Any techs in GM engine ?

R

r0k0

Guest
I've been having lots of bogging problem with the engine,

2000 Chevrolet Blazer 4.3L Vortec 5 Speed

What i've changed :
Autolite Platinum Spark plugs
NGK Spark wires
Cap / Rotor
MSD Ignition Coil
GM Fuel Filter

Now, i should of went for AC Delco plugs but at 16$ a pieces, 120$ wasn't available.. would NGK Iridium IX be better then the Autolite Platinum ? AC Delco are Platinum plugs

other options are maybe low fuel pressure from pump ( need a fuel pressure gauge if someone has one to...
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whateverworks

Guest
We need more information before the help will come...
What kind of vehicle? And what size engine?
A clogged catylitic will idle fine and can also get you to speed as well... But getting power when you put the throttle to the floor or going up hill will be an issue to to massive amount of restriction of course...
Also... New catylitics will emit the smell of rotten eggs until about 1500km are put on them, Old cats will only give a burning smell like an old furnace will put off... and when you stop if the cat is plugged it will be as red as a cherry tomatoe
Kelly
 
R

r0k0

Guest
no i cant seem to find someone with any gauges for it... i'd have to run in town to rent one but where can i got ?

also added truck info, sorry i forgot about that lol
 
0

07RUBI

Guest
I know gm's are picky for spark plugs may dad ad the same issue with is Buick u could try the E3 plugs i had some good experience with my civic but i know its not the same and sometime mix matching parts from companies to companies isn't the best, i know ngk are good but there a jap companie u could try ac-delco and could fix the problem
 
W

whateverworks

Guest
AC Delco PN... R44LTS6 SPARK PLUG, STANDARD PLUG... This is a very common part number... I do not understand why they are charging you $16/plug...
Also... Did you check the gap on the spark plugs before install? Gap should be set at 0.060... Maybe you tapped the electrode and accidently closed the gap on install? Not assuming you did anything wrong but sometimes when they come out of the package they are not gapped correctly...
For the year and mileage (possibly) of the vehicle IMO it is not worth putting in iridium plugs... Also from experience I have found that the AC Delco plugs seem to work best in most domestic cars and trucks of those model years with no issues at all...
You could also look at the plug wires... Maybe one is grounding out somewhere on the engine or one or so is just plain fawked... Look in your service manual for resistance specs and throw a multi meter on the wires and read resistance in OHMS... If off spec it could be time for a new set of ignition wires...
Hope this will help some...
Kelly
 
W

whateverworks

Guest
The other thing... Have any "codes" popped up? I mean... is the check engine light on? The OBD2 systems in GM cars is pretty reliable for pushing out a fault... Have it scanned and see what codes are coming up... Maybe the CEL is burned out and thats why you do not see the code...
Have a look for the MAF sensor... Give it a light tap with the handle of a screwdriver and if the engine idles better that could need replacing (This technique is actually in a GM service tech manual) Maybe the MAF is contaminated inside? Been awhile and correct me if I am wrong but I believe the 2000 OBD2 system in GM cars ran both the MAF and MAP sensor... Any vacum leaks or cracked vacum lines?

Oh yes I misread that you had already gone and done the spark plug wires...

Kelly
 
R

r0k0

Guest
no codes, light worked good, had lean on bank 1 before, installed 2 new 02 sensors then erased the codes and never came back up, gap was set at 0.060

i'd like to try out the AC Delco but not at 16$ each... i'll take a look at the maf.. what should i look for ?

no Vaccum leaks, engine runs very smooth at idle just not under load
 
R

r0k0

Guest
as soon as i got above lets say 20% throttle then the truck will start to bog, if i go WOT its bogs for a bit then i get full power but lose it when i shift then its all starts over :p
 
X

xxss

Guest
I'd say start with checking fuel pressure. Should be between 60 and 66psi.

Other possibilities are TP sensor, egr, water in fuel, injectors. How'd the plugs look when you changed them?

Gotta love diag on the net!

Cat Convertor would likely throw a CEL and P0420.
 
R

r0k0

Guest
i've threated the fuel with a bottle of seafoam in gas only and another one ( 1/3 ) threw vaccum,

i still have to find someone, somewhere with a fuel pressure gauge and the plugs some we're white due tu the 2 front falty 02 sensor making cylinders lean on bank 1 others we're just blackish
 
Mlorint

Mlorint

Well-known member
What you need to do is see what the computer is seeing for data. Mass air flow, and fuel pressure would be the first things I would check. Where the O2's no good? where they checked or just replaced? Fuel pressure needs to be 60-66psi , gm 's are very picky on this
 
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B

Big-Hoe

Guest
Fuel pump most likely, downstream o2 sensor should have tripped a code if the cat was bad. I've had many 4.3/5.0/5.7 Vortecs, they are not sensitive to plug gaps or type, if they have spark and fuel they will run. You don't say how bad of a bog it is, if the engine is nearly quitting on you it's the pump. If it's minimal but frequent then it's likely the distributor gear is worn down. Mark your plug wires and distributor base, pull the dist. and check the teeth on the gear. If the teeth are "knife edged" instead of flat on top, you will have a correlation error between the cam and crank sensors. It will cause bogging, poor performance/emissions/fuel economy. Make sure to mark the base of the dist. and the position of the rotor before removing the distributor. Either way, it's a good idea to check that gear, it won't cost you anything to look and you don't even need a timing light. If it's the pump, I'm sure Logan would be happy to teach you how to use a hammer and punch to make an "access hole" in the floor of the truck to change the pump.

Gear should run around 60$ at Benson's and the pump should be around 120$ I think. I always use Delco OEM parts for my drivetrain, but that's a personal preference.

Just my 2 cents. I'm not a mechanic, just a guy that's owned a lot of Vortecs.
 
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