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Chevy S10/GMC S15-Sonoma: Problems & Solutions

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  • pugstersjpugstersj Member Posts: 1
    steve.
    i'm going to guess computer, because i'm having the exact same problem. i just put in a brand new complete crate motor from gm and still have the problem.#2 cylinder is fuel fouling. my new motor came with injectors, sensors, throttle body, coils, plugs, wires. only thing left is computer.
    good luck.
    maybe someone will post that help us both.
    dave
  • tjdudetjdude Member Posts: 3
    My god! that's exactly how it happens, i think that will be!!!. I didn't think that was the problem because the mechanic said it wasn't but now that you describe the problem, i'm sure that you are right. Thanks
  • dmblair78dmblair78 Member Posts: 7
    I have a 99 s-10 with a 2.2 in it. For the mileage it could not run any better, however when I try to start it when it is still hot, usually after it sits for about an 1/2 hour to a hour it doesn't start well at all. Usually takes about 10 to 20 cranks to get it to finally run. Once it starts it runs just fine, doesn't miss or anything. When I start it in the morning or in the dead of winter when it's cold outside it starts on the first turn. I've changed just about everything including plugs, wires, ign. module, coil packs, alternator, starter, TPS and probably a few other things I can't think of right now. Also, shouldn't my hwy mileage be about 30 or so? I'm only getting about 22mpg on the interstate. Should this be some kind of hint??? Any help would be much appreciated. Thanks.
  • alcanalcan Member Posts: 2,550
    Remove the vacuum hose from the fuel pressure regulator and check for the presence of gas. If so, the regulator diaphragm is ruptured and requires regulator replacement.
  • canufixitcanufixit Member Posts: 165
    Just wondering - Is your engine running a little too hot ??? Could be that it's running on the hot side - then you shut it down - and all the latent heat in the system continues to elevate the engine temp a little more (after a 1/2 hour or so ...) - but after that time - the engine cools down and it starts OK... Check the temp, Gauge, Thermostat, etc ... Just a guess - but easy to check ....

    Good Luck!!
  • dmblair78dmblair78 Member Posts: 7
    I actually went to a lower degree thermostat. That made no difference. My truck doesn't run hot at all, well except when I have the air conditioning on. Thanks for the regulator tip, I will for sure check that out.
  • argp101argp101 Member Posts: 1
    Hello there, just looking for a bit of help here. I ran into this problem and cant seem to solve it. I have a 97 chevy s-10 V6 4.3liter, 4x4, auto. Now I have started to have some problems with the electrical gauges, 1st, when I turn the lights on the air bag signal comes on, turn the lights off, light goes off??? 2...check engine comes on after I have been on the highway and reach 100km/h for more than 10 mins... but eventually turns off after I have driven in the city for a day or 2 at relatively slow speeds?????? I have brought it into a few different garages and had them run the computer checks, but they cant seem to find a problem.... The last problem has to do with the voltage meter,, it is constantly jumping up and down from 10 to 14 on the volt meter.. I have changed the alternator, that was not the problem, I have repalced the positive battery cable and the power wire leading to the back of the alternator??? So this has become a process of elimination that is becoming expensive.... any one might know what the problems may be????? Oh last thing My truck has been through 2 alternators in the past 8 months, now I know thats not right,,, so whatever is causing my alternators to fry out I assume is what is causing my voltage meter to jump up and down??? any help or input would be appreciated Cause I am stuck!!!
  • chevlvrchevlvr Member Posts: 18
    Hi,

    Sounds like you could have a short, probably in one of the power cables
    running to the dash. You can try pulling the possitive cable off the battery and
    see if the truck dies. Also, does the alternator your putting in have voltage
    regulator built in, or is your regulator mounted somewhere else, if seperate
    that could also be the problem. good luck!
  • chevlvrchevlvr Member Posts: 18
    hey tjdude,

    I replied to your tps problem, just wanted to let you know about the other
    code they pulled on your truck, that code also has something to do with the
    tps, mine also pulled another code from the rearend, and mechanic said it was
    something to do withover acceleration on the rearend, like I had did a burn-out
    or something. So, what it is, is the tps being bad is telling the computer that
    the truck is over reving, so inturn the computer retards it so you dont blow it up.

