So I still haven't rented the leakdown test, but I have come to grips that I am probably going to have to rebuild the engine. I have also come to grips that the mileage of my vehicle isn't to blame, it's the fact that it has had a misfire for so long that it damaged the internals of the engine! So I'm back to the question of what is causing the misfire? The misfire is apparent at idle....The lights dim, car/steering wheel shakes, heater blows less, etc.
The plugs look ok (some white on the electrodes, no oil or gas). But I noticed that after replacing the valve cover gasket, tube seals, and grommets, there is a very small amount of oil around the base of the plugs above the threads in the bottom of the tubes. This is probably coming from the tube seals but I need to check again to see if it is collecting.
Will the leakdown test lead me to the reason for the misfire or only tell me the condition of the engine components? Should I test spark with an in-line or HEI tester? Have the injectors tested? Possibly test fuel pressure?
If I do end up needing to get the engine rebuilt, I will probably rebuild it for performance and look to add some boost later but that is a completely different thread.

 

what is the idle speed currently set at?

 

I don't really know. For the emissions test the idle has been between 850 and 750, which is on the high side right? It seems to me that the ecu is adjusting the idle based on a low A/F ratio. I will try disconnecting the IAC while running to see if the idle changes.

 

i'm just worried that you're confusing misfiring with a low idle speed or rough idle. a random misfire will be like a sudden pulse. a dead misfire will be a pulse which occurs through 25% of the combustion cycles. low idle speed would cause dim lights and slower fan speed. a bad ground would as well. a bad ground could easily cause rough running/idle as well. check/clean all your major grounds-transmission to chassis ground, chassis to battery ground, and both battery terminals. also, your thermostat housing ground while you're at it.

try that first. if that doesn't help with your rough idle, check/adjust the idle speed. follow the procedure exactly as specified. vehicle at operating temp, disconnect iacv. adjust idle screw until idle reaches 500rpm. reconnect iacv. idle should sit at roughly 750rpm. if so, clear iacv code and allow idle relearn. that is, idle for 10 minutes completely undisturbed.
since you say you're already at 750, it may not be the issue. but check anyways. base idle is what you really want to see. base idle is what you have with the iacv disconnected. no iac interference.

you mainly want to try the cheap possibilities first. however, i am a huge fan of the HEI tester. so if both of those don't help, pick one up and test the ignition system. you really should have anyways. especially with how prone honda ignition systems are to failure

 

Worn valve springs or Burt valves is worse case scenario. Will know after leak down test.
One thing people over look is ignition wires not full pushed all the way in and if its pinch or has a super little crack u prob won't even noticed.

Do a cylinder kill/balance test by pulling spark boot barley above spark plug and noticed how engine reacts.
Best bet is pull all plugs out and if one looks diff than others u should start with that cylinder.

 

I took a look at your readings again and looks like u prob have a vacuum leak. Could be a small one.
Hook up vacuum gauge and check vacuum Hg at idle. It's prob lower than usual.
A vacuum leak can cause wired idle and fool the o2sensor to add more fuel and cause high hc. I would check this first.

 

excellent point. however, the iacv will usually be commanded closed to offset the vacuum leak, since the iacv's job is to maintain steady idle at the desired speed. how it works is a vacuum leak will raise idle speed. the ecm sees that raise in idle speed and closes the iacv to bring idle speed back down to its desired speed. you can actually go outside to your car, run it, and pull any vacuum line off. idle speed will raise very briefly, then drop right back down to 750 or 800. that's the ecm controlling speed through the iacv. the iacv is just a controlled vacuum leak. this is why even an engine that produces lower than normal vacuum, through let's say worn piston rings, will still maintain it's desired idle.
furthermore, again, he is not running rich. he's just not burning the fuel delivered adequately. to be running rich, the CO numbers would be high. considering the fact that his cat is toast, those CO numbers are actually reasonable.

a vacuum leak can, however, can cause a loping idle. as it will confuse the ecm and the iacv will be commanded open and then closed.

 

So I came across a few things today. I checked the transmission ground, it's secure but has some very light corrosion on the cable which I don't think is a big deal. I also checked the front engine ground, and I believe there was a problem there. I took my dremel and ground off some of the paint where the ground points were so there was bare metal.



