rsmith

hey all
I had the check engine electronics light come on about 3 weeks ago. I looked at the forum and most said mass airflow sensor. I reset the code and it stayed off . Today it came on and I started losing power gradully until I got down to 10mph and pulled into a parkinglot and got it towed home. It will start but the engine shakes real bad at idle and has no power will only rev up to 2000rpm in park. If I floor it it will die. Plugged Cats? Fuel? I had a 85 pontiac that clogged the cat but it idled smooth just lack of power this is the same just idles rough.
Here is the codes:

PO-300 random misfire
PO-301 cyl 1 misfire
PO-302 cyl 2 "
PO-303 cyl 3 "
PO-306 cyl 6 "

MAF 1.36-1.49
MAP 21.9
IAT 66
IGN Advance -4 to -7 @ 875 idle
compression shows 125-130 all cylinders

Fuel pump? Filter clogged? pulled the plugs and the drivers side looked covered with brown crud pass side dark but clean. no Idea how long plugs have been in there. Have had the car for 6 years and 30k mi. Mom's car she dosent go far.Cats have been ratteling since I bought the car for her.
Exhaust has good flow and is not too hot to hold your hand over.?????

ohlord

have finally bit the dust. Which are rattling pre or post?
plugs are every 5 years so you are way overdue.

Plutoe

If you do not have the proper fuel pressure testing equipment, all you can do is disconnect lines and determine if you have flow or start changing parts, filters and pumps without testing, however that is expensive and you haven't even touched the fuel injection system yet!!

Regarding the cats, just because you have some rattle does not always mean they are shot.

Put the car on a lift, let the engine warm up and take the temps of the cats with an inexpensive hand held in fared temp tester. Alternatively, but not easy, disconnect and create a leak, does the reduced back pressure smooth out the engine. Good Luck!

rsmith

Put the new plugs and wires in today fired it up and the same thing. The fuel does shoot out pretty good with the shraeder valve depressed.
Barely had enough power to get it up on the ramps. Only ran the engine for less than a minute and it threw the check electronics and check engine light. After about 10 min I got under to start loosening bolts.I found the cats on the drivers side still red hot and the pass side stone cold. One side clogged? Which one?

ohlord

1,2,3 are all misfiring. Pass side cat is cold. which do you think is shot?
Drivers side 6 is missing that side is going also.
Lucky the engine has not sustained serious damage from neglect.
Now all you need do is figure out if it is the pre or post cats.
Cats been rattling for 6 years most likely all of them
You can install universal cats or get each side complete pre and post and everything in between in SS steel from www.germanstar.net about 5 bills a side for the non california cars.

ohlord

disregard
"Regarding the cats, just because you have some rattle does not always mean they are shot. "
He would not know a Cat if it bit him on the ****

rsmith

I have the drivers side off. The pass side dosent rattle but I have it almost off but one of the bolts that hold the flange at the manifold has stripped and just turns. I hope its the bolt threads and not the threads in the manifold that are stripped. Any how I can see in each end of the pipe with the 2 cats and it dosent look clogged on the ends. Can I hook up a shop vac to it and see if it has flow? What would happen if I take a chissel and bust out the ceramics. would it at least run well enough to determine if it was the cats?

ohlord

need do is remove a pre cat o2 sensor on the pass side and start the engine.

rsmith

What is the purpose of taking the O2 sencor out? Air flow or computer issue. There is a bunch of stuff near the exhaust outlet on the Dr side. Kinda scared of melting something altho I wont run it more than a few seconds. I'm focused on the cats but what is the chance one of the mufflers in the back had a baffel move or collapse? how would I test that?

ohlord

if the engine runs fine and is not choked for air by creating a path to flow through the engine you know that the cat side is failing. You might not have a rattle on the pass side,the cat may have already completely collapsed.
muffler failure is rare unless a chunk of cat worked itself rearward.

rsmith

Finally got the passenger side down from the engine manifold. what I thought was a welded nut was actualy turning. It was a major PITA getting a 12mm shorty in there then holding it with my finger tips. turns out the shopvac hose fits perfectly tight in the manifold connection end of the cats. Passengers side is plugged tight. blew the hose off the shopvac. Drivers side freeflows and has no restriction at all. Untill I can get new cats could I just bust out the ceramic and put them back on? Would the engine run alright or would it throw codes.?

ohlord

run in closed loop operation,a few mpg lower,a bit rich,a few codes like cat efficiency,o2 codes, and maybe a secondary air code, Nothing that will harm anything in the short term.
You can get universal secondary cats magnaflow 53005 off ebay for 60 bucks or so and universal primaries from from several suppliers and have a good muffler shop splice them in.
or replace the primaries and delete the secondaries for a bit of rumble,with a H-pipe crossover installed.

rsmith

Both pipes are good with no rust. The primary cat exit pipe comes out on a 45* angle. Is there a weld in for that one? I'm a welder and to use one with the straight exit it would really have to be butchered up to work.

ohlord

is the secondary. If the primary is blocked they also sell universal with the angle

rsmith

Got the pass side completly out last night. I had to slice the slip joint to get it loose. No amount of heat or twisting would get it to budge. Looking down the inlet the cat is g o n e gone as in not anything in the cavity where it used to be. I turned the pipe upside down and all that came out was a little powder. Even the shop vac blowing and sucking wouldnt get the crap loose.It must be all plugged in the secondary cat. Makes me wonder what makes these things fail and at 151k the other side looks fine but while its off..... I still cant find the part # for the primary cats. Anyone have a #????
99176HM????

rsmith

Ended up taking a long piece of pipe and busting out the secondary cat. sucked out all the remains with a shop vac and it runs great now. Amazing what a plugged cat will do. The drivers side cats are intact and I dont want to run it too much with the restriction on one side and not the other. No codes at all though. But it sounds like crap. Guess I'm going to bite the bullet and do both sides.