By on January 7, 2015

 

U Relay Got A Problem? (photo courtesy: APaGttH)

TTAC Commentator APaGttH writes:

Sajeev!

Long time listener, first time caller. The patient: a 2005 Saturn Relay FWD3 with 151K miles, GM 3.5L V6 and 4-speed automatic. I am the fifth owner and this is our grocery getter and general abuse vehicle. I’m the longest owner – 4 years and about 55K of those 151K miles have been in my garage. I can’t comment on how well it was cared for from year 2 to year 6, but I have done everything by the book since 96K miles.

The Saturn developed a rough idle of sorts about a year ago. I swapped out the spark plugs, changed the fuel filter, and flushed the fuel injection. The car continues to idle rough. No CEL and no CEL history.

Rough idle doesn’t start until the engine is warmed up. There is an occasional difficult hot start, but nothing that falls into, “crap, I’m going to be left for dead because this won’t start,” hard. The rough idle isn’t shown on the tachometer, which is as steady as a rock. But the engine definitely feels like it is vibrating for a lack of a better way to describe it, and far beyond the general coarseness of the GM “high value” 3.5L V6.

The hood is resonating and making metal vibrating noises from it – which isn’t as alarming as it sounds as the fit and finish on the panels isn’t as tight as it should be. Put a few finger lightly on the hood and the noise goes away. The vibration is worse under load, like when the AC is running, and reaches a point you can feel it in the car seats. Acceleration is perfectly normal, driving is perfectly normal, and fuel economy is perfectly normal. No issues outside of idle. There is no rotten egg of burning match smell, and van recently passed emissions. Another thing we’ve noticed – living close to sea level, the problem is worse. If we cross the mountain passes and go to altitude, say about 2.5K feet or higher, the problem goes away. If I give the car light gas at idle, to say 1.2K RPM, the vibration goes away.

I’m stumped. Possible candidates in my mind include the IAC has gone, or is going bad, vacuum leak Hell, bad motor mount, or a dirty MAF and/or throttle body. Given the book value is under $4K and my plan is to drive it to 200K or death, whichever comes first, I’m not interested in pouring a ton of money into the van at this point, but I would like to get this addressed as it feels like something I can’t ignore.

Sajeev answers:

You “relay” should scan the computer to see if there’s a latent code that isn’t triggering the CEL.  And U “relay” should consider the smooth idle of LS4-FTW instead of this High Value LX9’s bad idle.

The engine vibration turning into body (hood) problems means that the mounts to the body are the problem. But perhaps new mounts aren’t in your budget, as you’re saving up for LS4-FTW, obviously. In the meantime, there was a TSB with a recalibration resolution to address the hot-restart issue. Get that done first, if applicable.

If that doesn’t cure the bad idle, or if it isn’t applicable? Well… maybe the Relay “relay” needs new mounts, especially the torque mounts (I forgot their name) as seen in the photo below.

Very professionally highlighted in red. (photo courtesy: gtcarlot.com)

Basically, LS4-FTW is the only answer.  We gotta believe, we must ensure the notion of a bad-ass V8 U-body actually turns into a trend.

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

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53 Comments on “Piston Slap: The U Body, The Relay Bad Idle...”


  • avatar
    PonchoIndian

    Bad engine and or transmission mount?

  • avatar
    dwford

    Obviously the solution to needing motor mounts is a V8 swap.

  • avatar
    psarhjinian

    I had the “difficult hot start” on my Montana of the same vintage and engine. Apparently they all do that. I attribute it to U-Body shame.

    But yeah, this sounds like an engine mount. Sajeev is right: if it’s not throwing a code and the operating parameters look normal, that’s likely the issue. See if you can get someone to help you visually inspect the engine.

    The LS4 swap… I hate to say it, but it might not be a bad idea for once. Anything you need to do to this car pretty much starts with “decouple or remove the engine” so, well, if you’re already partway there. A few people recommend a blown 3800 instead.

  • avatar
    Nick 2012

    OK an LS4 U-Body would be pretty fricking cool. And it’s fairly awesome you can bolt on GXP parts to a U-Body.

