06 Silverado type x 4.3

[oomag12]

From an earlier thread on this model concerning the fuel filter, they "are" in tank. Bummer, but thats the deal. I still have mpg issues. air filter clean and new. Map sensor is stock, not sure manifold pressure could be off, but should get a code i would think. I am not getting codes on O sensors. I'm 'told' if they are below their operating threshold, they throw codes. The plugs that were installed during my cat converter mess ARE the AC delco correct plugs, BUT, they are soot black and dry. The old plug chart says the plug is to cold and hotter plug is needed. AC and GM says it the right plug, but mpg went from 18 before the entire cat. con. mess to 14. Curious if anyone has had similar exp. with this motor.

[69halfton]

I geuss i must have missed something..

what was "the cat. con. mess?"

[oomag12]

I got a small shade tree so to speak, i do my own tune ups and such. But I had a Gm certified tech,who now operates his own shop replace a bad cat. converter. It was outside the mileage bracket the Gov. says the Mana. has to replace, so I trusted his shop foreman to use oe parts.....didn't happen.....problem not solved.....still throwin same code......he(owner of shop) returns from vacation, discovers what went down, advise me that maybe a "tune-up" is needed, since the truck had not the 100k tune, I agree.........problem not solved.....still throwin same code......he now decides to supply the oe y pipe with both cats, installs , truck runs great(at least a hell of a lot better than it had) not throwing any codes........BUT.......Milage sucks...he tells me give it time, it bounces between 14 and 15 highway......should be 18mpg, was prior to the cat. problem. So I was by him and more than one GM service writer that unless codes are being "thrown", no electronic diagnostic equipment can pinpoint the prob. Earlier Dude suggested changing the fuel filter..........Its "intank" on this model...2 GM service writers and 2 parts store confirmed....so there it is.....any thoughts would be appreciated..

[bwood]

Have you crawled under the truck to see if there is a filter? I should be on the inside of the driver's framerail. I looked on the AC Delco website and the show fuel filter GF652 of a 06 Silverado w/ VIN X 4.3L. It does not list a filter for the 07 though. I think I rember your post from a few months ago. What brand of plugs did they use? If they are not Delco's (#41-993 w/ .060 gap) that could be an issue. Many people buy the Bosch for their price (or the parts stores push them for contests) and have been unhappy with the results.

[oomag12]

edited

[oomag12]

i got pictures, THERE IS NO FILTER IN THE FRAME RAIL!!!! NOT THERE!!!! READ ABOVE, CORRECT AC DOUBLE FREEKIN PLAT. 993'S...........

[truckdude239]

i have edit the posts above this is a family site and there is no need for that kind of language on this site. any more and this thread will be locked

[truckdude239]

but to answer your question there is not A Fuel filter on frame rails of the trucks they are inn the gas tank basically they use what i call a sock on the bottom of the fuel pump.

[oomag12]

It left the "question" catagory bout a month ago. I was just stating the fact. GM has been fairly consistant over the years in thier design but, but 06 and 07 "classic" as they call it has flaws. Here's another little tidbit on the classic and the new designed truck, GM has exclusive rights on the "new" generation tranny fluid. Was 7.50 a quart at gm dealers, prob. higher now.

[Bowed]

Originally Posted by truckdude239

but to answer your question there is not A Fuel filter on frame rails .

Maybe you can answer a question I have had for some time . When did they start putting fuel filters in to the tanks on 100% of installations . I had thought all the 88 up chevy FI trucks were in the tank but I now have a 91 k2500 with TBI and it has a frame rail mounted fuel filter , that is definitely a factory installed set up .


,

[truckdude239]

2003 and up is when they went to installing the fitlers in the tanks. the older trucks they are normally on the side of the block or frame rail

[69halfton]

thats a tough one. have you tried a little injector cleaner in it?

i know the fuel milage improves on the f*rd when we run a bottle through it. just make sure you tank is full when you put the bottle in.

