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GMC Jimmy Starting and Stalling Problems



  • Previous owner lied. They did NOT :mad: :mad: replace the fuel pump as they said. I dropped the tank and pulled the pump out. The sock filter was not on the pump and all kinds of trash :sick: was in the pump pick-up. It was like trying to breath through a pillow :P . I cleaned the tank and replaced the pump with a new bosch pump and filter. Runs like a champ. :shades:
  • it is getting gas to fuel pressure check valve. i was told i need to bleed the fuel injector is this right, and if it is how do i? does someone know how a site that would show step by step how to do this?
  • Fuel injector's bleed themselves when they open. If you are getting 55-60 psi of fuel pressure with the key on engine off, then pressure is good. I assume you have a 4.3V6. If you do, the injector is inside the plenum and you must remove the upper plenum to access the injector. You do have a fuse that is for the injector(s), check it. Do you have spark? You have several fuses and relays that can affect the no start. Purchase a Haynes Repair Manual at a parts store for around $20.00. I dont know what all of the problems that you have, but in short, get the manual if you plan on doing things yourself.
  • i have fire, can get the jimmy to run if i manualy pour gas through the choke. i have a manual (chilton) not much help so far anymore ideas really appreciate it. get all kinds of pressure at the fuel check valve on the fuel rail. so i think maybe the fuel injector. could that be it?
  • My '98 Jimmy won't start easily in the mornings. Turns over but takes a few times of key on and off to start.

    However, it starts up like a new vehicle on my lunch break and after work. I'm puzzled. Please help. I've changed both the fuel filter and fuel pump last year and haven't had trouble since until now.

    Any ideas???
  • Me thinks that you may have a bad distributor cap (if equipped) if you have 4.3 V6. When was the last time a tune-up was done?
  • Yes, you could have a bad injector providing there are no blown fuses. I assume that you have a 4.3 V6. Pull your oil dip-stick and see if you are getting gas in your oil. If you suspect gas in the oil, remove the cover on the upper plenum and remove the manifold tuning valve and look inside the plenum. There should be no presence of gas inside of there. If there is gas in the plenum, you have a cracked or broken fuel line. This common for the 4.3 that has the spider fuel injection system. If you see clean areas, you have a leak. This is a easy but expensive fix. I replace the spider when I replace the fuel line kit. If the lines are broken or cracked, do not repair the lines, replace the lines with a new kit.
  • Hi,

    Had similar problem. Found a breakdown on the coil to distributor high voltage wire inside the plastic protective cover. A pin hole area was covered with white high tension voltage arching. Replaced wire from a new set of spark plug wires, thread it into the protective covering and everything is fine.

    Hope this helps.
  • Thanks....I'll try looking at both the distributer cap and rotor (haven't done it in over 65000 miles).

    I'll also check the high voltage wire from the coil to distributor..

