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Chevy S10 - GMC S15 and Sonoma Engine and Underhood Problems



  • gonogogonogo Member Posts: 879
    Well I have read about fuel leakage with the 4.3 CPI system. If you do some googling on the system I think you will get loads of information. I have a 2.2 my self so can't help much.
  • mickeymouse2mickeymouse2 Member Posts: 161
    Since your truck has been sitting for a long time. Hook up a fuel pressure guage and turn the key on, engine off. Look for the pressure bleeding off after the initial prime. If it does, you probably have a leaky fuel injecter. When you first turn your key on, the pressure should go up to about 55 psi to 60 psi and hold there. If you are watching the fuel pressure slowly drop off and bleed down below 55 psi within about the first minut, yup. Leaky injector. Pressure regulators rarely fail on your truck. Good luck!
  • hopkins7hopkins7 Member Posts: 9
    2000 S10 4.3, 6 cy, auto, 145K. Running great. Problem is clunking/banging noise in right side of cab/wheel well area. Sounds like solid plastic housing banging against another heavy plastic housing. Glove box tight, new shocks, wheel lugs properly tightened, plastic wheel well housing tight, everything tight under front end. Doesn't sound like metal to metal sound. The banging/noise happens each time right front wheel hits a bump/rough spot in road. Mechanic has driven truck using electronic device to pick up noise in vehicles to no avail. The left side is not affected by the noise. Noise actually sounds like it's coming from under the right side of the dash. Haven't had the dash apart-yet.

    Any suggestions?
  • mickeymouse2mickeymouse2 Member Posts: 161
    Heater core might be bouncing arround a little. Try wiggling the outlets under the hood on the fire wall side, and see if there is some movement. Also check the blower fan motor, see if the mounting bolts came loose, or if the the plastic fan itself is wobbling on the end of the motor. You got a tuff one, good luck.
  • hopkins7hopkins7 Member Posts: 9
    Thanks, I'll give those a try.
  • 2002sonoma2002sonoma Member Posts: 6
    mudflaps / splash guards perhaps ?
  • jthill24jthill24 Member Posts: 3
    Hello All:

    I just picked up an 84 S-10 Pickup with a 2.8 v6, using the XBX vacuum diagram. The problem I’m having is finding where the Vacuum hose from the vacuum ball and Intake manifold plugs into. None of the dealers has any manuals left for those years. The XBX diagram doesn’t show the Vacuum ball or the vacuum line I need to hook up.
    All the other lines are in their spots.

    If I can put a picture up I will to show you what I’m talking about.

    If any of you have one like mine maybe you can look on yours and see where that line hooks to.

  • jthill24jthill24 Member Posts: 3
    Anybody ???????? I thought it went to the Vacuum mod on the transmission but I have the 700-R4 which doesn't have one.

    PLEASE, HELP.........................
  • jthill24jthill24 Member Posts: 3
    Well since no one thought it worth his time to try and Help.......................