[oomag12]

I have got "black sooty plugs" and like I said , the old school spark plug chart says "plug to cold" ...........dry black soot...correct new plugs.....I have plug wire issue, their new and or coil issue..not sure..thats the direction i'm leaning

[LEEVON]

14-15mpg is definitely not right for the 4.3L. Did you change tire size or do any other mods around the time of the cat issue? Are you running the stock spark plugs? Does your truck have EGR (tube from exhaust to intake)? Have you replaced the PCV valve? Also might want to check resistance on the coil packs.

Seafoam can do good things in these trucks. You can put some in the gas tank, some in the engine (right before oil change) and suck some into the brake booster line at the same time. If you've got buildup you will be amazed at the carbon clouds. You might also consider having your injectors cleaned.

Poor mileage and sooty plugs could also be the result of a lean condition causing the computer to dump fuel. My wife's Tahoe had an intake gasket leak and it resulted in both of these and the check engine light was very intermittent.

[finch]

I was under the impression that they moved the filters in-tank in '04. but that's neither here nor there

I agree seafoam that sucker!

[oomag12]

correct dub plat 993 ac delco plugs and thier new....cross referenced that a couple times. NO ENGINE CODES ARE BEING THROWN...2 GM service writers and an indy cert. GM mechanic told me .....no codes, no diagnostic machine can analyize the problem. I will use a can of the Seafoam.....used a can of BG's and no help...I think something in the coil area or something as said causing a fuel dump. Its a *****, i'm tellin ya.

[Josh]

Check fuel pressure and see if it will hold pressure. Running rich on the 4.3 is usually a fuel pressure regulator or injector problem. I would guess you have a leaking injector or regulator causing a rich condition that isn't severe enough to trip a check engine light.

It could be a oxygen sensor but usually it will throw a code. Start with fuel pressure and go from there. If you have an ignition issue it would likely cut out and try to backfire under a load. They are also full of crap that because it has no codes it means the scan tool is worthless. It should provide a valuable amount of info for misfire counters, fuel trims etc.....

Josh

[oomag12]

Originally Posted by Josh

Check fuel pressure and see if it will hold pressure. Running rich on the 4.3 is usually a fuel pressure regulator or injector problem. I would guess you have a leaking injector or regulator causing a rich condition that isn't severe enough to trip a check engine light.

It could be a oxygen sensor but usually it will throw a code. Start with fuel pressure and go from there. If you have an ignition issue it would likely cut out and try to backfire under a load. They are also full of crap that because it has no codes it means the scan tool is worthless. It should provide a valuable amount of info for misfire counters, fuel trims etc.....

Josh

I appreciate the info Josh. The independent GM mechanic did say a leaking injector could be the root of the problem. His top guy just went down the bad path with non-oe parts the first time round. thanks again.

[chevyfan87]

so...the whole idea that if its not throwing a code, it cant be diagnosed is complete bull...not that YOU are lying, but somebody is filling you full of it. a gm mechanic SHOULD have a tech 2 which will give you readings on every sensor, and a good mechanic knows when a voltage reading looks off...just to have my say...

[chevyfan87]

also...just throwing this out, somebody can come clean up the mess behind me...if what i have been hearing is right, the 2006 4.3 still has the old fashion distributor setup instead of coil on plug like the v8s, i have a 2000 4.3 that toasted the cats at one point so just a few questions worth looking into.

1. why did u replace the cats? plugged?
2. when did you last replace the cap?

the distributor for the 4.3, at least in 2000 has a body made entirely of plastic...not metal except inside the plastic housing, my cats went because when a garage replaced the cap before i owned it they broke the base of the distributor where the screw goes in...this caused a slight misfired that did not occur ofter enough to throw a code...but you could occasionally hear it, and it plugged the cats and mileage went from 23mpg before the amazing work they did to about 15....and my father owned the truck before me so weve had it since it was new...GM dealer didnt even notice the distributor, just charged the old man 1500 for cats and sent him home, now im cleaning up the mess since i bought it and the cats are pretty well plugged again i think.

aaanyways, just take a look at the distributor