I had a cam break on me which caused a couple of valves on the intake side to bend. I swapped in my stock cams and replaced the bent valves. Now after putting the head back on, I'm getting a rough idle from start, a bit of backfiring, carbon from the exhaust, and after running for a couple of mins the cat is glowing red hot and smoking!! I'm getting combustion in all 4 cylinders, but at first I was getting excessive heat from cylinder 1. I have good compression all around, and before the broken cam, it was running fine. at rpms higher than 2k the roughness disappears, but the cat glowing is cause for major concern. Anybody know what could be causing this? Please help!!!! This is in a 91 CRX Si w/ B16A SiR II OBD1 converted.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kur0ryu &raquo;</TD></TR><TR><TD CLASS="quote"> at rpms higher than 2k the roughness disappears, but the cat glowing is cause for major concern. Anybody know what could be causing this? Please help!!!! </TD></TR></TABLE>
The usual cause for a cat and/or exhaust system to glow red is alot of raw fuel going through. A missfire could be the cause. Have you done a compresion or leakdown tests?

 

I did compression test, 190-200 across the board.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kur0ryu &raquo;</TD></TR><TR><TD CLASS="quote">I did compression test, 190-200 across the board.</TD></TR></TABLE>
That looks pretty good. How about a cylinder balance test? With the engine idleing, pull of one spark plug wire at a time and note the drop in engine speed. They should all be about the same. If you find a cylinder that doesn't drop as much as the others, you have a misfire on it.

 

Did you adjust the valve lash back to your stock cam specs.

 

and your cat could be plugged

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mmuller &raquo;</TD></TR><TR><TD CLASS="quote">and your cat could be plugged</TD></TR></TABLE>



We had a car on the dyno and the cat was red hot and glowing after two passes, after checking EVERYTHING we pulled the cat off the it looked like melted lava inside. We replaced it and made another pass and all was well. Check the cat - it might save you alot of time.

Good Luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMSiGuy17 &raquo;</TD></TR><TR><TD CLASS="quote">Did you adjust the valve lash back to your stock cam specs.</TD></TR></TABLE>

I did .157mm on intake side, .172mm on exhaust, but I think I got a little tight-happy with them. I'll loosen them up a bit.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RageDzine &raquo;</TD></TR><TR><TD CLASS="quote">
Check the cat - it might save you alot of time.
</TD></TR></TABLE>

It's gotten red-hot twice while testing. Do you think that it may have melted by then? I don't have a replacement, nor will I be able to buy one right away. Although illegal, if the insides are melted, will I be ok gutting it and putting it back on for the time being until I can get a new cat?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
That looks pretty good. How about a cylinder balance test? With the engine idleing, pull of one spark plug wire at a time and note the drop in engine speed. They should all be about the same. If you find a cylinder that doesn't drop as much as the others, you have a misfire on it.</TD></TR></TABLE>

I'll give that a try too. I have new plugs on it right now, seems that when I changed them, it performed a bit better. The old plugs looked clean on 4 and 3, but 2 and 1 were pretty dark. I had been doing most of my troubleshooting with these plugs. Oh, also the first time the cat got red-hot, cylinder 1 was extremely hot on the header, but the other 3 were mildly warm. after I changed the plugs, they all get hot, but the cat right now is my biggest concern.

BTW, I'm running my Toda valvesprings with my stock cams, would that have anything to do with it? Also I still have my chipped P30 mugen program ECU hooked up. I'll try it with my stock P30 and see if there's a difference too.

Thanks guys, I'll post my findings.

 

Don't those Mugen programs run extra rich? Maybe that's the cause for rough idle and glowing cat.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by speedymon &raquo;</TD></TR><TR><TD CLASS="quote">Don't those Mugen programs run extra rich? Maybe that's the cause for rough idle and glowing cat.</TD></TR></TABLE>

Yeah, they do, but I was told with average bolt-ons h/i/e it's ok. Worked well with my Toda cams for a while though.

 

Ok, cat removed, confirmed - melted!! I gutted it, gonna run it gutted until I can get a replacement.


Now to find out what caused it! sounds like it's still misfiring, but I'm getting combustion in all. Gonna do valve lash right now.

 

Ok, valve lash was actually ok. Cat is still getting red hot after gutting it. I think excessive fuel is getting dumped into the header. I did the plugwire removal test, and the only one that changed when I removed the wire was plug #1, and the engine stopped immediately. All others there was no change in the idle speed. Also when I pulled the spark plugs out, these are brand new plugs, the tip of #1 is dark, while 2, 3 and 4 are still pretty white. I'm also running my stock ecu, not the chipped one.