    Right until it all goes horribly wrong…

    http://www.iihs.org/iihs/ratings/vehicle/v/chevrolet/venture

    • 0 avatar

      I thought the Chevy Uplander (and the Saturn) was upgraded (safety-wise) over the Venture from whence it came.

      http://en.wikipedia.org/wiki/Saturn_Relay

      • 0 avatar
        Nick 2012

        It was and is the reason for the beefy nose. The LS4 guy is building one off the soggy noodle structure.

        We had a 1998 Venture when I started driving. It was a pretty decent van for the time, with its Euro-style handling and handled my abuse well (folks only let me drive the van).

        I remember my parents were watching Dateline when they released the crash footage from the Chevy Venture test. Deformation was so bad the dummy’s metal leg snapped.

        Three days later, a Volvo V70 took the Venture’s place. My dad still bitches about the depreciation hit he took on the Chevy.

        http://www.iihs.org/iihs/ratings/vehicle/v/chevrolet/uplander

        • 0 avatar

          Now that is a good story. Thank you for sharing.

          • 0 avatar
            Nick 2012

            It was a watershed movement for an exclusively GM family, and my parents willingly endured the some of the worst crap to roll out of the General’s factories.

            GM had to know the Venture would crumple like a sponge but they sold it to families anyways. Even after the IIHS test, Chevy claimed in Venture ads that “Your family’s safety [is] top priority.”

            Here’s a run-down of their cars since I’ve been born until they mostly got over their Stockholm Syndrome:

            – Chevy Vega
            – Chevy Citation
            – X-Body Buick Skylark (making them the proud owners of 2 of GM’s deadliest sin)
            – Buick Riviera (this had the awesome touch-screen control thing that was so cool in 1988)
            – Chevy Celebrity “Eurosport” wagon
            – Chevy Astro AWD (I have fond memories of this thing)
            – The Venture
            – Buick Park Avenue Ultra (the reason I could only drive the van).
            – Volvo V70

            http://www.auto-brochures.com/makes/Chevrolet/Venture/Chevrolet_US%20Venture_2002.pdf

          • 0 avatar
            319583076

            Holy cow! Chevy Celebrity Eurosport Wagon!

            Tell us about that one…

        • 0 avatar
          28-Cars-Later

          You folks still have it? The MY97-98 V70 FWD was about as not fracked as you’re going to get in new world Volvos of the period due to the carryover motor which did most of its niggling problems in earlier 850s (but 940 wagon still spanks it in TCO). IIRC MY99 is when the newer Aisin came out with the “lifetime” fluid (but it may have been MY00).

          • 0 avatar
            Nick 2012

            They had a ’98 V70 2.4T for about 5 years and got another V70 (the P2 variant) after the first. I was off to college in ’01 but don’t recall any major issues except for the ECM.

          • 0 avatar
            Nick 2012

            Ahh, the Eurosport – its 2.8L V6 “high performance” badges, a pretty cool exhaust, and riding in the back were good memories. My dad added aftermarket shoulder belts for the rear seats that were a PITA to get on and off.

            I also recall regularly pulling off the Chevy-badged center caps on the Eurosport’s steel wheels and using them for various unsanctioned activities.

      • 0 avatar
        psarhjinian

        The Uplander/Montana/Relay/Terraza (was there a Silhouette version? I know there wasn’t a Saab or Cadillac U-Body, but probably not for lack of trying) was upgraded over the prior version.

        It’s still no great shakes: the packaging sucks versus Toyota, Honda and Chrysler, but at least it won’t kill you as easily and the interior isn’t half-bad.

        I truly hate the SUV-alike hood. Awful…

        • 0 avatar

          There was no Olds division to make them by 2005.

          Agreed on the horribleness of these, I had one as a weekend rental…but LS4-FTW!

        • 0 avatar
          bball40dtw

          Wasn’t the Silhouette, “The Cadillac of Minivans”?

        • 0 avatar
          CoreyDL

          I can easily confirm the Terraza is utter garbage. I shall list the faults.

