suddenly running rough, wont idle :(

[tomatofiasco]

prologue: sorry for the wall of text. its a longer story than i though. i put "=" at the particularly confusing parts...



i think i have a real problem now. about a month ago i found my hatch was a bit reluctant to start, and soon after that i noticed it sort of shuddering, or hesitating a tiny bit, when holding or accelerating slightly between 2000-2500 rpm. one day when i parked it, it smelt strongly of fuel so when i returned i had a look under the bonnet, and found the little acceleration pump that squirts extra fuel into the main barrel was leaking from its base. i took the carb out, cleaned it up a bit, re-sealed the pump with high temp silicone sealant and tapped back in a little brass hose spigot that had worked loose. it didnt leak anymore and the smell was gone but the slight cough and the reluctant starting continued.

i put that down to the cold damp tasmanian weather, and adjusted the ignition timing [rotated the distributor] slightly forward and back of its original position. advancing the spark a tiny bit made the hesitation almost completely disappear, but made the idle more uneven with regular popping and more vibration. i decided to put it back to its original position and just wait for warmer weather.

then the idle got really unstable and uneven, barely managing to stay above 800rpm, and just recently it wouldnt idle at all without choke. the first i noticed was when i rounded a corner, pushed the choke all the way in as usual, and then had the engine die completely when i stopped at the next intersection. i tried to re-start it but it just kept bogging and dying as soon as i released the throttle, so i pulled the choke back out and then it idled at about 1000rpm, though still quite rough. i didnt know what to make of this as a few seconds before it had been running happilly, not miss-firing and with no loss of power or anything, and continued to run happilly from 1500rpm up [as usual] as long as it was in gear. i put the choke back in and continued to run fine, untill i stopped again, and it died again. it was fully warmed up by this stage but still needed the choke to idle at all.

at this point the problem seemed to be that:

-starting was tedious
-it would hesitate a bit around 2000rpm
-it was idling unsteadilly at about 1000rpm
-it would stall immediately without any choke

on the way home however i found it was shuddering noticibly while cruising on the flat and coasting down hills [but not really under acceleration] and when i stopped the idle would bog down and the engine would shudder alarmingly and almost stall. this was at a busy round-about where it was sort of stop-and-go, and every time i released the accelerator and disengaged the clutch it would splutter. but it moved off normally through the round-about and up a hill, no sign of sluggishness or lurching or anything.

i was pretty annoyed at this so i stopped in the garage [still running] and popped the bonnet, loosened the distributor and moved it about. the idle was really rough and sickly, and advancing the spark raised it a little bit but didnt make it any less unsteady or poppy. i had run out of advance adjustment so i put it back where it had been and it died [wheezing] before i could even do the bolt up

i took the air cleaner off, re-started it and managed to get hold of the throttle directly before it could stall again, and kept a finger on the tab to keep it chugging. i found something weird: the choke butterfly has a secondary, very light spring that allowed me to flip it completely open without moving the button. this caused extra spluttering but with additional throttle it would keep going, whereas popping the button in would cause it to die immediately.

= what does the choke button do, besides move the cable and operate the butterfly?

today, it wont idle at all. it often takes a few attempts to get it to chugg off the starter and onto its own power. it will rev reasonably normally but bogs if i let it fall anywhere near 1000 rpm, and pops and splutters badly at 2000rpm. releasing the throttle is instant death, and moving the choke in either direction away from the first stop is also instant death.

i checked and cleaned all the ignition gaps and contacts and checked for vacuum leaks but didnt find anything very interesting.

= however i did find that, at TDC on the flywheel, the marks on the camshaft pulley were sitting a few teeth from horizontal. could this have slipped? i re-set it but it made diddly-squat difference to the situation [yes i changed the valve timing substantially and it had no effect ]

= i took the rocker cover off and found nothing sus, except this:



weird white residue clinging with the oil on the underside of the filler cap, and:



same residue, seemingly collecting in the vent baffles. it hasnt made it to the air cleaner barrel though.