    Any other ideas before I start?
  • I have now had my Jimmy at 3 places & one was a GMC dealer. The dealer said my fuel pump was bad that I just replaced. So, after replacing it & the fuel filter AGAIN it stills stalls mainly in the morning when I'm heading out for the day, but will start right up in the afternoon with no hesitation?! Is it possible that the fuel pressure regulator is bad??? I'm at my wits end with this vehicle? HELP!!!!
  • Does it stall frequently? Does it die at stops or letting off the gas? Does it smell like it is running rich? If your answer is yes, then I would start here. You may want to review post #99 from me. Then if need be, pull off the cover on the upper plenum and remove the tuning port and look inside for gas? The spider/injector/regulator is one unit and is non-serviceable (must be replaced as one unit $$$$$$). The Fuel line kit can be replaced as a kit if one of the lines are cracked or blown. If this is the case, you are getting gas into your oil as well. There are so many variables to consider with your problem. If your fuel pressure is leaking down fast or is erratic on the gage, you need to consider what I mentioned. There should be no gas of any kind in the plenum and there should be no clean areas like being cleaned with carb cleaner.
  • At first yes, it was stalling frequently when I came to a stop & let off the gas & it doesn't smell like it's running rich?!'s stalling only when I turn? It will start right back up but still only when turning. It's been 2 days & it won't start at all (it cranks) unless I try 6-10 times. And as before mentioned it will fire right up late in the day? It's supposed to be towed to another (NUMBER 4) repair shop today & hopefully someone there can figure this out. I'm replacing things as guesses & financially it's just killing me...
  • My 1995 Jimmy was great until I started to have issues with the EGR valve. It would start to run badly and blow black smoke. I would pull the EGR valve and clean the pintle and seat and it would run fine for awhile "maybe 1000 miles" and then it would do it again. Come to find out it was the nut kit leaking gas causing the carbon to get wet in the plenium and then the carbon would bake and get hard, once it hardened it would break off and travel through the manifold to the EGR valve and get caught in the pintle causing the motor to have a direct vacume leak. I replaced the fuel lines comming into the manifold "nut kit" and also pulled the manifold off and cleaned all of the carbon out of it. That semmed to fix that issue. I NEVER replaced the EGR valve. About a month later the I parked the Jimmy for the weekend and didnt't drive it for the entire weekend. On Monday I went to start it and it would crank but not start. I checked the EGR and it was fine. I finaly got it started after I let it set for a full day and it seemed to run fine for the next week. I parked it again the next weekend and it happened again. It would crank a few times and then cough like it was flooded. it would also smell like it was flooded. I checked the schrader valve and it didn't seem to have any fuel pressure. I dont have a gauge to test for fuel pressure but it has a pretty new fuel pump on it so I assumed that it is good. If i let it set for a day or so it will eventually start. I read a document about injectors bleeding back but that didn't seem to fit on this application. I also seen a note about the fuel cap. On a whim I pulled the cap and tried to suck through it. It was very easy to suck air through the cap which was causing the fuel system to lose pressure. Once I put a new fuel cap on it is workin fine now. If I let the truck set it would eventually build up enough pressure to get it started. I hope that this helps someone because you all have helped me plenty..Thanks...
  • ez1969ez1969 Posts: 2
    My 2000 Jimmy was starting hard the last couple weeks so I thought I needed a tune up. It would run fine once it started. This weekend I went to start it and it wouldn't. So, I changed the plugs distributor and still nothing. It has spark so I thought no fuel, maybe the fuel pump, but I can hear the pump come on when I turn the key. I'm going to check the pressure tomorrow when I get a guage. Does it sound like the regulator is bad?
  • ez1969ez1969 Posts: 2
    OK, I checked the fuel pressure and it read 50psi on the dot. So I figured I'd change the fuel filter to start with and the truck started right up! I checked the fuel pressure again it it still reads 50psi. I thought it had to be at least 60? It seems to run fine. Is there still a problem that might leave me stranded someday? Please help.,,, Thanks.
  • FOLLOW UP: since my post, I have replaced the fuell pump and inline filter (pump stopped working, had to bang on bottom of tank to make it start pumping). Truck ran fine for a little while. Now it won't start, if you prime it with a little carb cleaner it starts right up and runs fine (no sputtering, no hesitation, no rough idle). Check pressure at test valve 52 psi with key on engine off, stays at 52 psi with engine running. After engine warms up it is still 52 psi but if you shut it off, it now primes to 59 psi and will usually start on it's own. After the engine cools, it only primes to 52 psi again. I'm lost on which direction to go from here, could this be an O2 sensor or something else?
  • When you replaced the fuel pump, did you put in an OEM pump? I replaced my fuel pump 3 times in 3 wks (2 aftermarket, 1 OEM). After putting in the OEM pump ZERO starting problems. Per the GMC dealer it has to have the OEM pump & read at least 59psi to run properly. Hope this helps!
  • My Jimmy has started to do the crank and not start issue again. If i let it set for even a full day without driving the vehice it will not start. I did not replace the pump with an OEM one. I will check the pressure next to see where I am at there...
  • EZ1969, I had the same trouble with my 2000 GMC Jimmy.
    Replaced the in-line filter luck... Then the sparkplugs and wire..again no luck...then the distributor cap and rotor..yo guessed it no luck either. Like you I heard the pump come on when the key is i dind't even bother to look at that. However, it was the fuel pump of all things.....
    I found out after the vehicle left me stranded.... Save yourself the headaches and replace the fuel pump..Be sure and go with an oem one. Also if your gas cap is still the original one..replace that too... If it's getting old and the seal is no longer tight it will not allow the fuel system to build up pressure normaly.
  • O.k it turns out the new fuel pump was only putting out 52 psi at the pump, so I took it back and exchanged it (Master E3992M pump from Autozone). New pump works fine so far, trucks starts right up. I hope it lasts. :)
  • bee79bee79 Posts: 2
    Hey I'm having the same problem with my 98 Jimmy. It takes me about 15 minutes to start when its cold. When its warm no problem. What did you hear?
  • bee79bee79 Posts: 2
    I just bought a 98 Jimmy 4x4. It starts up just fine when it's warm out. Now that its cold it won't start. After about 30 attempts it will finally start. Once I get it started it drives fine until the next morning. It's starts every other time except in the mornings when it has been sitting all night. I have replaced the fuel pump, fuel relay, new battery got the fuel injectors cleaned. What else could it be? Please help im going broke. Thanks! :cry:
  • Did you put an OEM pump in it? I have had same problem over & over & over again. $2,000+ in the last 3 months. Aftermarket fuel pump, aftermarket plugs, wires, rot, cap, you name it I've done it!! Put OEM pump in and OEM (AC Delco) plugs, cap, rotor etc & runs almost perfectly!!
    91 Gmc Jimmy s-15, 4.3L throttle-body inj. 2 wd, 152K. Auto.

