Suburban still dead

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by bublitz3, Dec 11, 2010.

  1. bublitz3

    bublitz3 New Member

    Hello all, I own a 1995 Chevy suburban 1500 5.7 liter with 250K miles. I posted about a month ago about it not staying running. I finally got around to it kinda needing it for the holidays and being so busy plowing snow and working my other job. I replaced the IAC sensor and the throttlebody sensor, and I replaced the cap and rotor also because the spark looked weak and the to my surprise (not) they were corroded. Anyway it turns over and sounds like it wants to fire but doesn't. Im getting gas and Im getting spark. Ive replaced every sensor in it imaginable and the only thing I can think is the timing chain is done or stretched or something. I am at my wits end with this damn thing and I don't understand how a vehicle with such simple mechanics is so difficult to keep the matinence up. I'm ready to craigslist it, even though its the only means of hauling my entire family with me but I am willing to just cram them all in my pickup. Any ideas???????? I usually don't get stuck, but I am stuck.
  2. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    '95 down did have the old style timing chains, if its never been changed I would look into that.
  3. stephan

    stephan Rockstar 4 Years 5000 Posts

    You say you have fuel. What is your fuel pressure?

    At 250,000 miles, it could be the timing chain stretched, but it would have to be stretched enough for it to jump a tooth for it to keep it from starting. There's an easy way to check this without tearing it apart. Pop a valve cover off. Look for a valve that is open. Put a socket & breaker bar on the crank. Move the crank a slight amount against direction or rotation to remove any slack in the t chain in that direction. Mark the crank. Now turn the crank normal direction & watch the open valve until it moves. Now measure how many degrees the crank has moved. You don't need to be exact, even though anything over 5 degrees is a lot, because if you are less than 15-20 degrees it should not keep your engine from starting, as the ecu can compensate for this.
  4. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    I would look closer at the Fuel pressure.. Since even with 250K miles i havent really seen the timing chain be that much trouble, usually the more common problem is the fuel pump.... So id check the fuel pressure and go from there...
  5. bublitz3

    bublitz3 New Member

    Okay I did replace the fuel pump a year ago, I am told they do take a **** pretty quickly if you don't buy a decent brand. Mine was from AutoZone don't remember the brand but I had to buy the whole housing because the other one rusted away in my hands poor thing......I see fuel spraying in the TBI unit not a drip like last time when it did go out and smell fue. l I suppose I can hook up a fuel presure gauge quick. One thing though I did not hear it turn before I turned over the engine. Maybe it is faulty. The other thing is that it liked to miss at certain speed before it completely died 55-65mph was the speed. That is why I was concerned for the timing chain. The weird thing is the alternator went bad in it and ever since replacing that it seems to have just gone down hill. It always seemed to run poorly though ever since I bought it.
  6. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    I had a problem with the Distributor that caused a miss etc.. but you need to have at LEAST 13PSI of fuel pressure with the 350 TBI.... And even the good brand of fuel pumps will quit it was a poor design by GM all the way around.

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