After grinding away the paint the idle feels much more smooth, but it still drops temporarily when I press the brake or turn on the headlights. I also realized that my car is not actually completely stock. As you can see in this picture it's got a greddy 4-2-1 exhaust manifold, maybe that is helping to cause this issue as well but I know it has passed fine after it was installed.

I was also looking at the fuel filter on the firewall and I believe there may be a vacuum leak. Notice that there is no hose clamp and the hose is somewhat loose.

 

how was the chassis to battery ground?
that's the fuel supply line to the rail. it should just be a crimped coupler. no vacuum there. just pressure.
how much does the idle drop when you turn on the headlights? and for how long? same question for the brakes.
although, you're idle should drop slightly with the brakes depressed, as your booster draws engine vacuum when the pedal is depressed. that's normal.
the iacv is what controls idle, on command by the ecm. when you depress the brakes, the bulbs draw more current from the alternator. when more current is drawn, the engine works harder, since the alternators mechanical resistance will be greater. this would normally drop the idle. that's where the iacv comes into play. the ecm sees signal from the brake switch and commands the iacv open a number of "counts" (counts are what iacv movement is measured in). by opening the iacv, it's allowing more air, through it's passage, past the throttle plate. this in turn increases idle speed and voila, stable idle. works exactly the same with your AC or any other loads put on the vehicle.

basically what i'm saying here is the iacv is pivotal to idle control. service it.
to do this, remove te intake boot. there will be 2 passages inside the throttle body, in front of the throttle plate. if you only have one passage, then your vehicle doesn't use a fitv. if there are 2, the iacv will be the top one. if one, then, that's the one. start te vehicle. with a can of intake cleaner and the nozzle straw attached, spray directly into the port. the engine will want to stall, so you need to work the throttle with your other hand. spray liberally and snap the throttle a few times. this exercises the valve and really works the cleaner in. this technique also cleans the passage as well. which can become clogged with carbon. try that out and see how she fairs

 

also, one way to confirm whether or not you have a vacuum leak is to remove the air cleaner boot. with the vehicle running, cover the throttle body bore completely with your hand. if the engine does not stall immediately, there is a leak somewhere

 

Ok I will do all that stuff soon. The chassis to battery ground looked fine but next time I work on my car I will remove and clean it up. I removed the map and iacv, then cleaned them both, the iacv was very dirty with brown goop all over it. After cleaning them the idle is way worse now dropping several hundred rpms instead of around 100 before the cleaning. The idle really is my secondary concern though, I suspect it is because the alternator cannot keep up with all my electronics. I've got two amps drawing around 900 watts, so I probably just need a higher amp alternator.

What I really need to figure out is the HC level. No pass emissions, no register vehicle. Once that ignition tester arrives I will be able to check the ignition more thoroughly but the tester will only tell me if that cylinder is firing correct? Which I am sure they all are. I put in new OE plug wires yesterday as well. Thanks for the vacuum leak trick and also for your input hondaguy. You guys have provided me with a lot of stuff to try and it will take me quite a while to get to all of it.

 

I would say still say vacuum leak or compression fault. Not major vacuum leak but small one.

 

the ignition tester puts a load on the system comparable to the load placed on it in the cylinders, while driving. reason i'm interested in clearing up the idle is because it's possible the 2 problems are related.
try running the vehicle with the amps disconnected. see if idle clears up any. if the problem got worse after cleaning, you may have damaged teh map sensor. if you have a multimeter, i can give you a test procedure for it. also, if you clean the iacv using the method i'd mentioned, without removing it, you would be cleaning the passage as well. which is prone to carbon build up

 

Well I am very happy to report that it appears the idle issue has been solved! Last night I drove with my stereo system on, headlights, and heater. The idle did not dip and held steady. There must have been some excess throttle body cleaner which needed time to evaporate after doing the cleaning.

 

agreed

 

 

Well crapi I did the throttle body test that you suggested and the engine immediately stalled, looks like I am ready for another emissions test. If it fails guess I may be in for some more costly maintenance. Thanks again for all your help hondaguy and crapi, I will let ya know the outcome.

