The Truth About Cars » Idle Air Controller http://www.thetruthaboutcars.com The Truth About Cars is dedicated to providing candid, unbiased automobile reviews and the latest in auto industry news. Sun, 27 Jul 2014 20:45:49 +0000 en-US hourly 1 http://wordpress.org/?v=3.9.1 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 » Idle Air Controller http://www.thetruthaboutcars.com/wp-content/themes/ttac-theme/images/logo.gif http://www.thetruthaboutcars.com Piston Slap: Bad ECU, Cowboy? This Ain’t my First Rodeo! http://www.thetruthaboutcars.com/2012/01/piston-slap-bad-ecu-cowboy-this-aint-my-first-rodeo/ http://www.thetruthaboutcars.com/2012/01/piston-slap-bad-ecu-cowboy-this-aint-my-first-rodeo/#comments Wed, 18 Jan 2012 12:47:30 +0000 http://www.thetruthaboutcars.com/?p=426424

TTAC Commentator Tree Trunk writes:

Hello Sajeev,

I comment on TTAC as Tree Trunk from the frozen tundra in interior Alaska and am looking for advice on how to deal with an out of control repair of an old beater. I have a ’95 Isuzu Rodeo with 130K that until recently had been a pretty low maintenance, reliable ride.

Out of the blue the check engine light came on and the engine stalled.  A handy friend checked all obvious things to get it running again without success.  It would start up run for a few min before reving wildly and then die.  Luckily I thought, it broke down close to a reputable shop (NAPA certified) so we towed it there.

Seven weeks and two thousand dollars, not to mention the rental car cost I am back at square one. First they diagnosed bad PCM, a rebuild unit was in five weeks later, two weeks behind schedule.  I made it half a mile down the road before it stalled again.

This time around it was supposedly a slack timing belt hitting the crankshaft sensor causing the engine to stall. Week and another thousand dollars later, after first ordering the wrong parts and then not all the needed parts the engine started up, but wouldn’t you know it stalled again.

In hindsight, I should have scrapped it the moment it broke down.  But short of finding a time machine that is not an option.

Now I am waiting the next call from the shop and need advice from you and the best and brightest. It seems obvious that the one or both of the diagnostics were faulty and some third thing is causing the stalling.

What do I do, keep paying with a smile, demand a full repair free of charge or something in-between?

Sajeev answers:

First off, this is NOT the Isuzu’s problem. Sometimes I treat Piston Slap like a child psychologist, blaming the parents for the bad behavior of a little kiddo.

That said, I am sure you are a wonderful “parent” and I’d never think otherwise. I blame your shop: my first indication was their first suggestion, a bad ECU.

Folks, the computer is rarely the culprit in a poorly-performing electronic fuel injection (EFI) system. Yes they are wear items, other more actively engaged EFI gizmos are far more fragile as time goes by. Many times a problem like this comes from a bad TPS (throttle position sensor) or the electronic idle/choke system, normally called an idle control valve.  The only way to know for sure is to scan for engine codes, write them down, and look up the diagnostic tree associated with that problem via searchable database. Any decent mechanic should do this. Thanks to Google, anyone reading this website can do it, too. I am not sure if your rig is OBD-I or OBD-II, and the latter is universal and rather easy to diagnose.

You need to know the codes generated from the Isuzu’s self-diagnostic test. Do you know them? If none are present, the EFI sensors themselves need to be tested to see if their electronic guts are to spec. In this case, I suspect the Idle Control system is at fault…but that’s just a wild-ass guess.

So what should you do? Demand answers.  Demand engine codes.  If the shop stutters and sputters in their answer, demand a full refund for your lost time/wages/money.

From what little I see, it really, really sounds like they didn’t diagnose the problem. And threw your money at the problem instead. Not good.

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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