95 jimmy vortec 4.3 Rough Idle, Gas and carbon Smell, Engine shakes

Hello, I bought 1995 jimmy 4.3 vortec about 6 months ago. It currently has 125,000 miles. I have been having numerous problems. First problem ended up being the EGR Valve. After taking it off every couple days and cleaning out the carbon peices I got smart and bought a screen gasket which did the trick. During that time it was rough idling, killing when I would come to a stop, loss of breaks, stinking, running hot, about everything you could think of it did. Alot of people on here have the same problems and I would suggest taking off your EGR Valve and if it becomes a problem get a screen gasket. Well since I fixed that now I have more problems. I was starting to get the same symptoms but when I took off the EGR Valve it was fine, the screen blocks all the carbon peices. So I put that back together and tried replacing the plugs. That did nothing. Also during the EGR problem I would get a check engine light and codes. This time I get nothing, computer reads no bad codes. I think it is running really rich since I am getting even worse gas millage than before. I also noticed that sometimes the tailpipe will start spitting black liquid/carbon and leave a spot on the ground. Other times its fine. Does anyone have any ideas for me to try? Basically for the last few weeks now it starts hard and idles bad and the motor shakes until the you give some gas and get the rpms up about 2000. When taking off from a stop it will feel like its missing until again it reaches 2000 rpms. It constantly stinks like gas/carbon/exhaust. When I turn the AC on it gets even worse it idles lower and shakes more. I was thinking about cutting out the cat/convertor and when under the truck I notced a leak of antifreeze. I couldn't see exactly where it is coming from but appears to be under the water pump. When running it does not leak. As soon as I shut it off it will start leaking bad for about 10 mins and then slows down to a drip. So I think I also now need a water pump. If anyone could give me ideas, it would be very helpful. once I fix this thing I think its time to get rid of it. Its looks like brand new but after learning the problems with these things I am afraid of whats going to happen next. Thanks, Rob.

do these searches on this forum if you plan to fix ...

search: cpi, nut kit, washing
search: intake manifold, rad cap, weep hole
search:rotten egg smell


Hello, I bought 1995 jimmy 4.3 vortec about 6 months ago. It currently has 125,000 miles. I have been having numerous problems. First problem ended up being the EGR Valve. After taking it off every couple days and cleaning out the carbon peices I got smart and bought a screen gasket which did the trick. During that time it was rough idling, killing when I would come to a stop, loss of breaks, stinking, running hot, about everything you could think of it did. Alot of people on here have the same problems and I would suggest taking off your EGR Valve and if it becomes a problem get a screen gasket. Well since I fixed that now I have more problems. I was starting to get the same symptoms but when I took off the EGR Valve it was fine, the screen blocks all the carbon peices. So I put that back together and tried replacing the plugs. That did nothing. Also during the EGR problem I would get a check engine light and codes. This time I get nothing, computer reads no bad codes. I think it is running really rich since I am getting even worse gas millage than before. I also noticed that sometimes the tailpipe will start spitting black liquid/carbon and leave a spot on the ground. Other times its fine. Does anyone have any ideas for me to try? Basically for the last few weeks now it starts hard and idles bad and the motor shakes until the you give some gas and get the rpms up about 2000. When taking off from a stop it will feel like its missing until again it reaches 2000 rpms. It constantly stinks like gas/carbon/exhaust. When I turn the AC on it gets even worse it idles lower and shakes more. I was thinking about cutting out the cat/convertor and when under the truck I notced a leak of antifreeze. I couldn't see exactly where it is coming from but appears to be under the water pump. When running it does not leak. As soon as I shut it off it will start leaking bad for about 10 mins and then slows down to a drip. So I think I also now need a water pump. If anyone could give me ideas, it would be very helpful. once I fix this thing I think its time to get rid of it. Its looks like brand new but after learning the problems with these things I am afraid of whats going to happen next. Thanks, Rob.

