Knock Count

[koolbreeze]

I recently bought a cable setup to connect Tunerpro RT to my ’95 K1500 w/350 TBI and I’ve noticed that I’m getting knocks on the counter at about 50% throttle and above. It’s 5 speed with 178,000 on the clock and it’s almost never at 50%+ throttle but it still bothers me and I’d like to try to figure out what is causing it. Is there a normal amount of knock under load on a warm engine with that many miles?

I’m thinking maybe it’s carbon deposits, perhaps in the intake and or on the pistons. What’s the best way to clean that? Is there a product that will clean the intake effectively without removing it? I had it off a few years ago to replace the gasket but I didn’t see any carbon to speak of. I also replaced the EGR a couple years ago.

What about the TBI, what is there to clean/service on it besides the injectors? I plan to send them to witchhunter to be cleaned soon.

It hasn’t been all that many miles since I replaced the plugs, plug wires, distributor rotor, and distributor cap. I just replaced the O2 sensor, temp sensor, PCV valve and fuel filter last week. I also verified the timing, with a light, is at 0 TDC with the advance wire disconnected. I plan to verify it with a piston stop as soon as I get a chance.

Any other suggestions?

 

[Supercharged111]

With it running spray a can of carb cleaner down its throat as it tolerates it, the carb cleaner will make it a bit rich and it will want to stall. You could do the same with a can of trans fluid, but with that you soak the intake and let it sit for 30 minutes, then go for a drive to clean it out. Can also use seafoam on the i take. If you want a passive method though, just put a can of seafoam or injector cleaner in the tank. You'll want to do that anyway as that's the only way to clean the innards of the injectors.

 

[Schurkey]

You use any petroleum product to clean the combustion chambers, you'll create a huge cloud of smoke that the neighbors will despise. They might even call the fire department.

Drizzle a urine-stream of water back-and-forth down the carb primaries, or down the TBI bores, or into the throttle body at 2000 rpm. Water will steam-clean the combustion chambers so they look like new--and without the huge cloud of smoke.

Start buying "Top Tier" fuel. The fuel will be labeled "Top Tier" on the pump. Extra detergent to keep the fuel system clean.

 

[DerekTheGreat]

I've seen enough of the Seafoam videos to know that doesn't do jack to the combustion chambers, just a lot of petroleum based smoke like Schurkey said. I watched a ProjectFarm video (I think it was) which showed water vs coolant. Now, I've heard of and used the water method but only saw pics of cylinders "cleaned" by head gasket failures.. Farm did both and the water made more of a difference than I've ever seen seafoam or similar do but it was coolant that seemed to clean better than just water.

 

[94burbk1500]

I think what they are saying is, blow your head gaskets to clean your cylinders.

 

[Schurkey]

Farm did both and the water made more of a difference than I've ever seen seafoam or similar do but it was coolant that seemed to clean better than just water.

Coolant (anti-freeze) probably does not clean "better", but a leaking head gasket provides steam for miles, maybe months of driving (if the owner adds coolant periodically) compared to fifteen minutes maybe less for drizzling water down the throttle body.

Rig up a water-spraying system that can provide long-term steam, and the cylinders will be just as clean without poisoning the catalyst or the O2 sensor.

 

[Supercharged111]

Catalyst? What catalyst?

 

[DerekTheGreat]

Coolant (anti-freeze) probably does not clean "better", but a leaking head gasket provides steam for miles, maybe months of driving (if the owner adds coolant periodically) compared to fifteen minutes maybe less for drizzling water down the throttle body.

Rig up a water-spraying system that can provide long-term steam, and the cylinders will be just as clean without poisoning the catalyst or the O2 sensor.

Well like you said, in 15 minutes the engine running with coolant had slightly cleaner combustion chambers than the engine run for 15 minutes on water alone
I don't like the idea of poisoning the catalyst either, which is why I've only used the water method and right before I change the oil. I tend to run about 2 liters of water (No, not cola Farv..) through the engine held at 1800 rip 'ems sprayed through a bottle.

 

[c1500deathtrap]

slowly pour water down the throttle body.Don't drown it, make sure to get it down both throttle bores. Or use somrthing like MCCC https://www.amazon.com/Genuine-Chrysler-Accessories-4318001AD-Combustion/dp/B00BV4D97K

 

[pro17]

Bump up the octane you buy and see if that solves it. I hear that carbon deposits all over the insides can increase compression as a motor gets older.