Performing Honda K24a3/AST5 6spd Conversion

[lookforjoe]

Bonjour, Hussein la prochaine fois que tu viens au Québec tu dois nous faire signe afin que nous puissions se rencontrer.
I'm writing in French ... it is a start for you

Yes, indeed! I told my wife that next visit we have to allow for a couple of possible meets!

Today I removed the plenum & I spent hours on planing the plenum to get it flat - it must have warped again when I re-welded the AC mount ear

Clear evidence of the carb clean soaking through to the port all around the outer perimeter of #1

The outer rim of #1 appears to be bowed outward, and there is no bolt to pull it in

I ran over it carefully with the belt sander to cut back the entire plane, then block sanded the entire surface using much 240 and finally 400grit to get the outer ear level again

made another gasket (actually 3rd attempt). The phenolic gasket is too thin around the ports, and measuring it, is uneven in thickness around #1 - can't risk it leaking again

To get the plenum back in, I needed to remove a stud I added to the top plane, and the forward lower stud for the TB adaptor spacer - both made it very hard to remove the plenum in the tight quarters I have.



While I have it all apart again, I decided to also remove the exhaust & deal with a slight leak - I smoke tested the exhaust & found the slip coupler had a slight blow-by, made an annoying 'fart' sound. When I welded the collectors, two of the runners ended up longer than the others, and so the shorter pair were not fully seating in the flared sections. I cut about 5mm or so off all four collector legs, and leveled the four tube ends on the header side so they would seat fully. I ran out of time, so I'll smoke test it tomorrow after work & see if this fixed it

 

[Longitudinal]

Hussein,

Have you experimented with reducing the IACV's duty cycle? That can be manipulated in K-Tuner, and I found it helpful in preventing the K swap cars' idle from searching and rising.

Also, I believe that I always cut the VSS wire leading to the ECU. As far as I was concerned, the only thing that needed vehicle speed information was the speedometer. My memory on this point is a bit fuzzy after eight years, but I definitely reduced IACV duty cycle for a smoother idle.

 

[lookforjoe]

Hussein,

Have you experimented with reducing the IACV's duty cycle? That can be manipulated in K-Tuner, and I found it helpful in preventing the K swap cars' idle from searching and rising.

Also, I believe that I always cut the VSS wire leading to the ECU. As far as I was concerned, the only thing that needed vehicle speed information was the speedometer. My memory on this point is a bit fuzzy after eight years, but I definitely reduced IACV duty cycle for a smoother idle.

I have not found any category that allows for IACV manipulation - there are Idle Target & Advanced Idle, neither has any IACV parameters. The online 'manual' is pretty useless since it provides zero instruction for how to use the software, and no explanation of parameters that are adjustable.

I wouldn't disconnect the VSS since it does affect idle compensation, and I need it for cruise control.

Today I only had a couple hours after work, so I welded a couple small openings around the bolt sleeves on the header, and sealed the slip couplers. Hopefully that takes care of the minor leakage. It's continuing to rain for the next couple days, so I won't be testing it until the weather clears.

 

[Longitudinal]

I wouldn't disconnect the VSS since it does affect idle compensation, and I need it for cruise control.

Right, cruise control. I wasn't thinking about that addition. I will poke around and see if I can find something about the duty cycle. It always helped me.

 

[Longitudinal]

Here we are:

Hondata K-Series Programmable ECU Help

 

[lookforjoe]

Only partial rain this afternoon - so I took the car out & no more exhaust leaks! The downside is that the 'fart' noise is actually a loose baffle inside my new Solo Performance muffler resonating under acel/shift points - so now I need to contact them about that.

Idle quality seems to be good with the new idle valve. I did however leave a restrictor to prevent the idle from fluctuating & hanging as widely as before. Seems to be working as hoped. I'll find out tomorrow on the drive to work though.

 

[lookforjoe]

Here we are:

Hondata K-Series Programmable ECU Help

I opted for K-Tuner, which doesn't that parameter adjustment available. I don't think I would invest in changing the EMS at this point, however if I were doing it over, I'd just go Hondata from the get-go.

 

[Longitudinal]

I opted for K-Tuner

Ah, OK. This whole time I thought you were on Hondata. That's the only system I know. Adjusting IACV duty cycle always calmed the idle, and controlled its speed to some extent. It's strange to me that I had a problem with idle speed at all, considering that the whole engine was always factory stock. It must have been the difference in intake configuration.

 

[lookforjoe]

Making a test pipe so I can bypass the muffler & confirm the rattle is definitely coming from there. Solo Performance will send another.

 

[Longitudinal]

Making a test pipe

So they actually can be used for "testing!"

 

[lookforjoe]

Actually not that loud with no muffler at all. Definitely not for long term use or DD, esp. if I want the Mrs to accompany me

The rattle is still there on hard shifts, rapid throttle blips. It sounds like a loose baffle, but all that's left is the cat core and the flex coupler. I'll have to take it all apart & see what I can see.

The other ongoing issue is with the K-Tuned TB. No matter what I do, the throttle will stick under light pressure & release, so in normal driving conditions. Aggressive/ spirited driving its not a problem. I can make the plate stick by manually opening it, pushing on the butterfly - with or without the cables attached. Once removed from the plenum I cannot replicate the symptom, which suggests it's not the return spring/mechanism binding.

I reworked the throttle cable alignment once again, in case the angle I had it at was in fact causing a bind. Not the case. I'm getting to the point where I'm ready to ditch the K-Tuned unit & try something else.

