View Full Version : Ok need help, still having problems with my GMC jimmy?
04-16-2004, 12:10 AM
Ok guys i have about had it with this truck! If you remember i had a problem about a month ago were it wouldn't start had it towed to the local garage were it sat over night. The next day it wouldn't start for them so they rolled it into the garage and it started. Ran all there test no codes no problems other than a lower than normal psi on the fuel pump. Well i figured i would wait since the fuel pump $$$. Well it got worse it would cut out on me like it wasn't getting fuel driving down the road or on take off. Also didn't want to start when i was at the part store finally got it started and then it just died a 2 stop lights. So 3days ago i put in a fuel pump and filter. Take it for a test drive and still spits sputters. So i got ahold of a guy who is good with gmc and he ran every test on it. The whole fuel system checks out good psi, amp draw's and all the injectors tested fine. He did find a carboned up EGR valve and dirty very dirty injectors. So he flushed them and said it was running great. So i picked it up to day drove it home no problem then left for work and pulled out of napa and she spits and sputters. Went to the carwash vacumed it out and was going over to the wash station and it just dies. On the way home from work spitted sputtered on take off from the gas station and then 2 times at 70mph on 71. I am getting sick of this thing thanking of trading it in. Its a 1999 GMC jimmy 4dr, 4wd 4.3 L V6, only had 28K on it when i got it in december from private owner now has 37K and i have put fuel pump, fitler, rear rotors and brakes. Any help out there.
04-16-2004, 03:11 AM
hmm i have this same problem with a grand am i believe it is the fuel filter just to lazy to change it :) it sputters and wants to stall out and not start it all depends on the day i guess.
let me ask you this have you given this thing a nice tune up??? sometimes a bad plug or distributor cap will cause a vehicle to run real crappy. another thing id suggest is the carbeurator it might need cleaned. it could have bad jets in there. also run better gas that sometimes will take a miss out of a motor and make it run better.
but id start with the tune up. that is just me if you got all that money in there now a tune up wouldnt hurt. if all your valves are clean then id say a tune up and timing would be your next best bet.
04-16-2004, 07:13 AM
with the intermittent problem,if it was a ford,i'd guess at the computer module on the distributer as a possibility,but it ain't a ford.
just a thought here,since about every other thing has been eliminated.slight possibility of a bad inertia switch for the fuel system,or something hanging in the fuel pickup in the tank.
04-16-2004, 07:24 AM
I've had a fuel filter cause that too. For $8, it's worth trying. I also had a simialr problem this spring with my Chevy truck, though it never died. I changed the thermostat and flushed the coolant system and the problem went away. :confused: I can't explain it, but it runs fine now.
04-16-2004, 07:28 AM
I would try looking for a loose or cracked vaccum line, But then I'm not very good at fixing my own car. Maybe a fuel inhanser of some sort could help also, still just a guess. Hope you find the problem.
04-16-2004, 09:15 AM
I have had the same problem with my van before . I ended up replacing the sensor inside the distributor cap and life has been good since . :)
04-16-2004, 09:22 AM
I have replaced the fuel filter, fuel pump already.
I agree that new plugs wires etc (tune up) is a good idea it may have never had one yet and it has 37K on it could be some of the problem.
04-16-2004, 09:51 AM
I had a similar problem on my 95 Jimmy and it turned out to be what a GM mechanic called a nut kit. When it is cutting out do you notice a funny smell almost like sulpher and does it sound almost like it has a huge street cam in it? Mine first did it 1/2 way to Arizona then quit until I got home when it started again. It came and went until eventually it was doing it constantly. No engine codes came up while it was running bad. Finally I dropped it off to the GM guy and 2 days later I had her back running great. Mine is nearing 190K on the miles now and the original fuel pump just went out. I wouldn't give up on her just yet but if ya do, I can hook you up with something else being that I just happen to sell cars for a living ;)
04-16-2004, 10:31 AM
Could be a fuel or electronic problem. Does it only act up when hot? You can have bad sensors and not trip a code. Crank/cam sensor,ing module,ecm the list go on and on. Fuel problem, could be fuel pressure regulator. That year doesn't have a "nut kit" (17112705). That's a common problem with that engine. If I think of any thing, I'll PM you
04-16-2004, 11:36 AM
You may not want to hear this,but if you don't want to get another truck take to the dealer.They see more of these problems than the average mech does.Or you could just keep throughing money at it & hope you get it fixed.Good luck Daryl
04-16-2004, 12:11 PM
You are wasting money if you can't do it yourself and you go somewhere besides the dealer. I worked at a few in my life and the stories I have heard from people who took it to Pro-Care, etc. They work on EVERYTHING- the dealer works on your brand. Chances are, they have already worked on one doing what yours does.
