ezone

P0420 is never defined as a clog.

That doesn't mean it isn't clogged though. Serious lack of power might be a good indicator of that. Should be easy enough for a pro to check backpressure or vacuum drops to find out. Or just drop the pipe off of the manifold and give it a drive.

If the cat element (substrate) broke apart, it could have sent pieces downstream into the rest of the exhaust....That could cause clogging, and may be random as chunks move around. Banging on the pipes and listening for rattles would be a good thing to check.



Check your regulations about what is acceptable when replacing a cat. Again, California has its own rules.

rekomstop209

I do sense a lack of power in general, or atleast until I hit 3000 RPM and my RAM air gives me a boost. My last honda was a 2000 LX and this one is a 99 EX and I feel like the LX had more power.

Also, with my recent ignition troubles and misfiring, I could have done damage to the cat.

Also I smell exhaust fumes in the cabin sometimes. I inspected the exhaust system and visually I could not find any leaks.

Hey ezone, do you think its at all possible that my cat has been slightly clogged for awhile now and that is what caused my head gasket to leak?

Oh also I wanted to know if when I replace the cat, do you think I should replace the O2 sensors as well? Even though the computer threw no codes for them.

ezone

HAHA...oh....

If it pulls STRONG all the way up to redline, I'd assume the exhaust isn't clogged (much?).


Absolutely. It can happen in a matter of minutes.

Whole bunch of "depends" for that one.

No.
But liquid coolant can poison O2 sensors and cats if the head gasket was catastrophically bad.

I wouldn't unless there is a good reason.

rekomstop209

If I floor it, the car gets up with only a very slight hesitation at first, but if I just drive it like normal, it seems bogged down a bit and I can feel a slight hp boost around 2800-3000 RPM.

There doesnt seem to be any top end loss of power, which is strange.


The hg never blew bad enough for fluid transfer, BUT the cat that is on there now is definitely aftermarket, and the mechanic who did the hg job said the engine had been worked on before, so it is possible that someone blew the hg badly before and never replaced the cat, so it may have already been damaged, and my recent problems have damged it enough to throw the CEL.

Tomorrow, I'm gonna use an IR gun to check both sides of the cat and see the temp variance. I'll also bang around on the resonator and muffler to check for loose particles.

And I do need to pull the valve cover and reset the gasket tomorrow as well so I may just take off that lower pipe like you said and drive it.

And in CA we use TWC converters that MUST have a CARB stamp. And I need OBDII so its twice the price of OBDI...around $275 for a cheapo, but I did find a muffler guy who said hed weld anyone I bought for $50.

ezone

I bet you are not gonna gain anything by pulling the pipes off of the manifold then. Try it anyway?



You should see a little higher temp on the outlet side while the cat is lit and operating, but it is not a reliable test.
Far too many variables.
If the cat (the guts of it) is missing completely, your exhaust should stink like exhaust.

2 things come to mind:
Ignition parts-- plugs, wires, cap and rotor.....NGK plugs? Proper gap?
and
Disconnect the EGR valve and drive it. See if that makes a big difference.

And basics like compression and valve adjustment....

I'm kinda lost on this right now. Maybe if I could actually drive it I'd have something else to go on.

rekomstop209

Distributor is brand new, Richporter. Plug wires are like 5000 miles old. I have not changed the plugs, but did a compression test about a month ago, all cylinders passed and the plug gaps looked good. I'll look into getting some NGK plugs tho, couldnt hurt.

I know I wish you could drive it too. The lack of power is really hard to describe, but its something I can feel in the accelerator pedal. I don't even think a video would really help.

rekomstop209

I have an A/T D16Y8...no EGR valve on it. Maybe pcv passages are clogged?

rekomstop209

I have an A/T D16Y8...no EGR valve on it. Maybe pcv passages/actual valve are clogged?

ezone

No EGR huh? Ok.... A PCV valve is easy to check if you can reach it but I don't think it would cause a noticeable effect at average driving RPMs.

Fuel pressure correct?

Will it act noticeably bad if you just rev it up sitting still, or do you have to actually drive it to feel it?

rekomstop209

Tried to pull the PCV but there are 2 hoses attached to it, one runs from the back of the engine, the other runs to my air intake. I pulled the clamps and tried to pull the hoses off to take the PCV valve but the hoses are so stuck on there I couldn't get them off and I'm afraid to rip them.

At any rate I have a new problem...was changing the valve cover gasket and when I was tightening the bolts, one snapped. Total BS because I had the torque wrench set to 86 lbs ft just like the service manual says and it just snapped. Honda doesnt have them in stock. So its off to pik and pull but first to extract the broken piece out of the head. FML.

It revs fine, its only when I drive it that it feels underpowered.

ezone

I bet the manual says INCH pounds, not foot pounds.

Common sense should have been screaming at you that 86 lbs ft wasn't right for tiny little thin bolts.

Left-hand drill bits are darn handy.....

I have had to install heli-coils in many many VC bolt holes. We had a kid that loved to use an impact gun on them. If they didn't break off, they stripped the holes out.

rekomstop209

Lol I totally 86 inch lbs.

ezone

Don't be chiefin til after work, man.
LOL

rekomstop209

I swear ive been sober all day (maybe thats the problem).

The extracting is not going well...may have to drill a larger hole and use a 12 mm for that one bolt

rekomstop209

Alright, drilled a 1/4inch hole, tapped it, inserted helicoil, valve cover is back on, gonna let the silicone dry all day before I fire her up. Thank god this is over with. I think we spent like a total of 4 hours drilling out that bolt tip, went through 4 bits.

ezone

Slowpoke.

We usually bill at .5 labor per, plus parts, and I can usually beat that easily.

rekomstop209

Well I didn't use a drill press and at first we were trying to be careful not to dmg the threading, hoping we could drill a divet and use extractor, but the exractor just wouldn't bite enough. And plus, I have school and work, and am using a buddies car at certain times of the day, so I've really only had like 2 hours a day to work. Also, had to careful not to get any shavings in the engine. I wasn't working slow, I was working smart! :P

ezone

Drill press? I do it all by hand. Sometimes half blind.

Tip-Trick: Shop vac while drilling takes care of the majority of shavings. Creative nozzle adapting may be needed though.
Parts department always gets all pissy when I get OIL in their shop vac, the hoses drip oil forever when I'm done. LOL

Tip-Trick: When drilling steel, place magnets near the drill site. A donut shaped speaker magnet is great for this. Cover the magnet in paper/plastic/cloth/something to make shavings just peel right off.



Someone posted this link in another forum, check it out: http://metalshapers.org/101/index.shtml


HTH

rekomstop209

wow that is a really great link, I'll check it out in greater detail after work, and after the 49er game lol.

We did use a magnet the whole time, had a wand right by the drill bit. Also used some 3 in 1 oil when drilling. The speaker magnet with plastic wrap around it, AWESOME IDEA! Wish i'd thought of it. Instead we just covered the cam with thick plastic wrap and duct taped it to the head to prevent any alluminum shavings from getting in.

I'll change the oil filter in a day or two just in case any shavings did make it in, hopefully the screen will catch them, but I'm pretty confident no shavings made there way down inside the engine.