Bobful

Hi everyone,

This is a last resort questioning before I put a stick of dynamite under the hood of my 93 22re 4x4 pickup. I have tried everything. Here are my problems.

1. the engine revs up and then almost stalls out, only to rev up again. This makes the truck horrible to drive. I have tried to find a vacum leak using carb cleaner and double checked all vacum lines to no avail.

2. I have exhaust in the cabin. After 15 minutes in the cabin I smell like I was in the shop for a week. The engine makes a loud noise like there is no muffler attached to the engine on acceleration. I have checked the exhaust manifold, but can't notice a thing.

3. Finally, the engine has very little tuorque, especially after the warm-up cycle. There is no check engine light, so I suspect the o2 sensor is okay.

I am at my wits end and would appreciate any suggestion whatsoever!!! If nothing works, Ipost picks of the dynamite aftermath!

Thanks,
Bob

chasmc2

this is just a guess in the dark. try the cat maybe its clogged. I had one clogged and the engine would act like that. like i said just a guess. let me know what you find out
good luck

CrazyDiamond

The loud sound on acceleration sounds definitely like an exhaust leak. Check the flange where the exhaust manifold meets the downtube that leads to the cat. There are 2 or 3 bolts that hold those 2 pieces together and if they have worked loose, it can leak like mad right there. You may be able to find the leak by looking for a bit of black soot where the exhaust is squirting out.

Check engine sensors like O2, temp sender, MAF sensor in the air filter box, etc for the cause of the surging. Picture it like this example: If you have a bad signal from the MAF sensor telling the engine that less air is entering the engine than really is happening, the computer will DECREASE the fuel injector open time, which will lower the idle. THEN, the computer will sense that the idle speed is too low and try to compensate with idle, mixture, or timing adjustments. It will OVERcompensate, thus causing the surge. Then it will let off the adjustments, rpms will drop again, and it starts over again.

Sensors are usually the cause of a surge like that when there are no vacuum leaks, at least in my experience. You can check nearly every sensor with a Haynes manual, a multimeter, and about 30 minutes of time.

Hope that helps!

CrazyDiamond

Also, exhaust leak, if it sounds like it's under the hood, could be a crack in teh underside of the exhaust manifold, where you can't see it. Start the car with a cold engine and quickly put your hand over, NOT TOUCHING, suspected areas and feel for air puffing out. You may have to do this all the way back to the muffler. Just don't burn your hand on a hot cat or manifold! :-)

rimpainter.com

I agree with Crazy. It sounds to me like "unsniffed" exhaust is getting by a sensor. That points to a pre-O2 sensor leak. I would go from the 02 sensor forward and trace the exhaust routing, all the way to the manifold.

Bobful

Thanks everyone for the help. Here is an update:

The exhasust manifold seems to be attached and sealed correctly.

MAF Sensor seems to be in order.

I will check the cat tomorrow.

I am rechecking all the vacum lines.

It seems this problem might be out of my reach and I will have to take it in to the stealership.

Any fleeting thoughts would be most appreciated!!

Thanks,
Robert

rimpainter.com

Intake manifold leak...?

PirateFins

It sounds like a clogged cat to me also, building up to much back pressure. The leak might be at the connection of the manifold/down pipe. The donut gaskets might be gone from the extra heat. Also the down pipe, has a weld for the two chambers into one. That weld is famous for going bad and leaking. I have replaced it twice. My exhaust manifold also had a hairline crack in it and was only found by the black soote marks along it. Take the cat off and check it out. You can make up a cheater pipe for a temp testing setup. See if it goes away, with the cat removed.

CrazyDiamond

Have you checked for cracks in the back of the exhaust manifold and cracked welds in front of the cat yet? Just wondering. The noise has to be an exhaust leak. No other reasonable possibility. I know you said the manifold was tight...just wondering if you found cracks...

Email me if you have questions...I'm happy to help in any way possible. I've been pretty damn intimate with every part of my 22re lately. :-)

Bobful

Thanks to all those with all the advice!! Here is an update:

Exhaust leak: there are a strange looking coiled wire gaskets I forgot to install before re-attaching the exhaust manifold. So once I put those in everything should be fine.

Strange idle: Looks like this too was overlooked. All I did was turn down the idler screw and it seems to be running fine.

I feel really silly overlooking these simple things, but like my buddy said about the rebuild: "Looks like a German Teacher and 2 students rebuilt this engine!!"

Thanks again everyone!!!

-Bob