In a '99, is there even a distributor? Is that a distributorless engine? I know many of the GM and other brand cars here in the last 10 years have gone without a distributor- just coil packs and the crank/cam sensors. I would be looking at those real close. If the problem "suddenly" comes on and then "suddenly" quits, I would suspect a bad sensor. Crank sensors seem to be weak spots on many newer vehicles. Since it acts up somewhat regularly, I'll bet a sensor is going or you have a harness issue. Losing signal to the computer somewhere.
Unless you know somebody that is GOOD- use the dealer. It may save you money in the long run. While it may cost more up front, they may fix it the first time. Apparently the guy you took it too wasn't as good as he told you he was. You now have $$ dumped in it with a pump, filter, injector cleaning and all that and it still isn't fixed. That's money dumped in the toilet.
04-16-2004, 01:11 PM
Maybe some sort of vapor lock going on?
04-16-2004, 01:30 PM
That year Jimmy has a dis system. No distributor, cap, or rotor. I think your on the right track, lookin at a sensor or module. Had a 92 Bonneville 3.8l that stop running intermittently. Ended up being a crank sensor. Tracked it down with an voltmeter/ohmeter. Never tripped a code, but the wife sure did!!!
F4F there's a lot of garage's out where that have no business lifting a hood. Cheapest is not always best.
26 years in the automotive trade
04-16-2004, 01:54 PM
Hey slipring what king of cars do you work on?I do mostly volvos,have been doing them for over 20 yrs.when I have a harder problem with my chev truck I call the dealer & talk to the mechs there to save me time.I have had my faRE SHARE OF heating & air problems at home only to find out you will most of the time save money with the professionals.Daryl
04-16-2004, 02:16 PM
Is nearly a thing of the past due to fuel injection.
Vapor lock can occur on vehicles that run carbs because the fuel is "sucked" from the tank and then pumped up to the carb. When you have a liquid under negative pressure, it's boiling point drops. The fuel pump, being on the engine, is a good distance from the tank. Figure 10 feet or better of fuel line being under negative pressure. Should the fuel boil and get bubbles in it, the pump can't pump it and you get vapor lock. Vapor lock is, as far as I am concerned, a widely over-used diagnosis. There is almost ALWAYS another reason for the concern.
Fuel injected vehicles nowadays have a pump in the tank. ( Most at least.) This pumps fuel under positive pressure to the fuel injectors. Most will provide at least 40 psi. This effectively eliminates any chance of the fuel boiling. Not to demean you or anything Chuck, but vapor lock really cannot occur on a newer fuel injected vehicle, UNLESS you have a fuel line laying directly against a heat source such as a manifold. That would require some major re-routing of a fuel line, and anymore, many vehicles use a plastic fuel line. It would melt anyway.
Slip is on the right track- electrical issue.
04-16-2004, 09:19 PM
The local dealer was the first place i went and they had no idea other than maybe a fuel pump. The guy i just got it back from told me that the injectors were real bad need cleaned but that he can't say that was the problem as it never acted up on him. He was well recommended and worked at the local dealer ship for 15 yrs and has been to every gmc class available. He already told me to bring it back and he will find the problem at no cost since he didn't find it and its still doing it. I agree its got to be something stupid a sensor flaking out or something it died on me twice today. However i did get the boat all ready and test ran the motor will get her on the lake soon leaving for chicago sunday be back thursday night. Will have to find a good trolling motor and fish finder eventually.
05-06-2004, 12:05 AM
Forgot to tell you guys what we found on the jimmy. Left if with the mechaninc while i was in chicago april 17 week. Well he thought i had a bad fuel pump agian i am like i don't believe that its got to be something else. Well as luck would have it as he is leaning on the fuse box under the hood the fuel pump kicks on then off. Further investigation finds that the plug in for the relay and allot of the wiring under side of the fuse box is messed up forks spread apart wires coroded etc. He fixed it all for $70 bucks and i have been driving it since put almost 900 miles on it and hasn't acted up once.
05-06-2004, 08:55 AM
Slip is on the right track- electrical issue.
F4F glad to see ya got it fixed. Now if we could just get Jim's boat going! He needs to find me some new fishin spots :D :D
05-06-2004, 11:39 AM
Had the same type of problem a few years back. After numerous dollars spent, a buddy of mine suggested that it might be bad gas. We drained the tank and changed the fuel filter. Ran great after that. Might be something to think about. :rolleyes:
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