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Chevy S10 - GMC S15 and Sonoma Starting problems



  • Pressure is right at 60psi. Strange, everything checks out......yet when it's turning over periodically it stops for a sec, then turns over repeatedly again. I can't figure out what's causing the occassional snag. We removed the serpentine and tried and got the same thing. All other pulleys were like new. Crank and starter going it alone and still something acted like it was trying to stop it. I'm kinda lost on this deal........ :confuse:
  • dunc2dunc2 Posts: 1
    I have tried for about 4 weeks to get my 1991 sonoma 2.5 going. I lent it to a friend who ran it out of gas. It 's fuel injected so I was not happy to hear that this happened. I have pulled the distributor changed the ignition module, throttle position sensor, O 2 sensor, fuel injector, checked all fuel lines. The only thing left is the fuel pump which is only 1 year old I just put it in. Can it lose pressure from being run out of gas? I put more than 1/2 a tank in to make sure that was not the problem. And if some one pours gas on the fuel injector it will run long enough to burn the gas they pour on it. Help I am at my wits end. And out of money!!!!!!!!
  • Any more ideas?..............Anyone?...........I'm lost too
  • gonogogonogo Posts: 879
    You already proved it's a fuel problem. Do you hear the pump run for 2 seconds with key on run?
    Try to start it and at the same time have some one hit the bottom of the tank below the fuel pump with a mallet or piece of 2X4, see if it starts.
  • Mine isn't a fuel problem, lol. I posted before the one about the loss of fuel pressure. Then when I asked for other ideas I ended up under someone else's post...................................... Don't know what kinda problem I got
  • gonogogonogo Posts: 879
    Ya, clicked on the wrong one.
  • tony78tony78 Posts: 16
    Interesting story, 1st thing to remember is to never jump start a car that has a computer or several computers that operate different systems, the proper way to jump start a comp controlled car is to disconnect the pos/neg cables,then charge the battery, preferably with a trickle charger if the battery is really low (checked with a volt/ohm meter first). The biggest problem with jump starting is that $en$ative and expen$ive electronic systems don't really like to get hit with a voltage spike. As for the starter the maximum time it should spin is about 15 seconds with a 3 to 5 minute cool down time between each cycle, the cycle time is variable as it depends on ambient/radiated temperature (heatsoak). Spark can be tested with GM tool ST-125 (looks like a spark plug with an alligator clip attached) blue spark=good, yellow=weak ignition, as for checking the ignition system follow in this order : plugs, plug wires, distributor cap, rotor, igntion module, coil. Hope this helps.
  • tony78tony78 Posts: 16
    oops! refer to forest gump, it happens.
  • tony78tony78 Posts: 16
    The possible reason the truck wouldn't start after your friend (?) ran it dry was because the fuel lines had air in them, back in the day we called that ' vapor lock' , try bleeding the air from the fuel line, the shop does this at the point where the fuel inlet line connects to the pressure regulator fuel rail assembly, or where the fuel line connects to the throttle body, this can be accomplished by using a vacuum pump (snap-on tools # YA 4000A, or equivalent). caution a flash fire can result if you try and loosen line while engine is cranked, wrong way to bleed air.
  • tony78tony78 Posts: 16
    A. volt/ohm meter
    B. test light
    C. compression guage
    D. vacuum pump/guage
    E. torque wrench
    F. screw drivers/phillips/standard/torx
    G.socket set /metric/english/ 1/4, 3/8, 1/2 drive
    H. wrenchs /box/open end/crow foot
  • Getting new starter tomorrow..........if we get the GM tester and it proves to be a weak spark, then what?
  • Boosting the truck was our only resort, as we didn't have a charger. Still didn't change anything. It does the same thing now as it did when it wouldn't crank. I'm sure that GM tool is the same as the spark tester I got. Just goes 'in-line'. Don't know how well it checks it as far as 'color-coded' goes.......but it happened to be light blue. May just be the color of the bulb though, lol. Any spark will fire with gas and air both present though, right? Weak spark would just make it run crappy......or so it seems. New starter still not in.......or haven't heard yet. :lemon:
  • woodnrustwoodnrust Posts: 1
    i have a 1987 s10 2.8L front wheel, 150,000 miles, just replaced o2 sensor, pcv valve, air filter, oil, and oil filter. inspected gas pump and lines, the vaccume lines, cleaned carburetor, (with carb cleaner spray) i replaced the plugs cables and distributor cap last year, used high end stuff, inspected it all.

    i have to crank the engine over three times to start it, or one good 10-15 sec one to start it. it fires during the crank over.
    when this problem started occurring the check engine light intermediately comes on, at the same time the light is on the truck runs ruff, mostly this happens in the morning. so when the light is on it runs ruff when no light, it runs good, and the hole time its takes 3 good cranks to start.????????????
    any help much appreciated...
  • tech3363tech3363 Posts: 2
    manual fuel pump or electric???
  • cruzer23cruzer23 Posts: 4
    Recently installed new fuel pump assy because old went bad. Ran great for 1 week then all of a sudden loss of power badly going up a hill, running at about 20 percent power. Puttered it home and changed fuel filter and it then ran at approx 60 percent power. Two days later it will not start, cranks hard and will fire with starting fluid for a couple seconds. Fuel flowing thru filter (disconnected engine side/soaked driveway nicely) and blew compressed air thru supply line to disconnected end at fuel meter block without prob. Still no start, ANY ideas???? Thanks
  • dbruckerdbrucker Posts: 3
    My s-10 would run after using starter fluid but would not fire without it. Replaced the TPS and it runs and starts fine.