    Car will start and runs great for 7-10 minutes. Then sputters and dies. Replaced plugs,
    cap, rotor. Pulled in-line fuel line at t-body & it's pumping like crazy. Also...when it
    dies, I can still see fuel squirting into the t-body. After it dies, I check for
    fuel...plenty of fuel & plenty of spark> This makes no sense? I have spark /fuel, &
    compression, yet it dies every 7-10 minutes.
    Will not restart for 10 minutes or so...runs great agian for 7- 10 then the cycle returns!!
    I did replace the fuel pump ,filter & pressure reg. @ T-body not to long ago. Whassup???
  • FWIW:
    I fixed it and here was the problem.

    check for any codes if you haven't already. It's an easy DIY on older GMs stuff:
    The 12 code is just the computer saying hello. The code string starts and ends with 12, usually three times, with the faults in between, i.e. 12-12-12-34-34-34-42-42-42-12-12-12.
    Lots of help here:,312755/in...cleSelect4.htm

    I then ran the codes .12-12-12-15-15-15-12-12-12

    15=Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds.

    Hmmm. replace the Coolant temperature sensor??
    Put a new sensor in ($14.61 @ NAPA) and it ran for 35 minutes!!!!!!
    Drove it last night with no problems
  • Just purchased a '94 GMC Jimmy - was told that thereis oil in the gas and will start if it has a supply of gas going through the carb. Please Help!


  • oil in the gas and will start if it has a supply of gas going through the carb. Please Help!>

    EDIT: Should have been "there is gas in the oil"!!


  • i have a 1990 full-size GMC Jimmy with a 350 tbi motor in it, after the vehicle gets warmed up its starts to idle very low and almost dies whenever i come to a full stop, then if i turn the wheels either way it will die on me, we have replaced the injectors, cleaned out the egr valve, replaced all the spark plugs, and replaced the fuel pump, none of these things seem to help although when we replaced the injectors it did seem to die less on us though. i really notice it after i drive about 10 miles, but it drives perfectly fine and when you shift it up into park it idles fine, its only when you have it in gear and stopped is when it wants to die on you.
  • just bought a 97 Jimmy. It starts up just fine when it's warm out. Now that its cold it won't start. After about 30 attempts it will finally start. Once I get it started it drives fine until the next morning. It's starts every other time except in the mornings when it has been sitting all night. I have replaced the fuel pump, fuel relay, new battery got the fuel injectors cleaned. What else could it be? Please help im going broke. Thanks!
  • 1996 gmc jimmy 4.3 vortec yes drove it to store last night run fine.
    got in it just morning to sart it,turn the key on spun the starter tried to start at first.
    then it just started to spin and would not fire up. sprayed ethier in it and poured gas in thru the throttle body but still would not fire up.any suggestions
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