Sound board, Intermittent cold weather power loss...

[VTEC_Inside]

Ok, I've got two issues that re-occur when they feel like it and I'd like to get some feedback and bounce some ideas.

My car runs fine when its warm outside, no issues no matter the weather. My idle controller doesn't seem to want to work properly but does hold vacuum. I suspect the cause to be a leak elsewhere in the system. Car pulls just over 20inches at idle though so otherwise it runs fine.

Bring on the colder weather and particularly cold and rainy and these two issues pop up, but are not easily re-created.

1) Cruising along (80-100kph+) nicely at a steady speed and it'll start to stutter. I floor it and it takes off with reduced power, but runs steadily and pulls up through the revs. This HAS to be a sudden (possibly stuttering) vacuum leak as the car will run smoothly and accelerate if I step on it a little.

Car will idle like crap, but not stall if I clutch in. Depending on what it feels like it will run properly again within half to a couple minutes of just idling. Other times I've had to shut it off, and within minutes its fine again.

I have already obtained another Air control valve B and Anti-afterburn valve from the wreckers. Air control valve A is a little trickier to get at, arg... I have yet to test either the ones on the car or the ones I picked up from the wreckers because I need to get a second vacuum pump according to the service manual.

Any thoughts on either of those valves being the cause here, or perhaps something else I'm missing.

2) Seems to be exagerated by rain. Cruising along (usually 120kph+) and I'll just start to notice that something isn't right. The car all of sudden barely has the power to maintain speed, and flooring it does little to nothing. It actually seems to lose speed unless I back off and find that sweet spot.

As in issue 1, this problem goes away (quite quickly) if I let it idle. For example, it happened today. I got to my off-ramp on the hwy, stopped at the stop sign for 10s and when I took off again it was FINE.

I'm at a bit of a loss as to what this might be caused by.



The more I think about it, I am inclined to believe that this could be an icing thing, or a hot air door issue (issue 2). What is infuriating is that I can't make either of the scenarios last long enough to start poking around.

Just typing that out makes me want to make sure that the EFE heater is actually hooked up. Few may recall that I had emissions issues traced back to a coolant temp sensor that had come disconnected. Wouldn't I experience more severe issues if the EFE heater wasn't hooked up though?

[MessyHonda]

sounds like you are having hesatation...my car would do that too...i changed the fuel filter and it helped out a lil bit. then i changed the fuel pump.i also got a new K&N air filter and planitum 4+ plugs and accel super thick wires..after that i rechecked all my vacuum lines were in the right place and that i did not have an air leak. After that i rebuilt the carb and it didnt help out...so i was all pissed and shit...so i went to the junkyard...tired to pick out a car that was rearended or something like that just to make sure they didnt throw it away due to mechanical problems...then i let my uncle rebuild it since he knows somewhat about carbs. installed it and it runs alright now...the idle is still a bit jumpy but the car does not hesitate on the freeway

[VTEC_Inside]

Have to add that no matter the temperature or weather, when the car is idling it the exhaust sounds like its making popcorn. The engine idles smoothly otherwise, just these intermittent pops. Instant you touch the gas and get it off the idle circuit it sounds normal.

I doubt that this is related, but thought I'd add just in case.

[VTEC_Inside]

sounds like you are having hesatation...my car would do that too...i changed the fuel filter and it helped out a lil bit. then i changed the fuel pump.i also got a new K&N air filter and planitum 4+ plugs and accel super thick wires..after that i rechecked all my vacuum lines were in the right place and that i did not have an air leak. After that i rebuilt the carb and it didnt help out...so i was all pissed and shit...so i went to the junkyard...tired to pick out a car that was rearended or something like that just to make sure they didnt throw it away due to mechanical problems...then i let my uncle rebuild it since he knows somewhat about carbs. installed it and it runs alright now...the idle is still a bit jumpy but the car does not hesitate on the freeway

I changed both fuel filters and the fuel pump last year when this happened.

Air filter, plugs and wires are also relatively new. Once again, this is a very intermittent thing.

If any of those were the cause I would expect it to occur more often.

I am starting to lean on the carb being bad internally. The car does have 388,000kms on it, and its the original carb.

[A20A1]

+4's will foul cause they are not the right heat range... but if you're running a hotter engine they should be okay.
Like for me if I idled for long periods of time the plugs would always be black, but if I drove hard for 10 minuets or so and checked them they would be relatively clean.



I would check the float level

also your ignition timing and mechanical advance in the distributor.

I dunno if your carb is icing, but you can flip the lid and take in engine bay air which should be hot once you've driven for a while, just startup would be crap.
Then perhaps check the water pump, the belt and thermostat to make sure your coolant is really circulating and providing coolant to the carb.

Also check the fluid level in the radiator.


Another thing to check would be the charcoal cannister, and the float vent.
And maybe water in the gas, gas vapor or maybe condensation messing with the carb.

