92 K1500 problems/"gutless"

[jamesslcx]

I used 10-40 on my 1992 purchased new until I sold it two years ago with never a problem. I sold it to my nephew and he drives it everyday and uses 10-40 Lubro-Moly anti Friction. The 305 was o.k. in that truck but I went with oversize tires and rims that killed power and gas mileage. 10-30 is o.k. though but I never thought going up one weight was bad.

[j cAT]

Originally Posted by jamesslcx

I used 10-40 on my 1992 purchased new until I sold it two years ago with never a problem. I sold it to my nephew and he drives it everyday and uses 10-40 Lubro-Moly anti Friction. The 305 was o.k. in that truck but I went with oversize tires and rims that killed power and gas mileage. 10-30 is o.k. though but I never thought going up one weight was bad.

back in the mid 80's and before that , 10-40wt was used most often. then GM came out with the news of high wear/lack of proper lubrication with this used in their engines. so I had to believe it then and would say in the 305cu I still own no wear issues and the other 1983 I sold , had no engine issues as well.

[hunter4ever12]

Originally Posted by j cAT

since the exhaust is wide open no restrictions , I would say the cam lobes are worn and the compression is low. no sucking no power.

engines are like pumps. when they lose compression they no longer can suck air and fuel to create power.

you most likely will find low vacuum as well.

305 is a gutless engine . when used in a truck at this mileage I am suprised it still can climb a hill.

1992 truck is a heavy vehicle.

I have considered that because it is old and has high mileage and the "chug" I get after accerlerating and then letting off resembles a hot rod engine with a low cam at idle(like when it lopes) So trust me i have thought of cam issues and the fact that the engine it just plain worn out but what leads me away from thinking that are these things; the engine burns less than 1/4 quart of oil between changes, it ocasionally runs like a raped ape and has all sorts of power and acceleration(very rarely but sometimes it happens just out of the blue) as well as after i put my stock air intake back on after modifying it and making it free of restrictions (so its a free flowing true cold air intake) it does seem to run better and downshift less frequent at higher speeds.

Those things lead me to believe that the issue lies somewhere other than a "worn out engine" I have also considered the fact that the problem could lie in the drivetrain. It does have a rebuilt transmission and a new torque converter but the transfer case is not in the best shape(it takes a little while for 4 wheel drive to actually engage and sometimes you can hear a clanking sound when shifting from park to OD, it was also driven without oil in the transfer case for a couple hundred mile by the previous owner I am kinda just limping it along till i absolutely have to get a new one) as well as the rear diff isnt new either so that has crossed my mind It could be any of those things, and even thought the torque converter is new sometimes i do think thats my problem it acts like the torque converter is the wrong rmp stall for the engine.

Is it possible that it could be drivetrain related or is that a crazy thought?....I realize i need to do the test stated in the previous posts but i wont have time to do so till this weekend so any more info i can get to help me and help pinpoint is greatly appreciated.

[j cAT]

well this just adds to my belief that this is worn engine.

the 305 has a very restictive intake to the combustion chambers from day one. the cold air intake, when used in the warm air temps does greatly improve power output of this engine.

if the vehicle must down shift to maintain speed going up slight grades at hywy speed indicates insufficent power. the transmission gets damaged from this .

when the cam wears out the valves do not travel as much as they should this reduces intake of the fuel air mixture.

gradual loss of power with wear issues you have no idea how it should be with a 305 that had the spec HP ability. you get used to and drive the vehicle to compensate.

all thats needed is a compression check.

one possility is the compression rings maybe carboned up. thinking about your problem I did see this a long time ago. fuel used in the 80's had nasty additives that created carbon on these rings.I use and still use today marvel mystery oil to the fuel to help remove these deposits and lube the rings . another product called regain by gumout works good to quickly remove combustion chamber deposits.

the egr if it has over 150,ooo mi on it should be replaced. too much EGR adds carbon to the combustion chamber. any EGR thats over 10yrs old also is in need of replacement. diaphram issues.

[jamesslcx]

Oil consumption is not bad at all and The engine seems well maintained. I use Marvel Mystery Oil regularly and Gumout Regane also, I believe these additives help. Torque converters are important to engine performance, I would check out the egr system further as well since sometimes performance is great. Good luck and lots of good information here.

[hunter4ever12]

I will definitely try to do a compression test this weekend at the very least, hopefully check my vacuum too! I will let you know the findings. I will also look into the EGR and replacing it. I have a 350 with only about 63k miles on it in another pickup with a blown head gasket(this summer once it warms up i plan on putting a new head gasket in her and putting that engine in the pickup we are currently talking about) So for the time being I will see if I can swap out the EGR valves and see how much of a difference it makes.