Monday, June 11, 2012

The 500,000 Mile Computer Change / The “Crank – No Start” Solution

June 10th, 2012

Some time ago, when my full-size mid-90s GMC vehicle was approaching the 470,000+ mile mark, my vehicle again began to exhibit minor symptoms of the infamous “Crank – No Start” condition.  Basically, sometimes in the mornings, the vehicle would not start on the first attempt but then immediately fire-up on the second attempt.  In the past, I was always merely able to replace the fuel filter and the condition ceased.  However, this latest time R&R-ing the fuel filter didn’t seem to solve the problem as the crank – no start condition soon after began to recur (but only in the morning, really).   Otherwise, the vehicle ran great and never exhibited any signs of power loss under any driving conditions. Regardless, this intermittent condition began to weigh on me, especially as I was preparing for another coast-to-coast jaunt. 

What do we need to start a vehicle’s gasoline engine?  Spark, fuel, and compression, right?  So after changing the fuel filter which didn’t remedy the situation, the first thing I did was to check the compression (see: as I did a complete tune-up:  spark plugs, cap, rotor, then spark plug wires.  I then replaced the ignition coil and even the ignition module followed by a new ground strap from the block to the frame.  I replaced everything that had anything to do with spark creation that could have been the source of the issue except the distributor itself.  (And, no, neither the battery nor the starter was absolutely not the problem.  Duh!) The vehicle ran fantastic!  But, then soon after, the crank –no start condition started to return, sure enough. 

Most said, ‘who cares?  It runs great and always starts, why worry about it?’  On the other hand, the possibility of being in the middle of nowhere with the vehicle not starting and leaving the whole thing to chance did not thrill me.  Yet another suggestion was to merely keep a bottle of starter-fluid on hand in case of any significant starting problem – they reasoned: ‘it’s only 3000 miles across, right?’  And I was considering taking the possibly feeble advice too, mind you. 

I started to become somewhat frustrated (and maybe even obsessed) by the seemingly perplexing situation and wanted it to go away.  I began to ponder how I could get to my solution without needlessly replacing armfuls of parts that never needed to be replaced in the first place – merely to chase this ghost from the machine.  Nevertheless, I began to look to the reality of replacing the fuel system components such as the injectors, the fuel pump, fuel pressure regulator, and even the fuel lines,

I also began to do considerable research on the internet.  I found the problem to be extremely widespread throughout several makes of cars made from the mid-80s to Y2k+.  The internet websites suggested everything from a clogged catalytic converter (mine was new) to a faulty timing chain (mine is reported to last forever and never to break).  A couple of on-line experts hinted at a faulty computer (PCM/ECM) but most of those afflicted with the problem scoffed in response at such a suggestion due to the excessive cost and the intermittent nature of the problem and in light of the fact that their vehicle was otherwise running fine.  The PCM/ECM suggestion was often qualified by stating that the issue may not be the computer but merely a temperature sensor. 

And then it occurred to me.  Where else do we typically see ‘ghosts in machines,’ I wondered?  Computers, of course!!  But before I was to take any action towards replacing the computer, I decided to see if there were any engine error codes - even though no error codes had been displayed as the check engine light never being illuminated.  Sure enough, there was one error code in the system and the Haynes book hinted that the PCM could be at fault – among other several other possible sources of the error. 

Anyway, I took a slight gamble and paid approx. $200 for a rebuilt PCM/ECM and EProm and easily replaced it myself.  Three thousand miles and three weeks later, I have hadn’t had any ‘crank – no start’ scenarios/conditions as yet.  It doesn’t appear as any will be materializing anytime soon either.  The vehicle now runs and starts fantastically every time!    


PS.  I purchased the PCM/ECM from


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