[2oodoor]

If it were my car, I would check the egr valve operation, and the thermo valve controler for the egr valve vacuum routing may not be correct. Also I would check anything upstream from vacuum controller for EGR if vacuum routing is correct at the thermovalve. Usually EGR problems only show up at idle or decel, but if its opening suddenly at cruising speed , the mixuture will change and you will 'feel' the car 'trailering' . This is more common on larger cars, but essentially if you have ever pulled a trailer, in layman's terms it feels the tug of a trailer and wind resistance etc.. EGR is usually open during acceleration and tapers off at cruise speed. Popcorn exhaust.. huh thats a thinker....

[VTEC_Inside]

+4's will foul cause they are not the right heat range... but if you're running a hotter engine they should be okay.
Like for me if I idled for long periods of time the plugs would always be black, but if I drove hard for 10 minuets or so and checked them they would be relatively clean.



I would check the float level

also your ignition timing and mechanical advance in the distributor.

I dunno if your carb is icing, but you can flip the lid and take in engine bay air which should be hot once you've driven for a while, just startup would be crap.
Then perhaps check the water pump, the belt and thermostat to make sure your coolant is really circulating and providing coolant to the carb.

Also check the fluid level in the radiator.


Another thing to check would be the charcoal cannister, and the float vent.
And maybe water in the gas, gas vapor or maybe condensation messing with the carb.


Float level is a little high, just nudging the top indicator in the window. Adjustment is out of the question unless I want to pull the top hat off. I've tried, it leaks like a siv(sp?).

Coolant is full and I'm pretty certain everything else is working well in the cooling system.

The charcol cannister had crossed my mind as well. I can't recall for sure, but I was under a quarter of a tank today, it may be linked to fuel tank level as well for all I know at this point.

[VTEC_Inside]

If it were my car, I would check the egr valve operation, and the thermo valve controler for the egr valve vacuum routing may not be correct. Also I would check anything upstream from vacuum controller for EGR if vacuum routing is correct at the thermovalve. Usually EGR problems only show up at idle or decel, but if its opening suddenly at cruising speed , the mixuture will change and you will 'feel' the car 'trailering' . This is more common on larger cars, but essentially if you have ever pulled a trailer, in layman's terms it feels the tug of a trailer and wind resistance etc.. EGR is usually open during acceleration and tapers off at cruise speed. Popcorn exhaust.. huh thats a thinker....

I was able to eliminate the EGR (I think) when it did it once last winter. I pulled over during one of its stuttering episodes and opened the EGR valve by hand. It was fully down during that episode.

[2oodoor]

yea I did not know if it was ignored during the vacuum removal or not. Your geting some good feedback so far, im just thinking why the temperature thing, put these things under each field to sort it out. what controls are reactive to these cold temps, thermovalves vacuum and electronic, electronic component type circuits like ignitor, coil, fuel pump, that solenoid on the carb itself.
You probably would not be throwing money away by changing both filters, still consider the old gas could be coming thru there, I am not really sure about that car, but I have heard of the charcoal canisters breaking down the internals and making there way back to the tank and bowl too.
Just bouncing some things around ok. A parts car is really handy sometimes yes.

[VTEC_Inside]

yea I did not know if it was ignored during the vacuum removal or not. Your geting some good feedback so far, im just thinking why the temperature thing, put these things under each field to sort it out. what controls are reactive to these cold temps, thermovalves vacuum and electronic, electronic component type circuits like ignitor, coil, fuel pump, that solenoid on the carb itself.
You probably would not be throwing money away by changing both filters, still consider the old gas could be coming thru there, I am not really sure about that car, but I have heard of the charcoal canisters breaking down the internals and making there way back to the tank and bowl too.
Just bouncing some things around ok. A parts car is really handy sometimes yes.

Just to clarify, the full vacuum system is in place with the exception that I have bypassed the secondary barrel thermovalve.

I welcome each and every idea and suggestion. This is by no means a critical issue for me, but a puzzle that I would LOVE to solve.

[VTEC_Inside]

Update, its still at least 6c here today, but raining HARD.

I haven't yet had a chance to do ANY work on the car.

The car started to do its sputtering again while cruising on the highway. I would gun it and it would take off, but try to cruise and sputter city. Idle was also quite bad, but didn't stall.

I accelerated and then coasted for a 10-15s holding the revs at about 1000rpm and then resumed driving normally. I did that a couple times and it was fine again.

Its too bad the weather here is going to be complete shit all weekend or I would change out air valve B just because. I have an extremely strong suspicion that the problem is with either air valve A or B as they should be the only on/off vacuum source functioning while cruising. By on/off I mean that they would cause a vacuum drop while cruising to lean it out, but would essentially close below 2500rpm.

Not really looking for a reply, but I will keep people updated as to what I end up doing.