    I finally found a diagram in a manual that shows this line was to the Vacuum Mod for the Cruise Control. The truck I have doesn't have cruise control in it. I guess some did have it in them.
  • backjetsbackjets Member Posts: 2
  • backjetsbackjets Member Posts: 2
    I was driving my 2000 s10 pickup with 200,000on it. I swapped the motor a little while ago, and the new motor has 34,000miles on it. When i was driving it, there was a minor knock on the rear left side, only when i get on it. The oil pressure gauge went from 20-50psi too. The knock only occured from 1500rpms-2200rpms. I think that the oil pick up might be loose, but not sure. Oil level is fine, and has been changed constantly since ive had it. Any Ideas on what might be going on??
  • acobboldacobbold Member Posts: 3
    automatic, changed front actuator valve $130 labor in 10 minutes to change, the 2x4 to 4x4 would not engage, it would stay in 4x4 all the time, whining noise front passengers side, changed valve now 4x4 to 2x4 works, apparently a common s -10 problem but still have front end noise,
    (sounds like heavy tire tread at hi way speed). it's not the tires though
    may have worn parts because of problem with actuator valve. only have 87,000 kms on truck, any suggestions :
  • kthompson2kthompson2 Member Posts: 1
    Timing Chain and tensioner broke on my 1995 S-10 2.2 had the timing chain replaced and now the truck will not start. I checked to make sure the timing chain was lined up right but still will not start.
  • mickeymouse2mickeymouse2 Member Posts: 161
    If all that checks out and the engine cranks but still doesn't start, check the compression. Valves may have got bent when the chain broke. Minimum compression is 100 psi on each cyclinder.
  • retiredflyguyretiredflyguy Member Posts: 1
    It all started at a stop lite. The service eng lite came on, started to miss and then died. It started up but was running real rough. Checked codes and said bad egr. Changed the egr, cpi unit as it was leaking, new ac plugs, wires, coil, cap, rotor. It runs great at an idle or when your rev it up, but when you put it in reverse or drive it starts to run rough. Take it out of drive and it runs smooth. fuel pressure is good.
    Need help.
  • darb324darb324 Member Posts: 1
    Having trouble getting my 2000 Sonoma with a 4.3L V6 to start on cold mornings when its around 20 degrees or less. The engine turns over but doesn't seem to fire at all. Not sure if its an electrical/ignition problem or a fuel delivery problem. The fuel pump runs when the key is turned on but am not sure if I should eliminate that as a possibility? It starts and runs fine when the temp outside is above freezing. Any suggestions or ideas would be appreciated.
  • ralveyralvey Member Posts: 1
    Hey guys i have a 1994 chevy s-10 LS extended cab with the CPI 4.3 and select trac 4X4 system. i have many issues with this truck that i need help/advice with.
    1. How hard is it to replace/rebuild the CPI system, what do i need other than the spider injection kit?
    2. Where can i get a new cable for my 4X4 system(from the shift lever to transfercase)
    3. both my windshield washer and intermittent wiper settings have gone. the wipers only run on the "high" setting. they both went at the same time so would that be the switch that has become inoperable?(cruise control still works...)
    4. How hard is it to replace the antennae cable as mine was burned apart due to the exhaust manifold.
    Any help would be greatly appreciated as i need to fix this vehicle asap for my summer work.
  • freddy0872freddy0872 Member Posts: 6
    Greetings! My dads 2001 S10 decided to take a mind of its own the other day. All of a sudden out of the blue it started to REV VERY HIGH! I can pretty much put the truck in first gear take my foot off the clutch and hold the brake and it wont stall out. I get three codes when I plug my reader into it. I get P0137 which is on O2 sensor and that is because he has an exhaust leak. I also get P0453 with is the EVAP and i also get P0507 which is Idle air controll system RPM higher than expected. Now between 507 & 453 i get lead back to the EVAP. Is this my problem? can anyone help me out please! We reciently changed out the fuel pump on it. and did plugs and wires. Thats about it.
    And help is appreciated!

    Thanks in advance

    Fred S.
  • acobboldacobbold Member Posts: 3
    update From message #321, after all was said and done, I changed the actuator valve, the mechanic said that there was moisture in the air line and when it is cold the truck is in 2x4 even in 4x4 after it was fixed !

    I then had to fix front Premium wheel bearings , after pricing 3 different suppliers Canadian Tire was the cheapest except for eBay, which by the way if you order O2 sensors off eBay make sure to ask if they are OEM, one's I bought had to be tampered with in order to fit properly, and no recourse because of the mistake, ask more questions...
    all in all I forked out $686.00, truck runs perfect now YEH!!!!
  • 92s10blazer92s10blazer Member Posts: 1
    I have a 92 4.3 TBI.... If it's the same hose as i had leaking then broke when i tried to remove it, then i went to hardware store and bought a fitting w/ a nipple and spliced it in. by the way i had to use an easy out/reverse drill bit to get the old zinc type fitting out of the manifold. :sick: Mine was a quick connect fitting hose too... Hope that helps.
  • egummeregummer Member Posts: 1
    Check into the cadilidace converter.(sorry for spelling weakness).I've had same thing happen and it was a blockage in the exhast.when engine has no presure from trans it can expel the exhast easier but when it is drivin it builds up and bleeds back into the engine causing it to run like crap,draging an anchor,lack of power.
  • gilmiigilmii Member Posts: 2
  • gilmiigilmii Member Posts: 2
    Just picked up this S-10 guy said only problem with it is that it doesn't shut off, you have to pop the clutch then disconnect the battery cause the key won't turn anything off just on. I am thinking that its the ignition switch but the seller said its the linkage is outta wack. Just looking to see it anyone has any info they can lend me or at least point me in the right direction. Thanks Dan
  • xxmjjxxxxmjjxx Member Posts: 2
    The intake is the TBI setup I think; looks like a carburetor with two direct injectors. If the truck has been sitting the check engine light goes on, but once warmed up it turns off. In park or neutral it idles ok with a bit of a miss, but in gear with brake pedal pressure it idles very rough. The stored codes read MAP sensor, and ESC/Electronic Spark Control. The truck runs great when traveling at any speed, with no hesitation or stumbling. My friend let me install a new MAP Sensor to see if it would help solve the issue, it did not. I also replaced the spark plugs and seen a minor improvement when gapped at .35 (old plugs gapped at .47). Please let me know what logical issues this could be before I go on a spending spree of sensors and what not.
  • xxmjjxxxxmjjxx Member Posts: 2
  • glen14glen14 Member Posts: 2
    Hi Guys. I've seen some very similar issues posted, but just not quite my truck's problem, nor have a seen a definitive answer posted.

