Another car problem question - 87 accord ($5 paypal for correction solution)

[blahblah99]

Here's the problem with this little booger - The car idles at at VERY high 2000-3000 when it starting up from cold. After about 2 minutes at that rpm, if I step on the gas it would drop down to about 1500. If it drops to around 1000 rpm, the engine would bob up and down between 1000-2000 until I feed the gas a little.

After it warms up to normal driving temperature, the engine idles at about 1300RPM and the pulsating between 1000-2000 stops.

Steps I have done in trying to resolve this problem (and normal maintanance):

1. Changed timing belt, water pump, oil pump, tensioner.
2. Changed spark plugs and spark plug wires.
3. Changed air filter.
4. Adjusted the idle speed screw.
5. Changed radiator and hoses.
6. Adjusted distributor.
7. Changed power steering belt, A/C belt, and alternator belt.
8. Changed oil pan gasket/oil/oil filter.
9. Changed transmission fluid.

Item #4 doesn't seem to do anything to the idle speed (or maybe I am not turning it enough even though I turned it one full rotation).
Adjusting item #6 has a drastic impact on whether the engine bobs up and down between rpms. Advancing the timing via the distributor fully clockwise causes the engine to slowly idle down to about 1300. Changing the timing the other way (counterclockwise) causes the engine to run very roughly (causes it to bounce between those two rpms).

I have also checked the carburator (sp?) and the throttle plate is FULLY wide open with no foot on the pedal and this seems a bit odd to me. Also, one of the vacuum hoses has been cut off and has a screw in place of it. My dad says the mechanic did that in order to pass a smog check?

Now, my question is how do I get the idle speed down to about 850-950rpm while in DRIVE? Also, why does my engine idle at a whopping 3000rpm with a cold start?

I will paypal $5 to the person(s) who suggests a working solution to each question!

 

[morkinva]

if you pull the throttle manually (the thing the idle screw is attached to), what happens to the throttle plate and the rpm's? It seems strange that it is fully open, which would be like WOT.

 

[Thegonagle]

I'm sure he's confusing the throttle with the choke.

And a "mechanic" put a screw in a vacuum hose? What a dumbass, horsesh!t mechanic. Seeing crap like that pisses me off.

Anyway, your carb probably needs work, and all vacuum hoses need to be hooked up properly, with no screws in them.

EDIT: Just more to add.

It idles high after a cold start because it's supposed to, but it's not supposed to be quite that high. In my experience with this model, 2000-2500 is probably more normal. Thankfully, I never had any trouble with the carb. I hate carburetors, especially if they have trouble. The old timers can keep their carbs, but I'll take fuel injection any day, thank you.

I'd try to give more advice, but I'm being selfish, as I need to go to sleep. Sorry. Carbs suck donkeys anyway. I can't believe Honda used them through 91 (on the Prelude S). Even GM had the right idea back in the early eighties to start moving everything to electronic fuel injection.

 

[blahblah99]

I'll check the car out this weekend since I go to school in LA and my parent's car is in orange county.

Some more clues:

1. If I manually close that choke plate (sorry, i confused it with the throttle) using my finger, the rpm would skyrocket to 3000-3500.
2. In the black box at top left of car (looking at engine from front) where all the vacuum hose goes through, there is a clicking noise coming from it. Is this normal?
3. Another thing that bothered me was that a home mechanic (one of those guys who fixes cars in his home garages) did the timing belt and misaligned the timing mark and seemed like he turned up the idle speed a little to compensate for the roughness in the engine. When I took the belt out, I had to turn the crankshaft by about 20! degrees to to line up the mark with the pointer and the cams. After re-doing the timing belt, the engine runs much smoother, but the idle is still high.

Please fire up an tips/suggestions! I will mess around with the car again this weekend and post up $5 (maybe $10, or $15 if I'm in a good mood) via paypal.

 

[Thegonagle]

#1 - I don't know what to say. I'm man enough to admit, I fear carburetors, so I don't touch them, except to spray a little cleaner in them from time to time. I can only guess that when you close the choke by hand, you're also tripping the high idle mechanism, both of which are supposed to work together to get the car started when the engine is cold. The choke enriches the fuel mixture by cutting off some of the air. It's supposed to be fully open as soon as the car warms up a bit.

#2 - No, that may be related to the freaking screw in the vacuum line, or it may be your problem.

#3 - What can I say? Keep your car away from hacks with a low IQ, who don't take care or pride in their work.

 

[morkinva]

Maybe you could find out something by looking at the trouble codes

Anyhow, my guess is it's vacuum related; like the vacuum activated choke pulloff which may be what that mystery hose goes to.

edit>> I am not a mechanic, nor do I know anything about Honda's; I'm just tryin for the $

 

[LAUST]

Don't know too much bout the 87 Accords but did you replace the TPS if it has one on that year? (Throttle Position Sensor) I know the GM trucks just put them on in 88, not sure where Honda was then.