Thanks, I am finding alot of help on here. I think it is the CPI unit, or Nut Kit. Now I am in search of a deal on those parts. I looked inside under the vortec cover and I can't see alot which I am sure I will see alot better once I tear it apart. I can't see any washing but it does smell strong of gas and looks very wet inside and very dirty.

From Reading through these posts and talking to machanics I come to realize that people that have had carbon problems with the egr, ect.. is most likely from a non repaired gas leak with cpi or nut bolt. I been told it is the most common problem with the jimmys and it is also the reason you produce soo much carbon, so I would recommend anyone with my first problem I had with the EGR carbon issues you should check your CPI unit, it may be the reason you are having carbon problems.

Can anyone post a list of all the new problems I am going to run into?? LOL Thanks for all the help. This website saves alot of money.

If indeed it is your CPI, after you fix the CPI, change your oil ASAP ! Gas in your oil will kill the lubrication properties of your oil. Change it. Also, I've seen many posts about catalytic converters going bad after CPI problems (due to excess fuel and rich mixture ruining the catalysts). Might check your spark plugs too although extra gas may burn away quickly.

Hopefully you've found some of the great pictures on this forum about the CPI.

Good Luck!




Thanks, I am finding alot of help on here. I think it is the CPI unit, or Nut Kit. Now I am in search of a deal on those parts. I looked inside under the vortec cover and I can't see alot which I am sure I will see alot better once I tear it apart. I can't see any washing but it does smell strong of gas and looks very wet inside and very dirty.

From Reading through these posts and talking to machanics I come to realize that people that have had carbon problems with the egr, ect.. is most likely from a non repaired gas leak with cpi or nut bolt. I been told it is the most common problem with the jimmys and it is also the reason you produce soo much carbon, so I would recommend anyone with my first problem I had with the EGR carbon issues you should check your CPI unit, it may be the reason you are having carbon problems.

Can anyone post a list of all the new problems I am going to run into?? LOL Thanks for all the help. This website saves alot of money.

When I do this CPI project, am I able to access every part of the intake to clean all the carbon that leads to the EGR VALVE? Also, is there something I should run in the oil to clean out the gas when I do the oil change? and anything in the gas tank to clean that? And last of all I tried changing my plugs about a week ago and I could not get the driver middle plug, I just now read in here of 2 ways to get to it, removing the tire and using extensions or removing an 11mm bolt from the steering colum thats in the way and pushing it back, what is easier? I can get a socket on the plug but not a rachet or even an extension. I did not replace anything but the plugs, which really didn't look all that bad. Since I have been running into these fuel/carbon problems, I want to fix or clean everything that got messed up in the mean time and give it a good tune up, could someone tell me everything I should do as far as a tune up goes. I am also replacing my leaking waterpump and my fluid looks dirty so I supose I should flush that along with it. Again, thanks for all the help, this site has answers to everything. Anyone got any good ideas for lower back pain? LOL!!! I haven't done a search yet, maybe its posted!!!!

Blgs3xy:

You can get that middle plug out of the 4.3L without taking off tires etc...I just did mine about ten days ago. It is a tight fit over there. Keep playing with the various extensions and positions for the ratchet. It will come out and you will claim victory.

If you use the method of moving the steering column, use a marker and mark where the steerring-column parts fit together before separating. That will make it easier to align the teeth and allow it to slide back together when you're finished. I had to use a few gentle taps with a soft-face hammer to get mine to "telescope" out and go back in.

Make sure your steering wheel is straight before you do this.

Even with this method, I still went through the wheel-wells. Whatever works ... just don't break that plug or strip threads !!

I don't think you need to run anything special through your engine ... just change the oil. To be safe, if you want, maybe change it and then change it again 200 miles or so later.

Lower back pains can be harder to diagnose. The dealership mechanic can solve most lower back pains but the result is usually a pain a little bit lower ... in your wallet!! haha!


Blgs3xy:

You can get that middle plug out of the 4.3L without taking off tires etc...I just did mine about ten days ago. It is a tight fit over there. Keep playing with the various extensions and positions for the ratchet. It will come out and you will claim victory.

