Acty Stumbles - Engine won't rev and white smoke then engine recovers

1991 Acty HA4, MT, No air condition, w/slightly over 26,00 KM, has been running well (except for minor alternator loading issue) has now developed a major issue.

Major issue: Starts and idles fine. However: 1). After driving about half a mile, the truck abruptly quivers (like engine cuts off and on for an instant). 2). Shortly there after the engine speed limits (but does not stall). At that point the truck will only go about 5 - 10 MPH. 3). The engine emits white smoke. 4). After a few minutes the engine comes back to normal RPMs and the white smoke stops. I suspect the condition occurring at the approximate half mile point is coincident with the choke becoming fully opened (off). - This condition has repeated the last two times the truck was driven (same location). 5). In starting the truck in the shop it runs fine. I suspect that is due the engine not being warm and therefore the choke is closed (on).
[I have given all of the vacuum lines in the area of carb a visual inspection and they appear to be in good condition. Also, I have checked the coolant levels (possibly related to the white smoke).]

Minor issue: While the first condition is new, there is a second condition which I suspect is a malfunction. That is when lights or the heater are turned on, the engine speed drops (but does not stall). The increase in alternator loading is pulling the engine speed down (but not stalling the engine). Possibly related is that two alternator belts had to be replaced withing the last 600 miles or so. I have been writing these broken belts off as due to incorrect belt size. I suspect this condition of alternator loading is due to sensor/solenoid not responding the additional alternator load and therefore raising engine speed.

If anyone has encountered either of these issues (especially the first issue of capped engine speed) and would comment I would appreciate it.

 

normally when lights are switched on or the AC compressor, the idle speed should go up. https://minitrucktalk.com/threads/acty-ac-idle-help-with-idle.22078/
also check the 2 solenoids on the carb as shown in the link, at least my 1997 Acty HA3 truck with Engine E07A had that and I had a problem with these, but then black smoke came from the exhaust = unburnt fuel, not white smoke

Please add to you profile a signature with the car details, easier for other members to help you, example from my car: 1997 Honda Acty HA3 truck, Frame: V-HA3, Engine E07A, RHD
On top right click on your name and then click signature

 

shogun, I appreciate your input. Your posts are valuable.

On the speed dropping down and limiting, which is the primary issue, those solenoids need to be tested. I assume it is best to test those solenoids removed from the vehicle. To do so apparently it is best to pull the carb. If that is the case, it is probably best to have replacements solenoids on hand. Please check me on that. - Also, I assume the purpose of slow cut solenoid is slow the throttle closing but I am curious what the air vent cut solenoid does.

On the issue of raising the idle speed to accommodate alternator load, from the information I have been able to dig out is, trucks equipped with air conditioners (and possibly automatic transmissions) have additional circuits that manual transmissions don't have. Still digging on that one for the first issue is catastrophic and needs to be solve first.

On the signature, it has been entered and hopefully there is now enough info there.

 

Does your 1991 also have the E07A engine? On my 1997 Acty I could remove both solenoids w/o pulling the carb, but not sure how your 1991 carb looks like and if it has these solenoids. For my built year the part numbers of both valves based on my 1997 E07A engine
16031-PZ3-000 SOLENOID, AIR VENT CUT
16024-PZ3-000 SOLENOID, SLOW CUT
http://jp-carparts.com/honda/part_d...TY TRUCK&cartype=30822&fig=E&fig1=100&fig2=13

 

Thanks for quick response.

My notes indicate engine is E07A. I have to verify however I am almost certain.

Again, my notes indicate:
16031-PZ3-000 SOLENOID, AIR VENT CUT
16024-PN3-000 SOLENOID, SLOW CUT

Picture attached (Note, I failed photography 101!!). Oh, wishful thinking! I can't see them, not to mention change them.

 

I have had a similar issue. Starts fine, sounds normal, but when I try to accelerate, no power, rpm drops. It would happen on hot or cold engine. Shut off and restart usually fixes. I then noticed one morning that my heater blower wasn’t running and no radio power, then I tried to drive and had same issue. Restart fixed both. I found that there is a problem in the key switch. Sometimes when I turn the key on, engine off, no fan. If I jiggle the key it comes on. The next time I had the engine issue, I jiggled the key and all power came right back. I don’t know what all is electrically controlled by ignition switch but it definitely effects something that makes it run poorly.