 

alright, cool. i am doubtful that it will pass though. as the iacv really shouldn't effect hc readings. not much anyways. but give it a shot i suppose.personally, i think those rings are what's causing the high reading though. keep us posted. thanks

 

Yeah I was doubtful too crapi, and it didn't. But I took it to a new shop this time, and they told me the same thing the other two shops did, the cat isn't heating up enough to do it's job. They also told me the ignition timing was slightly advanced, so I guess my light is bunk.

They also told me that the greddy exhaust manifold is probably contributing to the problem, along with the cat being installed further back. They have been putting on a universal (more than likely cheap) cat and welding it on well after the A-pipe/o2 sensor. They recommending putting a stock header back on and a better quality cat, so if I go that route I demanded a direct fit that will bold right up to the A-pipe.

Aftermarket parts have not been good to me with this vehicle. I do also agree that the rings are probably causing a higher number but I am under the gun on this so if I can get a quicker fix I'm all for it. With this scenario, I buy the OE exhaust manifold/cat and hopefully pass, then get the internals fixed afterward and I can sell one of the headers.

This shop also rebuilds engines and has a machine shop, so I can get all that done there.

 

Well ****. Honda is going to rape me in order to get this back to stock. The greddy header is all one piece but the OE is 2 pieces, the EM and A-pipe. The dealer wants ~$1000 for both and I don't have time to look for used parts. So pissed.

I'm also going to run into trouble with the cat because the OE cat has the o2 sensor built into it and right now there is an exhaust pipe with the sensor on it and it's hard to find one for my year that has a place for the sensor. Ugh.

 

aw man those stock manifolds have got to be a dime a dozen, I would think.

 

Almost, a bare intake manifold at a PicknPull is $19.99 the exhaust manifold is $25.99 and under $50 for a complete exhaust, that's not even $100, for the $900 differance, I would make the time. 94

 

i'm afraid they are not understanding emissions. this is a misdiagnosis. or they have no care in actually fixing the problem. i have no doubt it will pass the vehicle (which is really all they probably care about), but those "repairs" aren't solving anything.
a bad catalytic convertor does not increase HC emissions directly from the engine. it only ceases to reduce them. your HC numbers are high even for pre-cat readings. this alone tells us the problem is not the cat. or i should say, not the only problem. same thing with the manifold. it will not increase HC. it's simple. HC is raw fuel. it hasn't been burned. that's it. that's all. fuel is not burned in the manifold or the cat.
it helps if you know what acceptable pre-cat readings are. an acceptable pre-cat reading for HC would be 300ppm. and that's being generous. this tells us that your engine, not emissions system, is creating/allowing too much HC.
i also don't believe that your timing is advanced. i think they know that retarding the timing will decrease your HC readings (because it will), and they're trying to cover their ***. fact is you shouldn't have to retard it beyond 16*btdc if the engine is operating correctly.personally, i think your rings/compression are the root problem. bad rings burn oil. and oil becomes diluted with raw fuel. they also lower compression. and compression is necessary to burn fuel adequately. your cats are burning out for a reason. which is what high HC does.
you can replace the cat and manifold and retard the timing, but you'll be back in the same boat in a year or so. or whenever it become necessary to smog it again

 

I do agree with you, but the major issue for me is that I only have 3 days left to pass emissions. It sucks. On one side I have the county (the rock) and on the other side I have Honda and the repair shops (the hard place). The county has not given me near enough time to deal with this situation.

I do believe this shop understands the situation and they see my position but are trying to start with the less extreme measures first. They rebuild engines there and I am sure they are not dummies.

I was contemplating this yesterday, trying to decide if I want to keep dealing with this **** or just sell the car. I'm just exhausted. I decided that I am going to get a waiver through the county, it buys me time but is also my get out of jail free card. They will only let me do it once in the lifetime of the vehicle. Shitty situation.

 

i apologize. i'm sure the shop is a refutable one. it's just you see it so often; replace cat and o2 sensors. get the pass. job well done. if the shop is being honest with you and you both have an understanding of the situation, then i retract my previous statement.
i understand your position here. it's tough. spend money and get the pass, or use your one get out of jail free card. i'd use the card for sure. no use spending money when it isn't going to net you a permanent solution