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View Full Version : Rough idle after cat install..



d1giPhux
10-20-2008, 07:53 AM
So i had a couple of new cats put on my BD.. and it seems like the idle is a bit more 'rough' then normal. Strange thing is.. the RPMS dont go up or down or anything.. just seems like the car has a bit more 'grumble'. Not sure if this is because these are diff / new cats and o2 sensors.. or what. Doesnt seem to affect the driving at all either..just wondering what it is. Also.. the car seems to be a bit louder.

I'm pretty pissed at the shop who installed this stuff to begin with.. and actually think they stole some stuff out of my car as well.. so.. I'm not exactly trusting their job too much right now.

Make suggestions please. Thanks!

anothernord
10-20-2008, 12:09 PM
Well, the "grumble" you speak of could simply be the new cats if they flow better than the old ones, or it could be and issue with the o2 sensor.

Have you reset the ECU yet? That might help.

Huffer
10-20-2008, 12:14 PM
I would say any additional sound would be because of the installation of parts... are these OEM cats or shop-made ones?

A leaky fitting right after the header can create a grumbly sound.

d1giPhux
10-20-2008, 12:29 PM
They are shop made to 'oem' specs... i bought them on ebay.. so.. might be that. I did reset the ECU.. and it just seems like my shift knob rattles around and such more now when the car is idling.. i'm assuming this may be like you said because of higher flow? Hmm.. i dunno, just seemed a bit strange to me.. guess I will have to get use to it. What else might i want to look for?

Huffer
10-20-2008, 12:34 PM
Did you use new gaskets? And scrape the old gaskets off the header and midpipe?

d1giPhux
10-20-2008, 12:54 PM
yeah, used new gaskets that came with the cats / pipes.. and I'm assuming the shop did scrape them off.. either that or they are f'in idiots.. which now.. im starting to think they are. I'm gonna take a closer look at the rpm range / noise and shit today.. also gotta make my damn heat shields stop rattling so i can get a more accurate understanding of whats happening... damn things sound like a skeleton on a tin roof! LOL

anothernord
10-20-2008, 08:16 PM
+1 on checking the gaskets.

d1giPhux
10-21-2008, 09:38 PM
I looked under the car the other day.. and looked like one of the areas where the gasket was.. was smoking a bit? Then again.. when i got the car back.. the whole exhaust was smoking.. however.. i think the problem may be something more complex.

Now cylinders 1 & 3 are misfiring with codes:

PO301
PO303

fun fun.. so anyone wanna make some suggestions on that? Spark plug wires? The plugs are new.. however.. the wires are prolly old as hell. What type of wires are good to buy?

need some ideas here...

Huffer
10-22-2008, 07:26 AM
Buy OEM wires. You have OEM plugs.

d1giPhux
10-22-2008, 08:17 AM
I meant like.. brands.. and what I should be looking for. Also.. my plugs im assuming are OEM... meaning they were made to OEM spec.. but they are NGK. I just want to get a nice set of red wires.. i love me some red wires :lol: .. anyone know where i can get some that are made to OEM spec that arent crap?

Also.. if its not the plugs.. what else might it be? Coil? I was reading around and it said to look for stuff on the coil.. what should i be looking for?

decke48
10-22-2008, 11:51 AM
if you want them red. thats not crap. would be MSD wires or Taylor wire if you can find them red. misfires 1,3 are on a shared coil. so i would look for any burn marks on the coil.

d1giPhux
10-22-2008, 12:16 PM
So you think its the coil then? Hmm.. now im debating maybe doing the msd / neon coil upgrade or not at the same time if that is the case. Don't really understand what parts i would need and such from the DIY.. flat pin, round pin, etc.

I'm assuming the coil is bad, and the wires are probably crap anyways.. so if i do need to pick up a new coil.. should i just get OEM and OEM or MSD wires? Good places to find these?

decke48
10-22-2008, 01:16 PM
oem wires are good enough the stock coil or neon/msd coil. the only reason people dont recommend aftermarket oe style wires is because the ternimal covers are made of plastic and not rubber/sylicon. so they tend to break under heat and just cause problems short after you install them..
i said msd wires because you wanted red wires. idk if you would see anything better from 8.5mm wires over the stock 7mm

Wiscon_Mark
10-22-2008, 02:00 PM
I have red Bosch 7 mm wires with rubber boots. They work just fine.

d1giPhux
10-22-2008, 03:10 PM
Where did you get them from? Local auto store.. or online? The ones i have on my car right now are red.. and have rubber boots.. but they dont even say who they are made by.. hmm.

d1giPhux
10-23-2008, 11:39 AM
Hmm okay, so the only place i can find that can get red wires is advanced and they are made by some company called 'magstar'.. anyone ever heard of them?

Here are the other types i can get.. let me know which arent junk. I'm assuming the NGK's are decent.

Duralast - $57.99
Bosch - $69
NGK - $57
Xact - $59
Autolite - $65
Magstar (only ones i can get in red so far) - $46
NAPA (guy said the brand was blue) - $54.50

Let me know what you think..

jey
10-23-2008, 01:35 PM
Get your exhaust fixed first. If you have an exhaust leak it could be altering your O2 readings and creating a misfire condition.

d1giPhux
10-26-2008, 05:30 PM
Its been fixed buddy..

replaced the spark plug wires.. no difference.. i'm thinking the coil is shot.. so I'm going to try that next. Wondering if i should just waste the money on an MSD or not. Bit confused about which wires i would need if i did that.. and the proper way to wire it up. I'm mostly just confused about what the DIY meant by flat pin / round pin connectors on the wires.

decke48
10-26-2008, 06:33 PM
i think on most 99 the put the 4 wire coil. so the MSD wont work. i

d1giPhux
10-26-2008, 07:31 PM
Really? hmm.. that sucks. What years can you do it to then? Thats strange.. i thought people with the BD's were able to modify? Oh well.. guess i'll just get a stock one then!

decke48
10-26-2008, 07:46 PM
90-98 except some 97 have 4 wires. maybe some 99 have the 3 wire. you can always check

d1giPhux
10-27-2008, 09:22 AM
Damn.. so i guess there is no way around this? I thought the extra wire was just a ground wire anyways? Hmm.. thats kinda lame..i'll have to check mine out.