engine would start in a second but when i left the light on for 5 min with the engine off the battery was dead and i had to use a jumper. i put in a new one a few weeks ago and that prob is solved.