loss of power on hills or under load

loss of power on hills or under load

Postby lessloop [OP] » September 18th 2009, 6:26am

Just wanted to post this as a thank you to this forum. My 2003 Astro Van was slowly becoming undrivable with noticable, then moderate, then exterme power loss under load, especially on hills. I literally had to get off the freeways here in LA for the big hills and use slow surface streets! ( Got a MAF sensor code when it first started, but cleared the code after replacement of MAF and it kept getting worse with no more codes.) I did a bunch of snooping around, most of it here, and noticed a pattern of failed, (clogged), cat converters. I put in a new, factory cat converter and the van runs like it was brand new at 100,000 miles!
Thanx astosafari.com!!
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Re: loss of power on hills or under load

Postby Jasen » September 18th 2009, 6:31pm

Wish I'd seen your original post on this. CAT would have been my suggestion. I had the same problem and replaced mine a couple weeks ago.

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Re: loss of power on hills or under load

Postby Matrixx » September 19th 2009, 7:17am

Thanks for the kind words lessloop. That's what this site is all about, people helping people.:)
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Re: loss of power on hills or under load

Postby castle_Rock » September 20th 2009, 12:33am

From what Haynes manual stated, checking the CAT is very complicated since it requires expensive equipment in order to fully check it out, since I have never messed with the CAT before, is this fairly simple task, as mine may need to be replaced, but havnt checked it out. I have the slow acceleration, which I did replace the cap and rotor, left the old plug wires in since they were replaced last year, and the plugs, I left since they were replaced 4 years ago, but it would require alot of time to get to the plugs with the way their positioned about the engine. But its super slow accelerating, and doesnt shift normally.
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Re: loss of power on hills or under load

Postby astro355 » September 20th 2009, 3:16am

Just remove an O2 sensor that is mounted between the engine and catalytic converter and see if it runs any different. Converters cause engines to lose power because of the back pressure created by the clogged cat. If that is your problem, removing the oxygen sensor will allow the back pressure to escape and the engine will have more power.
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Re: loss of power on hills or under load

Postby castle_Rock » September 20th 2009, 3:25am

Thanks Astro - I'll try that tomorrow when there's light.
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Re: loss of power on hills or under load

Postby Matrixx » September 20th 2009, 7:44am

Hi castle_Rock

If you plan on removing an O2 sensor, then might I suggest you save yourself a hole lot of trouble and pick up an O2 sensor removal socket (picture below). If you do much work on your vehicle, it's a good tool to have in your collection anyways (I do). Just a thought.:)
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Re: loss of power on hills or under load

Postby castle_Rock » September 20th 2009, 8:09am

Ok, thanks Matrixx, I will see about buying that at the local Auto Parts, since I will possibly need it to remove it, as I don't want to tear it up with my wrenches. 8-)
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Re: loss of power on hills or under load

Postby Leeann_93 » September 21st 2009, 2:15am

You might need the shorty O2 sensor socket instead of the one pictured above. I had the long one and I can't get it on the O2 sensor on my truck, I had to get the low-profile offset version.

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Re: loss of power on hills or under load

Postby Matrixx » September 21st 2009, 5:08am

The picture I posted above is the same one I have and used a few times on my van. Odd that you can't get it to fit on yours leeann. What do you mean by truck? Van or Pick-up? thanks.

Having said that, the shorty does look more versatile, but I have never used it, so I can't comment more on it. Thanks for the info though. :)
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Re: loss of power on hills or under load

Postby Leeann_93 » September 21st 2009, 12:59pm

My Bravada, actually. There was no way I could get the long one on there (that fit on my Lumina, Dodge van, 240sx...). Haven't looked under my Astro yet, so I don't know.
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Re: loss of power on hills or under load

Postby castle_Rock » September 22nd 2009, 9:38am

since i don't want to start a new topic in regards to this, i thought I'd add it here,

The lever that connects to the servo slides freely when i press the accelerator down, is this supposed to move or be locked tight? Maybe this is why I'm getting poor acceleration.
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Re: loss of power on hills or under load

Postby astro355 » September 22nd 2009, 5:30pm

castle_Rock wrote:since i don't want to start a new topic in regards to this, i thought I'd add it here,

The lever that connects to the servo slides freely when i press the accelerator down, is this supposed to move or be locked tight? Maybe this is why I'm getting poor acceleration.


What lever are you talking about?
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Re: loss of power on hills or under load

Postby castle_Rock » September 22nd 2009, 10:57pm

well, i call it a lever, ;)
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Re: loss of power on hills or under load

Postby astro355 » September 23rd 2009, 1:14pm

The cable is for the cruise control and would not cause you to have poor acceleration.
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Re: loss of power on hills or under load

Postby castle_Rock » September 23rd 2009, 8:28pm

while it may not affect the acceleration, didnt answer the question.
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Re: loss of power on hills or under load

Postby astro355 » September 23rd 2009, 8:55pm

Its supposed to move, that's why the hole is elongated like that. Sorry for missing it earlier.
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Re: loss of power on hills or under load

Postby castle_Rock » September 23rd 2009, 10:09pm

astro355 wrote:Its supposed to move, that's why the hole is elongated like that. Sorry for missing it earlier.


Its all good, I guess it would make since that it moves with it having the long hole to slide back and forth on, but i dont understand how it works with the accelerator if is used for the cruise.

btw: what spark plugs are recommended for this vehicle as well as wires? I plan on replacing them all this weekend when I remove the radiator to put the new one in. I'm not sure what brands work best.
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Re: loss of power on hills or under load

Postby Leeann_93 » September 23rd 2009, 10:25pm

Plugs: AC Delco CR43TS
Wires: some say AC Delco, but I've had really good luck with Autolite Professional (not the standard ones).

Oxygen sensor is on the y-pipe, under the truck just behind the front passenger tire, sticking straight up.
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Re: loss of power on hills or under load

Postby castle_Rock » September 23rd 2009, 10:51pm

ok thanks, that info helps out alot.
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