This is real fun. Just thought I would let everyone know how I am making myself spend more money. I am in the middle of putting my truck back together after replacing the water pump and cpi unit. First I am cleaning the upper plenum and I take off the idle air control valve and try to clean it out and I break it. $80 part :( Then I am putting the bottom water pump hose on and the stupid clamp has to be squeezed so I use a vicegrips and it slips off and pokes a whole in my radiator. $150 Part. :( Yeah, this is great!!! Well, anyway.... Good news is that the CPI should have been the problem because the whole passenger side wash washed, and there was puddles of gas in there. My opinion, since I see its always an argument in here, is that you really need to rip the upper plenum off to really know whats going on in there. Other than smelling gas I could not see any washing from looking down the hole under the IMTV. But I am sure a strong gas smell should tell you something is wrong anyway. And also got the water pump out and seen the leak from the weap hole. So thanks to this site I located my problems without letting the shops rip me off. But mechanically I break more things than I fix. So maybe I should have went to the shop it may have been cheaper and I wouldn't have had to use my days off and get dirty all day. But good thing is that I have learned more about jimmys than I ever thought I needed to know. and thanks to my clumbsiness, I will have alot of new shiney parts. I got my intake spotless, changed the impossible driver side middle spark plug, and changed the oil, and the uni belt and whatever else I did. and now I got to send my wife to work the corner to buy all the parts I broke. LOL. Anyone know if I should try to get my radiator fixed verses buy a new one? And will I get by with going to the junk yard and getting a idle air control valve? Last thing, I found this dude on ebay selling new in the box ac delco cpi units with nut kits for $200, does that sound like a scam? He is selling tons of them. Thanks, Rob. AKA The guy you don't want touching anything under your hood. :)

If it's not too late, replace any of the stupid squeeze clamps with the threaded, screwdriver, nutdriver type. It's worth it. That lower rad hose took me an hour to get it on with the squeeze clamp!! Sucked.



This is real fun. Just thought I would let everyone know how I am making myself spend more money. I am in the middle of putting my truck back together after replacing the water pump and cpi unit. First I am cleaning the upper plenum and I take off the idle air control valve and try to clean it out and I break it. $80 part :( Then I am putting the bottom water pump hose on and the stupid clamp has to be squeezed so I use a vicegrips and it slips off and pokes a whole in my radiator. $150 Part. :( Yeah, this is great!!! Well, anyway.... Good news is that the CPI should have been the problem because the whole passenger side wash washed, and there was puddles of gas in there. My opinion, since I see its always an argument in here, is that you really need to rip the upper plenum off to really know whats going on in there. Other than smelling gas I could not see any washing from looking down the hole under the IMTV. But I am sure a strong gas smell should tell you something is wrong anyway. And also got the water pump out and seen the leak from the weap hole. So thanks to this site I located my problems without letting the shops rip me off. But mechanically I break more things than I fix. So maybe I should have went to the shop it may have been cheaper and I wouldn't have had to use my days off and get dirty all day. But good thing is that I have learned more about jimmys than I ever thought I needed to know. and thanks to my clumbsiness, I will have alot of new shiney parts. I got my intake spotless, changed the impossible driver side middle spark plug, and changed the oil, and the uni belt and whatever else I did. and now I got to send my wife to work the corner to buy all the parts I broke. LOL. Anyone know if I should try to get my radiator fixed verses buy a new one? And will I get by with going to the junk yard and getting a idle air control valve? Last thing, I found this dude on ebay selling new in the box ac delco cpi units with nut kits for $200, does that sound like a scam? He is selling tons of them. Thanks, Rob. AKA The guy you don't want touching anything under your hood. :)

http://www.image-hosting.ws/direct/1352.gif Hey guys, look at the google "related text" ads on this page. One of them says "Fishy Vaginal Odor? - How To Smell Fresh At All Times". The "rotten egg smell" must have triggered it. http://www.image-hosting.ws/direct/1352.gif

I keep forgetting to ask. I noticed before I started doing all this work to my jimmy that my radiator fan always spins. When cold or hot its always spinning. Is this normal? Or what?