    If the TPS is bad it won't signal the ECM that it needs full as it is telling it that it isnot starting.

    I bought my TPS at Advanced Auto for about $30.

    Any repair shop should be able to hook up a computer to tell you what degree opening it is showing at idle which will tell you what is up.

    Good luck
  • cruzer23cruzer23 Posts: 4
    Thanks for the advice dbrucker I will give that a shot.
  • cruzer23cruzer23 Posts: 4
    Tested theTPS with a meter and it met the specs in my repair manual. I got a cheap fuel pressure guage and it shows 16 pounds, anybody know what range it should be in? Thanks
  • I have a 2002 2.2L s10 thats having similar problems. As soon as I turn the key to start it, everything dies. Anything that draws alot of current does the same thing. If I turn on the lights it happens. If I put my foot on the brakes it happens. Afterwards the power slowly comes back. I had my battery check and it was good. Several days later, I put the battery back in. It started right up 8 - 10 times. I did this about 2-3 days. On the fourth day, when I went to drive it. Boom, it started all over again. Did you ever find out the real problem to this issue? Give me a call at 706 527-8740. Thanks. I look forward to hearing from you. I really do need this truck!
  • The truck will not start. When I try to start it, I lose all power. Afterwards, the power slowly comes back. I've had the battery checked and it checked out fine. If anyone has any suggestions, I have open ears. I really need this truck!
  • Check with the dealer. With the miles being as low as they are, it should be still covered under your factory warranty. Unless it has timed out.
  • jes87gmcjes87gmc Posts: 1
  • magnum1bmagnum1b Posts: 4
    We have a 99 S-10. My wife drove home from work yesterday and when I went to take it to get gas for her it wouldn't start. I bought an OBD-II reader and I get a P0420 code indicating the catalytic converter is not working as it should. I replaced the cat about three months ago (first of April) with a new unit I bought online. We have had no problems with it running since and it passed state emissions inspection fine after installing the new Cat. Could a bad O2 sensor cause the P0420 code as I did not replace it. Any other suggestions would be appreciated.

    J in Atlanta
  • timothys1timothys1 Posts: 2
    Situation, while driving the security light will come on, the fuel gauge will move to empty and the battery light will come on. This occurs randomly. after a while the gas gauge and battery light will go back to normal, but the security light will stay on for a while then go off.

    Also it will not start all the time, gmc nor mechanic cannot determine why. Last check there where no error codes but they thought it was a corroded ground cable. That did not correct the problem. 4 years and no one can help.

    Any Suggestions!!!!
  • magnum1bmagnum1b Posts: 4
    I have a 99 S10 with the 2.2 L. I think it's jumped timing. The wife drove it home Monday running fine. I went to get gas and it fired once and then wouldn't start. It cranked fine. It has ignition, fuel to the rail and all the normal things I would try. When I tried a little ether into the throttle body it backfired flames. I can also feel back pressure pulses when I crank it coming from the throttle body. I know next to nothing about these engines but am an A&P Mechanic and have worked many other engines in my time. I have a Manual (Haynes I think). In trying to remove the fan to get to the timing chain I am stumped as to how to get the bug nut loose which holds the fan and fan clutch. Looks like I need about a 1 7/16 open end or 18" Crescent wrench and an adjustable pin spanner to hold the pulley from turning. If anyone has an idea of something I should check before digging further into the engine I would greatly appreciate any help. I bought a code reader and it gave me a P0420 but I put a new cat on it in April 2008. I removed it to see it I could see anything and other than the O2 sensor possibly being bad I see nothing wrong. The manual says the engine runs open loop till the O2 hits 600 degrees so that shouldn't cause it to not start at all.

    Jack Ferguson
    Atlanta, GA
  • gonogogonogo Posts: 879
    I use a hammer and punch or chisel, it is right hand thread. Or go the big wrench and hammer, I don't.
  • magnum1bmagnum1b Posts: 4
    I found that there's a special tool J41240 which has a crowfoot adapter for a 1/2" breaker bar for the nut and a pin spanner to hold the pulley. It's available for check out from Advance or Autozone Auto Parts.
  • gonogogonogo Posts: 879
    I'm too cheap to buy a tool I don't need.
  • magnum1bmagnum1b Posts: 4
    I was able to loosen it with a long drift punch and a hammer. Torgueing it properly would be difficult that way though. I did rent a tool (no cost if you being it back in good condition) from NAPA to retourque it.
  • Hi folks, My 1991 S10 will not start. When I turn the ignition switch to start the vehicle, the engine does not turn over. Dashboard lights come on, but nothing else. This problem started a couple of weeks ago, but I would turn the key back all the way and retry, and then the engine would start. The problem has got progressively worse (increased frequency) until no matter how many times I turn the ignition switch, the engine no longer turns over. Any suggestions? Thanks.
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