    But anyway, I dread it that in hot weather (never a problem in other seasons), I will be at a stop sign or light; I may often hear the engine racing, so to speak - then when I attempt to pull away, I have a complete loss of power. Not a stall, but nothing when I put my feet on the gas pedal.
    It is a nightmare. People honk at me, and I create a hazard. I know from experience what to do: quickly as I can switch off the ignition, and re-start, fiddling with the key (and my steering column often locks). I then get it going, hear the engine race again, and hold clutch at half way, with gas pedal down, and I get out of there. Talk about stressful?

    During these episodes, or prior, I may or may not get engine warning light: "service engine soon." But oil pressure and temperature read normal.

    I should say also that I virtually have no AC in the truck. It's never been great, and I've had it serviced once with little or no long lasting benefit.

    Otherwise, I love the truck, have sunk in a thousand dollars recently into it, between brakes and tires. So I'm inclined to want to get this thing remedied once and for all, but if it means major cash, I might just have to trade it in. Don't feel comfortable selling it privately, with this known problem.

    Any ideas? Someone who drove it mentioned air intake as a source of the issue, but I have no clue.

    And does anyone feel as if I'm better getting myself fixed up with another truck (any good deals out there?). I'm moving to Atlanta in the next month, hotter weather, and I'm at decision point. Would ideally like to keep the truck and not fork out for another - but it might be more hassle and a false economy in light of this horrible issue.

    Any thoughts, greatly appreciated. THANKS.
  • glen14glen14 Member Posts: 2
  • rickb5rickb5 Member Posts: 1
    Replaced lower manifold gasket, now it won't start, since then, replace fuel pump, coil, and many other parts.
    would like some help. Thanks Rick
  • gonogogonogo Member Posts: 879
    You need to trouble shoot, have you lost fuel or spark, you need to check it out. Throwing parts at it can get expensive.
    If it ran before you replace the gasket, check all electrical plugs and grounds for proper hook up.
  • rtdmn92rtdmn92 Member Posts: 1
    Hi, I have been having the same problem with the same truck. If you do get this fixed please let me know what it was. Thanks.
  • fws4fws4 Member Posts: 5
    My 98 S10 2.2 2WD lost its drive belt with resultant loss of power steering. My son was driving and was only 3 miles or so from home, so drove it home. In the driveway, it was overheating but not horribly (220-230 on gauge). I did not hear it running, so unsure of taps, clanks, etc. Got new belt and it cranks but it will not start even with starter fluid. Good spark on all 4 plugs. Have fuel pressure of 44-45 psi on the fuel rail. Compression is only 30-40 in front 3 cylinders, 90 in rear cylinder. Comp. improves to about 60 in front 3 after I add a few squirts of oil in the spark plug holes, rear cylinder stays 90-100. All valves & lifters working when I took off the valve cover. Can my timing be thrown by the belt loss, resulting in valve bend/damage? Ran well prior to this, no speedster but dependable. Just rebuilt my wifes jetta after bad timing belt caused valve damage and don't want to do it again on this one. I'm not great at evaluating compression readings, how do you tell if it's valves or rings leaking? Thanks for your help, this site is incredible!