Depends on how fast it is spinning. The clutch fan is attached to the water pump shaft. This shaft receives it's rotation from the engine itself. The fan is not directly attached to the shaft, it is actually bolted to a viscous clutch. The clutch then sits between the fan and the shaft. The purpose of the clutch is to keep the fan at a (fairly) constant speed, and to only engage the fan when it is needed. Think of the clutch as a very simple mini torque converter. Inside is a fluid. When this fluid is cool, the clutch is freewheeling, and thus the fan turns relatively slowly as the clutch slips. As the engine heats up, so does the clutch as hot air from the rad flows over it. The fluid thickens up, engaging the clutch and turning the fan at engine speed up to about 2000 RPM. At this point, it begins to slip again to keep the fan at the most efficient speed. Thus, more air flows through the rad, cooling the engine. The clutch cools down as the engine does, and then disengages. Thus, the cycle repeats.

Thank you. That explained it perfect. I will have to check again once I get it running again. I have noticed when its cold it is not spinning real fast. and I know when I was replacing the water pump that I could turn the fan blade without the water pump spinning. So I think its all right. Thanks.

I am almost done with all my repairs, I have a question about the cpi. I cleaned the intake, and I am wondering as far as where the 6 spider lines connect in, do I have to try and clean those out? They look dirty and I am not sure how to clean them out. I don't want to put everything back together and have something leak. Thanks, Rob.

well all put back together and running. All Problems are gone. Runs like new. My exhaust sounds bad though, I think it did a number on my cat. I had one strange thing happen though, the first time I started it, I let it idle for about 30 mins. I drove it around the block and everything seemed perfect. But then I went to drive home and the battery light kept coming on when I gas it gas, and the headlights dimmed. IT did that like 5 times and then it was perfect again, should I worry about that? It was pretty strange. But running fine now. Thanks for all the help, Rob.

Congrats. I hope I never decide to tackle something like that. My Dad is/was a GM certified mechanic for over 25 years, so I;ve had him do it all.

I put my jimmy off in the river a few weeks ago and had to do numerous things to it. One of them was the plugs. The easiest way is to just put the socket on with your fingers and use a norman closed in wrench that is bent at both ends and take it off like that. Everyone surely has a set of those wrenches.

http://www.automotiveforums.com/vbulletin/showthread.php?t=455035

in this thread i posted the part#s for the cpi, nut kit, and the upper plenum gasket.just incase u need them.

Let me say something. I am very fond of this forum. I have found alot of useful information on this forum. I have been having alot of problems out of my egr valve. I just want everyone to know, I tried the 2 gasket thing with a screen in between them and it seems to be working great now. It was a stainless steel screen. I am hoping the heat wont bother it. Now I just need to change the cpi(i think) on it. I have that hesitation or miss in it that I seen on here earlier. Is it a hard job to tackle? I know the egr vavle was a pain to get off and back on. But like I said I have found this forum to be the most helpful. Thanks to everyone that posts here.


Auk

Let me say something. I am very fond of this forum. I have found alot of useful information on this forum. I have been having alot of problems out of my egr valve. I just want everyone to know, I tried the 2 gasket thing with a screen in between them and it seems to be working great now. It was a stainless steel screen. I am hoping the heat wont bother it. Now I just need to change the cpi(i think) on it. I have that hesitation or miss in it that I seen on here earlier. Is it a hard job to tackle? I know the egr vavle was a pain to get off and back on. But like I said I have found this forum to be the most helpful. Thanks to everyone that posts here.


Auk
http://www.automotiveforums.com/vbulletin/showthread.php?t=462726

Hey guys while on the subject, ever heard of the gas smell returning like a month after replacing the spider assembly, nut kit and upper intake gasket? If so what would cause this, I wouldnt think it would turn around that fast. Im clueless as to why you would have no fuel smell for awhile then suddenly its back, not my car though so I cant get more specific.

95 gmc jimmy 4.3l