    take care
  • beckie24beckie24 Member Posts: 1
    Having transmission problem, when code has been reset shifts fine, when it gets hot trans starts slipping again code pops back. Dealer saying its a solenoid problem, trans shop saying its an electrical problem, or maybe a thermostat issue. Does anyone have any ideas??? Need help :cry:
  • alcanalcan Member Posts: 2,550
    P0758 = Shift Solenoid B Electrical/ 2-3 Shift Solenoid Circuit Electrical

    Solenoids are electrically operated valves, so they're both right. Pretty simple to use the diagnosis flowchart for P0758. Might want to start by checking the trans wiring harness connector.
  • jbaker3jbaker3 Member Posts: 2
    1999 S10 V6 AOD just yesterday after 150,000 miles my truck started shifting funny into second gear. RPMs way up before slipping into second. Up till yesterday everything was working fine. Reverse is now gone also.

    Any suggestions
    Jay Baker
  • alcanalcan Member Posts: 2,550
    Are you sure the shift is into 2nd and not 3rd? If the sun gear drive shell fails (common problem) it'll lose 2nd, 4th and reverse. Requires removal and disassembly, and at 150K you might as well have it rebuilt.
  • walt03walt03 Member Posts: 6
    I have a 95 2.2 S-10. I have just put new wires on that are 8mm and I still have the spark jumping through them(OE is 7mm). I have checked the plugs, all the grounds, and I have also ohmed the coils and they are ok also. So what else could be the problem???
  • alcanalcan Member Posts: 2,550
    Use AC Delco wires.
  • walt03walt03 Member Posts: 6
    The thing is I have used AC DELCO, and they do the same. That's why I now have ACCEL performance wires witch are 8 mm.
  • jbaker3jbaker3 Member Posts: 2
    Only slips into second then its fine. Just changed the fluid and filter tonight. It looks very clean but I change it more often than needed. Still no reverse and I have not taken it for a ride to check on the slipping. With two kids in college I doubt I will be having the trans rebuilt. I can get one with 29,000 from a yard for $500.00.
    Any idea what a rebuild costs?

