Discussion in 'Reader's Rides' started by Husky gas axe, Sep 8, 2018.
Just crank and cam sensor, throttle body connection and mass air flow sensor. Should set code.
lean miss - up a hill under load -- coil on plug, plug or coil going south, dielectric integrity of boot, plug, coil could be breaking down, plug loose or cracked. also seen this with a pcv leak ( vacuum) if 4x4 with auto hubs vacuum leak there. because something isn't firing all the time other sensors say too rich computer leans out mix- sneaky as sin.
Forgot to mention, inspect the ground wire on the right rear of the cylinder head, make sure the bolt is tight and the wire isn't damaged, it's known to cause problems.
Sneaky as Sin yes !
Those little gremlins that we chase. I am going to inspect vacuum hoses, and as Steve suggests too, I am going to check that head ground. thanks
Yes, this is a 2500 4x4 Suburban with dash control so probably Vacuum control front axle lock. This thing has the strange T-case with internal clutches. Np 246 I think.
I had my mech install new GM plug wires at 90k and the odo is on 100k currently, and he said the Coils were "fine" _ _ _ according to him.
(with these newer fuel injected engines all the intake plumbing must fit tight with no leaks or we get a no-start) vacuum and electrical issues can cause hair-thinning.
Blades, like I think I had mentioned earlier about the waste-gate vacuum leak problem with my -95 Suburban 2500 4x4 with the 6.5 TD, The vacuum fitting was glued together with Locktite Gasket-maker, and didn't discover the leak until I pressure washed the engine and it blew the plastic fitting from the hose.
( some earlier mech had put a hose clamp on a small plastic fitting, and it caused the nipple to Taper, and hose to fall loose, but looked snug ) Even with trying to glue the two together with Loctite gasket-maker, it separated. And at that time, I had not noticed the slight Taper. The little gremlins that challenge us right !
Front axle is engaged by an electric motor, no vacuum. An intake leak will makem run lean, always the red intake gaskets that caused problems, never the green. I do like the clutches in the transfer case. Is yours full time? That's where I mostly see the clutches in the transfer case.
Only thing vacuum that I remember is brake booster, unless you got hydo-boost, pvc system on those trucks, GM done away with vacuum controls long time ago, early 90's. My 94 Silerado 3/4 4x4 was all electric. Just had vacuum for brake booster and pvc system.
hate to tell you this Vacumm controls - their back yep electric motor engages transfercase- if you have auto hubs vacumm engagement on some makes. don't think newer stuff has pvc any more it is pcv fed into intake manifold. on indirect fuel inject not too much of a problem but on direct injection loads up the valves.
Newer stuff, GM wise, still has pvc systems, metering system built into valve/camshaft covers piped over to intake. Trucks have a belt driven vacuum pump for the brake booster now also.
Do you see intake manifold leaks with the 2007 era 6.0L engines ? I know that the buick 3.8L V-6 plastic intakes are troublesome.
4-wheeler magazine awhile back had an article on the different new process transfer-cases, and that was where it mentioned the 246 having internal clutches, and I think they are electronically controlled is my guess with solenoids maybe, and the ABS wheel sensors may control the clutches.
The 4x seems to work very well, as I backed the stock trailer down through a swale to load up fir rounds, and I was actually surprised the suburban pulled the trailer up and out without fuss. It was several months after that test that the wife was reading through the 'build-sheet' that was with the vehicle when we bought it "used" and the doggon thing has an optional Locking Differential in the rear. That is why it didn't fuss much pulling that trailer out of the swale.
Fuel-trim …………. hmmm …….. a new arena for me.
It would be cool to be smart enough to just plumb-in a manual (milliamp) rheostat controller to adjust on-the-fly the fuel-air ratio while watching the f/r gauge to fatten-up the mixture when feeling the Lean-miss. But I am not an electrician.
I wonder if relocating the O2 sensor to a hotter location would fool the ECU into fattening up the f/r ratio ?
And, too, I wonder if my mechs are looking at the individual injector data to check the pulse data of each. I doubt that I have a partially plugged injector, but I don't know who had their hands on this engine for the first 70k miles, or what the original owner put it through towing in the 112 degree summers here.
The 4L80E automatic transmission behind the 6.5 td free-wheeled in direct, and really needed an exhaust brake or something to help slow it down on descent pulling a trailer. ( I know, just burn the trailer brakes I think TDI offered a kit to reprogram the shifting which may have incorporated the lock-up in the torque converter for descent. I don't know, because rather that buy the kit for $1200, I just cussed a lot whenever I had to go to the Pacific Coast and back to the Sacramento Valley pulling a trailer.
