[Smackeyacky]

 

[Smackeyacky]

Both heads on, gaskets correct this time. Timing gear is now on and engine turns over fine, so tomorrow we fit the valve covers and intake, refill the fluids and try starting it again.

 

[Smackeyacky]

Top buttoned up, exhausts, dipstick, fluids and accessory belt next.

 

[Smackeyacky]

Guess who forgot to hook up the exhausts before trying to start it. THIS GUY WHO IS NOW DEAF.

It runs!

 

[Smackeyacky]

Obviously it helps to have your gaskets on the right heads. Not only do they leak, but you'll have no compression. You can definitely hear the difference just cranking it over with the fuel pump fuse pulled.

Putting the fuse back in, it started in like half a crank and went off like a bomb. Will try to get the exhausts back on this afternoon and start checking for fluid leaks and bleed the cooling system. That's four months of pulling it apart and putting it back together several times. If I had only listened at the start and done a compression test as the first port of call, we could have done this in a much shorter space of time.

Lesson learned: if it's running on 7, do a compression test. No ifs, buts, maybes, "I think I know what's wrong" etc. A compression test is simple to do and takes no time and tells you a lot.

 

[79jasper]

Obviously it helps to have your gaskets on the right heads.

Been there.

Thats a two person job

Try it with long tube headers bolted on. Have to play jenga/tetris while doing so.

Sent from my SM-G988U using Tapatalk

 

[Smackeyacky]

...and the craziness continues. When the exhausts are hooked up it runs terribly and won't idle.

I unhooked the exhausts at the manifold today and it runs fine.

I think the cats are clogged, which is probably due to it shooting unburnt oil when it had a hole in the piston. Not sure if they can be cleaned, i am guessing they are both junk now.

Good news is when its idling, it is not throwing codes. With the exhaust hooked up it threw a multi cylinder misfire code.

So now I am glad i started it without the exhausts the first time otherwise it would be a much bigger mystery.

 

[magnuman]

And the beat goes on. Sounds like you're almost there. Your assessment sounds plausible. My guess is that the ceramic honeycomb core, which has a coating of alumina impregnated with noble metals - platinum, palladium or rhodium, has either gotten plugged up by engine debris, oil and gunk, or has overheated and melted these innards. Will the engine rev at all? Are all the misfires on one cylinder bank or on both sides? Usually, if things are really plugged up in an exhaust system, it will sound like it is really laboring to rev and/or won't rev very well at all, or the RPM will "flatten out" as the engine is accelerated. If you could get it to a reliable muffler shop, they should be able to verify the condition of the cats. They usually do it by checking back pressure before and after the cats. It should be about the same on both sides. Also, if you don't have emission testing down under, you can just cut the cats out and replace them with straight pipes between the head pipe and muffler(s). Another option, if you have emission testing and they don't know what they're doing, you can gut the cats and leave them in place. You'll get the wonderful P0420/P0430 codes, but if you have a good tuner, you may be able to turn the codes off with it. The last, and most expensive option is to replace the cats.

 

[Smackeyacky]

They don't do emission testing here, although there is a fine for fooling with your emission equipment - usually people get busted for having things obviously missing.

The symptoms when the exhaust are hooked up were massive clouds of brown smoke, laboured idling (wouldn't idle), wouldn't rev out, multi-cylinder misfire codes getting thrown. With the pipes loosened off all that went away. This is both sides of the motor. The honeycomb is visibly caked in black much but I thought that might burn off. I reckon I would ruin the engine by the time it did.

I think I'll remove the front pipes (there is a slip joint near the front) and see if the rest of the exhaust is OK with a vacuum cleaner, then try a few home remedies on these cats (acetone bath?). Looking on ebay it seems you can buy generic/replacement cats for not a lot of money.

I haven't run it long enough to check properly for fluid leaks, but it seems OK so far.

 

[magnuman]

Your description certainly sounds like there is a pretty massive back pressure in the exhaust system. If the cats. are really caked up with oil and other crap, I doubt you'd be able to burn it all off any time soon. I don't know whether any "non approved" cleaners like acetone or tolulene will further ruin them or not. I know they make cat. cleaning stuff, but I have no idea whether it works or not, or will it work on ones that are super gunked up. If you don't want to dump more $$$ into it, you may want to gut the cats and leave them in place......if you feel the emission nazi's wouldn't catch you. Otherwise, once you've verified it is the cats. causing the problem, you may want to spring for some new ones.

Please keep us posted.

 

[Smackeyacky]

Your description certainly sounds like there is a pretty massive back pressure in the exhaust system. If the cats. are really caked up with oil and other crap, I doubt you'd be able to burn it all off any time soon. I don't know whether any "non approved" cleaners like acetone or tolulene will further ruin them or not. I know they make cat. cleaning stuff, but I have no idea whether it works or not, or will it work on ones that are super gunked up. If you don't want to dump more $$$ into it, you may want to gut the cats and leave them in place......if you feel the emission nazi's wouldn't catch you. Otherwise, once you've verified it is the cats. causing the problem, you may want to spring for some new ones.

Please keep us posted.

Well, I'm somewhat leaning toward what I might call the "ultimate cat cleanout" that involves wiping a smear of acetone on the end of a wrecking bar and gently dislodging the buildup, which might have the side effect of loosening the honeycomb . Just looked at the codes again and it has 8 "Heater Control Circuit" codes that I originally dismissed as something to do with the HVAC. Clearly the oxy sensors are all toast as well since the carb cleaner doesn't seem to have worked it's usual magic on those.