Anybody know what's going on here?



Modified by kur0ryu at 1:16 PM 5/17/2004

 

SOunds like 2, 3 and 4 are not firing...dumping fuel into the exhaust system and jacking up your cat.
1. Check voltage at the injectors to see if you're getting a signal?
2. Swap out injectors. Seems far fetched that 3 would go out completely
3. Check ignition system in general. Ignitor, cap, etc....
4. Don't know much about OBD conversions but check to make sure your wiring is correct.
Anyone else care to chime in.

 

I'll give it a try. Injector wiring is ok, it was working fine before my Toda B intake cam broke, and I havent done anything with the wiring afterwards. I've tested 2 known good distributors, and I'm using a brand new one right now while testing. (my old one was on when the cam broke). I will test the injector signal though on the clips. I'm gonna try spraying carb cleaner in the intake too to see if I get a favorable reaction. I'll post my findings, but if anybody else has anything to add that I should check please let me know. Thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kur0ryu &raquo;</TD></TR><TR><TD CLASS="quote"> I did the plugwire removal test, and the only one that changed when I removed the wire was plug #1, and the engine stopped immediately. All others there was no change in the idle speed. </TD></TR></TABLE>
Running on one cylinder that thing must idle like a corncob. The compresion test you did was recent? Plug wires routed right? Getting spark at all four plugs? Plugs wet with fuel?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
The compresion test you did was recent? Plug wires routed right? Getting spark at all four plugs? Plugs wet with fuel?</TD></TR></TABLE>

Yup, yup, yup and yup. compression test was done after re-assembling head. Plug wires are good, firing order 1342, tried cranking with the plugs in the wires out of the head, and all four spark. plugs 2 3 and 4 wet with fuel and pretty white, plug #1 is dark already and it's a brand new plug.

 

check cam timing?????????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eLusive ek4 &raquo;</TD></TR><TR><TD CLASS="quote">check cam timing?????????</TD></TR></TABLE>

timing is perfect everything lines up right at TDC.

 

check your plugwires. Are they in the right order. We had a bronco in the shop once that someone brought in that was idling rough and the cat was GLOWING red. Turns out they did a tune up and had the wires in the wrong firing order. That little mistake cost them a cat.

So I would check the firing order if you haven't already

-Proper

 

Yeah, I have plugs wired properly 1342 firing order.

 

i am having almost same problem with spark plugs, #1 and #2 spark plugs r almost white and #3 and #4 r black or wet, please email me if u know anyting at victoriasamantha@comcast.net and send me your email so if i figure it out i will tell you

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Proper &raquo;</TD></TR><TR><TD CLASS="quote">check your plugwires. Are they in the right order. We had a bronco in the shop once that someone brought in that was idling rough and the cat was GLOWING red. Turns out they did a tune up and had the wires in the wrong firing order. That little mistake cost them a cat.

So I would check the firing order if you haven't already

-Proper</TD></TR></TABLE>

Ok, here's a update. I got it running. It seems that when I was taking the time to do the head, and putting it back on, I believed i put it in the right firing order, 1342, but stupidly and sleepily I put it on as 1234. What a dumbass I am. That fixed it immediately.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kur0ryu &raquo;</TD></TR><TR><TD CLASS="quote">

Ok, here's a update. I got it running. It seems that when I was taking the time to do the head, and putting it back on, I believed i put it in the right firing order, 1342, but stupidly and sleepily I put it on as 1234. What a dumbass I am. That fixed it immediately.</TD></TR></TABLE>
LOL, how the hell did you get it to run like that? Oh well, you only melted a cat, no big deal. Don't be surprised if your muffler develops a rattle from the cat guts. BTW i've seen alot worse dumbass stuff done to cars.

 

BTW, thanks to everyone who helped me with this, I think my troubleshooting skills are getting sharper

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
LOL, how the hell did you get it to run like that? Oh well, you only melted a cat, no big deal. Don't be surprised if your muffler develops a rattle from the cat guts. BTW i've seen alot worse dumbass stuff done to cars. </TD></TR></TABLE>

yeah, I have a rattle already. Kinda annoying But at least it's runnning rite. I don't have to have emissions done until October so I should be good till then. As far as running 1234, I dont know, it seems that cylinder 1 was running the whole show!