 

[jimmyx]

I can make the plate stick by manually opening it, pushing on the butterfly. Once removed from the plenum I cannot replicate the symptom

Any chance the two mating surfaces might not be perfectly parallel? If you loosen the TB mounting bolts/nuts and run up finger tight do you still have a bind? If it does it mounted, but fine dismounted, it might be that housing is putting the shaft or the butterfly in a slight bind when torqued down.

 

[lookforjoe]

Any chance the two mating surfaces might not be perfectly parallel? If you loosen the TB mounting bolts/nuts and run up finger tight do you still have a bind? If it does it mounted, but fine dismounted, it might be that housing is putting the shaft or the butterfly in a slight bind when torqued down.

That was my thought process also - I have a phenolic gasket there, so perhaps the surface is irregular & twisting the housing. In some of the testing I only had two diagonal mounts tightened and the condition existed. I'll try it with the mount nuts loosened.

 

[lookforjoe]

Here's the problem.

Removed TB & flange, removed cables checked all parts for interference, checked butterfly is centered, removed TPS. Throttle ONLY sticks when engine is running!!!!

 

[kmead]

Here's the problem.

Removed TB & flange, removed cables checked all parts for interference, checked butterfly is centered, removed TPS. Throttle ONLY sticks when engine is running!!!!

That’s only because it sucks, if it sucked and blows you would have just the ticket..

 

[jimmyx]

Here's the problem.

Removed TB & flange, removed cables checked all parts for interference, checked butterfly is centered, removed TPS. Throttle ONLY sticks when engine is running!!!!

Well the good news (if there is any) is that the problem is isolated to the TB and it doesn't appear to be heat related. The only major variable left might be vibration. Not sure where it goes from here, but if you remove the TB and shine a light behind the butterfly and use a small screwdriver to try and move the assembly either up or down or side to side is there any movement at all? Sometimes it only takes a hair for the butterfly to hang up. If you have a endoscope/bore-scope might want to try and see any sign of contact between the butterfly and housing while it's running and actually stuck - admittedly a long shot, but might provide a clue?

 

[lookforjoe]

That’s only because it sucks, if it sucked and blows you would have just the ticket..

Well the good news (if there is any) is that the problem is isolated to the TB and it doesn't appear to be heat related. The only major variable left might be vibration. Not sure where it goes from here, but if you remove the TB and shine a light behind the butterfly and use a small screwdriver to try and move the assembly either up or down or side to side is there any movement at all? Sometimes it only takes a hair for the butterfly to hang up. If you have a endoscope/bore-scope might want to try and see any sign of contact between the butterfly and housing while it's running and actually stuck - admittedly a long shot, but might provide a clue?

Indeed! One friend suggested it is tied to the vacuum draw through the TB, I can't see it, but since it only happens when the engine is running, maybe there is something tied to the pressure differential on either side of the plate?

While I had it all apart to check the flange for true, I did loosen the butterfly & make sure it had a uniform gap all around - previously it appeared to be off center a hair, but that made no difference. I may try knife edging the butterfly in case it is in fact hanging that way, although there are no marks in the bore to indicate a scuff or rubbing of the butterfly in the bore. Earlier TB hub/return spring modification

tested it this way to see if it caused any bind. I even filed down the inner side of the cable barrels in case they were causing the wire to hang in the wheels, as the reduced spacing in-between the wheels didn't allow for any lateral play as it was.

 

[jimmyx]

This one is the puzzle palace. I've run into this on mechanical fuel injection intakes, Hilborn primarily, but the bind was always heat related. Tight tolerances with aluminum manifold, steel shafts and bronze butterflys and shaft bushings all with different expansion rates. On the pressure differential you would think it would have to be massive to overcome the return spring, but the real unknown is the tolerances of an aftermarket TB. Bore could be out of round a hair, butterfly might be out of round a hair, and maybe when a pressure differential is introduced it's just enough to make it stick? Odds are if you substitute an OE TB the problem would disappear, but still not helpful in getting to the reason the one you have is acting up.

 

[TonyK]

Hussein, with the thottle body off of the car, why not connect it to a vacuum cleaner and see if it is still sticking. That way you can mess with it to your heart's content and resolve the problem on the bench.

TonyK.

Grimsby Ontario Canada.

 

[lookforjoe]

So, hopefully resolved my two main issues today. I removed the exhaust back to the header collector & found that the runners are vibrating at the collectors. When I trimmed back the collectors to fix the slip coupler leak, it pulled the header runners closer together. I've wedged some SS folded plate in between the three that were vibrating against each other when revved. I'll see if that has improved the situation.

I removed the IACV restrictors first, ran the motor & found no change. Then I removed the TB, and did a few things. First I removed the butterfly, edged it & put it back making sure it was centered. Put the TB back on the engine & ran it. No change to the sticking condition,.

set 1/4 turn off the stop

Removed it again, and dismantled the wheels/hub/spring end & checked the movement of the plate. What I found curious is that the RSX TPS acts as a buffer, and dampens the closing of the plate for the last few mm. So, I wonder if when it is energized, it actually offers more resistance. So, I drilled a new stop hole for the shaft spring as I had run out of tension adjustment with the provided holes. Tensioned the spring an addtional 20-25º, and put it all back together. That seems to have resolved it. I couldn't make it stick from the gas pedal or from the TB, so I'll road test it when the rain ends & know for sure at that point.

this is the revised deflector I have for the cruise cable to prevent it crossing over under hard access/shift. It does the trick. The first one I made did not protrude enough & when I did a quick 1-2-3 pull under hard accel, the cable crossed & locked the throttle open. I turned the motor off as it climbed to 8+K in an instant & coasted to a stop. I did a pull yesterday with this one, no issues.