Truck won't drive more than 30mph and throws smoke a lot

[Kunjanlama]

Hi,
I have 1988 p30 chevy 6.2L diesel truck. I recently changed everything alternator and more but it still seems to have problem. First, it blows a lot of smoke. Second, it barely goes more 30mph after a while. Third, after I take my feet off the acceleration it dies. Also, sometimes it dies while I am driving my truck. I have no idea what is wrong with it. Is it because of glow plugs? Does damaged glow plugs stops truck? Is it because of injector or fuel system? Also, water in tank light keeps popping up while I accelerate. Does anyone know what can be the problem?

 

[Will L.]

Water warning light is probably your issue. You need to drain the water from the system. Drawing a blank where the wif drain is.

Water in the fuel can keep any diesel from running at all if there is enough, and even a little it does damage. When that light comes on it is a warning to stop driving and drain the valve asap. Address that first.

Checking your airfilter is clear is a freebie and could e contributing, but bad fuel is most likey you deal. An entire tank of bad fuel isn’t worth saving economically when you price the parts alone that is will destroy.

 

[Kunjanlama]

Thank you very much for the response. I am new with diesel engine so I don't know much. Do you know how do I drain the water from the system. I once checked that to the mechanic and he told me it is common it will fade away so I never thought about it much.

 

[ak diesel driver]

I'd start with the fuel tank and make sure it's clean an water free first. Then move towards the engine. My guess is the water drain is part of the filter assembly.

 

[Will L.]

Welcome btw.
He is not a good diesel mechanic if he thinks that, avoid him in the future.

Keep checking back in here —sure someone who has that era truck can verify.

the fuel filter on this truck is the metal rectangular cube about 2”x4”x 8”. Follow the metal lines from there and look for a small manual valve. It’s just been too long since I drained one of that style.

replacing the ip fuel return line with a clear one is strongly advised to see there is no air intrusion and water will show up in it there to. Water in the fuel mixed in will look white.

 

[Kunjanlama]

Yes, I didn't find him reliable that's why I came here to ask for more solution. Sure, I will follow your lead and will keep you updated.

 

[Kunjanlama]

I took out the fuel filter and tried to bleed the diesel. I saw it does have water but when I tried to bleed all the fuel, I cannot because my truck starts and fuel flows stop. If i change the whole fuel filter, will that help, sir?

 

[Jaryd]

I replied in the other thread to. Changing the fuel filter will probably only help for a few minutes if it has enough water in it to run rough. You really should drop the tank and get all the water out

 

[Kunjanlama]

Thank you very much sir. Are you saying Drop the fuel tank mean taking out the whole fuel container. I will keep that for final option but thank you that is very gold advice. Do you know where the drain might be located? Around engine areas or near fuel tank?

 

[ak diesel driver]

FUEL FILTER ASSY, DIESEL, 12471725; GM 6.2 DIESEL | eBay

Find great deals for FUEL FILTER ASSY, DIESEL, 12471725; GM 6.2 DIESEL. Shop with confidence on eBay!

www.ebay.com

this is a fuel filter on a 6.2 I believe the black tube thing on the bottom of the picture is the water drain. Yours being a p30 may be different

 

[Kunjanlama]

I dont know how thankful I am to you for guiding me so much. Yes the fuel filter is excatly like that and there is one black line that goes from bottom from it but I couldn't keep track of it because of the very low space but I will take a look at it again tomorrow and will update you

 

[Will L.]

So drain it until clean diesel comes out with no water.

it would be a good idea to test the tank for water. If you have no water in the tank then after draining filter it would be a good idea to change the filter and try driving it.

if there is water in the tank, you need to drain the tank 100%. Then remove the fuel filter and blow out the fuel line. Install new filter and refill tank. Bleed the air, then start engine.

 

[Kunjanlama]

Thank you sir. I will do it in the first thing in the morning.

 

[1994ch]

I took out the fuel filter and tried to bleed the diesel. I saw it does have water but when I tried to bleed all the fuel, I cannot because my truck starts and fuel flows stop. If i change the whole fuel filter, will that help, sir?

If I understand correctly...... when the truck is running, then no fuel comes out the drain valve? This makes me wonder about the fuel lift pump. There should be a low pressure fuel pump (probably mounted to the front passenger side of the engine) that supplies fuel to the high pressure Injection Pump that is in the engine valley (top center). If the lift pump failed, the injection pump has to pull fuel all the way from the tank resulting in loss of power and stalls due to fuel starvation.

 

[Kunjanlama]

I saw the one on top is to bleed air and below I guess that is the one I have use to drain. Am I right sir?

 

[Will L.]

Yes