"OH NOES BLOWN HEAD GASKET " is what i thought, but i didnt find oil in the coolant, or the residue anywhere else around the valvetrain etc. or on the spark plugs.



so i said "rrraaarrgh!" and decided to stop wasting my battery charge and post it all for the experts. halp!

[carotman]

My first guess is that there is a vacuum leak somewhere that makes the engine run too lean. The fact that it likes to run on the choke also points to this.

Make sure that every vacuum hose is connected where it should be. Spray carb cleaner around the hoses. Spray some around the base of the carb and on the intake manifold gasket. If there is a vacuum leak, the idle will rise.

That white residue is water mixed with oil. Since you said that it's cold and humid these days in tasmania should be the reason for that residue. If you drive the car only for short trips at a time, water doesn't have a chance to completely evaporate and will just do this white residue.

[tomatofiasco]

[edit] i checked the camshaft more closely. it was binding at the middle bearing. no apparent damage luckily, i made a ghetto shim out of tin can and torqued it all up properly and now its much easier to spin. i should probably replace the drive belt, but i'll test it in the morning

-------------------------------------------------------

im pretty sure its all hooked up properly, there arent that many pipes anyway. i'll buy some carb cleaner asap and look for leaks. i have been doing short test drives recently, and the weather has been constantly dreary so any water that evaporates would probably be replaced as soon as i put it back in the garage :p

but what about the misaligned cam pulley? how hard should the cam train be to rotate? i cant rotate it by hand with the belt off, is that normal?

whats most worrying me is the car is undriveable at the moment, whereas yesterday it did at least get me from a to b. it seems like whatever is wrong is getting worse

[tomatofiasco]

freeing the camshaft didnt seem to do anything. i think the word for what it's doing is "missing" - as if one or two cylinders intermittently fail to fire. i set the ignition timing to 4 degrees btdc but it wouldnt even start at that, so i rotated it all the way over to god-knows-what, probably more that 10 degrees btdc. on this setting it will start and run [poorly] with plenty of extra throttle, but will stall very quickly below 1200rpm. i set the throttle stop screw so it would idle above this at about 1500, so i could try removing and pinching vacuum tubes at different rpms.

this didnt seem to have any effect. i pulled off the vaccum advance tube and the throttle opener tube and also pinched them but the crappy chugging continued unaffected.

also i couldnt pick up any marks on the flywheel with a timing light [i guessed it would be well out of calibration range anyway] but it did suggest that the spark gets more stable / regular at higher rpms - when its coughing along at 1500, the flash illuminates all different points of the flywheel surface and it just dodges about like crazy, whereas at 2500 rpm it seems to settle more on one point and the flywheel looks much more like its standing still, as it should.

this correlates with how it wasnt stuggling to get up hills / rev out, just stalling at low rpms.

so maybe something is up with the ignition system, and since there isnt much to the ignition system, maybe the distributor has finally had it. i guess it runs better at higher rpms because theres more sparks to make up for the ones that go AWOL and more inertia to smooth it all over. theres still definitely no smooth, pop-free spots though.

i have another distributor. i took it off this engine when i swapped it for the original one, because the '77 wiring didnt have the little two-terminal clip for the side of the newer distributor. i stuck the old one back in instead, and it WAS disagreeable at first, but i just cleaned up the points and wiggled the leads and its been ok ever since.

the other, newer distributor doesnt have the same point system a cam and follower, its got what looks like 4 blades that dont actually physically contact with anything, but which i guess do the same job. anyone know what that extra plug on the outside is for, or if i need it?

also, that ticking noise [from the spark plug thread] is still loud and clear... it actually sounds like a zapping spark. its quite regular, but i cant feel it on the block, and it doesnt get louder or heavier with load. i want it to be coming from the distributor. i think. could it be?