 

[Angrymarshmello]

That's pretty much normal iirc - think it mentions that in my dad's 88 LX manual somewhere. It does that on his too - we replaced some valve (PC or PG something) and it cut down on what you're describing above. (But did not totally solve it)

 

[LAUST]

Originally posted by: RagingBITCH
That's pretty much normal iirc - think it mentions that in my dad's 88 LX manual somewhere. It does that on his too - we replaced some valve (PC or PG something) and it cut down on what you're describing above. (But did not totally solve it)

Yeah, PCV Positive Crankcase Ventilation Valve

 

[Angrymarshmello]

Yea PCV valve, thanks LAUST

 

[Angrymarshmello]

Alright - just busted out the old repair manual, it says:

When the engine starts, the choke plate on the carburetor will open slightly. As the engine warms to operating temperature, the plate will slowly move open allowing more air to enter the top of the carb. After a few minutes, the choke plate should be fully open. Tapping the accelerator will disengage the fast idle cam. Engine speed corresponds to the plate opening. WIth the plate fully closed, the engine should run at a fast idle speed. As the plate opens and the throttle is moved to disengage the fast idle cam, the engine speed will decrease.

 

[bcterps]

Sounds similar to a problem I had with my 1990 Accord (manual transmission). When I my engine was cold, the engine would constantly rev by itself, from 0 to 2500 rpms. Once it warmed up it was ok. I took it in to the dealer to have some other work done on it and they say that my "fast idle valve" was dirty. They cleaned it and the problem went away. They said however that it might need to be replaced in the future. Does that help at all?

--Ben

 

[Thegonagle]

Originally posted by: benchiu
Sounds similar to a problem I had with my 1990 Accord (manual transmission). When I my engine was cold, the engine would constantly rev by itself, from 0 to 2500 rpms. Once it warmed up it was ok. I took it in to the dealer to have some other work done on it and they say that my "fast idle valve" was dirty. They cleaned it and the problem went away. They said however that it might need to be replaced in the future. Does that help at all?

--Ben

Sorry, that car has fuel injection, a completely different system with nothing in common, neither conceptually nor physically. The Accord DX and LX were carbureted through 89.

 

[blahblah99]

Ok.. I'll take a look at both the PCV valve and figure out where that vacuum line with the screw in it gets connected to this weekend and will post up some paypal for your guys time and effort... Man I hate carburated engines. Too many vacuum lines and adjusting screws and the Chilton repair manual only provides chicken scratches for diagrams and doesn't give enough details.

 

[Thegonagle]

PM me and I will give you my paypal email address (if I win anything)

 

[Pepsi90919]

i wouldn't even begin to diagnose it without fixing that vacuum hose, and getting the idle screw set back to factory spec, and getting a new cap and rotor.

 

[NutBucket]

Originally posted by: blahblah99
Ok.. I'll take a look at both the PCV valve and figure out where that vacuum line with the screw in it gets connected to this weekend and will post up some paypal for your guys time and effort... Man I hate carburated engines. Too many vacuum lines and adjusting screws and the Chilton repair manual only provides chicken scratches for diagrams and doesn't give enough details.

A good reason why I never recommend carb'd Honda engines. Big PITA b/c off those 20 gazillion vacuum lines.

 

[Brutuskend]

On the side of the Carb. there is a stepped plate that a adjustment screw rests against, this affects the idle speed when the choke is operating. Basicly it meters how far open the choke butterfly is during the warm up period. If you want the idle slower you need to back off this screw.

Now for why it it may be pulsating until the engine warms up.
My guess is that you have a vaccum leak. More air is being drawn in until the engine reachs operating temp. What happend is, when the engine get warm, things expand and the leak goes away.

The best way to check for vaccum leaks is.

Get a can of starting fluid or carb. cleaner and spray it around the base of the carb (A prime place for leaks to happen) and around the carb area in general. (While the engine is running but hasn't reached operating temp yet)

If the engine speeds up while your doing this, the starting fluid is being drawn into the engine. By watching where you are spraying when the engine speeds up, you should be able to narrow down the area where the leak is pretty closely. Spray around the hoses as well. (DON'T spray into the mouth of the carb. Air and fuel are SUPPOST to be going in there, so it will DEF. speed up the engine!!)

BTW: All the symptoms you have can be caused by a vaccum leak!!

 

[Ns1]

well try this

exact same thing happened to my friend's prelude

got the fast idle something-or-other part replaced, works fine now

check your helms manual (i assume you have one, right?) for the correct name of the part, if you pm me (which your pm's are off) i could get the correct name of the item for you

 

[blahblah99]

bump for some more help/suggestions.

the car is an 87 Honda Accord LX Carburated engine, not fuel injected.