Car will turn over 389,000kms on the way home today.. woot woot.

[VTEC_Inside]

Update: I had two Air Valve B's and an Anti-Afterburn valve I picked up from the wreckers.

One of the Valve Bs that I got was bad. The other AND the one on the car seemed to be fine. Nonetheless I swapped it with the one from the wreckers.

Was driving today and it happened again, 3c light rain. It seemed to progress much slower this time. It almost seemed as though it wasn't going to get any worse at one point, but it did.

Fortunately I was able to pull over and have a quick look again. It continued running like a bag of $hit, idling lower than 500rpm the whole time. I popped the lid, choke was wide open, pinched the hoses comming off both air valves with my fingers, no change.

Heres where it gets good. I lifted the EGR by hand and the revs INCREASED and the engine almost sounded like it was running normally, slight sputter remained, but healthier revs.

What the heck could it be that the revs increase when I open the EGR???

In any event, I shut the car off for 15-30s, restarted and it was fine again, maybe a slight remenant, but completely normal after 15s of driving.

other notes:
- Full tank of gas when this happened

[VTEC_Inside]

Again today.

Full tank of gas again, 5-6 degrees celsius, but raining pretty good.

When I noticed it starting to "miss", I clutched in and backed off the gas. Interestingly the RPMs hung at about 2000rpm for a sec and then fell. Perhaps this will mean something to someone.

I jumped the slow mixture cutoff straight to the battery during its little episode and it made no change.

This is the first time it has actually stalled out during one of these spats.

I could smell something this time though. I'm not entirely sure what it was because I have a bit of a cold. Could have been an electrical short, or just the smell of it running lean.

It was a little reluctant to start back up, but still fired back pretty quick and everything was behaving normally again.

I've now ruled out:
-fuel pump
-fuel filters
-EGR problem
-Slow Mixture cutoff

The on/off nature of the problem plus its apparent sensitivity to water/moisture now has me thinking pretty strongly that its an electrical issue.

I think I'm due for new wires, anyone think this could in fact be distributor related? Perhaps coil or that little radio thingamabob?

Haven't looked up the fuel pump relay yet, but could it be faulty? I see fuel in my fuel filter, but that doesn't mean its being pumped sufficiently...

I feel kinda bad for the car, and its bugging me that I can't fix the stupid thing.

[VTEC_Inside]

I believe I have come across either the cause or a substantial cause of my troubles.

There were many little signs that I started to piece together yesterday.

It all started when I had the accessory belts changed about 2 years ago now. I immediately had trouble with the alternator belt squealing like a pig. I had gone to the dealer to have them changed so I just let them take care of it. There were problems with the alternator bracket and such, blah blah blah.

In any event they had to give me another belt because the one they just put on was glazed to hell. Note that in those scenarios, enough time running battery only and the car would start to idle at about 2000rpm regardless of anything else for some reasone.

I've had continuing trouble with that belt, squealing in the rain, etc..., culminating in my replacing the entire alternator mount (on the block).

One day I went to start the car and it was as if the battery was near dead. Didn't make sense to me at the time since it was otherwise running fine and it didn't happen again.

I checked the voltage to the slow mixture cutoff the last time it acted up and it was only showing 12v and change with the car running, as was the battery. I don't know why it didn't click in at that point, but whatever.

Yesterday, I hopped in it in the rain to go return a movie. Car started up fine, but the dash lights seemed rather dark. I like them dark, but not that dark.

Then the belt started squealing again. Once it stopped the lights came up to the level I'm accustomed to.

I guess my problem was that I dismissed the possibility of a slipping belt just because it wasn't making any noise. I'll change it and keep people posted.

[2oodoor]

I believe I have come across either the cause or a substantial cause of my troubles.

There were many little signs that I started to piece together yesterday.

It all started when I had the accessory belts changed about 2 years ago now. I immediately had trouble with the alternator belt squealing like a pig. I had gone to the dealer to have them changed so I just let them take care of it. There were problems with the alternator bracket and such, blah blah blah.

In any event they had to give me another belt because the one they just put on was glazed to hell. Note that in those scenarios, enough time running battery only and the car would start to idle at about 2000rpm regardless of anything else for some reasone.

I've had continuing trouble with that belt, squealing in the rain, etc..., culminating in my replacing the entire alternator mount (on the block).

One day I went to start the car and it was as if the battery was near dead. Didn't make sense to me at the time since it was otherwise running fine and it didn't happen again.

I checked the voltage to the slow mixture cutoff the last time it acted up and it was only showing 12v and change with the car running, as was the battery. I don't know why it didn't click in at that point, but whatever.

Yesterday, I hopped in it in the rain to go return a movie. Car started up fine, but the dash lights seemed rather dark. I like them dark, but not that dark.

Then the belt started squealing again. Once it stopped the lights came up to the level I'm accustomed to.