    Jay
  • alcanalcan Member Posts: 2,550
    Usually around $2,000 in my area. Make sure the salvage yard unit has a warranty which includes labor if it's a dud and has to be replaced again.
  • alaskan1001alaskan1001 Member Posts: 2
  • alaskan1001alaskan1001 Member Posts: 2
    1989 GMC S-15, 4.3l engine. When it's cold it will not hold an idle. I have found out today that if I gun it and the tranny jumps into the next gear it will be OK. Is there a sensor or something between the engine and tranny that might make this happen? My mechanic had it for 7 weeks and called uncle. So far the fuel pump, filter, relay, pressure reg., strainer, computer and prom, coolant temp sensor, ignition module, both TBI injectors, map sensor and Idle air control motor have been replaced. Also the the sensor ground has been repaired and the TBI base gasket replaced. Does anybody out there have a clue? I live in Alaska and winter is almost here I need the truck to idle.
    :confuse:
  • walt03walt03 Member Posts: 6
    Try the EGR valve for carbon,or the PCV valve, I have also have had the MAP sensor do the same thing. I would try the MAP sensor first. I hope this will help.
  • joeygenojoeygeno Member Posts: 12
    Joe, I have a real problem with a 98 S-10 and it may be related to the "dead fuel pump" dilemma. Replaced fuel pump assembly and filter. But to no avail. Still had a dead fuel pump when ignition key applied. Jumpered across FPRelay and engine would start and run----as long as I had the relay jumpered. When I removed the jumper, the engine immediately shut down. Looking at the schematic, the oil pressure switch should have kept the pump running once the engine started. I get battery voltage at the PCM with ignition on, but the fuel pump relay will not close. Haynes book is not very clear on the ignition circuit layout. Really need help here.
    Joeygeno :confuse:
  • joeygenojoeygeno Member Posts: 12
    FYI-----sorry I am late with this, but when you removed the bed-----you also removed the ground. Fuel Pump is grounded at the left rear, along with the lighting harness. (Two Grounds) and grounded to the frame. You would have had to remove them to take the bed off.
    Joeygeno
  • joeygenojoeygeno Member Posts: 12
    Alcan, please help!!!
    I am not getting voltage to the FP relay when the ignition switch is turned on. If I jumper the switch contacts of the FPR, the truck starts and will run-----But if I remove the jumper, the truck immediately shuts off. Schematic shows the oil pressure switch should have kept the FP running. Cannot figure this one out. Your answer to Jameyw in March 14 was very helpful in at least understanding the system function. I do not have a decent schematic of the PCM other than Haynes,. Please help
    Joeygeno
  • rundgreniterundgrenite Member Posts: 1
    We have a 99 Chevy S10 and I need to know where the Manifold Absolute Pressure Sensor is. We have been having problems with it cutting out and dying on us, sputtering. When it is cold it is fine, but once it is hot forget it. We have done so many things to it by now. We have checked a few sensors, but would like to check the voltage on the manifold absolute pressure sensor. Thank you.
  • joe3891joe3891 Member Posts: 759
    Sorry been busy installing DSL, the 99 schematic does not have the fuel pump relay. The relay coil is power 12 V from PCM, DK GRN/WHT # 2 relay wire C2 pin 8 at PCM black 80 way connector. #1 relay coil is BLK/WHT ground.
  • joeygenojoeygeno Member Posts: 12
    Thank you so much for replying. My 98 has a purple, (16pin), blue (24pin) and brown (24pin) . But as I said, I only have the haynes schematic and it does not have PCM pinouts or show the source IGN power . But I am sure the fuel pump does not run when the ignition sw is on. If I jumper the fuel pump switch contacts at the fuel pump relay socket (fuse box), the pump runs and the truck will start. With engine running, removing the jumper will immediately shut the engine down.
    According to my haynes schematic, once the engine starts, the fuel pump oil pressure switch should takeover.. My assumption is that the fuel pump relay (Fuse box) is only active in ignition start, and the oil pressure switch takes over when the engine starts.??? Again, I am confused
  • alcanalcan Member Posts: 2,550
    The schematic is below. Do you have V+ at the relay's green/white terminal with the engine running?