The oxy sensors will get replaced for sure. Mostly I'm relieved it runs and I didn't cause any huge screwups this time. I mean, all the rest of the problems I bought with the car so we're definitely making progress.

 

[Smackeyacky]

Codes from oxy sensors. There are 8 in total but the last 4 are a repeat of the first ones.
edit: the oxy sensors all looked pretty janky (oil contamination) but not sure that would affect the heater circuit. Will crawl back under there and check the resistance on them. Found this thread that seems to indicate it might be something else.

Car is throwing codes... not sure what happened.

First off, I need to explain what I did before the car began throwing codes. 1) After I got my car back from the body shop, I installed new HID's in the fog lights. Car did not throw codes after the install of these. 2) I installed a cathode tube in the grill, wired to the same relay as the...

www.lxforums.com

.

 

[magnuman]

Yes, it's almost certain your 02's are bad. I don't know about your Aussie vehicles but in the US the Hemi's only like NTK Sensors. I can attest to that first hand when I installed Bosch ones in my 5.7 Hemi Jeep. Here's a thread I did about it over on one of the Jeep forums: Oxygen Sensors and Their Role in Engine Management--A Primer

On the cats, it sounds like you don't have anything to lose by trying to clean them any way you can. If it works.....great, if not....no harm, no foul. Good luck, I hope you get it all working without having to spend any more of your $$$.

 

[Smackeyacky]

Driver side upper oxy meter measures 4 ohm across the heater pins as does the lower one, so they oxy meter problem still exists.

I got the drivers side cat off, started with a gentle clean with some citrus based degreaser (hoping that is the least reactive thing to clean out a an oily cat). Gentle with the power washer and water/detergent started coming out the other end. Figured that if a little pressure was good, more would be better. Turned the pressure on the power washer up a smidge too much and shattered the innards

A post-mortem on the ceramic matrix looks like the entire length was contaminated with oil, so there was likely nothing to save.

 

[magnuman]

So, now why not gut the other one too, put it back together and see how it runs??

 

[Smackeyacky]

So, now why not gut the other one too, put it back together and see how it runs??

Um, the plan is to thoroughly clean them out, make them so clean they are see through I dropped the 2nd one yesterday, will give it the same treatment then refit.

edit: somebody got to the other cat before me. It's empty! Why would you drive around with one empty cat and one clogged one and not expect a giant piston meltdown?

I'm really no closer to working out why the original engine damage occurred, other than it was a cyclone of stupidity converging on one unfortunate engine bay.

 

[Smackeyacky]

Not much progress. It doesn't want to run, still throwing oxy sensor codes. I hate to fire the parts cannon but I'm going to put 2 fresh oxy sensors in the manifolds and see what happens. It wants to run, you can hear it trying to make sense of the oxy sensor outputs but it quickly tunes itself into a non-running state. I was hoping my sensors would show up yesterday but no go, so it's tuesday next week at the earliest

 

[magnuman]

OK, you've shattered the innards of one cat? Did you clean everything out or is all that crap still plugging up the cat? Is the other one now completely cleaned out? IMO, at least for now, totally gut them and remove all the innards....ceramic honey comb. That way you'll know for sure there are no significant restrictions in the exhaust because it'll be straight through. Then the next order of business is the O2's.

With regard to the O2's, you said earlier that you "cleaned them with carb. cleaner". I'll guarantee that every one you did this to is no good. They are extremely sensitive to any contamination. You also said that there are 8 O2 Sensors in the exhaust system??? If there are indeed 8, I'd like to know the layout of the exhaust system and where exactly all these O2's are located in the system. The U.S. ones only use 4 sensors.....2 for each cylinder bank....1 before each cat (helps control fuel mixture) and 1 after each cat (verifies the cats are working properly)....see my "Primer" in Post No. 113. Another question for you.....does the engine run at all or just a little when first started and then either die or start misfiring?

A little more on the O2's....is there one screwed into each intake manifold? If so, those should be the first ones you replace....at least for now. Those are the two what help control the fuel mixture, along with other sensor inputs to the PCM. Also, make sure your engine, transmission and exhaust system are all properly grounded (bonding straps) to the chassis.

Keep the faith.....with patience and perseverance, you'll get it running as smooth as a kitten's purr.

 

[Smackeyacky]

There are 4 sensors total.

The 2nd cat was already empty, so cleaning up the first one equalised things. Waiting on some new o2 sensors before i do anything this week

Edit: didn't know carb cleaner would ruin an o2 sensor. Lesson learned. I think the dowstream ones are probably ok as i didnt try cleaning those, they werent oily like the upstream ones.

 

[magnuman]

Four sensors is more like it. I was trying to figure out what they'd do with the other four in a dual exhaust system.

From my thread on O2 Sensors:

-are easily contaminated which can render them "lazy/sluggish" or inoperative.
--effectiveness will deteriorate or fail if exposed to such things as lead,, phosphorus, EXCESSIVE OIL, WATER, silicone sprays/gasket sealers (unless certified to be O2 sensor safe), some fuel additives, road salt, dirt, or mishandling. The amount of moisture and oil that gets by the inferior Positive Crankcase Ventilation (PCV) system on the 5.7 Hemi’s would, IMO, be cause for concern for premature O2 sensor and/or Catalytic Converter contamination and deterioration. Not regularly checking/changing the PCV Valve could aggravate this. IMO, Hemi owners should always check the PCV Valve and behind the throttle body butterfly at each oil change.
--that have completely failed will usually indicate a rich condition and, if not replaced in a timely manner, could cause the overheating and failure of the Catalytic Converter on the affected side.