Idle/Throttle Problem

[SavageG]

Okay... About a week ago (300mi) My car started making a Tap-Tap sound and over the next couple of days my idle climbed from 900 to 1150-1300. The tap tap sounds kinda like a rod bearing and I can't see how the idle would be related.
Today I adjusted the valves and did the timing. After I was done I took it out for a run, at about 4800rpm there was a single "bang" sound from somewhere in the engine compartment. Now I am having trouble with both the cold idle and the throtle while driving. For the first 1-2 minutes after starting the rpms go to 2000 rpm than drop very sharply to 1500 in about a 6 second cycle. If you are driving at 2800rpm and let off the gas it will sharply jump to 3000 then drop to an unusualy high 1200rpm idle.
My car has 243,000mi right now with almost everything stock. :thumbup:

[Immeraufdemhund]

sounds like something gave out on you. When I heard a large bang one of my hoses broke.



For the first 1-2 minutes after starting the rpms go to 2000 rpm than drop very sharply to 1500 in about a 6 second cycle.

that sounds like a really slow surging. Not too sure though what it could be. Get a can of carb cleaner and spray all your vacuum hoses. If your idle rises, either change or fix that hose. Also Right next to your wiper blade motor is an electronic valve thingy for your idle. Disconnect that and see if anything changes.

[A20A1]

Sounds like some kind of vacuum jump maybe adding pull to thew vacuum advance and rasing the idle... depends how fast you let off the gas. Sudden drops in rpms could be a vacuum leak or a plug missfire... have you checked your plugs? you may want to make sure your PCV valve is still good too.

No more Bangs from the motor?

My car ran for a while with 3 pistons and the 4th one loose on the crank. I don't remember it ever raising the idle though, but I'm carbed not EFI.

[SavageG]

I messed around with the idle controller for a couple minutes and it's not surging now. I don't know if this was it, but I had been messing around in the area when I put in my prelude arms. If I disconnect the top vacuum hose that goes to the PGM-Fi box it surges exactly like before.
I'm going to put in a new PCV valve, temperature sensor, coil and rotor tomorrow.
I'm still puzzled by the rpm surge when driving, it will only do it after being under load for over 30sec or so.

[SavageG]

I got the PCV valve, Thermostat, distributor cap and rotor in. None of these have cahnged the symtoms. 2100rpm for 5 sec at startup 15-20 sec at 1400 then a 1100 idle. It will also hold speed, or even slightly accelerate @ around 3000rpm in 3rd. It has good vacuum and I couldn't find and leaks in the vacuum system. Could the ignition system (Distributor, coil, ecu...) be to blame for this?

[A20A1]

So the idle jumps while in 3rd gear to 3,000 rpm with your foot off the thorttle...

Maybe you just need to lower your idle or your cable or linkage is getting stuck...
It could be that valve on the intake manifold with the coolant lines running to it is broken... but then I guess it sounds like your cold idle works casue you said the idle drops.

You have 2 vacuum ports on the vacuum advance... I'm guessing but on carb #25 is only for cold advance and is disabled once the car is warmed up... maybe the #25 on your EFI distributor is getting vacuum when it shouldn't.
Though if the problem happens while under load and the thorttle OPEN then there shouldn't be vacuum to any of the advance ports so that would rule out that. However on the carb car once vacuum drops the thorttle / idle controller tries to raise the idle... usually it wont affect anything cause the thorttle is already open. If you have the thorttle closed and there isn't enough vacuum or vacuum is bled to the thorttle contrller then the throttle controler raises the idle. Does your EFI idle controler work in a simmilar fasion?

Is the Idle solenoid a vacuum vavle that bleeds vacuum so that a spring loaded diaphragm can move or is it a vacuum valve that applies vacuum to move a spring loaded valve when open? I don't have an efi setup in front of me so I'm asking all these questions. Is the idle controller a part of the manifold / TB or is it a diaphragm near the thorttle linkage with an rod that pushes open the thorttle?

Still no idea what the bang was?

[SavageG]

HONDAS DEAD Well... On the way home from work today it died. I was going down the interstate @65 and all the sudden no power. It felt kind of like when you run out of gas power, no power, power then dead.
It now seems like there is no spark, if I hook up a timing light while cranking it wont flash.
I tested the ignition coin yesterday and (I think) it tested bad.
Coil to terminal A 11.51 k-ohms Spec 9-13.6
Terminal A To D 0.02 ohms Spec 1.2-1.5
Terminal B to D 2.22 ohms Spec 2.2
Could this be a coil failure? I didn't replace it ASAP since it was still running OK at the time.

[Mac]

It looks like only A to D is out of spec. When you touch the 2 leads of the meter together does the meter read 0.02 ohms? If so, then your primary winding is shorted. Another check you can do is A to C. It should be a short. If it is open, the coil is bad.

[SavageG]

I replaced the coil this morning before work. It started and idled VERY rough for about 20 seconds before it died again. I suspect it is the distributor, it is the original and shows signs of failure (red dust). The cheapest I could find one is $223. Ouch!! I think I will try the Pick & Pull for $20 first. Does anyone know if the distributor off of a A20 lude would work?

P.S
I don't think that it's the ignition control module, you can hear it cycle as when the pgm-fi light goes out.

[A20A1]

you migh just check this one out... though I'd replace the distributor anyways.
http://www.3geez.com/showthread.php?t=22648

I had my distributor explode on me and the gap was way off... it never gave high idle problems.. just bad start and bad idle and intermitent stalling. I fixed the gap and the problms seemed to go away... but if it was the bearings that caused the reluctor to slam into the stator then I'd get the same problem again after driving for a while...

which it did happen again... I never saw much dust but I usually clean out parts... so I might have just wiped what was there and didn't take much nottice... anyways this time the reluctor grinded chunks out of the stator plates... I opened up the gap a little on both sided to help save what was left.

[shepherd79]

get compression tool and test the compression in the cylinders. make sure they are all even. when i busted my headgasket between cylinder 4-3 my car was idling on 2 cylinders. if there is not compression, you won't ignite anything and it will idle ruff. plus this test will tell you if you have leaky valves or rings.

second, distributor. go to the yard and get a few of them. i had a few problems with mine and usually it is the ignitor. the distributor is good but the ignitor is bad or not making connections or something like that.

[SavageG]

I pulled out the distributor and dissected it. Fried! The bearings are so gone that you can move the shaft 1/8" side to side, the seal is leaking oil and the insulator on the ECM is cracked between terminals. I won't know if this is really the problem until next week when I can get a new one in.
I will check compression just as a precaution, but right now I'm getting no spark at all.
By the way, If anyone is shopping for a new distributor here are prices at local auto places.

Car Quest $398 :rocket:
Radke $300 :mad:
Auto Zone $258 :thumbdn:
Baxter $223 :rolleyes:

[SavageG]

Got the new (Really new!!) distributor in. Started right up, no problem with lining it up or anything. Timed, adjusted all the idles and it's doing better than it was before, 800 and dead steady. :cool:
I think that the "bang" that I heard was a loose or broken (rear?) engine mount, still have to make sure.