    http://www.autozone.com/images/cds/gif/large/0900823d8018c179.gif
  • blitzo1blitzo1 Member Posts: 1
    My friend, About a week ago i got some major smoke bellowing out the exhaust pipe on my 95 sonoma. I found out it was my Head Gasket. Im an auto part driver for a major parts company, so i asked quite a few mechanics what they would charge me i was quotes frome 600 ta 800. ok and a sister company of ours right up the road can mill the head and pressure check it at there place for 45 mill & 25 pressure check. Long story short since i have a good friend thats a mechanic i decided to do it myself.....(NOT RECOMENDED)....Luckily i get a discount on parts so i got a few gaskets, a few hoses, some head bolt$, much brake and carb cleaner, & a few other last minuite back to the store things. Got my head milled and P.C. for 25 bucks<---DEAL Paid like 50 bucks for all the gaskets,etc... all in all from the lowest quote i saved like 400 dollars.There 2100 sounds a little high.I am a real novice and my friend pointed most of it out to me and i should think a shop worth there sand can do what i did in no time flat.ALL I CAN SAY IS SHOP AROUND. To as many shops it the area you can call. sorry for the ramble..
  • joeygenojoeygeno Member Posts: 12
    Thank You,
    I will check voltage and get back to you. Do you have a component location schematic for the PCM system on a 1998?
  • eskimoyeskimoy Member Posts: 6
    :cry: 2 of my placemat were soaking wet all the time, and I tried to see where its coming from, but I couldn't find it, anybody here know the solutions thanks.. :)
  • eskimoyeskimoy Member Posts: 6
    :cry: 2 of my placemat were soaking wet all the time, and I tried to see where its coming from, but I couldn't find it, anybody here know the solutions thanks.. :)
    by the way my car was 93 sonoma v6
  • joeygenojoeygeno Member Posts: 12
    I am finding new information daily on this problem. Now I realize that my 1998 S-10 has a 2.2L 4 cyl VORTEC engine. This explains why I have had so much trouble locating the PCM. It is not under the glovebox as Haynes manual states, but on the right front of the engine compartment behind the battery. As I said, the Haynes manual is very generic, and nothing pertains to the Vortec engine in either text or schematics. I pulled the whole damn bottom of the inside access panels from the glovebox to the drivers side. Found a 6 x 6 black box marked Delco electronics, pulled it only to find out it is not the PCM. Got myself into a mess, as I broke a pin on one of the plugs etc...etc. So, I am back to square one, looking for the fuel pump problem of not initiating with the key turned on. (Relay not energizing. But, now i can at least do some diagnostics with the schematic you provided, and now knowing where the damn PCM is. Hope you have patience with me...... we will lick this problem yet, I am sure.
    Joe
  • joeygenojoeygeno Member Posts: 12
    Joe,
    See my message to Alcan (#1107) I will continue using your info on the pcm wiring tomorrow.
    Joeygeno
  • joe3891joe3891 Member Posts: 759
    Yes I saw, do what alcan said, check for power out the PCM. Turn key on run, you should have power for 2 seconds. :)
  • walt03walt03 Member Posts: 6
    I have a 95 S-10 and I keep blowing the fues for the turn signal. I have checked all the grounds and they seem to be ok. I am not sure what else it might be. I have even put in 30 amp fueses to try and find the problem but it just blowes them also. If anything it should burn a wire with the much voltage. Anyone have any more ideas??
  • burtmarburtmar Member Posts: 1
    While heading to the dump this last weekend my 1999 S10 4.3 just quit and now it will not restart. I had to tow it home. My son thought it might be the MAP sensor because when he tapped on it when we tried to start it it would fire but not run. Now with part replaced it's still a no-go.
    Any body have an idea?
  • joeygenojoeygeno Member Posts: 12
    OK, back on track now. Did what you said about 12 V from ECM on pin 8 DKGN/Wh wire. Found I only am getting 5.86VDC instead of Battery voltage(Measured at the relay socket). I then removed the ECM, removed cables and tested the Pin 8 wire to the relay socket. Checked ok for continuity, and no ground or resistance shown. Can you tell me what pins are the IGN power in to the ECM. Where does the ECM get power from when the key is turned on?? I suppose next step is to get the unit to the dealer and have it checked. Will a dealer shop do that service?
    Joe
  • joeygenojoeygeno Member Posts: 12
    Getting closer!!! See message 1112
    Should have an orange wire (Hot at all times), and a pink wire (hot in run/start), but I do not have the pinouts for the ECM. Asked joe to help . I am a retired mechanical Engineer, however , my lack of orientation with this vehicle shows in this instance. Usually when I see half voltage on a circuit it indicated a blown fuse or high resistance short. Not the case in the dkgn/wh wire to the relay socket. Asked joe for the pinouts to the source voltage.
    Joeygeno
  • joe3891joe3891 Member Posts: 759
    PCM blue connector. Pin 19 pnk circuit 439 Ignition Positive Voltage.
    PCM blue connector . Pin 20 orn circuit 440 Battery Positive Voltage
    The ignition power comes from the ign sw to the underhood fuse block feeding ECM1 15 amp fuse. That&#146;s all I can find, look for a ECM2 fuse that should be battery power.
