[shawchadw]

Hi everyone, this is my first post. I lurk in the background and read through the forum. Every question I have had has already be answered by someone here until now. Thank you all who contributed to the forum.
I have an 85 6.2 in a K5. I don't know the full history of the truck but do know the engine has been rebuild at some point. The engine has been running great for the past 1 1/2 years that I've had the truck then all of the sudden it started acting up. The first symptom was it died when I slowed to a stop. Started back up fine and continued my drive. This happened a few time more symptoms showed up. Driving down the highway it would die if no throttle. Then lost power. Had to keep foot on throttle to keep from dieing. Truck sat for 6+ hours, started fine, I drove it for about 15 minutes the symptoms reappeared. Truck would not respond to throttle and died. Had it towed home and been working on it for the past 2 months when I have time. I had previously replaced the box filter with a screw on.
New fuel sending unit, new lift pump, new filter, rebuild ip (after symptoms started). After IP was rebuilt I got the truck to start, idled fine for a few minutes the idle dropped and truck died. I would appreciate any suggestions. I'm competent with working on things but honestly don't know a lot about the nuisances of the 6.2.

 

[OkDually]

Hi everyone, this is my first post. I lurk in the background and read through the forum. Every question I have had has already be answered by someone here until now. Thank you all who contributed to the forum.
I have an 85 6.2 in a K5. I don't know the full history of the truck but do know the engine has been rebuild at some point. The engine has been running great for the past 1 1/2 years that I've had the truck then all of the sudden it started acting up. The first symptom was it died when I slowed to a stop. Started back up fine and continued my drive. This happened a few time more symptoms showed up. Driving down the highway it would die if no throttle. Then lost power. Had to keep foot on throttle to keep from dieing. Truck sat for 6+ hours, started fine, I drove it for about 15 minutes the symptoms reappeared. Truck would not respond to throttle and died. Had it towed home and been working on it for the past 2 months when I have time. I had previously replaced the box filter with a screw on.
New fuel sending unit, new lift pump, new filter, rebuild ip (after symptoms started). After IP was rebuilt I got the truck to start, idled fine for a few minutes the idle dropped and truck died. I would appreciate any suggestions. I'm competent with working on things but honestly don't know a lot about the nuisances of the 6.2.

Welcome

When you installed the new sender did you also install the correct tank sock on the sender?
Manufacturers tend to install a gasser sock on the sender and will cause a fuel restriction in diesel engines

 

[shawchadw]

Thank you for the quick response. Yes, I pulled the part number from rock auto and ordered it from Amazon. The sending unit has been installed for over a year. I replaced it because the fuel guage wasn't working.

 

[tnDan]

Thank you for the quick response. Yes, I pulled the part number from rock auto and ordered it from Amazon. The sending unit has been installed for over a year. I replaced it because the fuel guage wasn't working.

Amazon has a history of chinese knockoff parts being sold through them.
Personally, should have bought the part from Rockauto and even then no guarantee the sock is correct. It's possible over time it has started plugging up. The proper sock is AC Delco TS1020, even some of the off brands on rockauto are wrong. It's made of a different material than gas versions and has a spring controlled "bypass" to let fuel in if sock is plugged by paraffin during cold weather.

Have you checked lift pump pressure between the filter and IP?

Another thing to check after it quits is power going to the fuel solenoid inside the IP.

 

[shawchadw]

Thanks for the thought. I haven't check the pressure, I have to buy a pressure guage. I haven't checked the solenoid after it dies. I did function check the solenoid by jumping the wire. It's supposed to be a rainy day tomorrow so don't know if I will get to it this weekend. Will report back when both are tested.

 

[OkDually]

Thanks for the thought. I haven't check the pressure, I have to buy a pressure guage. I haven't checked the solenoid after it dies. I did function check the solenoid by jumping the wire. It's supposed to be a rainy day tomorrow so don't know if I will get to it this weekend. Will report back when both are tested.

For electric lift pumps: If you can jumper the lift pump then open the t valve and let fuel flow into a container for 30 seconds and you can get 1/2 pint of fuel within 15 seconds, your lift pump is functional

 

[tnDan]

For electric lift pumps: If you can jumper the lift pump then open the t valve and let fuel flow into a container for 30 seconds and you can get 1/2 pint of fuel within 15 seconds, your lift pump is functional

By his description of a 85 6.2 in a K5 sounds like it's a mechanical pump.

 

[shawchadw]

Correct. I still have the mechanical lift pump. I did not get an opportunity to test the fuel pressure after the filter this weekend but I did confirm that I'm getting 12 volts to the solenoid after the engine dies.

 

[Twisted Steel Performance]

Have you turned the idle screw in?

 

[shawchadw]

I got some time last night to check a few things. Fuel pressure seems a bit low, it hovered around 8psi but did not change when the idle dropped. I think I'll add an electronic lift pump in the near future. It ran for a while at very low idle but finally died. I turned in the idle screw about 1 turn and the truck never died. I haven't done a road test yet to verify if I'm still getting power loss. Hopefully tonight I can get out.

 

[grabowski]

8psi is great!

 

[joeq]

Wouldn't happen to be any water in the fuel? And winter makes it worse, if it freezes in the lines. Just a thought.

 

[shawchadw]

Baby steps. The truck idles fine now, I let it idle for about 20 minutes. I'm not sure if the idle is still too low. I took if for a short drive and if I quickly come off the throttle the engine dies but it starts back with no problem. It did seem to have power but I didn't want to push it on the busy roads around my house. I noticed that I have a drip from a couple of my injector return lines so I need to replace those.

 

[shawchadw]

I hope there is no water in the fuel. I fueled up shortly after it started acting weird. I have full tank and don't really want to drain it. Tempature wasn't a problem when it first started happening and not now. I'm just north of Atlanta.

 

[OkDually]

I hope there is no water in the fuel. I fueled up shortly after it started acting weird. I have full tank and don't really want to drain it. Tempature wasn't a problem when it first started happening and not now. I'm just north of Atlanta.

I would take a fuel sample from the tank and put it into a glass container then let it sit.
If there is any contamination it should show when the fuel settles in the container

 

[shawchadw]

I will try and pull a sample this evening. I'm going to be away for the next 3 day so progress will be slow.

 

[stinky one]

There should not be any pressure on the injector return lines so if you have drips possibly the return is blocked/pinched/deteriorated hoses and not allowing the return fuel to get back to the tank which would affect the IP operation.

 

[shawchadw]

The return lines are brittle. I'm sure I cracked a few when I checked for fuel at the injectors after replacing the pump.