On the intake leak, if it has/had the red seal intake gaskets, they leak, the green seal intake gaskets fixed the problem. I think it was different materials on the change. Only wau to know which one ya got is pull intake, but I'd spray some carb cleaner around it and see if RPM changes. If it dont, it's not leaking.
The 02 sensors read how much oxygen is in the exhaust, more oxygen it will richen, less it will add more fuel. ECM tries to keep it around 0 fuel trim, -3 or +3 is ok.
Yes, I believe my wife's Suburban is full-time with a knob on the dash to select 2x or 4x ( I think ). With her Suburb being a 2500 series, it has pretty stiff suspension, but rides nice for a 3/4-ton truck, and it has the light corp. rear end with 3.73 gears.
The local GM dealer said our transmission needed replacing, and we did have extended warranty, so they installed a GM refurb auto trans. The GM parts guy said the GM no longer has new replacements, but refurbs now. That was new news.
Whew, just finished splitting and stacking our firewood for the winter. 7-chords worth. My splitter got a good workout and me too. Thanks to this Arboristsite forum, I was able to diagnose a problem when my hydraulic fluid began belching out the hyd fluid tank vent. The union coupler on the intake hose to the pump had loosened.
That was an easy fix, after pumping $30 worth of fluid into the dirt, and I hadn't noticed. We have an abundance of Digger Pine in our area, so I watch the local Craigslist ads to scarf-up free wood.
When you look at all the work involved to maintain equipment and fuel costs, it really is Not-Free. hahaha, but lots of Isometrics and pulled muscles.
( I am currently wrestling with replacing hydraulic lifters on a '95 Honda Passport with the 3.2L Isuzu V-6 engine. The Honda service manual says to clean and inspect the lifters to see if they pump-up properly before replacement ). Hmm, and am about ready to remove timing belt and then the SOHC cams and rocker assemblies.
I wish there was adjustable rockers for this 3.2 engine, but I haven't found any in my travels. This hobby project will be my "holiday-puzzle" for the next several weeks.
Personally, I don't prefer engines with non-adjustable lifters like the early Olds engines, where the valve stem height determines the hyd lifter pre-load. This is because if using too thick of a head gasket (aftermarket), the pre-load may not be enough to prevent noisy Lifters ! a real PIA I prefer not to deal with.
Happy holidays coming up !
Be glad it doesn't use shims on top of lifters to adjust valve slash, those are a paiiiiin.
Do you think my 2007 6.0L may have the red intake gaskets ? I am not familiar with what years the red was used.
Blades has some real good points. As he mentions the direct injection loads up the intake valves _ _ _ he is Correct because that is what I have also noticed with the direct injection Suzuki, Honda, Toyota and Isuzu engines that I have torn down. And too, the oil rings are stuck-tight in the piston ring glands with Carbon ! hmm, were the previous owners driving the engines low on oil and way-beyond normal service intervals ?
Fuel-Trim _ _ _ a new animal for me to digest ! and it really makes my brain 'foggy' too. like mush trying to absorb all that technical data.
I am just finishing up with a Isuzu 3.2 liter V-6 intake rocker-shaft and intermediate rocker-arm replacement.
When re-furbishing the engine the "first-go-around" I had overlooked that the intermediate rockers (which open the exhaust valves) had worn into the intake rocker shaft by about 0.040" and caused the exhaust tappets to be LOOSE with the 0.040" clearance with the hydraulic lash adjusters fully extended. Go Figure ! _ _ a good thing this is my project and not a clients.
The exotic valve train on this engine reminds me of working on a motorcycle engine but on a larger scale.
This engine is in my 1995 Honda Passport, which is like a scaled-down version of the Chevy Surburban, but with all aluminum engine and transmission / T-case. And I like the torsion-bar front suspension and the Dana 44 rear-end. The length to width ratio should make it pretty stable on the snow covered roads.
I sure have enjoyed this Forum for learning some good pointers on keeping my three Husky chainsaws operating reliably.
My oldest "old reliable" is a 1984 Husky 2100 cd, then there is the 394 XP which year I am not so sure, but about tweaked my pull-wrist trying to start the engine without the comp. release, until I finally figured out it would work. And then my little general-purpose yard saw which is the Husky 142 with 16-inch bar. great working saws.
You guys have a very Happy Holiday through the end of the year !
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