          -It’s boaty and floaty, yet crashes over bumps.
          -The transmission is dim and you must push too hard to get a downshift. Also loses speed up even small hills.
          -Even on highways at ~70, you don’t get more than 19mpg.
          -The interior dome lights have always flickered.
          -Seats offer little thigh support.
          -Not enough passenger space, almost no luggage space.
          -Panel gaps: interior, laughable. Exterior, laughable.
          -Impossible to see out the back because of the giant headrests.
          -Getting to rear seat a pain because of the installed fold-down cup holders between row two.

          A positive: The gauges are nice and clear, and the CXL version leather looks decent, in grey with charcoal piping.

  • avatar
    danio3834

    OK, so the consensus is LS4 swap. Count my vote in for that solution.

    Barring that, I’d go after mounts too since it seems like a vibration rather than an engine miss.

    • 0 avatar
      bball40dtw

      Isn’t you vote always for an LS swap? Not that it’s ever a bad answer. I’d vote for a presidental candidate who answered a question, “Well, the obvious choice, Bill, is LSX-FTW.” I think it would solve many political issues in this country.

    • 0 avatar
      bball40dtw

      You are always on board for an LS swap solution. It’s almost never the wrong solution though.

      • 0 avatar
        danio3834

        A turbo’d LS engine in a U body is now a dirty fantasy of mine. I feel the GTDI Flex needs a competitor at the drag strip.

        • 0 avatar
          bball40dtw

          There are GTDI Flexes at the drag strip? I’m not hanging out in the right places.

          • 0 avatar
            danio3834

            12s on a tune!

          • 0 avatar
            bball40dtw

            I keep looking at the Livernois tune, intake, and other upgrades for my wife’s MkT. Then I think, “Why am I going to let her drive around in a 500 HP hearse while I commute in a C-Max?!?” Obviously, I need to get a Mustang or something to replace my reliable, efficient, practical, cheap, and well designed C-Max.

    • 0 avatar
      Nick 2012

      Glad I’m not the only one lusting after an Ecoboosted Flex or MKT. I’ve only seen a few in the wild, one of which was rocketing up I-77 through the mountains in W.Va leaving everything else in its (substantial) wake. Fully loaded with a roof and bike rack. My pentastar van couldn’t come remotely close.

      • 0 avatar
        bball40dtw

        With 17″ wheels and winter tires, our MkT ecoboost is an absolute beast in the winter. It eats highway miles at a voracious pace. I see many Flex Ecoboosts around here since they are a preferred Ford management lease option. Limited trim, two tone, black roof, 20″ painted wheels, ecoboost, and loaded up.

  • avatar
    danio3834

    Use a pry bar to rock the engine fore and aft while checking for play in the mounts. Also check for things attached to the powertrain that might be grounding out on the body like the exhaust pipe, A/C hard lines etc.

  • avatar
    Arthur Dailey

    Had 2 of the original Montanas (1997 and 1999). Got them to replace Caravans (a 1993 and a 1996 which had replaced a 1992) because 1) I was tired of having transmissions replaced, 2) I was tired of the shoddy service from the local Dodge/Chrysler dealer, 3) We liked the ‘modular’ seating. Each of the rear 2 levels of seating was comprised of independent bucket style seats, that could be individually removed and configured in a myriad of patterns.

    The only problem we experienced was with the A/C system.

    Replaced them with 1) another Caravan (the redesigned 2005 model), 2) a 2002 Venture with 2 bench style seats and the ‘built-in’ child seat option. The GM child seats were terrible compared to those in the Caravan. The poor kid would cry if she had to sit in the Venture’s seats. Also for some reason one of the sliding doors never fit quite right. Multiple in warranty visits to re-hang it.

    Traded the Venture for a 2006 Montana SV6 (the ‘pig-nose’ version). Used this to commute through some of the worst roads and during some of the worst recent winters in Southern Ontario’s history. Never felt unsafe. Possibly due to its heavy front end. Even the gas mileage was pretty good as it handled 114kms per hour at just over 2,000 rpm. The interior has worn very well. Not a speck of rust or even stone chips (good quality paint?). It far outperformed the Caravan (a 2005 model).