AND where can i find some clear pictures of the vacuum setup for a 1602 manual? mine has a weird t-junction that i dont quite know what to do with. its always worked fine in the current configuration but i'd like to finally know what its actually for

[79cord]

Sorry I don't have any brilliant ideas beyond dirt in carburettor..
Once had mixture adjustment screw go missing! Somehow the car still ran & got me home but wouldn't even attempt to idle.
'79 & on Accord had electronic ignition presumably earlier models didn't, not sure what connector wiring actually connects to offhand...
edit: Manual shows it connecting to an "igniter" relay/transistor box with wires/signals from earth, coil, ignition switch & a "radio noise condenser".

Looking in manual for Vacuum diagram but can't spot anything usefull to pass on yet...
& it's a '79 manual; my '81 prelude has slightly different vacuum lines.
If the vacuum advance on your distributor is acting up that might explain it running happier at certain revs.

[tomatofiasco]

my vacuum tubes might be mis-matched from both cars.. i cant remember. there are a lot of one-way valves though. ideally i'd buy a roll of tubing and re-plumb it all. i have fragmentary pictures and diagrams but not a complete overveiw.

Manual shows it connecting to an "igniter" relay/transistor box with wires/signals from earth, coil, ignition switch & a "radio noise condenser".

i think i have the same wiring diagram. it doesn't detail HOW it connects to those things.. it just sort of goes into a box and then its up to your imagination

i'll try it out. it cant be THAT different to what i already have, surely...

but if it is, can i buy a new distributor? is it horrendously expensive?

and where is that mixture screw? i know about the one with the plastic limiting cap on it but i dont know what it does or how to set it. i think its an air bleed for the idle, i twiddled it but nothing happened. there could be some crap stuck in my carb, but im reluctant to take it apart because last time all the springs went sproing and it was highly unpleasant.

either way something is breaking down, i just hope its somewhere near the top of the engine, not the bottom.

[79cord]

Complete Wiring diagram might help but you'd probably need both '77 & '81 since I noticed even the ignition switch wiring varied '80-'81 on my Preludes.

Mixture screw? i know about the one with the plastic limiting cap on it but I dont know what it does or how to set it.

That's the one! though I suppose that isn't your problem.

[Detlef]

Hi
First, what year is your Accord and what engine code?
I think, it's not cvcc?
I'm pretty sure, that your problem is caused by dirt in the carb, but in between you changed much too much things, I'm a bit afraid of this...
A leak acceleration pump is a direct result of a flood overflow. You have to open and clean the carb, especially the float valve (very very carefully!). And you need a carb repair set for this, contains new gaskets and o-rings.
Here some pics of this (scroll down):
http://www.cardomain.com/ride/2174711
After this replace the fuel filter (near tank) and clean the fuel pipe with compressed air. If you do not, the carb got new dirt instantly.
Obviously you got no shop manual? You should have before start working!
I can send some scans, if you like.
Detlef

[tomatofiasco]

its an EL engine, non-cvcc, from an 81 accord. my hatch however is from 1977. the distributor and probably some of the vacuum lines [i know i know ] are hand-me-downs.

thanks for the link, your write-up is interesting, you got that carb spotless.. but then the dirt came back through the fuel line? damn, duly noted, i will get a new fuel filter too.

i have a spare carb of course, its main gasket it dead but the rest of it is ok i think. maybe i can do a switcheroo of that too just for diagnosis.

as for manual scans, i could use anything on carb rebuilding and adjusting, and a diagram of the older, pre-79 wiring if you have it. my silicone sealant wasnt specifically stated to be fuel-resistant, but the guys at the car shop thought it would be alright. maybe its got in the jets somehow.. either way it fixed the leaking problem i did look for stuff that was specifically for use in carbs or with fuel but in the whole huge rack there honestly wasnt any ><

anyway gotta go grab that distributor / carb / belt / pipes / doohickies and experiment

[Detlef]

i have another distributor. i took it off this engine when i swapped it for the original one, because the '77 wiring didnt have the little two-terminal clip for the side of the newer distributor.

