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T5 1999, hunting at idle S70 1999

posted by  rickansaldo on  Mon Nov 1 08:40 CST 2004
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last visit: Sat Jul 9 12:53 CST 2011
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I recently bought a 1999 T5 V70 wagon....5 speed stick with 100,000 miles. All is fine EXCEPT, the car hunts at idle between 500 and 1000 rpm. There is a regular pattern of speed-up and slow down.

This is the first fly by wire year, with frequently failed throotle bodies, but this throotle body was already replaced by th last owner in 2003. It has no engine codes, no check engine light. The car starts fine. The throotle body is clean. My independent mechanic thought it was the throotle body...the dealer will not replace it since there is no code. (The dealer is stumped.) The car starts fine and idles at 1000 rpm, then when warm...it hunts. The car runs very smoothly when driving, no drivability issues, good gas mileage.

I've been told is could be a bad coolant temp sensor...but there is no error code.

Any ideas/similar experiences and solutions?








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    T5 1999, hunting at idle S70 1999

    posted by  jda2000 on  Mon Nov 1 13:07 CST 2004
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    last visit: Sun Jan 1 21:27 CST 2012
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    ETS modules can fail again, and I've read some failing withing 10k miles.

    If the dealer replaced the ETS last year, they know there is a 12 mos warranty on the part, so they pretend that the ETS is not the problem because there is no codes, just waiting to charge you again after 12 mos period expires.

    If I were you, I would take the vehicle for diagnosis to a different volvo dealership, and don't mention that the ETS was just replaced, just tell them the symptoms. Let them put it to the test and I'll bet they'll come up with a failing (not fully failed) ETS. Get the documentation in writing and return to the first dealer with the diagnosis.
    --
    '88 240, '92 745, '98 v70 John, Tampa Bay








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      T5 1999, hunting at idle S70 1999

      posted by  rickansaldo on  Tue Nov 2 03:42 CST 2004
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      last visit: Sat Jul 9 12:53 CST 2011
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      Thanks John. Rechecked the note from the prior owner...repair was $1000, done in July 2003. So I out of luck on a free part, but maybe I'll get a break from my dealer if that turns out to be the issue.

      By the way...starting is actually another issue. When warm it starts fine. Wnem cold it stalls once. Then starts right way like a normal car.

      I'm thinking it is some other issue...not the throotle body. It just seems so unlikely that they would fail again...within 2 years.

      I need a new thermostat...is doesn't always reach mid temp...runs cold according to the guage.








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        Take care of the simple first.... S70 1999

        posted by  jda2000 on  Tue Nov 2 03:56 CST 2004
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        last visit: Sun Jan 1 21:27 CST 2012
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        You have to take care of the simple and inexpensive stuff first, before you spend money on expensive components.

        The temp gauge should reach midpoint within 5 min.

        First, I would replace the t-stat and the coolant temp sensor (CTS) at the same time. These are inexpensive parts, and a failing CTS can give you weird symptoms.

        Second, I would clean the TB, and move the horns out of the front radiator area. Heat and sludge is what kills the TB/ETS module. By moving the horns out of the way to the left fender area, you allow better air flow thru the radiator area for better engine components cooling. Cleaning the TB and throttle plate prolongs the lifespan of the ETS module.
        --
        '88 240, '92 745, '98 v70 John, Tampa Bay








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    T5 1999, hunting at idle S70 1999

    posted by  rd on  Mon Nov 1 12:28 CST 2004
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    last visit: Wed Feb 18 04:10 CST 2009
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    See if the Electronic Throttle Module was replaced. That is the cause
    of most throttle problems in our new fly-by-wires.

    Never heard of the temp sensor being a culprit in idle hunting. But then again i've seen some crazy things with my car. I have had idle hunting for a few years like yours with no adverse performance.
    --
    C70 hpt m







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