    Traded in the Caravan. Having replaced the alternator and water pump. Rust was starting to appear on the bottom of the sliding doors.

    Felt confident enough about the Montana that my employer bought it as a company delivery vehicle and they rave about its dependability and capacity. The only repairs other than regular maintenance have been to replace the front struts.

    Wish that I still had the money that I wasted by replacing those other vehicles as often as I did. During that period also had a Malibu (no problems at all, a very good car for the money) and a Grand Cherokee (another in warranty transmission replacement) and briefly an Explorer which was basically useless because the driver’s seat was so small that I could not put on the seat belt while wearing a winter coat.

    • 0 avatar
      APaGttH

      The pic of my Saturn above is from about 18 months ago. I can confidently say, the paint quality is excellent. It is smooth, deep, and even after all these miles the front nose has only a couple of small chips. The van definitely “cleans up” well. I’ve reached the point where regular washing and waxing is no longer a priority for the vehicle.

  • avatar
    alawat

    Fixed a similar hard start/surging idle problem with the same engine in my Malibu by cleaning the throttle body. Problem has been gone for a year. If you also read the linked g6owners site to conclusion, the OP fixed their problem the same way. The idle relearn takes a while but it will eventually normalize.

    • 0 avatar
      EAF

      +1. This is where I would begin as well. It is practically free to try. You just have to buy the solvents.

      I would remove and clean the air flow sensor.

      Inspect the intake boot for rips and tears.

      I would remove the t/b and clean both sides of the plate (toothbrush). It isn’t necessary to remove a drive-by-wire but I do because I am OCD. You can have someone you TRUST turn the key to ACC and hold the trottle pedal down (opens plate) while you clean the throttle body bore. Watch your fingers. Lol

      Reinstall everything, new air filter, and perform the relearn procedure.

      I ¿BELIEVE? the relearn for you would be just allowing the car to idle in Park with auxillaries off for 5 minutes. Turn off for 60 seconds and repeat. Check engine lamp must be off for relearn.

    • 0 avatar
      EAF

      +1. This is where I would begin as well. It is practically free to try. You just have to buy the solvents.

      I would remove and clean the air flow sensor.

      Inspect the intake boot for rips and tears.

      I would remove the throttle body and clean both sides of the plate (toothbrush). It isn’t necessary to remove a drive by wire but I do because I am OCD. Or, you can have someone you TRUST turn the key to ACC and hold the trottle pedal down (opens plate) while you clean the throttle body bore. Watch your fingers. Lol

      Re-install everything, new air filter, and perform the re-learn procedure.

      I BELIEVE the re-learn for you would be just allowing the car to idle in Park for 5 minutes. Turn off for 60 seconds and repeat. Check engine lamp must be off for re-learn.

  • avatar
    APaGttH

    Thanks for posting this.

    Fun fact about this van. It’s first 13 months it was a GM press fleet unit. Yup, it is possible that TTAC writers past or present may have driven this very van, and lambasted it in reviews, a decade ago. (not while with TTAC).

    • 0 avatar
      seth1065

      Drive it to 200 K and than give it to Derek !

      • 0 avatar
        28-Cars-Later

        Cali is an interesting place, between the climate, size of the state, and numerous highyways it is not uncommon for cars to be very old and have incredibly high miles compared to some of the stuff you see in the Northeast.

        • 0 avatar
          dal20402

          When I moved from Seattle to Boston I quickly learned that a 40,000-mile used car was no longer “low mileage.”

          • 0 avatar
            Lorenzo

            My sister bought a 42k low mileage Subaru wagon in Massachusetts, and within 3 months had to put a double rubber mat in the front passenger footwell. That kept water and slush from coming up through the rust hole in the floorpan. She’s bought new ever since.

  • avatar
    SCE to AUX

    Replace the fuel injectors. Flushing them is a waste.

    I’ve had the same symptoms on two V6s around 80-100k miles. The injector is just a glorified mechanical poppet valve, and when they wear out they leak. When they leak, they dump pressurized fuel into the cylinder at the wrong time, and you get misfires and rough idle. The O2 sensor tries to compensate by leaning out the mixture, which whacks everything.

