99 K3500 454 overheats under throttle

[99BB3500]

There are different flow rates for the pumps. 20gph, 32gph and 70gph. I guess I could just take the VIN in and see what comes up.

 

[alpinecrick]

It hasn’t thrown an SES light at all so maybe it’s already done? The existing exhaust is old and getting ready to fall apart so it’ll get replaced also

Check to see if the SES bulb in the cluster is burned out. It happened on my 96 G1500………

 

[99BB3500]

It’s working. Only code that came up was for a knock sensor that’s been replaced.

 

[454cid]

NF2 is Federal emissions, Tier 1. Maybe the hanger assembly has an extra vent tube or something. I don't know how the fuel pump would be affected.

NF2 RPO Codes | RpoCode.net

NF2 rpo code meaning is EMISSION SYSTEM,FEDERAL,TIER 1.

nf2.rpocode.net

Some of the pumps have a pressure sensor for the evap system and some dont. It looks just like the map sensor on the intake manifold.

 

[Schurkey]

Some of the pumps have a pressure sensor for the evap system and some dont. It looks just like the map sensor on the intake manifold.

I don't doubt that the HANGER assembly might be different--vent tubes, pressure sensors, diameter of the seal or whatever...but if you replace the pump and filter sock (only) and keep the hanger...I don't see how the pumps are any different.

 

[454cid]

I don't doubt that the HANGER assembly might be different--vent tubes, pressure sensors, diameter of the seal or whatever...but if you replace the pump and filter sock (only) and keep the hanger...I don't see how the pumps are any different.

On the later trucks the whole thing gets replaced.

 

[99BB3500]

Would the knock sensor make it lose power if it’s broken and the wire is playing a good game of hide and seek with me? The drivers side one is broken and somebody either cut the wire and hid it, or it got ripped of somehow. Can anyone point me in the right direction on where I might be able to find it? Or know the where it’s pin is in the ECU connector? Just trying to eliminate everything to get it to run the way it should.

 

[Erik the Awful]

The knock sensor is a piezoelectric element that generates a voltage when the shock of a ping exerts pressure on it. If it's disconnected or the wire is broken, there is no voltage signal to tell the PCM that there's pinging. So, no, it shouldn't cause a loss of power.

 

[99BB3500]

Actually it was the knock sensor. Found the second wire, crimped and heat shrank a new pigtail on it and now it runs like it’s supposed to. I’ve heard that a bad knock sensor will pull timing out of the engine and make it run like crap. Either way. Runs good now.

 

[1965truckrod]

I had a similar issue with my K2500 L29. The clutch for the Manual fan tend to fail before anything else. if you have no visual leaks and your level hasn't changed, you'll be look at replacing the Clutch Assembly which is part number: 15-40109 .

This will require removing the top half of your shroud, releasing the load on the belt via tensioner, then 4 nuts to remove the fan assembly. Then you need to swap the new clutch onto the existing fan blade, and then reverse direction. If you are still running Dex-Cool this would be a good time to do the flush. Doesn't hurt to swap out the thermostat if you have no record of it being done. I'd run a check on all of the hose clamps to insure they are all tight.