I guess my problem was that I dismissed the possibility of a slipping belt just because it wasn't making any noise. I'll change it and keep people posted.
Sorry VTec, I usually do not have alot of time on line so I just check the newest posts and recent follow ups, I have not been ignoring this thread deliberatley... I am interested in what you find with this problem. I can not stress enought the importance of checking the simple things first, as we have here thus far, except for battery cable condition/connection. Sounds like you do have a voltage drop somewhere with the 12v reading with engine on, it should not be less than 13.4 running (12.6 with engine off)
opening the egr valve to introduce a vaccum leak sounds like it is already a vaccum problem, or possibly a vaccum advance diaphagm busted. I thought you disabled the egr, you still have to make sure the valve is not hanging open because of carbon obstruction.

[VTEC_Inside]

Sorry VTec, I usually do not have alot of time on line so I just check the newest posts and recent follow ups, I have not been ignoring this thread deliberatley... I am interested in what you find with this problem. I can not stress enought the importance of checking the simple things first, as we have here thus far, except for battery cable condition/connection. Sounds like you do have a voltage drop somewhere with the 12v reading with engine on, it should not be less than 13.4 running (12.6 with engine off)
opening the egr valve to introduce a vaccum leak sounds like it is already a vaccum problem, or possibly a vaccum advance diaphagm busted. I thought you disabled the egr, you still have to make sure the valve is not hanging open because of carbon obstruction.

No worries. As I said in the thread title, my primary goal here is to state progress and bounce ideas. Any suggestions or tips are appreciated as usual.

I cleaned the battery terminals quite throughly a few months back. I can say with a good amount of certainty that there is no problem there.

EGR is still hooked up and functioning properly as far as I can tell.

I don't discount that there is probably a small vacuum leak somewhere, but I do not believe it to be the cause of my intermittent power loss at this time.

What I suspect at this time is that a slipping alternator belt slowly causes the running voltage to drop down into the 12v range. The more I think about it, the way the car behaves during these intermittent spats is quite similar to previous times when I have fried the alternator or lost the belt.

I will be replacing the belt as my next course of action and go from there.

[shakakan]

Definitely sounds like carb icing. The primary is icing at cruise, causing the engine to run very rich. When gas it, the secondary opens, which isn't iced, allowing to the car to accelerate. When you sit while idling, the ice melts.

Things to check: Test the air heater diaphram on the top of the air cleaner snorkel. If it is leaking, you will not be getting any carb heat, hence the icing.

[VTEC_Inside]

Just an update...

It hasn't done it at all in the past month now.

The only thing I've done is make a little extension between the slow mixture cutoff connectors so that I had something to touch a multimeter probe too when the car was running.

Other than that I discovered that when water overflowed the top of the cowl, drivers side base of the window, it was running down the inner fender, across the shock tower and then dripping right onto the alternator/belt.

I didn't even really address that either.

I'm not complaining but its just running normal again, with the exception of comming off fast idle way too soon (only if you touch the gas). That only started when I turned the fast idle way down though, so that answers that.

[backhatcher]

the whole idle issue your having while driving on rainy/ cold days is the exact issue ive been having along with very annoying cold starts on really cold days where the car seems to not regulate the choke very well. I assumed automatically it was fuel filter but it goes fine on a warm day. but the previous owner of the car mentioned that he had rebuilt the carb but never touched the diaphrams and they seemed to be deteriorating im thinking it has alot to do with that, due to cold moisture affecting it. Its probably not much help to you but this thread has really got me thinking, thanks for the valuable info

[2oodoor]

Just an update...

It hasn't done it at all in the past month now.

The only thing I've done is make a little extension between the slow mixture cutoff connectors so that I had something to touch a multimeter probe too when the car was running.

Other than that I discovered that when water overflowed the top of the cowl, drivers side base of the window, it was running down the inner fender, across the shock tower and then dripping right onto the alternator/belt.

I didn't even really address that either.

I'm not complaining but its just running normal again, with the exception of comming off fast idle way too soon (only if you touch the gas). That only started when I turned the fast idle way down though, so that answers that.
Good job at paying attention to the big picture of things!
A lot of people would have never been so observant, glad things are better.

[2oodoor]

Just an update...

It hasn't done it at all in the past month now.

The only thing I've done is make a little extension between the slow mixture cutoff connectors so that I had something to touch a multimeter probe too when the car was running.

Other than that I discovered that when water overflowed the top of the cowl, drivers side base of the window, it was running down the inner fender, across the shock tower and then dripping right onto the alternator/belt.

I didn't even really address that either.

I'm not complaining but its just running normal again, with the exception of comming off fast idle way too soon (only if you touch the gas). That only started when I turned the fast idle way down though, so that answers that.
Good job at paying attention to the big picture of things!
A lot of people would have never been so observant, glad things are better.