So now I always turn key on, check for fan, jiggle key if necessary before I start engine.

I don’t know if this will help, just a thought.

 

I also only run with just one key. I don't have my entire key ring hanging. Happened once while running. I figure that the extra weight of all the other keys caused it. Again, I jiggled the key, and all power came back. Someday I'm sure I'll have to change the ignition switch.

 

better get a new ignition switch, here you can find the p/n with your chassis number https://honda.epc-data.com/

 

Thanks shogun for the link. I’m going to take a look inside sometime soon and see if some contact cleaner will do the trick.

 

I will add ignition switch as a potential piece to the puzzle. There is only one key on the ring. Note that the two times the condition has occurred it was at the same place/running time (ie. choke state, engine temperature, distance). From when I looked at the electrical diagrams there may be additional control circuits run through the switch besides just ignition. It is on my list to re-visit those diagrams. -- Since this truck has MT and no air con the electrical paths are less.

Two thoughts that had been mentioned outside this forum are that "white smoke" due to head gasket leak. And also to pull the air cleaner so as to monitor the choke position the next time the fault condition occurs.

 

Mountain-artisan, I had this same issue on a '93 Honda ACTY street-g I owned a while back. In my case it turned out that it was a fractured wire to the slow cut solenoid and air solenoid that were broken within the jacket that wasn't immediately obvious since the wire showed no signs of breakage externally. The van would be extremely sluggish at times/smoke black *BAD*like a diesel truck w/ bad injectors especially after restarting warm even if I stopped briefly to get fuel. It would 'magically' alleviate itself if I restarted several times in a row with cranking and immediately shutting down the engine after it started. That lead me to check the wires again as the solenoids both clicked with 12v dc applied to them since all that shaking from the engine cranking, starting up then promptly shutting down was jostling the harnesses enough for contact to be made between the breaks and work intermittently. This sucked because it happened to me on the on-ramp to a freeway more then once and I had traffic behind me. Suffice to say they got a cloud of black smoke and the same acceleration as a fully laden semi-truck from me hahaha.

TLDR; It might be worth it to do some continuity tests on the wires that lead to your solenoids. Just my 2 cents worth though.

 

flair, I decided to test, pull, and replace the the Air Vent Cut-Off Solenoid. The solenoid did not pull in with voltage applied nor is there continuity. The wire was pinched where it passes through the lower carburetor plastic housing. (I cannot see the pinched area.) And the wire broke when I removed the solenoid. After installing the new solenoid, the throttle linkage was restricted. In removing the linkage to fix the linkage binding the "wear washer" dropped down into the plastic carburetor housing. So before I can test the engine I have got to fab a new "wear washer" and figure out how the throttle linkage should go together at the diagram. [If any one can post a good diagram/picture/procedure I would appreciate the post.]

I can appreciate your encounter on the freeway ramp. A slow down on the freeway is a concern. I live on a winding, dead end, mountain road. A surprise to a car coming upon a slow moving Acty on a curve may not end well.

 

Update - Solved MAYBE: Acty Stumbles - Engine won't rev and white smoke then engine recovers: I replaced the Solenoid, Air Vent Cut 16031-PZ3-000 and thus far the problem of "After driving about half a mile, the truck abruptly quivers ((like engine cuts off and on for an instant). Then the engine speed limits (but does not stall). At that point the truck will only go about 5 - 10 MPH.))" has not reoccurred. More running time is needed to completely verify.

Before removing the solenoid I applied 12V across the solenoid and the solenoid did not make a noise. Then I checked the resistance across the solenoid and it indicated open. In removing the solenoid I found it's lead wire pinched somewhere underneath the carburetor. In taking the solenoid apart the plunger was bound (but could be moved with some effort).

Take away tips: 1). Before starting, pack the area under and near the carburetor with rags and a paper towel to prevent parts from getting lost. 2). The associated diaphragm linkage is held on with what I measure to be a M7 X 1.0 Nut. The size of the nut is not published and is part of Diaphragm Set.

What does the Air Vent Cut-off Solenoid do - In my words the purpose of the Air Vent Cut-off Solenoid is to route fuel vapors accumulated in a canister into the carburetor.The solenoids control voltage seems to be supplied by the speed sensor. Feel free to add comments?