So you fitted the (contact controlled) 1977 EG distributor to the 1981 EL engine? A rough mix, but not the cause for ideling problems!
With that distributor, you should adjust the timing like EG engine:
Dwell adj.:
52° +/- 3°
Idle speed:
Manual (neutral): 750rpm
Hondamatic (2 range /='star' mark): 680rpm (EL: 700)
Manual and Hondamatic general:
6° btdc (yellow mark on flywheel)
Australia, Canada, Sweden, Hondamatic only:
2° btdc (red mark)
But first, fix the carb. for exact ideling speed!
Btw:
The contact free electronic ignition of the EL needs not much additional wires, I think, i had changed to this, including the transistor unit.
PS:
got a wrong email address here, but now it's changed, so email me, if you need manual scans. But it's many stuff, around 300-600kB each page, hope you got high speed internet...
D.

[Ichiban]

I would confirm that the idle mixture solenoid on the side of the carburettor is receiving power and functioning properly. Use a test light to check for power with the ign ON, and then remove the solenoid (careful with the little o-ring) and supply 12v and ground the case, confirming the pintle moves at the end. This thing has been a common problem for me on all import carbs, for some reason.

It does sound like something is up with your timing though, could you be out a tooth on the distributer shaft/camshaft for some reason?

[Detlef]

... something is up with your timing though, could you be out a tooth on the distributer shaft/camshaft for some reason?

Timing is out of range, because of high idle speed. For adjusting, the engine should ideling at 700 / 750 rpm.

[Ichiban]

Many people will time engines at 3000+ RPM in order to get a more accurate timing at a range where the engine will actually be under load. The reasoning behind this is to max out the centrifugal advance and time above it's range, as varying spring conditions and such can cause inaccurate readings within it's range ie at idle.

Obviously the factory timing marks and procedures are not set up for timing in this manner, but with the advance curve tables it would not be hard to do. However, if functioning properly, the #1 cylinder ignition pulse should be enough to time the engine at idle, if it will in fact idle.

[tomatofiasco]

@ Detlef: yeah i was just happy to have it running so i left the distributor on there. i've never had a problem with it, its always been reliable and smooth.

i went and got my '81 distributor and '77 carburettor, i couldnt be bothered with the timing belt because the shed my engine is hiding in is full of spiders and the weather was foul. it only took one look at the '81 distributor to suggest it wasnt going to be any use. the shaft was rattling in the body and the internals were covered in filth and corrosion. however, it had my '77 distributor cap, which hasnt got any red dust on the inside of it and has heavier, blue ignition leads.

i think maybe the '77 distributor and cap are actually replacements. quite a few engine bolt-ons in my hatch had been replaced so this wouldn't be that surprising. the points dont look heavilly worn and the contacts arent heavilly pitted like you would expect for a 30 year old distributor.

so i think im actually better off with this mis-match
i gave the '81 distributor and run anyway, but it showed no signs of functioning. i didnt of course have the associated electronics box, because i didnt fancy unthreading the wiring for it from the loom in the freezing rain, especially after i saw the condition of the distributor it was going to be connected to.

so its out again and the original gangsta one is back in, but this time with its cleaner cap. performance is the same - missing like its going out of style and wont run below 1500.

but i think i should clarify: when you start the engine, it chugs and shudders and misses heavilly and sounds like its being smothered, and usually bogs and stalls when you try to rev it up the first time. once you manage to get it over 600 rpm or so though, it picks up. it runs crapilly but it does run. it will rev up past 3000 rpm with pretty much normal throttle input, its only when you lelt it slow down into the lower ranges that it get nasty.

i think whats happening is that it needs to develop more vacuum than is possible at idle rpm to draw enough fuel out of the jet to maintain that rpm. similarly it cant accelerate very well at all from idle rpm, and it needs almost half-throttle to run below 1500rpm, whereas it only needs a quarter or less to hold at 3000rpm.

i dont think theres a vacuum leak, but something like what detlef had - a partial blockage somewhere in the carb. i tried the timing light with the new cap and wires and i found the spark seemed pretty stable on all wires and couldnt really account for all the missing. the points probably need adjusting though.

