The Truth About Cars » 4DSC http://www.thetruthaboutcars.com The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. Thu, 04 Dec 2014 19:13:59 +0000 en-US hourly 1 http://wordpress.org/?v=4.0.1 The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. The Truth About Cars no The Truth About Cars editors@ttac.com editors@ttac.com (The Truth About Cars) 2006-2009 The Truth About Cars The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. The Truth About Cars » 4DSC http://www.thetruthaboutcars.com/wp-content/themes/ttac-theme/images/logo.gif http://www.thetruthaboutcars.com Piston Slap: Maximum TPS Reporting? http://www.thetruthaboutcars.com/2014/09/piston-slap-maximum-tps-reporting/ http://www.thetruthaboutcars.com/2014/09/piston-slap-maximum-tps-reporting/#comments Wed, 03 Sep 2014 11:47:01 +0000 http://www.thetruthaboutcars.com/?p=903553   TTAC Commentator Eiriksmal writes: I read your plea for questions, so I’ll lob you a softball. Why has my 2005 Maxima’s TPS decided to randomly poop out on me after doing a warm start? Specs: 2005 Nissan Maxima 6MT. 135,000 miles. Electronic throttle. Stock air intake + (new, put in the first time the […]

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TTAC Commentator Eiriksmal writes:

I read your plea for questions, so I’ll lob you a softball. Why has my 2005 Maxima’s TPS decided to randomly poop out on me after doing a warm start?

Specs: 2005 Nissan Maxima 6MT. 135,000 miles. Electronic throttle. Stock air intake + (new, put in the first time the TPS acted up 3K miles ago) K&N filter. The car’s now on its third owner, having spent its whole life in Evansville, IN, Lexington, KY, and now Louisville, KY. At the rust belt’s frayed fringe, I guess. No surface rust anywhere on the car, though. Electrically speaking, it’s in good shape. (Save the rear ABS sensors… a rant for another day)

Relevant codes*: Throws a P2135 for sensor voltage being out of spec whenever it acts up.

Scenario: Drive the car a while to be fully in the operating temperature range. Turn the engine off. Wait for a long train to pass/run in and renew your driver’s license/do some quick shopping, now turn on car. Car slow to start. Throttle goes into fail safe** (hold the pedal to the floor, wait a few seconds, revs rise slower than a DD15). Turn car off. Wait a second. Turn car on. Blip throttle, engine roars. You’re back in business.

Attemped fixes: The mechanic at my work suggested I clean the MAF. I did that. He suggested I check the connector and clean it. It looks good, I sprayed some of the MAF cleaner on there, too. No luck, it still acts up. His newest suggestion is to follow the harness to the firewall and look for a pinch or something. That sounds like work to me, and I’m a pretty lazy guy, so…

My question is, how does a throttle position sensor go bad? It’s way up high out of the way of muck from the road, so what’s the deal? Specs state it should be between 0.36V and 4.75V (at full throttle), so it’s not like there’s some high current load burning it up. The problem is that I can’t find an actual throttle position sensor in the Nissan parts diagrams, and I realllly don’t want to spend $615 on a new throttle body (file away this nugget: try CourtesyParts.com, they’re the best OEM retailer of Nissan parts I’ve found.).

Question 2: What’re the chances that something’s wrong with the harness? Why would it go away after a restart? (Yeah, that latter question is a crappy one)

*Other codes: Dreaded P0420 on the precats I installed 2 years/30,000 miles ago to treat the environment right and turn off the P0420. Also lit is the parking brake light, the traction control disabled light, the “your wheels are slipping/TCS engaged” light, and the ABS light. The car’s upset that I snipped two fusible links in the engine bay to kill all power to the ABS actuator. Cough. That was about three months ago and is wholly separate from the throttle control.

**From the FSM:
“The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10 degrees. The ECM controls the opening speed of the throttle to be slower than the normal condition. So, the acceleration will be poor.” No, really!?

PS: How’s Sanjeev doing these days? He’s been quiet for a while.

Sanjeev answers:

It’s about time you people demanded my presence!

We know I don’t respond with garbage like “ZOMG SON U SWAP LS4-FTW lest Panther Love because I’m a big stupid jerk in my First Generation Mark VIII”…or whatever he normally says. Wait, what’s your problem again?

Sajeev answers:

While my arch nemesis with the far more common Indian name continues to disappoint, let’s talk Nissan Maxima TPS. Engine code P2135 points to a problem with the drive by wire (i.e. no throttle cable) system, which is excellently described here. Long story short, there’s a sensor on the go-pedal, another 1-2 more on the engine’s intake throttle plate, an actuator for said plate, and some wiring to make it work.

The wiring could be bad/dirty/corroded/loose at either sensor, but odds are cleaning and checking won’t cure the problem.  There’s a good chance one of these sensors went south.  That’s because anything that moves does indeed wear out: remember scratchy old records on the Hi Fi? That’s the wear a seemingly non-moving sensor endures!

And lucky you: if the sensor on the throttle body side is bad, you get to replace the throttle assembly.  Because that’s how modern drive-by-wire systems work: yeah, how fun!

Do yourself a solid, read the above hyperlink.  If the throttle body is bad and you’re broke, consider a reman part instead of the original: they’re about half the price. And since this is a 10-year-old machine, be ready for the worst…you will need a replacement throttle body. Hmm-kay? Yeeah. 

