96 850 NA AT Serious Lack ofPower.

Billc1015 · Post by **Billc1015** » 24 Oct 2011, 15:19

Compression readings should be 189 - 219 psi minimum according to ShopKey. I don't know if thet is wet or dry.

Have you checked your vacuum yet? A good way to confirm a blocked (or partially blocked) exhaust is by checking engine vacuum. It is a quick and easy test to rule out an exhaust issue.

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I am here: http://maps.google.com/maps?ll=40.334313,-75.130694

waynej · Post by **waynej** » 24 Oct 2011, 17:41

Thanks Bill,
It doesn't surprise me that my compression is a little below specs with 130K miles. I wouldn't think compression should limit the RPM unless it's going up hill. Vacuum is 14" at idle, 13" at 2000 RPM, 10" at 3000 and 5" at it's limit of about 4000 in park. When driving it's between 0 and 5 most of the time.
A curious thing; I had driven the 5 miles home from work, so it was fully warmed up. It probably took about 15 minutes to say hi to the wife, find my vacuum gauge and get it taped to the windshield. When I re-started the engine it would go to 4400 RPM one minute later it would only go to about 3600 and I think the vacuum readings were about the same both times.

Post by **Ozark Lee** » 24 Oct 2011, 22:35

Th compression readings are within the realm of reality - depending on the gauge - and they are at least fairly even. There is no huge red flag on those readings.

I'm kinda stumped on this one since you have pretty much gotten to the bottom of my bag of tricks and you have done it on your own.

...Lee

waynej · Post by **waynej** » 24 Oct 2011, 22:48

Thanks for trying Lee,
I'm going to start unplugging things-one at a time. I found the O2 sensor connections on the back side of the transmission .
Where is the knock sensor? Is there any other sensors I don't know about? I already tried the MAF and TPS. Do ECU's ever go bad?

Post by **Ozark Lee** » 24 Oct 2011, 23:49

Where is the knock sensor? Is there any other sensors I don't know about? I already tried the MAF and TPS. Do ECU's ever go bad?

There are actually 2 knock sensors bolted onto the forward facing side of the block. You really need to remove the intake manifold to get to them but once the manifold is off they are easy to get to.

The ECUs can go bad (not often) but they normally just crap out altogether when they die. We have had many more members with issues at the ECU edge connectors than with the actual ECU itself. Over time the edge connectors can get corroded.

...Lee

waynej · Post by **waynej** » 25 Oct 2011, 00:13

Are the connections right at the knock sensors or can they be disconnected somewhere else?
I already removed and replaced the ECU's a couple of times to clean the connections.
Thanks,

swede_speed · Post by **swede_speed** » 27 Oct 2011, 07:36

My money is on the plugged CAT theory... because I too have the same type of symptoms when running hot and after climbing a hill or mountain. When I finally reach the top and get to my parking spot at the top of the mountain I smell rotten eggs after I get out. That to me says my CAT is plugged or something of that nature. I also have low power at low RPMs when i'm turming . Like really scary when I turn and a car is coming....I have to baby it to get into the area I want to go. Kinda like "LIMP MODE"
I'm going to remove my CAT this weekend and see if its plugged. or getting there.

swede_speed · Post by **swede_speed** » 27 Oct 2011, 07:43

The lack of power for me happens after 1--- an hour of driving in hot weather, and 2---after climbing a long hill or mountain slope.

waynej · Post by **waynej** » 27 Oct 2011, 08:25

My lack of power begins about 1 or 2 minutes after start up. I did the test someone suggested with a vacuum gauge to checked for a plugged cat and apparently the readings I got are OK. If I remove the CAT how do I see if it's plugged? Your lack of power on turning is a different issue. Is it just on a left turn or both ways? Have you checked for cracks on the air tube between the MAF and throttle body?

Post by **Ozark Lee** » 27 Oct 2011, 09:03

The bad catalytic converters that I have had detonated internally and they sound like they are filled with gravel if you climb under the car and smack it with your hand. Do that only after the car has cooled off to keep from burning yourself.

...Lee