    If the problem isn’t acute, you won’t get a CEL, but it will run badly.

    • 0 avatar
      28-Cars-Later

      I agree with this, barring that my thought is replace the IAC and clean the throttle body which may or may not be mounted on said throttle body (it is on my Saturn SL).

      I’ve owned two Saturn SLs and there is still another one in the family. All three of them developed an issue where the transmission did not downshift properly when going down the steep hills ubiquitous to our local topography. For nearly 80K I drove the MY98 and simply shifted into neutral when heading down a steep hill until the throttle position sensor (TPS) mounted on said throttle body completely s*** the bed and needed replacing. I noticed AFTER this was replaced the car miraculously started downshifting correctly. I then replaced this on my like new 35K otc MY02 which was doing the same thing, which suggests this sensor simply degrades with age and not mileage or use. I’ll bet dollars to doughnuts this age related sensor degradation issue is symptomatic to plebeian model GM cars, if not *everything* they sell – you simply never notice because the old 60V6s and 3800s keep running regardless of these kind of issues. The TPS was $40 at Advance and was stamped “Made in Japan”. If you’re going to mess with the throttle body anyway, I say spend the $100 or so and replace its various sensors as I did. The whole van may drive better afterward even if it does not solve your idle issue per se.

      Additional: Did you, or plan to, drain the devil’s kool aide as well? I realize this was supposedly “ok” for the 3500 vs 3400/3100, but 28 does not trust the orange death in any iteration.

      • 0 avatar
        Arthur Dailey

        Having in the past year come into possession of a 2005 Buick with a 3800, could you please (or other reasons) expand upon this? Should the Dexcool be flushed out and permanently replaced with another fluid or is it sufficient to replace old Dexcool with new Dexcool on a regular basis?

        Or should this be another question for Sajeev to post on?

        • 0 avatar
          28-Cars-Later

          @Arthur Dailey

          That’s an excellent Sajeev question and I would ask him, but I flushed it out of my MY08 3800 Pontiac in 2011 and replaced it with Prestone (I can’t recall but I think green). The issue with DexCool was it became too acidic over time and ate though gaskets (notably the LIM gasket) in many of GM’s legacy motors (3100, 3400, 4.3 V6, 350 V8) and it also can gum up and harden (check your rad and reserve tank caps). Supposedly this was “fixed” around MY04 or 05. 3800 is still an iron block and came out decades before DexCool was even an idea so the Church of 3800 says to hell with the devil’s kool aide. AFAIK no other mfg but GM uses DexCool, so if this stuff were the real deal wouldn’t other mfgs catch on?

        • 0 avatar
          APaGttH

          There are no issues with the GM Series III 3.8 NA or forced induction and Dexcool.

          There were some problems (but not epidemic) on the Series II 3.8 in the early 2000’s. Addressed in 2004.

      • 0 avatar
        APaGttH

        No Dexcool issues on the 3.5 or 3.9 – I use it – has been the case for 152K miles and no issues.

  • avatar
    dal20402

    The 3.5 V6 is a good example of an engine that will run poorly longer than most engines will run at all.

  • avatar
    28-Cars-Later

    U-body’s most deadly sin was spawning the Aztec and Rendezvous.

  • avatar
    StudeDude

    I owned a ’96 Intrepid, 3.5, 125K miles and and had the identical issue. Did a complete tuneup, changed the motor mounts, even changed out the vibration damper—no real change. Car ran fine under load, got 26 MPG on the highway, etc. The issue was a leaking intake manifold gasket. I found this possible solution on an internet forum and since the gasket kit cost $6 @ Advance Auto, decided to give it a shot. I used Permatex Copper forma-a-gasket in addition to the Felpro kit, let it dry for 24 hours and Presto, the car idled smooth as silk–problem fixed.
    I would also point out that a defective check valve at the power brake booster can give similar symptoms, not to mention the booster itself if it has an internal leak. Hope this helps.

  • avatar
    lonborghini

    “…about 55K of those 151K miles have been in my garage.”

    That is one big garage. I’m green with envy. I don’t have a garage.

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