- #1 of 8
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94 4.3 vortec cpi chugging
by biggestmexi
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Nov 19, 2007 (10:27 am)
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I just started looking at this board today seems great. Especially repair dog.
The problem I am having has occured and got worse over a couple months. It will start perfectly fine. It then at start at about mid RPM range start to chug then running a minute longer it will over come the whole RPM range and wont be able to accelorate and then sometimes putt out. But then not even 10 seconds or as soon as possible i can restart and then have the same problem. It has a recently new pump(4months), new plugs-wires-cap-rotor(yesterday), new fuel filter last week. Cleaned the TPS and IAC. Removed and blocked EGR. Took care of a couple vacuum leaks I could see. Fuel pressure tested OK and volts to the pump was right around 13.7. The oil seems a little gassy to me but not exactly sure. There is no smole out of the exhaust and no cat. Also i am going to try to clean the map/f sensor soon but where is it at. I am at work now no chiltons
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- #2 of 8
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Re: 94 4.3 vortec cpi chugging [biggestmexi]
by jnewnam
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Jan 10, 2008 (11:13 am)
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Replying to: biggestmexi (Nov 19, 2007 10:27 am)
I am having basically the same problem it runs pretty good until its heats up then it just seems as if gas is being dumped it to the engine i replaced the spider injectors and it runs better because my intake was full of gas but then it still wasnt running the way it should so i replaced the cap rotor plugs and wires but its still doing it does anybody have any suggestions i havent replaced the coil yet but im getting kind of tired just throwing parts at it because it is kind of expensive so if anybody can help me i would appreciate it
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- #3 of 8
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Re: 94 4.3 vortec cpi chugging [jnewnam]
by biggestmexi
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Jan 11, 2008 (4:16 am)
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Replying to: jnewnam (Jan 10, 2008 11:13 am)
I ended up taking my jimmy to a mechanic and he did a Vollume test on the fuel system. Needless to say it failed. Changed the pump and all ok.
I would suggest changing the fuel pump. It was only like 60 dollars. FAR cheaper than the spider system. and i got a 1 year warranty.
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- #4 of 8
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Re: 94 4.3 vortec cpi chugging [jnewnam]
by stanman7
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Jan 13, 2008 (6:19 pm)
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Replying to: jnewnam (Jan 10, 2008 11:13 am)
Well, I just turned sixteen a few months back, and a '94 jimmy was my first car. The person who I bought it from was selling it due to something that he thought was a gas leak. The car did exactly what you explained; it would start up, run for a while, and then stall out. after replacing the cap/rotor/plugs/wires, it still didn't fix the problem. Then I got word from a car mechanic saying that one of the main problems that he encountered with jimmys was with something called the "nut kit", which is the part of the fuel line that's under the engine head. Turns out, that was the problem. I took off the engine head, turned the key, and gas started spraying out of the broken part of the nut kit. Of course, replacing something like this is taking me a while, especially with the cold weather.
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- #5 of 8
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Re: 94 4.3 vortec cpi chugging [biggestmexi]
by pcgeek
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Sep 03, 2008 (7:51 pm)
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Replying to: biggestmexi (Nov 19, 2007 10:27 am)
That sounds like the 'nut kit' needs to be replaced. If the oil is gassy, or the exhaust smells rich or gas drips off the back of the engine, spend the $40 on the kit. It made a big improvement for me.
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- #6 of 8
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Re: 94 4.3 vortec cpi chugging [pcgeek]
by garys_nj
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Mar 29, 2009 (10:23 am)
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Replying to: pcgeek (Sep 03, 2008 7:51 pm)
I think the "nut kit" you're referring to is the gas feed and return lines to the CPI (Spider). I have a problem with my s-10 blazer 4.3 vortec where it stalls and then won't restart without either (and then still sometimes won't start). I tried a couple things fixed some vacume leaks and changed spark plugs. it always had a lopey idle, now much worse idle and still stalling.. I removed the plenum and see a lot of gas in the intake belly around the spider and the gas feed line is almost worn through (contact with a poppet line). with pressure, I only see a weep from the feed line but I'm changing the spider and the feed/return lines (the nut?). seems like there's a bolt on a holding plate for the feed/return nipples) but I can't get a wrench or socket on it. anyone know how to replace the feed/return lines??
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- #7 of 8
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Re: 94 4.3 vortec cpi chugging [garys_nj]
by tony2980
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Oct 19, 2009 (10:56 am)
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Replying to: garys_nj (Mar 29, 2009 10:23 am)
its not a nut its a star head to change those lines after you remove the star and the plate the lines slide out i had to use a tool that looked like an L shape they sell them at auto zone in a kit it was like 9.99 itwas a t30 ithink its been awhile or a t15 torx head thats what they are called
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- #8 of 8
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cpi unit
by tony2980
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Oct 19, 2009 (11:02 am)
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my blazer cranks up and runs but it sounds and idles like i have a big cam in it it runs really rough but at 65 70 it runs alot smoother i had it checked out at shop because i kept changeing stuff and my pockets are not that deep they are tellin me its the spider injection cpi unit and its kinda costly any suggestions
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