Side issue: In the heat of the battle I had sent two email requests to Yokohama Motors (using their form) for delivered price on a rebuilt carburetor. A response was never received. Just curious, has anyone had recent experience with them?

I appreciate the posts by Shogun and Old Machinst's. The information they provide is valuable.

 

10 years ago when I had the same problem I was told by a Japanese Tech: The air vent cut-solenoid function is return to inlet and suction side for vaporization of fuel from fuel-tank. Then, mix it with fresh-air and filling for cylinder. If doesn’t work for these parts, not enough air for air fuel ratio. So accordingly too rich-condition. These similar problems are many occurrence to HONDA-Acty.' https://minitrucktalk.com/threads/performance-issues-resolved.14267/

 

Shogun, reading your referenced post, "not enough air upsetting the air fuel ratio" (caused by mechanical failure of the air vent cut-solenoid) is the bottom line, interesting. In my case I say mechanical failure because: A). The solenoid's wire was pinched in addition to no continuity , B): The solenoid's armature was binding. Regarding the binding, I can't help but wonder about a comment Old Machinist made regarding that solenoid's failure due to fuel. While I can hope, it will take additional hours on the engine before I can call it solved. As for the "white smoke" mentioned in my original post, that was described to me. I did not actually see it.

Question, just curious, have you any thoughts as to why Yokohama Motors does not reply to request for parts quote (on a rebuilt carburetor)?

Thanks

 

Maybe your email landed in their spam folder. That is not normal, that they do not reply.
On their website I see 2 email addresses https://www.yokohamamotors.com/index-5.html
telephone:+81-70-1435-8279 9:00am to 7:00 pm (Japan Time) , FAX:+81-45-622-8503 ,E-mail: Parts (at) yokohamamotors.com , info (at) yokohamamotors.com
https://used-parts-solution.com/contact-us.html

 

The email addresses I used for Yokohama Motors were info@yokohamamotors.com and Parts@yokohamamotors.com (per the Yokohama Motors web site). Am I missing something?

Today, I added about 20 Minutes running time on the replacement air vent cut-solenoid and the original problem did not reoccur. - Regarding the electrical control of the air vent cut-solenoid. I would add, looking at the wiring diagram, the solenoid gets it's control only from the speed sensor. Thus the solenoid appears to be only actuated by road speed.

If the air vent cut-solenoid does solve the intermittent limiting of engine speed problem then I will look into the second problem I described in my original post. That is, engine speed drops with alternator loading (ie. turn on the heater blower or lights and the engine speed drops). Per the Danko manual this Acty being a manual transmission and no air conditioner does NOT have an idle control unit.

 

SOLVED: Upon warm up, the Acty engine won't rev, white smoke, then engine recovers. - I replaced the Solenoid, Air Vent Cut 16031-PZ3-000. Thus far the problem has not reoccurred. As indicated above, the solenoid's wire was pinched, there was no continuity , and the solenoid's armature was binding.

Now, on to addressing the second issue of when lights and/or the heater fan are turned on, the engine speed drops (but does not stall): The increase in alternator loading is pulling the engine speed down (but not stalling the engine). I have seen several posts on this forum of a similar condition but no solution(s). It seems there should b a carburetor control driven by a sensor to compensate for this additional alternator loading. Acty models with automatic transmission and/or air conditioner do have load compensation. However, this Acty has a manual transmission and no air conditioner thus has no load compensation as those models have. Can some one that has an HA4 Acty with a manual transmission AND no air conditioner comment on their experience with drop in engine speed with alternator loading?

 

check this video, maybe it helps, Honda Acty carb adjustment and idle adjustment there is mentioned:
I never noticed the screws because I had my rubber groomers still there, thanks for pointing out the right one haha! Very helpful.
The screw on the left side that I didn't know what it did, Adjusts the idle when the AC is on. The engine needs to increase the idle a bit for the additional load, and that screw on the left side is what raises or lowers the idle when the AC compressor kicks on.

 

Shogun, I will have a look for that adjustment the next time I have the engine access cover off. I don't remember seeing a plug. And per the Danko manual, non-air conditioner and manuals do not have compensation. The (main) idle speed is currently set high and alternator loading occurs. -- Thanks, Bill

 

Shogun, it is still on my list to have a look for that second idle related screw mentioned in the video you posted above, just waiting for warmer weather. Actually, there are several reasons to look into idle speed: 1). Pulling engine speed down related to alternator loading, 2). Rough idle at rated idle speed, 2). Also, engine timing has not been checked since I had the distributor out to replace the outer distributor o-ring.