  • gonogogonogo Member Posts: 879
    From reading your message it got a lot hotter than 230 F, most likely got hot enough to take the temper out of the piston rings.
    The belt runs the water pump, a tow would have been cheaper, sorry.
  • mickeymouse2mickeymouse2 Member Posts: 161
    Sounds like it got too hot and blew a head gasket. Quick check is to fill cooling system so it is full. With radiator cap off and water to the very top crank the engine over. If water comes flowing out you have combustion gas in your coolong system and either a cracked block or blown head gasket. OOOps!
  • gonogogonogo Member Posts: 879
    Addition to my other post, ever since car manufactures came out with aluminum heads they have installed temp gauges, no idiot light. The reason being, overheat a aluminum head and it will crack, just about guarantied.
  • surfnturfsurfnturf Member Posts: 1
    There is a service bulletin about loose hood hinge bolts causing a clunk.
  • hopkins7hopkins7 Member Posts: 9
    mickeymouse, thanks for your help. I finally got around to checking out Technical Bulletin 01-08-63-001B through a friend. The cause of my noise was the Hood Hinge on the right side - excessive clearance. Had to install a spring washer. Problem solved.
  • hopkins7hopkins7 Member Posts: 9
    surfnturf, Thanks for your assistance. I got to the Techincal Bulletin through a friend - Excessive clearance in the Hood Hinge attaching bolt. Inserted spring washer, problem solved.
  • giakamogiakamo Member Posts: 4
    I am new here ad will try to get to the point. i bought my truck new in 02 and it has only 40k miles on it. my battery died, replaced it with a new one, i am now getting P0304 cylinder 4 misfire ses light is on and idles rough over 30MPH and it flashes. I have replaced spark plugs, to no avail. I then looked at the cap and rotor and they were corroded so I replaced them. ( i thought that would fix it honestly)and I still have the misfire in cylinder 4. very rough idle, stuttering when driving from a stop. once at 50MPH it's smooth as silk. I have put fuel injector cleaner in the gas tank as a preventive measure after this prob started just in case. I am going to try changing out the wires next. anyone have any ideas on this? After the wires, I will have spent 260 dollars on this problem. Thank you for your help
  • gonogogonogo Member Posts: 879
    Can't help you with a 4.3, don't know much about them. I do know if you keep driving with the check engine flashing, it will ruin the cat converter.
  • giakamogiakamo Member Posts: 4
    No worries there.. i am not driving it at all.. i baby this thing and don't drive a whole lot... ( i have agoraphobia and require meds to just leave the house) warranty ran out in april.. and just want this fix as cheaply as possible. if it's not the wires, then i can't imagine anything else but the fuel system... I am still open to ideas as i haven't had the chance to get to autozone for the wires
  • giakamogiakamo Member Posts: 4
  • giakamogiakamo Member Posts: 4
    ok update.. wires did not fix problem. should I be expecting to replace the injector, or the spider? and does anyone know where the poppet valve is ?
  • 814bigbuck814bigbuck Member Posts: 1
    i have a 2003 chevys10 4.3l vin x . on a hard up hill pull kicked down into 2nd gear the check engine begins to flash and it feels like its holding back, if you let off the throttle a little bit it seems to be ok but the light flashes for a little bit when i check the codes its usually misfire 5 or 6..all the tune up stuff has been done. at idle it seems to have alittle bounced to it. going to check fuel pressure tomorrow at work.thanks in advance for any help
  • sarahlee87sarahlee87 Member Posts: 1
    Hello. I have a 2001 Sonoma :lemon: that will not start. It seems to have problems when its damp outside or if i dont drive it for the weekend. Come monday it will not start. So today..monday.. i go to start it and all it does is turn over and thats it...or it tries to start backwards...ive got it to start every time it has done this but this is the worst its ever been. Ive tried jumping it... it has a brand new battery, not even a month old! my dad recently put new plugs and wires in it also. this truck hasnt even seen 98,000 miles yet! its also has a new cat that probably a little over a year old now.. no one can really seem to figure out whats wrong! HELP! thanks for your time... :) P.S. its a V6 automatic if that helps at all.
  • butch31butch31 Member Posts: 1
    i have a 1997 gmc sonoma 4.3 vin x it only misses on #1&2 cyl only . i thought it was the engibe, so i put a good one in and stll misses on 1&2 cyl, changed computer plugs, wires . injecters and pretty much everything under the hood and STILL misses on 1&2 cyl.....HELP!!!!!!

  • gonogogonogo Member Posts: 879
    Intake leak, head gasket leak.
  • mmmotorsportsmmmotorsports Member Posts: 2
  • mmmotorsportsmmmotorsports Member Posts: 2
    1996 GMC Sonoma 4.3 V6 5sp manual trans.
    At 3/4 to WOT throttle the vehicle surges/bucks and is not making the power it should.
    No codes, runs fine other wise.
    Also yesterday while stuck in traffic it appeard to become stuck on high idle at 1900rpm, pushing the vehicle along and idleing at 1900 at stop lights.
    After sitting 2 hours was back to normal.
    Again no codes.
  • plexico48plexico48 Member Posts: 2
    Hi Guys...I have a 2000 GMC sonoma 4cyl.auto flex fuel truck and i keep getting 2 codes Po179 and one for transmission slippage but after reading it all points to the flex fuel sensor located on the chassis under the ac unit on the passenger side ......my question is can i change some stuff to get this back to just a regular gas vehicle and what would it take to do this ..........same chocolate truck on learnmore page

  • plexico48plexico48 Member Posts: 2
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