@2ndGenGuy: yeah i checked that early on i was never sure quite how it worked but i figured it out once i removed it and watched it in action as i let it rev and then decelerate. it only cuts the fuel at above-idle rpms and when theres no throttle. i can hear it clicking when i connect and disconnect it, which means when i turn the ignition on its definitely activating and opening and not dead.

ANYWAY

so i took the carburettor out. i will look at detlefs pictures and see if i can find a blockage and also watch out for dodgey old seals. i managed to get the top off it without tearing the gasket, and i have my '77 carburettor for frankenstein-ing bits from if i need to. the float chamber is full but not over-full and the valve that the float works.. works. its not stiff or stuck, so i guess its working that far in. i cant see any filth lying in the bottom of the chamber either and the fuel is clean. those screws in the top are the jets right? am i alright to just take them carefully out? and whats the brassy thing in the bottom of the float chamber? anyone got a walkthrough for this?

[tomatofiasco]

[edit] i just realised this is in the general section though i meant to put it in the mechanical section ><

i took all the jets out and any air bleeds i could find, but i didnt find anything obvious. i made it all twinkle like jewels and put it back together, but back in the car its doing the same thing. i managed to get it to idle ok on choke and at almost normal [not super-advanced] timing, so i took it for a run. my driveway is downhill and then my street is uphill from there, and it wouldnt even climb out onto the road. it was fully warmed up and i tried allt he way up to 3000 rpm but it just bogged and died every time i tried. i couldnt reverse back up my driveway either so i did a many-point turn and brought it up forwards. it needed half throttle just to trundle up the driveway in first and just seemed to have a mind of its own. power was almost completely gone and the idle wanders all over the place, sometimes buzzing too fast and then dipping, and even stalling.

i parked it again and took off the oil filler cap, which greeted me with a seriously thick white coating that looked like whipped cream. the head gasket is blown isnt it?

[carotman]

Oh, if you have alot of "creamed" oil now in the valve cover/oil cap, it's not related to the cold weather but to the head gasket indeed

Does the car tend to overheat? When the car is cold, remove the radiator cap and start the engine, if you see bubbles comming out, that's a blown headgasket.

[tomatofiasco]

do you know what. i am going to go and do that as soon as i've finished this cup of tea. the whole area isnt full of foam or anything, but its really thick on the filler cap now and there is a trace on the dipstick. i's definitely got worse, even without the fact that what used to be a 3rd gear hill is now a first gear hill, and i stalling happens without fail every time i disengage the clutch.

i cant see any oil in the coolant though, but its a kind of muddy brown colour and i cant really remember it looking that rubbish before. and the oil isnt jet-black anymore, it looks a bit lighter.

and im just twisted and want to take the head off anyway i guess. i've taken everything else off, i'll have to start going to uni again soon! i can get a gasket hot off the truck at the local parts shop for AU$30, and manifold gaskets too just for fun. and i'll get a timing belt while im at it and make a real day of it

[tomatofiasco]

test results inconclusive, carotman ><

i couldnt get any bubbles to appear in the radiator just then. i wiped the oil cap clean and i got a bit of white residue re-applied, but not a coating. i took spark plug 1 out and it didnt have any white residue on it. it doesnt tend to overheat, though it heats up fast when its idling in the shed.

but its still running rubbish

is it normal for the engine to huff some vapor out of the carb when it stalls? it sounds like a steam engine

[2ndGenGuy]

I would definitely say blown head gasket. You may not necessarily have it blown bad enough to get exhaust in the coolant, but just a small coolant leak into the oil, where it heats up and vaporizes... It sounds like mostly your coolant is leaking into the cylinders though, and that would explain your lack of power... Are you getting any steam out the tailpipe?

[Detlef]

Hi
A blown head gasket can show different symptoms, but mostly you can feel, if one cylinder fails and the engine is running on 3 cylinders.

Do you already checked the coolant for CO gas? Workshops got a 'sniffer' for this, or you can try, if the (opened) radiator smells like exaust.