Any recommendations on a timing light? Here is a timing light/tachometer that I am considering from Amazon https://www.amazon.com/dp/B0788F2DRD?linkCode=ogi&th=1&psc=1 2). I am looking for a timing light with a tachometer that will operate on the 3-cylinder. (I have one of those low end tachometers from China and 3-cylinder set up instructions are ambiguous. I don't trust it.)

Also, are there any recommendations on how to cleanly translate Japanese videos and text posts to English?

Bill

 

to translate text or pdf files I use https://www.deepl.com/translator
have not tried this: Auto Translate YouTube Video into your Language

https://support.google.com/youtube/answer/7296123?hl=en

 

shogun, I appreciate the info on translation. - I had experimented some with a browser translation extension . In addition to some videos not having closed caption, I recall there was another issue where the video was inhibited during close caption translation. Perhaps I was expecting too much! I intend to make a more serious effort at translation of videos. There is a wealth of information to be gotten from those videos. An experienced Acty contact could be valuable. - Bill

 

I believe this is happening to my truck as well. I have already replaced both solenoids about a year ago. They operate every time when 12V is applied to them, but my truck exhibits the exact same symptoms as yours.

Can you give me a general idea of the wire routing from the plugs to the VSS? I believe you said that's what controls them. Or the location of the VSS on the truck?

Thank you

 

pass1over, I gather you are referring to the "Air Vent Cut Solenoid Valve" wire routing. Check me if I am wrong on that. -- In my case there were two issues: The "Air Vent Cut Solenoid Valve" armature was binding AND the wire to the solenoid was pinched somewhere between the solenoid's plug and the solenoid. As described in the Danko manual on Page 117 (MT) and Page 118 (AT), wire routing to that solenoid is from the Speed Sensor. I have not found the location of the Speed Sensor. I would like to know the Speed Sensor's location. Perhaps shogun can shed some light on it's location.

 

yes, that's the wire routing I was referring to. My carb cover is off and the wires look fine from where then connect right by the alternator positive post. Your pinch was being caused by the carb cover? My solenoids seem to be functioning when 12V is applied to them, I can hear a clicking on each one when testing each. I suspect it's something in the wiring to them.

I have the Danko manual and have seen that wiring diagram as well. I have my contact in Japan getting me a picture of what the VSS looks like. At least that way maybe I can find it.

I was going to test voltage on the solenoids while my wife drives the truck when it's misbehaving. Then apply 12V to the solenoid if it's not receiving it and see if it clears up the issue.

 

When you say the solenoids armature was binding, are you referring to the plunger inside the solenoid? I haven't looked inside one in awhile so I don't remember exactly what it looks like. But basically, the inside of it wasn't fully opening or closing?

 

pass1over,
Carb box cover is missing on mine as well. Pinch was maybe 3" from the solenoid plug. Not ssure where. However, from what I could put together the pinch was not causing a short to ground. Seems like I heard a "clunk" like the solenoid pulling in at least on one occasion before I eventually pulled the "famous" solenoid. When out, the solenoid did not make a noise upon applying voltage. Upon taking the solenoid apart I found the armature to be bound and I seem to remember the coil is open.

Regarding the Speed Sensor, I am not clear on where it is located. Taking a quick look at the JP-Carparts diagrams I could not find it. I will look further. (I expect my network will be down later today for a gateway change out.)

So, here is a thought. Tap in to the solenoid control with long wire connected to VOM in the cab.

Hopefully you will comment on your finding of Speed Sensor and it's wiring. Beyond the Danko manual wiring info is scarce!

 

If I do get more information on the location or the appearance of the VSS, I will definitely share. It's a manual transmission, there can't be that many wires coming out of it. VSS and reverse lights are about all I can think of really. I'll try and get it on my lift so I can look around it a bit easier underneath.

 

I was rewatching a video of a guy pulling the engine and trans from a van and I think I've located the VSS. Next to the starter, about where the starter wiring comes out, there is an electronic device with 2 wires coming from it. One wire has a bullet end, like on the solenoid, and the other has a receptacle end that a bullet plugs into. The receptacle wire appears to be a greenish color and the bullet-ed end looks white, tan, or yellow - something lighter in color.