Easy way to remove pre cats?

[black g50]

Need to take one off but I don't see bolts on one side to remove.Does the whole header have to come out?

[qship96]

precat is actually built as part of the header.....no way to remove from the header, but could be gutted,although technically it is "illegal" to do so.

[BCC93QT]

Have to drop the exhaust to do that. Not a fun job on a Q but not very hard. More rust more issues. A significant fine if you ever get caught with that stuff lying on the shop floor! Even more expensive if you inhale some...

[black g50]

Bolts look pretty rusty,do I unbolt pipe after it then smash insides?Also will it be safe to let engine blow the pieces out,then put it together?

[BCC93QT]

No I don't suggest doing that but i'm sure it will do the trick. Ram all the guts out with a rod, spray in there with compressed air while covering your face. Make sure you have a box below to catch them gold nuggets as they fall out. Re-bolt exhaust. Pretty sure you have to unbolt the entire exhaust and slide it back of course. Its quite the exhaust system the Q has... Also, when I reattached my exhaust it looked like there was a crush washer type ring in there. Unsure if it actually was one. I applied some nasty stuff to make sure it will never come unsealed. Below is the result
Easier to have 2 people when re-attaching exhaust by the way

[black g50]

Thanks guys,have someone coming Sunday to look at it.Now are those lill nuggets worth anything????

[BCC93QT]

Each cat is worth 1-70$ depending on where you bring them. As far as the guts without them being in the metal shroud you have to explain that they are the insides of the cat itself. When I chopped my other Q up I brought 2 rear cats and the guts of the 4 pre cats. he offered me 40$ for each cat and 40$ for all of the guts of the other 4. I explained to him in nice easy words that the box contained 4x the amount as one of the cats I had. Took me 15 minutes to get the guy to realize that. Settled @ 180$. The early 90's cars had better cats. Hence my 2 cats are still not smelly @ 250k+ mileage and gutted cats. I have heard from a distant tech that they only are there for warm up reasons... The JDM VH does not have pre-cats so I hear

BTW, don't talk about gutting your cats in public. People don't take kindly to that.

[black g50]

Will the check engine light if I pretend to do this?

[BCC93QT]

Not unless you go past the pre-cat and nail the O2 sensor. Why do you want to gut them anyway? I don't if there is much if any horsepower gain? maybe 5?

[black g50]

It has a split down seam,where you can feel air leaking.Yet car is quiet,bucking on highway after hot.

[goody90q45]

......Yet car is quiet,bucking on highway after hot.

Sounds like your MAF may be on its way out. i just replaced mine since it was stalling on hot afternoons but would always restart right away. Driving down the road the engine would suddenly die or start bucking as I watched the rpm drop to zero and then back up to normal rpm. I never had any problems in the morning when it was cool. Swapped in a replacement MAF a few weeks ago and the problem went away.

[maxnix]

Just get some JDM headers that come on JDM pulled VH45DE.

[Q451990]

The MIL (a/k/a check engine light) will not come on from gutting the precats. Depending on the size of the crack, you could try smearing some exhaust sealer into and over the crack. If the honeycomb in the precats is loose, I would definitely look toward fixing that problem...

Heath

[black g50]

I'm thinking the crack was caused by it being plugged. exhaust trying to find a way out.Maf was opened and soldered,no seen defects.Will source another to check for difference.

[BCC93QT]

Put 2 of those electronically controlled exhaust cutouts in there. One for flow off to the side and one into the exhaust. With the flip of a switch it will sound like a rocket. Go back and its OEM quiet

[black g50]

......Yet car is quiet,bucking on highway after hot.

Sounds like your MAF may be on its way out. i just replaced mine since it was stalling on hot afternoons but would always restart right away. Driving down the road the engine would suddenly die or start bucking as I watched the rpm drop to zero and then back up to normal rpm. I never had any problems in the morning when it was cool. Swapped in a replacement MAF a few weeks ago and the problem went away.

last time she was scanned,both banks were lean.So is that air leak or indeed maf?

[goody90q45]

The lean condition caused by an air leak would be an air leak on the intake not the exhaust. The bucking I had was caused by an internal problem with the MAF. On a hot afternoon it would take a couple of minutes for the stalling to quit so I could start driving. At driving speed it would sometimes buck 3 or 4 times and I could watch the rpm drop to 0 accompanied by a loud clunk with each buck but the engine came back on on its own. Very annoying. I never had to use the key to restart the engine as long as I was rolling at more than about 30mph. I only had to use the key if it shut down at a light or stop sign. I resoldered the MAF this weekend and am waiting for the RTV to dry. I'll swap it back in in a couple of days to see if the repair was successful. In the meantime I've had no problems with the replacement MAF.

[black g50]

Ok just came from shop,it seems a hose near egr plugging into passenger side plennum ,has sucked in on it's self.They checked for intake leaks,none found.Told em about a whistle near egr that comes and goes when hose was found.printout of hoses they gave me shows it's 11823f...Dealer item.Can i find this anywhere else?

[Lokim]

The lean condition caused by an air leak would be an air leak on the intake not the exhaust.

Not necessarily true; I've had cracked exhausts read lean on the O2's due to air entering the exhaust stream...

[black g50]

The lean condition caused by an air leak would be an air leak on the intake not the exhaust.

Not necessarily true; I've had cracked exhausts read lean on the O2's due to air entering the exhaust stream...

Pre- cat does have a split in seam.Changed hose no change.

[black g50]

Also they couldn't get scanner to talk to computer to check for any codes.Told them the only time it lights is key on,then goes off as normal.

[black g50]

If I had a plugged cat,wouldn't it show up revving engine in neutral?