Once the truck gets warm it pings and stumbles badly, I am thinking some kind of sensor is NFG. Can anyone point me in the right direction?
96 gmc 5.7 l 4*4-need mech advice
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bullfrog123
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Sound like injector problems to me, if it stumbles the fuel isn't reaching the cyl's. First thing I would check is your fuel filter, that one alone is often misdiagnosed as engine probs.
More info on your truck would help us SW lead you in the right dirrection.
More info on your truck would help us SW lead you in the right dirrection.
it is a z-71 ext cab 4*4 with the 350 vortec (probably an 03 vortec crate motor,although I am not sure of the year). What else do you need to know?
I thought fuel filter too, but I figured that would affect when it was cold as well, it runs fine until it gets up to normal operating temp.
I am not a mechanic amd really appreciate any help I can get.
I thought fuel filter too, but I figured that would affect when it was cold as well, it runs fine until it gets up to normal operating temp.
I am not a mechanic amd really appreciate any help I can get.
it has a very bad ping as well.
injectors? i thought it was tbi on those years of chevys for an " efi " model. yeah check all the filters replace as needed.
pull a couple plugs it could be bad plugs/wires if they seem to be in working order try look at the rotor underneath the distributor it could be corroded.
and as for the pinging its running lean or your running too high of an octane for fuel, try changing the oxygen sensors they are one of the main factors for the TBI to adjust the mixture
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bullfrog123
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As TBW stated cap, rotor, plugs, wires, etc, the routine maintenance stuff can solve a lot of problems. As far as TBI, I think the 96 was full on injected, correct me if i'm wrong, but filters and routine maintenance is where I would start.
How many miles are on the truck?
How many miles are on the truck?
230 on truck, 120 on motor thats KMs so devide by 1.6 for miles
you might want to spend the 50 bucks to put it onto a diagnosing machine/programmer at your local mechanics shop that should give you a good reading if theres a sensor out
the ping is detonation, check to see if the distributor moved, or if you got bad fuel, one of my 95's will ping if i run cheap fuel in it, got to 88 or better in it, course i have souped it a little, also has the cap and rotor been replaced, wet or cracked will cause a crossfire effect,
or jack up the radiator cap and slide a duramax underneath
or jack up the radiator cap and slide a duramax underneath
This all came to light after a fill up.........maybe bad gas is the culprit, I will do fuel filter and change out the fuel to start. Thanks for the help!!!!
where did you get the gas at, what octane did you use?
I have a key lock card through work that gets me a discount, they only sell reg (84?). I fuel up there all the time.
well if it was me...I would do a full tune up, plugs, wires, cap ,rotor, filters,then add 2 cans of sea foam fuel cleaner...it is the only cleaner I have seen really work in 25 yrs of wrenching....that should fix it..while cap is off wiggle dist. shaft...if it is loose replace it....
I fought thi$ problem on my 90 302 ford and had it to quite a few shop$$$$...
On mine, it turned out to be carbon deposits on the tops of the pistons and heads. A simple injection cleaning(around $75) CURED the problem completely I chased my tail quite a while with plugs/wires and timing changes before they tried this; I thought "Yeah right, another rip off"
On mine, it turned out to be carbon deposits on the tops of the pistons and heads. A simple injection cleaning(around $75) CURED the problem completely
I chased my tail quite a while with plugs/wires and timing changes before they tried this; I thought "Yeah right, another rip off"The distributor shaft is a weak point in those trucks. I had a 92 that ran like poop until I fixed that....
Its a real ***** if it is the dist. there are no timing marks on these engines
there should be... Look real close, and if you have to, scrape some crap off the balancer. Worst case scenerio, pull the number one plug, and use a screwdriver to find tdc. Been a looong time since I worked on 350 chevys, but if I remember right, you shouldn't have too much of an issue. Good luck, and keep us posted. I have an '89 with similar issues, and i'm curious to see what you find.
to have your timing checked you will need to have a tech plug in a scan tool and check the cam retard. these distributors have gears that will wear thin and adjust the timing. good luck
all you need to do to check the timing is hook up a timing light just like normal..then before starting the truck there should be a timing spout that needs unplugged..normally it is under the black wire cover on the passenger firewall , but it may be right on the distributor wire pigtail or even inside the cab under the heater right against the floormat..it is a grey wire plug with a tan wire normally..just unplug it and set timing..then turn off truck and replug..simple
Correct. '96 was the first year of the Vortec.
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