TPSreports

photo courtesy: heatherpierceinc.com

 

Send your queries to sajeev@thetruthaboutcars.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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Piston Slap: 4DSC goes to Infiniti and Beyond? http://www.thetruthaboutcars.com/2011/12/piston-slap-4dsc-goes-to-infiniti-and-beyond/ http://www.thetruthaboutcars.com/2011/12/piston-slap-4dsc-goes-to-infiniti-and-beyond/#comments Wed, 21 Dec 2011 12:14:48 +0000 http://www.thetruthaboutcars.com/?p=422788   T.J. writes: Hey guys, The day I knew was coming but hoped would never arrive is here.  I have to decide whether its time to replace my trusty ride, a 1996 Infiniti I30 with estimated 235k miles (odo was broken years ago, repaired, and reset to a mileage amount we now think is low.  […]

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T.J. writes:

Hey guys,

The day I knew was coming but hoped would never arrive is here.  I have to decide whether its time to replace my trusty ride, a 1996 Infiniti I30 with estimated 235k miles (odo was broken years ago, repaired, and reset to a mileage amount we now think is low.  actual miles is probably around 250-260k).  The issue is an oil leak.

It’s now leaking at the rate of about 5 quarts every 3000 miles.  I’ve been content to keep topping off the oil, but now the leak is causing other problems; specfically, the a/c and alternator belt will not stay on because the pulley is soaked in oil.  Fixing the leak would be over $1000, and this would the third or so leak that we’ve plugged, only to have another pop up, so I’m convinced that if I was to fix it, a new engine is the way to go.  I have an estimate from my mechanic (a very reasonable, trustworthy independent shop) for $2200 or so ($850 for a used local engine with 90k miles, $200 in other parts, and 13 hours labor).

That estimate will probably go up to around $3k (my guess) as I told him I’d also want to replace the transmission (original, never been rebuilt), and engine mounts (needed to be replaced years ago).  The book says to remove the engine from the bottom, so since all those pieces are coming out anyway, he said there wouldn’t be additional labor, only parts.  I’ve sunk almost $2k into this car this year for new shocks, a new harmonic balancer, and 3 new tires less than 3 weeks ago.  A/C was replaced only 1-2 years ago, radiator, I’d say roughly 50-60k miles ago.  Nonessential functions are a mess, though.  Cruise control and radio don’t work (I have a 45 minute highway commute, so those aren’t luxuries), and I can’t use the trunk due to being rear-ended by an uninsured driver, which caused about $1200 in damage to my rear bumper and trunk lid, which has never been repaired.  I have more than enough saved to do this repair, and at my current savings rate, it would take me about 3-4 months to recoup the $3k.  I’m now driving about 15k miles a year.  If I was to replace the car, I would not be getting rid of it.  Due to its condition, its worthless to anyone else except me.  Plus, this is the only car I’ve ever had.  I’m almost 28, and I’ve had this car since I got my license at 16 and put almost all the mileage on it (it had 42k miles when we got it), so it feels like a high school sweetheart I ended up marrying.

My plan if I was to replace it now would be to park it until I had sufficient funds in a few years to get it fixed up and running again.  If I do replace it, I’d likely be waiting for a couple more months and driving an extra family car my parents are willing to loan me till then (I recently started a new job and probably won’t be off new hire probation for 2-3 more months and do not want to be buying a car till then).  Thanks for the advice.

Sajeev Answers:

Since you will keep this car forever (I LOVE HEARING THAT!) do not fix this motor, instead grab a low mile motor from an auto recycler, put fresh gaskets on it, and install. The extra cost incurred is totally worth it, as you’ll get a ton of extra life.

This is also a good time to consider LS4-FTW, but that’s because I haven’t said that in a long, long time.

Restomodding is the name of this game: I was in your shoes when I was 23, with a similar car…a fairly undesirable Fox Body Mercury Cougar XR-7.  Now, almost 12 years later, the Cougar is a bit of a cult classic, and everyone seems (pretends?) to love mine.  Sure, it isn’t a daily driver anymore, but it was at one point and I saved a ton of money driving it.  I call it “my soldier” as it always stood behind me and always impresses bystanders. Hell, I drove it for weeks while waiting for my new 2011 Ford Ranger to arrive, even though it needs a lot of work. It never did me wrong, and I love it for that reason.

Screwball Restomods are insane amounts of fun.  And since the Infiniti I30 is just a Maxima in nice threads, you can do the same. My Cougar woke up quickly with 5.0 Mustang parts, among other items from the Ford parts bin.  Your Infiniti can be a real 4DSC with a lot of Maxima.org forum searching and patience from both yourself and your mechanic: suspension upgrades, 5-speed stick, etc. It’s all in the palm of your hands. Ask stupid questions with respect.  Read the posts of smart people on the forum. Absorb everything.

Buy a newer vehicle whenever you need it…but keep it cheap.  You, by your own admission, are married the Infiniti. So don’t let any schmuck stop you from keeping your I30.

Listen to the madman typing behind the scenes on this webpage, you will NEVER regret this.

 Send your queries to sajeev@thetruthaboutcars.com . Spare no details and ask for a speedy resolution if you’re in a hurry.

 

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