tow rig WAY down on power after engine rebuild

Maverick · Jul 1, 2004

ok folks, the wonder burb is woefully down on power since the engine rebuild. Towing a Alan's 4runner up to our friend's house was pretty pathetic. I was in 1st gear going up a hill that I can usually do in 2nd or 3rd, accelerating. Pathetic. (ask Alan how he managed to break the toilet)

It was noticeable while not towing, felt like maybe it was at 80-90% of full power. While towing, it feels like it's at 50%. I doubt I could get the jeep out of my neighborhood.

Power is *much* lower throughout the powerband, from 1000rpm all the way up to redline. It still revs, but just smoothly struggles all the way through. No exhaust "roar" either.

The only thing that changed in the engine was the crank. Every other component is the same.

Oh ya, and I had the fuel pump replaced on Monday. When it rains, it pours.

Ideas?

There's a rattle in the exhaust now...A friend was thinking it might be bb's from the cat(s), he thinks they might be ruined from when the engine melted and possibly causing the lack of power...but would that be at the bottom end too? or just high rpm?

No codes on the 'puter. Timing has to be within 2* or the computer freaks out (and it's not freaking out).

I'm baffled, and so is my mechanic.

Brett

Caleb · Jul 2, 2004

it could very easily be cat...I have always understood that with a clogged cat you loose power across the board but I dont have first hand experience so I cant say for sure :-\

car problems (especially expensive ones) suck...

JeeperG · Jul 2, 2004

Supergper said:
it could very easily be cat...I have always understood that with a clogged cat you loose power across the board but I dont have first hand experience so I cant say for sure :-\

car problems (especially expensive ones) suck...

MMMM maybe Cat's (Meow) But I doubt that would cause that much lack of power? (could be wrong) Is there any way You can visibly look inside the Cats? Or are they welded on? I assume your running dual exhaust also? What about O-2 sensor??? Keep in Mind Crank was replaced! So is it possible something else got moved? like maybe a Distributor 180 degrees off?

I dunno any other info you can provide?

BlackSheep · Jul 2, 2004

check your fuel filters as well. if they are clogged, you won't be going anywhere fast.

mbryson · Jul 2, 2004

Have you done a compression check and all that good stuff?

Milner · Jul 2, 2004

I see 2 problems....
1 Its a Chevy
2 its Gas

J/K

James K · Jul 2, 2004

rckcrlr said:
I see 2 problems....
1 Its a Chevy
2 its Gas

J/K

OOOOOOOO thats gotta hurt

I would say look at the fuel filter also :-\

shmoesmith · Jul 2, 2004

JeeperG said:
MMMM maybe Cat's (Meow) But I doubt that would cause that much lack of power? (could be wrong) Is there any way You can visibly look inside the Cats? Or are they welded on? I assume your running dual exhaust also? What about O-2 sensor??? Keep in Mind Crank was replaced! So is it possible something else got moved? like maybe a Distributor 180 degrees off? I dunno any other info you can provide?

Yes, a cat will cause that much lack of power if it is clogged...if have had buddies cars that can barely limp home once their cat goes. Mine was severely clogged on one of my vehicles(happened right after a nasty trail run) and I couldnt get it up past 30mph -sawzalled the bcat off and ran a straight pipe until i could afford a new cat and it ran great....a cat test costs around 65-80 at many muffler shops..an aftermarket cat will cost just as much so if you think it may be the cat, might as well replace it....if you had an engine melt down, i'm told by an emmisions shop that you can VERY EASILY clog your cat.

cruiseroutfit · Jul 2, 2004

I can hear Russ now......

Farmer Jed · Jul 2, 2004

I had the same power loss problem with a chevy several years ago. took forever to diagnose it as the cat. Pull the cat and look down the intake side. You may be able to see or feel if it has been melted/clogged. Mine was pretty obvious.

chevtech · Jul 2, 2004

shmoesmith said:
Yes, a cat will cause that much lack of power if it is clogged...if have had buddies cars that can barely limp home once their cat goes. Mine was severely clogged on one of my vehicles(happened right after a nasty trail run) and I couldnt get it up past 30mph -sawzalled the bcat off and ran a straight pipe until i could afford a new cat and it ran great....a cat test costs around 65-80 at many muffler shops..an aftermarket cat will cost just as much so if you think it may be the cat, might as well replace it....if you had an engine melt down, i'm told by an emmisions shop that you can VERY EASILY clog your cat.

I've seen many cats go and yes they cause severe power loss that increases (as in power loss gets worse) as RPM and throttle opening increases. Easy way to check a cat is to pull an O2 sensor pre-cat. It has to be pre-cat (for obvious reasons). Take it for a test drive if your power is back you have a plugged exhaust most likely the cat (like over 99% of the time).

trpl xj · Jul 2, 2004

your cat is more than likely a bead bed, you won't be able to tell if it is plugged or not by looking in it. Take it to a shop and have them do a presure test on it. A presure test shouldn't cost very much it only takes about 2 minutes to do one. I've seen several cars come in the shop were the cat was plugged so bad that it wouldn't even run.

Hickey · Jul 2, 2004

Your cat is plugged. Go get a universal one from Autozone and toss it in, they are about 50 bucks.

crimsonride · Jul 2, 2004

Sounds like that's the problem. Melting an engine can cause the temps in the cat to soar melting the honeycomb-like material inside the cat, that can plug them up pretty good.

Hickey · Jul 2, 2004

If the cat is rattling or it sounds like something is rolling around in it, then the material inside is broken.

cyberduke · Jul 2, 2004

Most exhaust places can check to see if your cat is plugged. They punch a small hole just before the cat, put a pressure guage in it and rev up the motor to see what the pressure goes to. In my case it buried the needle. I had a hard time keeping up w/ traffic on I-15 before. New cat and exhaust, and it's a new truck!

-Earl

Maverick · Jul 2, 2004

cyberduke said:
Most exhaust places can check to see if your cat is plugged. They punch a small hole just before the cat, put a pressure guage in it and rev up the motor to see what the pressure goes to. In my case it buried the needle. I had a hard time keeping up w/ traffic on I-15 before. New cat and exhaust, and it's a new truck!

-Earl

WooooHoooooo!!!!!!!!!!!! Listen to y'all!!!!

Beach is gonna do a pressure test in the morning. Sure does sound like the cats though. Wonder if I oughta pull an O2 and drive around...though I donwanna set off any codes that aren't already there (none).

Thanks all!!!! 'cept Milner, he's gettin' his ass kicked

Brett

I Lean · Jul 2, 2004

Maverick said:
Thanks all!!!! 'cept Milner, he's gettin' his ass kicked

Brett

Does it change anything if I was gonna agree with his sentiments? (I got your back, Marc!)

Milner · Jul 2, 2004

I Lean said:
Does it change anything if I was gonna agree with his sentiments? (I got your back, Marc!)

RockMonkey · Jul 2, 2004

When I replaced a cat a few months ago I looked all over for Hickey's fabled $50 vatozone cat. I doesn't exist. Cheapest thing I could find was through Beach. Right around a hundred bucks, I think.

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