How look the spark plugs?
Remove all and check, how they look at the inside. Through the color of the ceramic isolation you can find out, which cylinder is not working ok.

Good luck!

[tomatofiasco]

hey detlef, i havent checked for CO or anything, but the coolant does smell a bit funny. though its hard to pin it down as the whole car smells a bit funny. the plugs did have white stuff on them which i understand to be a mark of moisture, but weren't hairy and carbon-fouled like a little while ago.

i definitely have steam. lots of steam. not great white clouds of it but it keeps coming out even when the car is warm or the air is already very humid. the coolant was also well down, almost to the radiator fins. when i checked under the exhaust pipe, there was a small pool of water. and the power loss is extreme. not like 3/4th full power, more like 1/4th. when i load it up it missfires at first then just smoothly bogs down. and the exhaust sounds weird though this is probably because the timing is so advanced. i totally dont want to run it anymore in case something decides to break

[Detlef]

... but the coolant does smell a bit funny. though its hard to pin it down as the whole car smells a bit funny...
...i definitely have steam. lots of steam...

What means funny?
Of course, the exaust can smell like coolant too.

...
...the plugs did have white stuff on them which i understand to be a mark of moisture, but weren't hairy and carbon-fouled like a little while ago...

What means 'white stuff'? Not the same as on the oil filler cap?

If the head gasket is blown, you can see normally very clear that the spark
plug of ONE cylinder looks different (black or wet). Is it so, or look all plug the same?

... the coolant was also well down, almost to the radiator fins...

How much coolant is lost?
Do you bled off the air, when you refilled water? (Bleed bolt is on top of the thermostat housing)
Is there air (...exaust) again in the radiator system, after running? (open bleed bolt for test)

... not like 3/4th full power, more like 1/4th...

The power itself is not exactly what i mean.
I mean, the engine is stumbling in a special way, if one cylinder is lost. Lean mixture feels different, rough of course, but more equal, steady.

Detlef

[tomatofiasco]

whoa, time for an update!

i got a head gasket, manifold gasket, timing belt and can of citrus flavoured carb cleaner from sparco. fruity!

then i got busy with uni and they sat on the bench for a bit, but now its the weekend and time to party hard! i mean, pull the head if i dont freeze solid first. im gonner leave the carb attached and just drain enough water to clear the head. i was advised to keep my head bolts for great justice so i will if they look ok.

i dunno if this will fix the problem or just create more, of course. im at the stage where it could still be some hidden passage blocked in the carb, or it could still be some feindish ignition irregularity, or it could be caterpillars in the crank case. but curiosity has taken over and at least when i've put a new gasket on, inspected the typical suspects and then done it all up again, i can cross that off my list.

i didnt know about the air bleed on the thermo housing though it seems obvious now you mention it. i didnt observe any bubbles getting into the radiator is what i meant. in fact i didnt observe anything but nice green coolant getting in there. but its all very suspicious, right?

the exact nature of the power loss is hard to explain. but it reminds me forcefully of the methanol-powered R/C stadium truck i had [HPI Nitro Rush]
which was horribly hard to start and would bog and stall and high rpm's. it was incredibly frustrating and after overhauling it i just bought a OS CVR-X Max motor for it. which worked pretty awesome for a while, and then had the same damn trouble. i had the opportunity to put the motor in another model and it worked faultlessly without any adjustement, so i think it was a fuel problem.

the 1602 engine is rather larger, but behaves similarly. well no, its not nearly as bad, but it simply feels as if theres a power theshold, and once you reach that, it just DIES. it revs fine in the shed and going downhill. but if you flaw it, theres just no pull. it feels like the engine is made from warm play-doh

[carotman]

I'm sure that the gasket is the problem. Replace it and I'm sure the car will run like a champ.

[tomatofiasco]

thanks man, i hope so :O



im an art student, and this is my masterpiece!


i pulled the head today. lots of tedious cleaning to do. i got lots of coolant in all the bores but i mopped it up promptly and spun the pistons, so it wont hurt will it?

as we say in australia: whaddya reckon, mate?