  • joe3891joe3891 Member Posts: 759
    Went and looked at my truck, has too be ECM B 20 amp fuse for battery power to ECM.
  • tmchaneytmchaney Member Posts: 1
    I own a 98 S-10, extended cab, 2wheel dr, 4.3L V6, auto. I just about reached 75K miles on the truck and just did an oil change. My Check engine light came on and im suposed to do a trip this weekend for my Bday. I have a 2 hold question. First does the 98 S-10 check engine light come on at 75K because its a major check point and they want to let you know to go into the dealership. And if so is there a way to reset the check engine lilght to see if thats the issue. I know in hondas they have a simple why of resettign the check engine light without using a module or a programmer. Please help, this is my baby and i want to make sure its alright. I spent 2 hrs going over the whole engine when the light came on looking for anything and found nothing and it still runs like a dream. thanks guys
  • joeygenojoeygeno Member Posts: 12
    Pin 19 Pnk and Pin 20 Orn Show full battery voltage. Both fuses ok, however I still am only getting 5.86VDC at the fuel pump relay coil. (Measured at the fuse block/Relay box.) This would lead me to suspect I have a bad PCM. I do not know of any other way to diagnose why the PCM would output 1/2 voltage from the fuel pump relay inside the unit. Any other suggestions before I bite the bullet?
    Joe
  • joeygenojoeygeno Member Posts: 12
    Joe
    One more mystery to this problem. It may not mean anything, however, the oil pressure switch still has me confused. Looking at the Haynes schematic of the pump circuit, and an additional schematic I obtained at the library-------- it is quite evident that this Oil switch will keep B+ to the fuel pump once the engine fires and oil pressure comes up. And I assume that as long as the oil system pressure is OK, the circuit maintains until the ignition is turned off and the engine stops.
    Circuit logic states: Turn on ignition key, fuel pump energizes momentarily (2 sec), then engine fires and upon oil pressure increase, the oil pressure contact maintains fuel pump power until the engine is turned off.
    Remember when I stated that I jumpered the fuel pump relay contacts, the fuel pump came on and then the engine started? But as soon as I removed the jumper (engine running), the engine immediately stopped. This should not have happened. Problem----I cannot locate where this oil pressure switch is located. Is it on the engine, or on the instrument cluster??? Before I replace the PCM, I sure would like to research this part of the circuit. After all, something had to make the PCM fail. Bummer if I replace the PCM and have the same problem due to an outside cause. Your thoughts please.
    Joeygeno
  • joe3891joe3891 Member Posts: 759
    Don't believe them aftermarket wiring schematic, you are looking at old wiring. I have the factory schematic and they have done away with that on newer models.
    Before I would buy a computer I would do this to be sure. Jumper 12 v to the dk green/ white at the fuel pump relay with the PCM connectors removed, then see what you have at pin 8 with a DVOM and a test light.
  • jjj4jjj4 Member Posts: 5
    The problem with my 99 2.2L was a lose clamp between the resonator box and
    the throttle body.
    On your 99 2.2L when you try to start it up can you hear the fuel pump running?
    If yes you may need to check the ignition coil.
    jjj4
  • jjj4jjj4 Member Posts: 5
    I`ve had my 99 2.2L Sonoma now for about 2 1/2 years now and it has allways
    taken a long time to shift up from 1 to 2. I just thought thats just the way it was.
    But after reading some of the post here I found out it`s a problem.
    So two weeks ago I took it to the shop to have it looked at.
    The told we that a new set of spark plugs and a new fuel filter would take care
    of that problem.
    Will I handed over the $ 113.00. They did the work and the trans has worked just fine. I`m not sure what plugs and fuel filter has to do with the transmission-but
    it fixed my problem. jjj4
  • joeygenojoeygeno Member Posts: 12
    Joe,
    Not surprising, I jumpered as you said, Battery voltage is there. Are you sure on my 1998 that there is no oil switch circuit to the fuel pump??
    Shall I go ahead and buy the PCM???
    Joe
  • joe3891joe3891 Member Posts: 759
    If you have a 2.2 4cyl I know you don&#146;t have the oil pressure switch, not sure on the 4.3. All my wiring schematics are for the 2.2 because that&#146;s what I own. One other idea, plug in the blue PCM connector and leave the black connector off. The blue are all inputs and the black is all output so this should work. Check for voltage at the # 8 pin out of the PCM, I like to use a 12 V test light, a DVOM will not measure amps. If it will light a test light to normal brightness it will close the relay. I learned from experience after 12 V with a DVOM a test light would not light ,no amps. Going away and won&#146;t be back until Tuesday . Good luck.
  • tkes68tkes68 Member Posts: 1
    Help - The bearing that the fan attaches to froze up (looks like a water pump almost) What is this thing called,? Are there tricks to removing it? Should I replace w/ a used one?
    Tim
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